CA1144837A - Method and apparatus for effecting hyperthermic treatment - Google Patents
Method and apparatus for effecting hyperthermic treatmentInfo
- Publication number
- CA1144837A CA1144837A CA000399706A CA399706A CA1144837A CA 1144837 A CA1144837 A CA 1144837A CA 000399706 A CA000399706 A CA 000399706A CA 399706 A CA399706 A CA 399706A CA 1144837 A CA1144837 A CA 1144837A
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- cannula
- end portion
- trocar
- assembly
- subcutaneous
- Prior art date
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Abstract
ABSTRACT
An assembly for use in establishing percutaneous communica-tion with a flow passage of a totally subcutaneous implant.
Within said assembly is an elongated percutaneous cannula having a subcutaneous end portion and an extracorporeal end portion, said subcutaneous end portion having an exterior peripheral cross-sectional configuration elongated in one direction with sharp points defining opposite ends thereof in the direction of elongation. The cannula has an interior passage extending from the extracorporeal end portion thereof to the extremity of said subcutaneous end portion and an elongated trocar including a pointed end. The trocar has an exterior periphery extending from said pointed end of a shape to enable said trocar (1) to be in-serted pointed end first through said interior passage of said cannula in a direction and to an extent sufficient to position the pointed end thereof outwardly of the extremity of said sub-cutaneous end portion thereof and (2) to be withdrawn from said interior passage in the opposite direction. The foregoing arrangement alleviates the problems of infection and blood-clotting which can arise in the use of exteriorized shunts for connecting the extracorporeal blood flow circuit with the blood system of the patient.
An assembly for use in establishing percutaneous communica-tion with a flow passage of a totally subcutaneous implant.
Within said assembly is an elongated percutaneous cannula having a subcutaneous end portion and an extracorporeal end portion, said subcutaneous end portion having an exterior peripheral cross-sectional configuration elongated in one direction with sharp points defining opposite ends thereof in the direction of elongation. The cannula has an interior passage extending from the extracorporeal end portion thereof to the extremity of said subcutaneous end portion and an elongated trocar including a pointed end. The trocar has an exterior periphery extending from said pointed end of a shape to enable said trocar (1) to be in-serted pointed end first through said interior passage of said cannula in a direction and to an extent sufficient to position the pointed end thereof outwardly of the extremity of said sub-cutaneous end portion thereof and (2) to be withdrawn from said interior passage in the opposite direction. The foregoing arrangement alleviates the problems of infection and blood-clotting which can arise in the use of exteriorized shunts for connecting the extracorporeal blood flow circuit with the blood system of the patient.
Description
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This invention relates to hyperthermia, and more particularly to impro~ed method and apparatus for efecting hyperthermic treatment specifically for the ; purpose of retarding the growth of growing cancer cells.
S There is mounting evidence that the application of heat within the range of 41.5C to 43.0C can be used effectively to retard the growt}. of cancer cells.
Recent interest in this subject has intensified to the extent that an XnternatiGnal Symposium on Cancer Therapy by Hyperthermia and Radiation was held in . .
~ - 2 -~4~37 Washington, D.C. in April of 1975 under the joint sponsorship of The National Cancer Institute of the ~.S. Public Health Service and The American College of Radioloyy, in cooperation ~ith the [Iniversity of Maryland School of Medicine.
Tlle Proceedings of this symposium are transcribed in a three hundred and four page ~olume containillg many articles dealing with varied aspects of hyperthermia and cancer. These articles and the cited references thereof represent a cornpreherlsive listing of available literature publications.
Other articles of interest since 1975, the date of the symposium are as follows:
Hofer, K.G., Choppin, D.A. and Hofer, M.G.: EXfect of ~-lyperthermia on the Radiosensitivity of Normal and ~lalignant Cells in Mice. Cancer, 38:279, 1976.
Larkin, ~.M., Edwards, W.S. and Smith, D.E.: 'i'otal 13Ody Hyperthermia and Preliminary Results in i~uman Neoplasmus. Surg.
Forum, 27:121, 1976.
Wheldon, ~.E.: Exploiting Heat Sensitivity of Leukemic Cells. Lancet, 1:1363, 1976.
- 20 Hyperthermia in the Treatment of the Cancer Patient.
Cancer, 37:2075-2983, 1976.
Much of the above literature includes reports to tile effect that hyperthermia utilized in a range of 33~7 temperatures between 41.5C and 43.0C causes specific anti-cancer effects when used either as a primary or adjuvant agent against a wide spectrum of malignant disease.
The literature indicates that hyperthermia has been shown to induce cytotoxicity in sarcoma and melanoma cells in tissue culture (Stehlin et al.) and strongly enhance anti-tumor effects of irradiation in vivo of L-1210 and Erlich ascites cells (Hofer et al~). The addition of hyperthermia to regional perfuslon chemotherapy of me:Lanoma resulted in an increased lncidence of tumor con~rol and patient survival without increased adverse effects (Stehlin e~ al.). Employed as a systemic agent, hyperthermia ~nduced objective regression in 13 of 18 (70%) patients with dissemlnated disease resistant to other therapy, 9iX of whom were surviving 11 to 22 months ~ post treatment (Larkin et al).
; Experimental work undertaken in contemplation of the present invention indicates the efectiveness of hyper-thermia against systemic dlsease may be even greater than indicated by Larkin et al. Although the levels of hyper-thermia employed by Larkin et al. ~approximately 42.0C) were adequate, the period of application was only five hours.
Moreover, the procedures undertaken to effect the hyper-thermic treatment would indicate that a stable temperature }evel of 42C was not maintained systemically for five hours. Larkin et al. employed insulating sheets and liquid ~ f~ 3'7 heatin~ blankets surrounding the patients for heat appli-cation. Due to the relatively poor conductivity of the skin and the further adverse effect to conductivity of profuse sweatinq, elevated systemic te~peratures cannot be rapidly induced. Moreover, this adverse co~ductivity condition can be expected to maintain the existence of large tem-perature differentials throughout the system. For example, blanket control temperatures of 120F (48.89C) ~ere utilized, a lethal systemic level.
Based upon the analysis of the type of problems enunciated above which are evident from the systemic pro-cedures and devices heretofore proposed and utilized, a set of desirable criteria Eor method ancl devices for effecting hyperthermic treatment can be listed as follows:
1. Systemic temperatures of 41.5 to 43.0C
induced.
This invention relates to hyperthermia, and more particularly to impro~ed method and apparatus for efecting hyperthermic treatment specifically for the ; purpose of retarding the growth of growing cancer cells.
S There is mounting evidence that the application of heat within the range of 41.5C to 43.0C can be used effectively to retard the growt}. of cancer cells.
Recent interest in this subject has intensified to the extent that an XnternatiGnal Symposium on Cancer Therapy by Hyperthermia and Radiation was held in . .
~ - 2 -~4~37 Washington, D.C. in April of 1975 under the joint sponsorship of The National Cancer Institute of the ~.S. Public Health Service and The American College of Radioloyy, in cooperation ~ith the [Iniversity of Maryland School of Medicine.
Tlle Proceedings of this symposium are transcribed in a three hundred and four page ~olume containillg many articles dealing with varied aspects of hyperthermia and cancer. These articles and the cited references thereof represent a cornpreherlsive listing of available literature publications.
Other articles of interest since 1975, the date of the symposium are as follows:
Hofer, K.G., Choppin, D.A. and Hofer, M.G.: EXfect of ~-lyperthermia on the Radiosensitivity of Normal and ~lalignant Cells in Mice. Cancer, 38:279, 1976.
Larkin, ~.M., Edwards, W.S. and Smith, D.E.: 'i'otal 13Ody Hyperthermia and Preliminary Results in i~uman Neoplasmus. Surg.
Forum, 27:121, 1976.
Wheldon, ~.E.: Exploiting Heat Sensitivity of Leukemic Cells. Lancet, 1:1363, 1976.
- 20 Hyperthermia in the Treatment of the Cancer Patient.
Cancer, 37:2075-2983, 1976.
Much of the above literature includes reports to tile effect that hyperthermia utilized in a range of 33~7 temperatures between 41.5C and 43.0C causes specific anti-cancer effects when used either as a primary or adjuvant agent against a wide spectrum of malignant disease.
The literature indicates that hyperthermia has been shown to induce cytotoxicity in sarcoma and melanoma cells in tissue culture (Stehlin et al.) and strongly enhance anti-tumor effects of irradiation in vivo of L-1210 and Erlich ascites cells (Hofer et al~). The addition of hyperthermia to regional perfuslon chemotherapy of me:Lanoma resulted in an increased lncidence of tumor con~rol and patient survival without increased adverse effects (Stehlin e~ al.). Employed as a systemic agent, hyperthermia ~nduced objective regression in 13 of 18 (70%) patients with dissemlnated disease resistant to other therapy, 9iX of whom were surviving 11 to 22 months ~ post treatment (Larkin et al).
; Experimental work undertaken in contemplation of the present invention indicates the efectiveness of hyper-thermia against systemic dlsease may be even greater than indicated by Larkin et al. Although the levels of hyper-thermia employed by Larkin et al. ~approximately 42.0C) were adequate, the period of application was only five hours.
Moreover, the procedures undertaken to effect the hyper-thermic treatment would indicate that a stable temperature }evel of 42C was not maintained systemically for five hours. Larkin et al. employed insulating sheets and liquid ~ f~ 3'7 heatin~ blankets surrounding the patients for heat appli-cation. Due to the relatively poor conductivity of the skin and the further adverse effect to conductivity of profuse sweatinq, elevated systemic te~peratures cannot be rapidly induced. Moreover, this adverse co~ductivity condition can be expected to maintain the existence of large tem-perature differentials throughout the system. For example, blanket control temperatures of 120F (48.89C) ~ere utilized, a lethal systemic level.
Based upon the analysis of the type of problems enunciated above which are evident from the systemic pro-cedures and devices heretofore proposed and utilized, a set of desirable criteria Eor method ancl devices for effecting hyperthermic treatment can be listed as follows:
1. Systemic temperatures of 41.5 to 43.0C
induced.
2. Selected ~emperatures ob~ained within one hour.
3. Hyperthermia maintained for 24 to 48 hours.
4. Fine temperature control and potential auto-regulation of temperature possible.
5. A rapid cooling as well as a heating effect readily achieved.
6. General anesthesia unnecessary or required for only a brief period.
7. Patients undergoing hyperthermic treatment 3~7 maintained in a setting conduct:ive to conventional caxe.
8. H~perthermla possible in diverse settings such as radiation therapy or isolation areas.
9. Repetitious induction of courses of hyperthermia over a several day period possible.
10. Hyperthermia lnduced with reasonable safety in neutropenic or thrombocytopenic patients.
It is an object of the present invention to provide a method and apparatus for effecting hyperthermic treatment which will meet the above-listed desirable criteria. In accordance with the procedural principles of the present invention, this objective is obtained by establishing a s~erile extr~corporeal flow path for blood having an inlet, an outlet and a temperature control zone therebetween, establishing communication of the inlet of the extracorporeal flow path with the patient's bloodstream so that blood can be withdrawn and supplied to the extracorporeal flow path without adversely affecting the bloo~ depleted areas from which the blood is withdxawn, establishi~g co~.lunication of the outlet of the extracorporeal flow path with the patient's bloodstream so that blood flowing from the extracorporeal flow path is returned to the bloodstream in such a way as to be distributed systemically, pumping blood withdrawn from the patlent's bloodstream along the extracorporeal flow path through the temperature control zone at a controlled rate and return ng the same to the patient's bloodstream to be distributed systemically, as aforesaid, controlling the temperature o the blood flowin~ along the extracorporeal flow path through the temperature control zone for ~n initial period during which the ~emperature level of the blood within the zone is raised without subjecting the same to localized temperatures in e~cess of approximately 45 C so that the systemic distribution of the returned blood gradually in-creases the core temperature of the patient's body to a generally stable temperature condition at a lcvel of ap-proximately 41.5C, but not higher than appro~imately 42.5C, and maintaining control of the temperature of the blood flowing along the extracorporeal flow path through the temperature control zone at the generally stable temperature condition for a second time period sufficient to retard the growth of cancer cells.
It is recognized that extracorporeal heating of blood for anti-cancer purposes has been undertaken in regional perfusion practices. Procedures of this type are discussed by Cavaliere et al. and Stehlin and are to be distinguished from the systemic hyperthermia induced by the present pro-cedures, as indicated above. In these regional perfusion ~ practices, the main femoral artery and vein are temporarily ; 25 occluded by vasoular clamps or tourniquets and a closed .
. ..
extracorporeal system is established, solely within the femoral extremity. In ~his extracorporeal circuit, heat is ayplied as an adjunct to the other treatments, such as chemotherapy, w}lich are utilized in the regional circulating S system. This system neceScitates the utilization of oxy-genating equipment o~ a ty2e similar to that used in open heart surgery. As is evident from the known time liml-tations imposed upon open hear~ surgery by virtue of the utili~ation of oxygenating equipment, the time frame ~ithin which such combined oxysenating and heating treatments can be continued even on a regional basis without imposing at least a percentile permanent dal~age to the blocked femoral areas of the patient is quite limited.
Pettigrew, in re~erring to these regional per-fusion practices as background to his preferred combined hot wax bath and heated respiratory gases procedure fo. inducing total body hyperthermia, appears to consider the regional perfusion procedures to be applicable to induce both reg-ional hyperthermia as well as total bGdy hyperthermia, perhaps by analogy to the open heart e~:~racorporeal shunt-ing. (Induction of Controlled Hyperther~nia in Treatment of Cancer, Henderson, M.A. and Pettigrew, R.T. Lancet, 1:1275, 1971 and Cancer Therapy by Whole Body Heating, Pettigrew, R.T. Proce~edings, p. 282). The P~ttiqrew Lancet article characterized the reyional perfusion ~ork of Cavaliere et al. ("Selective Heat Sensiti~ity of Cancer Cells", Cancer, 1967, 20-1351) as having "achieved very satis~actory tem-peratures in the malignancies using an arteriovenous shunt and a heat exchangar, but since ~his requires surgery it cannot be repeated indefinitely and can only be applied easily to peripheral malignancy."
It is of significance, however t to note that the recognized practitioners of regional perf~lsion, namely Cavaliere et al. and Stehlin et al., have both indicated that the regional perfusion pract.ices utilizing a shunt and an extracorporeal heat exchanger are limited to regional extremity applications and both have utilized other pro-cedures for inducing total body hyperthermia.
On page 135 of the cancer article Cavaliere et al.
state:
"This method of high temperature treatment obviously has limitations and at pre~ent is indicated ln patients with primary or recurrent malignant tumors of the limbs for whom the only alternative therapy would be amputation, which often does not prevent me~astases~
... It is evident that future progress in this field will come ~rom total-body high-temperature treatment~ We are now in the process of developing tech-niques towards this end, which are considerably different from those now being used."
The last paragraph of the Stehlin article in the Proceedings publication, page 271, sets forth the ~ollowing:
.~ 3~7 "As a result of our experience with regional perfuslon with heat, we are currently, and have for the past five years been investlgating the possi-bility that syqtemic hyperthermia induced with bacterial toxins will enhance the antitumor effects of various chemotherapy agents on melanomas and sarcomas~"
~ preferred minimum flow rate in accordance with the principles of the present invention, is approxi-mately 1 liter per minute. Such flow rate can be achieved by following the procedures of the present invention with-out affecting the femoral areas from which the blood i~
withdrawn, Thus, with the present procedure, there is no systemic femoral isolat~on as by a clamp or tourniquet occluding the main femoral artery and vein, but rather, a preerred procedure is to effect communication of the extracorporeal flow path between the famoral artery and the femoral vein through a side wall of each, so that systemic circulation in the femoral areas can continue.
The pumping proceduxe undertaken to effect flow of the withdrawn blood through the temperature control zone of the extracorporeal flow path achieves an adequate con-trolled flow rate while permitting adequate systemic cir-culatory flow through the femoral areas sufficient to prevent the type of adverse e~fects over extended periods of time which will occur in the aforesaid regional per-fusion techniques.
. ~
~4~ 7 The present invention also contemplates an improved implantable de~ice for facllitating the connection of the ex~racorporeal flow circuit with the blood system of the patient. Devices for establishing an extracorporeal blood flow path for the purposes of kidney dialysis as distinguished from systemic hyperthermic treatments are well-known. These devices, known as shunts, are made commercially available by several manufacturers. Typically, these shunt devices are implanted in the patient and include tubes which extend extracorporeally. ~hese exterior-ized tubes have caused considerable dif~iculty.
A good discussion of the difficulties encountered in the practice3 relating to such exteriorized shunt de~
vices is contalned in UOS. patent No. 3,998,222. In the opening paragraphs of the specification, one type of shunt device is described as a U-shaped loop, one end of which is connected to a vein and the other end of which is con-nected to an artery. The loop itself is implanted sub-cutaneously but outlet conduits extending from the sides o the loop protrude through open holes in the skin to outlet terminals on the outside of the body. Removable plugs fit in the outlet tubes and block the flow through these tubes during normal conditions. When the patien~ is sub-jected to dialysis, the plugs are removed and the out-let terminals are connected to inlet fittings for a dialysis machine~ (See 3,826,257).
83~
One of the problems enunciated in the opening paragraphs o the specification attributable to this type of exteriorized shunt is the ri~k of infection in the location where the outlets protrude ~hrough the opening holes in the skin~ While there is considerable reference to problems relating to blood clotting in shunt devices of the prior art, there is proposed in the patent a shunt arrangement which would at least have the effect of al-leviating the infection problem~ in that the shunt device of the invention is arranged to be implanted in a com-pletely interiorized or totally subcutaneous condition:
In order to effect communication of the totally interiorized shunt device with the extracorporeal flow path, the im-planted device is provided with mechanically movable valve members. These valve members are normally retained in a position within housings provided by the shunt device which maintain the valve members out of communicating re-lation with the blood flow through the shunt device. The valve members are provided with cooperating surfaces such as square apertures or threads which are operable to initially establish a fluid~tight communication with a hollow needle. The hollow needle is thus capable of being inserted through the skin into fluid contact with the ' valve member and then after such fluid coupling has been effected, the hollow needle is capable of effecting the ;, :
83~
movement of the valve member into flo~ communicating re-lation with the bloodstream.
While the patent describes the utili~ation of a Fogarty catheter for effecting the cleaning and declotting 5 o the device, no provision is made for preventing the clotting of the blood within the central flow passages of the valve members when they are disposed in their normal closed positions. Moreover, while provision is made for circulating blood between the periphery of the valve membexs and the housing retaining the same when the valve members are in their opened position, no such provision is made or the - valve members when they are in closed position and, indeed, the peripheral passages provided for continued ~low when the valve members are open are themselves closed when the valve member is closed, thus presenting, along with the interior passages o the valve members, spaces where blood would be trapped and become clotted.
While it is recognized to be desirable to overcome the disadvantages of the commercially available exteriori~ed shunt device, the arrangement disclosed in ~he aforesaid patent would ~ppear to present clotting problems equal to, if not worse than the clottiny problems noted in the prior art. When it is considered that it is quite usual for cancer patients to be hypercongulable, the clotting problems of the prior art assum~ greater proportions .
3~7 when contemplatillg the utilizatlon of such shunts for hyperthermic treatment of a patient for anti-cancer pur-poses. Moreover, effective hypert~,~rmic treatments in accordance l~ith the principles of ~he present invention require flow rates considerably in excess o that normally provided for kidney dialysis.
Accordingly, it is a further object of the pxesent invention ~o provide a shunt device of the totally sub-cutaneous type which is particularly suitable for use in hyperthermic treatment of a patient for anti-cancer pur-poses in accordance with the present invention, which device overcomes, or at least substantially alleviates, the clot',ing problems of the prior art heretofore noted.
This objecti.ve is obtained by providing a totally lS subcutaneous implant for use with the apparatus provi~ing the extracorporeal blood flow path~ including both a blood withdrawing and a blood returning percutaneous cannula, each of which is cooperable with a trocar for effecting the percutaneous disposition thereof, which cannulas co-operate with the implant ~o achieve the extrac rporealblood flow. The implant comprises a body of elastomeriC
material adapted to be implanted totally subcutaneously in a femoral extremity, the body having an arterial pas-sage therein, a spaced venous passage, and a bypass conduit extendil~ ~rom one end of the arterial passage to one end of the venous passage. An arterial tube and a venous tube of vascular prosthesis material are provided, each having one end connected in commw~icating relation with the other end of the respective ar~erial or venous passage anA an opposite end ad~ted to be connecte: with a respective main ~emoral artery or vein side wall in communicating relation respectively with the respective interior of the femoral artery or vein.
The elastomeric body is provided with means extend-ing from two spaced positions exterior of said elastomeric body inwardly thereof to two positions in communicating relation respectively with the arterial and venous pas~
;~ sages operable to move in response to the insertion of a cannula-trocar assembly from (1) a closed condition ex-cluding fluid containing space within the body between the ~, respective two positions so that blood flowing ~rom the arterial tube through,the arterial passage will pass there-~rom through the bypass conduit into the venous passage and out of said venous tube into (2) an open condition 2~ excluding fluid receiving space within the body from the exterior periphery of the.portions of the respective cannula extending between the two respective positions each of which also extends percutaneously and in com-municating relation with the respective arterial or : 25 venous passage so that blood flowing from the arterial i 337 tube throu~h the arterial passage ~ill flow through the bypass conduit as aforesaid and, in addition, will also ~low into the blood withdrawing cannula (with its trocar re-moved), through the ex~racorporeal flow path, through the blood retw ning cannula (with its trocar removed), back into the venous passage.
A further object of the present invention is the provision of an implant device of the type described which is simple in construction, economical to manufacture and eff~ctive in operation.
Another object of the present invention is the provision of cannula-trocar assemhlies particularly con-structed to cooperate with such implant, which cannula-trocar assemblies are simple in construction, economical to manufacture and effective in operation.
These and other objects of the present invention will become more apparent during the course of the follow-ing detailed description and appended claims.
The invention may best be understood with refer-ence to the accompanying drawings, wherein an illustrativeembodiment is shown.
In the drawings:
Figure 1 is a perspective view illustrating the method and apparatus embodying the principles of the present invention;
- ~6 -3~
~igure 2 is an enlarge~ v~rtical sectlonal view taken along the line 2-2 of Figure ~;
Figure 3 is a plan view ~ the implant part of the apparatus;
5Figure 4 is a longitudinal section taken along :~ the line ~-4 of ~igure 3;
Figure 5 is an end view of the implant shown in ~igure 3;
~igure 6 is an enlarged, fragmentary sectional view illustrating the entry of the blood withdrawing can~
nula with its cooperating trocar assembled therein into cooperating relation with the implant and specifically the arterial passage thereof;
~igure 7 is an enlarged fragmentary sectional view taken along the line 7-7 of Figure l;
Figure B is a top plan view of the blood with-drawing cannula with its cooperating trocar assembled therein;
Figure 9 is a side view of the cannula shown in ~igure 8;
Figure 10 is an end view of the cannula shown in Figure 8; and ~ igure 11 is a perspective view of the trocar shown in Figure 8.
33~
Referrin~ now more particularly to the drawings, there is shown therein a preferred apparatus 10 ernbodying the princi~les o~ the present invention ~or practicing the method of the present invention. ~hile it is posslble to utilize other apparatus in pract~cing the present method, since the apparatus 10 is preferred the principles of the present invention can best be understood by first consider ~ ing the pre~erred apparatus 10 ancl then considering the - me~hod pxocedures involved ln utilizing the preferred ap-paratus.
~; In its broadest aspects, the apparatus 10 includes sterile tubing, generally indicated at 12, which defines an : extracorporeal blood flow path. A pump mechanism prefer-a~ly in the form of a peristaltic roller pumpl generally ~ 15 indicated at 14, is provided for pumping blood along the :. extracorporeal flow path at a controlled rate from the inlet tubing end to the outlet tubing end. In addition, there is provided a temperature control zone preferably in the form of a heat exchanger assembly 16 through which the blood flowing along the extracorporeal flow pa~h has its temperature controlled, pre~erably both by heatins and cooling, through a control device, generally indicated at 18, ~or the liquid circuit of the heat exchanger assembly 16. Finally, the apparatus 10 includes means, generally indicated at 20, fox communicating the inlet end of the ;~ .
. .
3~
tubing 12 defining the extracorporeal flow path with the bloodstream of a patient and the outlet end of thc tubilly 12 defining the extracorporeal flow path with the bloodstream of the patient, so that the returning blood is systemically distributed without adversely affecting the blood depleted areas frorn which the blood is withdrawn.
The tubing 12 may be formed of any suitable plastic material, as, for example, vinyl polymer ~e.g. Tygon~), polytetraflouroethylene (e.g. Teflon~), or other plastic materials having known uses in medical applications (e.g.
Silastic~). An exemplary tubing size is 1/4" i.d., with a convenient length being from 3 - 5'. The pump assembly 14, as previously indicated, pre~erably embodies a peristaltic roller type pump driven by a variable speed electric motor.
peristaltic pump is preferred because it can utilize the replacement sterile tubing 12 for blood contact and does not provide pump part which must be maintained in a sterile condition. An exemplary pump is manu~actured by Sarns, having a 1-2 liter per minute capacity.
A preferred embodiment of the heat exchanger assembly 16 is available commercially under the tradename Travenol Mini-Prime, 5MO 337, which has a 57 cc capacity and rated flow of 1-3 liters per ~inute.
3~7 r~'ith reference ~o Figure 2, the ccntrol device 1~ is made up of individually known components. As shown, there is p~ovided a cooled liquid reservoir 22 and a heated liquid reservoir 24 each containing a bo~y of liquid. While any liquid may be utilized a preferred e~..bodiment is water.
Each reservoir is provided with a stirring or agitating means 26 for purposes of mixing the liquid contained therein so as to render the temperature thereof more uniform throughout. The cool liquid reservoir 22 is provided with a coolinq unit, schematically indicated at 28, while the heated liquid reservoir 24 is provided with a heating unit 30. A liquid circulating system is provided in cooperating relation between the cooled liquid reservoir 22 and heated . liquid reservoir 24 and the liquid side of the heat ex-changer 16. Such circulating system includes the utili~ationof two pump assemblies, schematicaily indicated in the drawings at 32 and 34.
As shown in ~igure 2, the pump assembly 32 is associated with the cooling liquid reservoir 22 and includes an inlet or suction pipe 36 extending from ~he reservoir 22 to one side of the pump 32 and an outlet pipe 38 extending therefrom. Similarly, an inl~t pipe 40 ex-tends from the heated liquid reservoir 24 to one side of the pump 34 which side has an outlet pipe 42 extending therefrom. Outlet pipes 38 and 42 are interconnected by a 83~7 T-connector 44 which has a pipe 46 extending therefrom to the liquid inlet side of the heat exchanger 16. A pipe 48 ~xtends from the outlet of the liquid side of the heat : e~changer 16 which by means of a Y-connection 50 coiNmuni-ca~es with two branch conduits 52 dnd 54 extending respec-tively to the opposi~e sides of the pumps 32 and 34. The : circuit is completed by pipes 56 and 58 connected respec-tively to the outlet of the opposite sides of pumps 32 and 34 and the cooled liquid reservoir 22 and heated liquid reservoir 24 respectively. As shown, an overflow pipe 59 is connected between the reservoirs.
The cooling unit 28 is of conventional nature and is adapted to maintain the liquid in the reservoir 22 at a substantially constant temperature as, for example, 30C.
Likewise, the heating unit 30 is of conventional construc-tion and is adapted to maintain ~he liquid within the heated liquid reservoir 24 at a substantially constant temperature as, for example, 45C. Pump 32, when operated, serves to meter from the reservoir 22 through pipe 36 an amount of 2~ liquid which is equal to the amount of liquid returned through pipe 56. In a similar manner, pump 34 when operated serves ~o meter an amount of flow from the reservoir 24 which is always equal to the amount returned through return pipe 58. A control, schematically indicated at 60, for varying the rate of movement of the pumps 32 and 33~
34, e.g. electrical controls for the variable speed elec-trical motors driving the same which form a part of the pump assemblles schematically illustrated is operable so that the total output of the two pumps is adjusted to and maintained at a substankially constant rate, as for example, approximately 10 liters per minute. The control 60 is also operable to effect a proportional variation in the rates which each of the two pumps assume of this total output from 0 10 to 10-0.
Control of the pump assemblles 32 and 34 is undertaken in accordance with the readout of three tem-perature recording de~ices 62/ 64 and 66 placed respectively to sense the core temperature of the patient's body (e.g. a rectal probe or isophageal probe), the temperature ~f ~he blood leaving the heat exchangex 16 being returned to the patient and the temperature of the liquid enteriny the heat exchanger, A pressure sensing device 68 is also provided in the liquid inlet line 46. It will be understood that the temperature sensing devices and pressure sensing devices are of any conventional design, pre~erably of the type providing a remote readout, as schematically indicated by corres-ponding primed numerals.
For illustrative purposes it is suf~icient to note that control 60 can be manually operated to determine .
4~3~
the proportion of the total liquid ~low through ~he heat exchanger which is provided by the ~ooled liquid at 30C and the heated liquid at 45C. Control 60 thus serves to directly vary the liquid temperature sensed by device 66 between the low limit of 30~C and upper limi' of 45~C, which in turn will vary the temperature of the blood sensed by : device ~4 which in ~urn will affect the patient's systemic blood temperature and hence the temperature sensed by device 62. It will be understood that while the operation of control 60 is set forth for illustrative purposes as being manual, the control 60 may be rendered automatic and pro-grammable if desired.
Referring now more particularly to Figures 3-11, the communicating means 20 preferably comprises a totally su~cutaneous implant device, generally indicated at 70, which serves as the means communicating with the patient's bloodstream and a pair of percutaneous cannula-txocar assem-blies, generally indicated at 72 and 74, which serve as the means for operatively communicating the implant de-vice 70 with ~ubing 12 defining the extracorporeal flowpath. As best shown in Figures 3 7, the implant device includes a ~ody 76 of elastomeric material such as Silastic~, molded so as to provide an arterial passage 78, a spaced venous passage 80 and a by-pass conduit 82 connect~d between the inner end of the passage 78 and .
: - 23 -; .
.f~ 33~7 the inner end of the passage 80. ~s best shown in Fisure 3, the passage, 78 and 80, together with the by-pass conduit 82, are of generally ~-shaped configurationO
Each of the passages 78 and 80 has a peripheral cross-sectional configuration which is elongated in one direction; namely, the direction in which they are spaced apart, wi~h sharp points defining opposi~e ends in the directio~ of elongation. The preferred configuration shown is further characterized by a pair of convexly curved lines extendinq between the sharp points, the distance between the central portions of the convex lines being appro~imately one-half the distance between the two end points~ While the by-pass conduit may be of other cross-sectional configura-tion, as shown, it too is of similar cross-sectional con-lS fiyuration. This preferred cross-sectional configuration for the passages 78 and 80 is provided for the purpose of cooperatively receiving the correspondingly shaped exterior peripheries of the cannulas of the assemblies 72 and 74, which assemblies are so shaped for the purpose of co-operating with a pair o~ slits 84 and 86 formed in thebody 76 in operative association with the passages 78 and 80 respectively.
As shown, each slit 84 and 86 extends from a position exterior of the body 76 to a position of com-munication with the innex end of the associated passage ~ 4~837 78 or 80. The width of each slit is generally equal to the distance between the end points of the associated passaye and is ori nted in its closed condition, as best shown in Figure 4, in longitudinal alignment with a plane passing between th~ end points of the associated passage.
In the closed condition shownl the two planar interior surfaces of the body 76 which dcfine the respective slit 84 or 86 are resiliently urged into engagement by the elastomeric characteristics of the body material. ~he engagement o the surfaces serves to exclude any spaces which could contain fluid such as blood between the two positions of extent of the slit as aforesaid.
The resiliency of the elastomeric material of the body 76 also permits each slit 84 and 86 to be moved by its lS respective cannula-trocar asscmbly 72 and 74 into an open condition where the planar body surfaces definin~ the slit are spread arcuately so that the profile thereof coincides with the peripheral configuration of the associated passage 78 or 80.
To aid the entry and insertion of each cannula-trocar assembly through its associated slit, there is molded in embedded relation within the body 76 a pair of metallic guide structures 88 and 90. Each ~uide structure is pre~
ferably made of a medically acceptable interior use metal, such as stainless steel (e.g~ Vitallium Metal manufactured by Howmedica~. The guide structures include similar ~ t7 inwardly tapering annular parts 92 and 94 respectively fixed to the exterior end face of the body 76 and similar parallel spring finger parts 96 and 98 respectivel~ em-bedded in the exterior of the body on opposite sides of S associated slit. The tapered part~ 92 and 94 provide the guide assist function previously noted while the spring finger parts 96 an~ 98 provide a spring assist function for the slits of the elastomeric body serving ~o resiliently urge the slit defining sur~aces toward one another i~
addition to the spring function provided by the elasto-meric characteristics of the material of the body 76.
The implant device 70 also includes a pair o~
tubes 100 and 102 made of vascular prosthesis material.
A preferred vascular prosthesis material is woven Dacron~
marketed commercially by Meadox Medicals although any other acceptable vascular prosthesis material may be utilized. As best shown in Figure 1, the tube 100 has one end thereof fixed in communicating relation with the outer end portion of the arterial passage 78, as by being molded in embedded relation. The opposite end of the tube 100 is adapted to be connected, as by suture, to a surgical openiny formed in the side wall of a femoral artery so that the interior o~ the tube 100 is in com-municating relation with the interior of the femoral artery. In a like manner, one end oE the tube 102 is Z3~
embedded in communicating relation wi~h the outer end por-tion of the venous passage ~0 and its opposite end is adapted to be sutured to a surgical side wall opening in the associated femoral vein so that its interior is in com-munica~ing relation with the interior of the femoral vein.
The implant device 70 also includes a layer offabric 104 which is fixed to the inner side wall of the elastomeric body as by Silastic~ glue or the like. The fabric 104 includes marginal portions extending laterally outwardly from the operative inner side wall of the body 76 to which it is fixed. The fabric layer 104 and particularly the marginal portions thereof provide for initial fixation by suture of the body 76 during implant and for subsequent semi-permanent ~ixation by tissue ingrowth. A preferred fabric material is Dacron~ double velour which is marketed commercially by Meadox ~edicals.
For identification purposes directly from the implant device itself, radiopaque identification (not shown) is provided on the operative outer side wall of the elastomeric body 76. Such identification insules that the proper cooperating cannula-trocar assemblies 72 and 74 will always be used since such assemblies can be ascer-tained from the implant itself after total implantation has been effected through X-ray identification.
~5 ReferrincJ now more particularly to Figures 8-11 3~
of the drawings, the details of con~truction of the car~nula-trocar assemblies 72 and 74 are sho~n therein. It will be unders~ood that since the assemblies 72 and 74 are left and right hand mirror images of one another, a description of one of the assemblies will suffice to give an understanding of both. The assembly 74 is shown in assembled condition in ~igure 8 and includes a percutaneous cannula, generally indicated at 106 and a cooperating trocar, generally indi-cated at 108.
1~ The cannula 106 includes a tubular body which includes a straight section 110 defining the subcutaneous end portion of the cannula and an angular section 112 which, together with an adjacent part of the straight section 110, defines the extracorporeal end portion of the cannula. The cannula 106 is preferably molded o~ radiopaque plastic material having sufficient rigidity to preven~
interior collapse when in operative pOsition within the implant device 70. Thermoset plastics are preferred al-though thermoplastic materials with sufficient functional rigidity and heat stability for sterilization can be used.
An exemplary material is ethylehe-propylene-terpolymer te.g.
where the third monomer is norbornadiene) impregnated with a radiopa~ue material such as barium sulfate.
As shown, the entire straight section 110 of the cannula 106 has its exterior periphery for~ed with a cross-sectional configuration which conforms with and engages - 2~ -33~
within the interior periphery of the body 76 defining the artery passaye 78 or venous passage 80. Such configuxa-tion, however, is required only in the extent o~ the sub-cutaneous end portion which is disposed within the passage and associated slit of the implant body during operation.
The cannula 106 includes an interior passage 114 which extends through the angular sec~ion 112 into the straight section 110 and out of the extremity thereof.
In order to maximize the interior passage cross-sectional area for an optimum exterior cross-sectional size, the cross-sectional configuration of the interior passage 114 at least in the straight section 110, conforms to the exterior cross-sectional configuration.
In this regard it will be noted that the trocar 108 consists essentially of a molded body o~ plastic ma-terial, similar to the plastic material of the cannula 106, which provides a blade part 116 and a handle part 118. The blade part 116 is of a longitudinal extent generally equal to the longitudinal extent of the straight 2~ section 110 of the cannula 106. T~.e main extent of the blade part 116 has an exterio~ peripheral cross-sectional configuration conforming wi~h the interior cross-sectional con~iguration of the portion of the interior passage 119 extending through the straight cannula sec-~5 tion 110. The blade part 11~ includes a sharpened tip - 29 ~
3~
portion 120 whic~ tapers gradually in cross-sectional con-figuration outwardly from the aforesaid configura~ion to a pointO
It will be noted that the extracorporeal end of the straight section 110 of the cannula 106 is closed as by a diaphragm or plug of elastomeric material 122 which pref-erably is preslit (although may be imperforate) to permit .the passage of the trocar 108, pointed end 120 first, therethrough.
The exterior periphery of the outer end of the angular section 112 is provided with gripping flanges.124 operakle to efect a fluid-tight connection with the in-terior of the tubi~g 12. When the trocar lOB is withdrawn, the elas~omeric plug slit, which has expanded to receive the trocar, contracts to close the end of the straight section of the cannula and insure that all of the blood will flow outwardly through the angular section 112 and into the tubing 12.
Formed on the exterior periphery of the straight 2~ section 110 of the cannula is an annular shoulder 126 which forms a stop sur~ace facing in a direction ~oward the open extremity of the straight cannula section operable to engage the guide part 92 or 94 of the implant device when the cannula is in its fully inserted operative position, as shown in Figure 7. The straigh~ cannula section 110 is 483~
~ormed with an opening 128 which extends inwardly from one exterior end point into communication with the interior passage 114 at a posi~ion to register with the by-pass conduit 82 of the implan~ body 76 when the cannula is fully inserted, as aforesaid. Formed on the e~terior pexiphery of the extracorporeal portion of the straight cannula section 110 is a stabilizing shield 130 which facilitates main-tenance of the cannula on the patient when in operative position.
A preferred procedure is to coat all of the blood contacting surfaces o~ the cannulas 106 ~i.e. interior passages 114) tubiny 12 and elastomeric body 76 (passages 78 and 80, conduit 82 and slits 84 and 86) with an anti~
coagulant coating. A suitable coating material for this purpose is marketed commercially under the tradename TDMAC~.
The manner in which the device 70 is surgically implanted is in accordance with usual implant procedures well ~nown to those s~illed in the art. ~or present pur-poses suffice it to say that the elastomeric body 76 isimplanted in an arterior femoral region spaced downwardly fxom ~he position o~ bending at the hip approximately the distance o~ the width of a normal-sized palm ~ap-proximately 4") as is clearly shown in ~igure 1. The large area faces of the body 76 are preerably disposed parallel with the skin with the face having the fabric ~ ~ 4~ 3~
104 ~ixed thereto in~ermost. The arterial and venous tubes 100 and 102 extend upwardly and the free ends are tapered and sutured to surgical openings i~ the side walls o~ the ~emoral artery and vein respecti~ely so as S to extend there~rom at an angle of approximately 45.
This procedure is accomplished in accordance with usual practices relating to the use of vascular prosthesis material.
The marginal edge portions of the fabric 104 are 5utured to tlle adjacent tissue to provide initial body 76 fixation, as aforesaid. ~11 of the exterior surfaces of the implant device 76 are contacted with tissue includ-ing tapered guide parts 92 and 94 (~ith fat).
AQ previously indicated, it is possible to use known shunt devices (e.g. U.S. pa~ent No. 3,713,441) in lieu of the device 70 so long as they provide the neces-sary capacity which is ordinarily not the case without modi~ication.
The advantages of the use of the implant device 2J 70 is that it is specifically intended for long-term surgical implantation in the thig}l of cancer patients t whereby its anastomosis to the femoral artery and vein, creates a high~low (1-2 liters per minute) arterio-venous conduit which may be repeatedly entered by per-cutaneous insertion of the cannula assemblies 72 and7~. , .~ .
4~3~7 As compared with other prosthetic partially exteriorized A-V Shunt devices as ~sed for renal hemo-dialysis the implant device 70 red~lces ~he risk of in-fection, reduces the risk of throm~osis, reduces the ris~ of disruption and improves the esthetics of normal usage. The renal dialysis experience indicates that partially exteriorized lower extremity shunts frequently develop infection along the tract of the shunt tubing.
The incidence and severity of this type of infection would be increased in cancer patients by the immunosup-pressive effects of malignancy, and the che~otherapy and radiotherapy they frequently receive. The implantable device '0 greatly diminishes the risk of infection and requires no increase in the amount of surgery needed ~or insertion. Cancer patients have a state of hypercoagul-ability or increased tendency to form blood clots in their normal and any arti~icial circulations. Ordinary A-V
shunts last only 2-6 months in hypocoagulable dialysis patients, and likely will clot much sooner in those with the "Stic~y blood" of disseminated malignancy The im-plantable device 70 has a shorter fluid path, much o~
which will be covered by a patient's own intravascular tissues, and hence will be less likely to thrombose.
Partially exteriorized shunts have press connections which ~,.ay be inadvertently loosened or disconnected.
Such events have caused deaths in dialysis patients but, in general, those shunts are small and a patient can contro.l.
a bleeding shunt before exsanguination occurs. However, disruption of the large shunt necessary for hyperthermia would result in massive bleeding, which could render a patient unconscious even before the shunt could be reached through normal clothing. This cannot happen with the de-vice 70 as the connections are permanent, as well as totally prvtected.
Unlike commercially known shunts, there is no external tubing associated with the device 70. A nor~al bath or shower could be taken by the implanted patient, whereas those with partially exteriori~ed shunts cannot submerge them and must resort to ~ess hyyienic methods, lS a probable factor in their increased incidence of in-fections. Furthermore, the device 70 does ~ot interfere with clothing or require any sort of dressing, leaving a patient's appearance unimpaired, an important asset to the depressed cancer patient.
The manner in which each cannula assembly 72 or 74 i5 inserted into cooperating relation to the im-planted device 70 should be apparent from the above. It is of significance to note the advantages of the utili-~ation of a main implant body 76 which provides increase~
palpation facility during cannulation. Moreover, cannu-lation is effected in a straight line relationship f ,.~
.
resulting in a straight line percutaneous communication with the extracorporeal flow path. The preferred cross~
sectional con~iguration of the cannula enables simple but effective alignment to be accomplished during insertion.
Such cross-sectional configuration ~lso provides optimal cooperation with the slits 84 and 86 of the elastomeric body 76 both in expandinc3 the slits during insertion and in contracting the peripheral portion of the cannula extending therethrough to insure a gsod fl-lid-tight con-nection. The extension of this cannular cross-sectional configuration with the elastomeric body passages 78 and 80 also insures non-distortion of these passages and a full flow area o~ 4 mm or larger.
The flow capacity provided is of extreme im-portance since it is a critical determining factor in the time re~uired to bring the patient's blood up to the desired treatment temperature and to the sensitivity of the temperature control available. The approximate 1 liter minute capacity provided is based upon the aver-2 age size of an average adult patient and, of course, shou~d be varied to suit the particular size of the patient being treated. The term approximately 1 liter per minute is there~ore intended ~o comprehend within i~s meaning such variation to suit the patient size.
It will be understood that once the inlet and 3'7 outlet ends of the tubing 12 are con~ected over the ~langes 124 of the .~annula of the assemblies 72 and 74 and the associated trocars 108 of the assemblies are withdrawn, pump 14 can be started to commence the flow of blood along the extracorporeal flow path at the approximate 1 liter per minute as aforesaid and through the tem2erature control zone thereof. In~tially, control 60 is set to pass 100~ 45C water through the heat exchanger 16. During this initial trea~ment phase withdrawn blood temperatures measured a~ 62' will show a gradual increase from the initial normal reading of approximately 37C. The cap-acity and effectiveness of the heat exchan~er 16 is such that readings of the re~urning blood taken at 64 closely approximate the 45C maximum water temperature utilized.
As the heated blood is returned to the femoral vein through the blood receiving percutaneous cannula 106, venous passage 80 and tube 102, it is distributed systemically which in turn, has the effect of increasing the total systemic tempera~ure. As the patient's core body tem-perature increases to~ard the 91.SC level control 60 must be operated to lower the liquid reading at 66 to a value below 45C as, for example, 42.5C. The liquid temperature level stabilized at 42.5C, the patient core body tempera-ture readings at 6~, and returning blood readings will stabilize at a desired level of approximately 41.5C and ~0.0C
respectively. This critical phase wherein the patient's 83}~
systemic temperature is increased and stabilized should, as aforesaid, normally be completed within one hour, al-though here again, variation because of patient size will occur.
O~ce temperature stabilization is achieved as aforesaid, treatment is continued for a time period ef-fective ~or the particular cancer which the patient has.
A preferred minimum time for all types including simple carcinomas is six hours although treatment times of 20 hours and longer will be re~uired for more complex ca~cer situationsO
.. Preferably, a third phase of the present method involves utilizing the continued blood flow through the temperature control zone o~ the extracorporeal flow path to reduce the blood temperature to normal and, hence, the patient's systemic temperature to normal. This phase is initiated by turning control 60 to pass predominately 3~C
; water through the heat exchanger 16. This has the effect of substantially lowering the readings of the returning blood taken at 64. ~gain, this cooler blood is distributed systemically, causing the systemic temperature to lower until a normal of 37C is reached. The decreasing tem-perature phase normally will require a time period ap-proximately the same as the initial increasing temperature phase although usually somewhat less.
83~
Preferably, the patient is maintained during treatment il a skin contacting environment approximating that of an intensive care room. While it is within the contemplation of the invention to provide a skin insulat-S ing environment and even compaxable elevated temperaturesto inhaled gases, the intensive care like environment is preferred because the temperature level o~ the skin and respiratory system does not vary significantly from the induced hyperthermia systemic level and access to the patient is much more readily obtained. Moreover, the ap-plication of radiation or chemotherapy treatments can be carried on simultaneously if desired.
I~ thus will be seen t.hat the objects of this invention have been fully and effectively accomplished.
It will be realized, however, that the foregoing preferred specific embodiment has been shown and described for the purpose of illustrating the functional and structural principles of this invention and is subject to ch~nge without departure from such principles. Therefore, this inYention includes all modifications encompassed within the spirit and scope of the following claims.
-.38 -
It is an object of the present invention to provide a method and apparatus for effecting hyperthermic treatment which will meet the above-listed desirable criteria. In accordance with the procedural principles of the present invention, this objective is obtained by establishing a s~erile extr~corporeal flow path for blood having an inlet, an outlet and a temperature control zone therebetween, establishing communication of the inlet of the extracorporeal flow path with the patient's bloodstream so that blood can be withdrawn and supplied to the extracorporeal flow path without adversely affecting the bloo~ depleted areas from which the blood is withdxawn, establishi~g co~.lunication of the outlet of the extracorporeal flow path with the patient's bloodstream so that blood flowing from the extracorporeal flow path is returned to the bloodstream in such a way as to be distributed systemically, pumping blood withdrawn from the patlent's bloodstream along the extracorporeal flow path through the temperature control zone at a controlled rate and return ng the same to the patient's bloodstream to be distributed systemically, as aforesaid, controlling the temperature o the blood flowin~ along the extracorporeal flow path through the temperature control zone for ~n initial period during which the ~emperature level of the blood within the zone is raised without subjecting the same to localized temperatures in e~cess of approximately 45 C so that the systemic distribution of the returned blood gradually in-creases the core temperature of the patient's body to a generally stable temperature condition at a lcvel of ap-proximately 41.5C, but not higher than appro~imately 42.5C, and maintaining control of the temperature of the blood flowing along the extracorporeal flow path through the temperature control zone at the generally stable temperature condition for a second time period sufficient to retard the growth of cancer cells.
It is recognized that extracorporeal heating of blood for anti-cancer purposes has been undertaken in regional perfusion practices. Procedures of this type are discussed by Cavaliere et al. and Stehlin and are to be distinguished from the systemic hyperthermia induced by the present pro-cedures, as indicated above. In these regional perfusion ~ practices, the main femoral artery and vein are temporarily ; 25 occluded by vasoular clamps or tourniquets and a closed .
. ..
extracorporeal system is established, solely within the femoral extremity. In ~his extracorporeal circuit, heat is ayplied as an adjunct to the other treatments, such as chemotherapy, w}lich are utilized in the regional circulating S system. This system neceScitates the utilization of oxy-genating equipment o~ a ty2e similar to that used in open heart surgery. As is evident from the known time liml-tations imposed upon open hear~ surgery by virtue of the utili~ation of oxygenating equipment, the time frame ~ithin which such combined oxysenating and heating treatments can be continued even on a regional basis without imposing at least a percentile permanent dal~age to the blocked femoral areas of the patient is quite limited.
Pettigrew, in re~erring to these regional per-fusion practices as background to his preferred combined hot wax bath and heated respiratory gases procedure fo. inducing total body hyperthermia, appears to consider the regional perfusion procedures to be applicable to induce both reg-ional hyperthermia as well as total bGdy hyperthermia, perhaps by analogy to the open heart e~:~racorporeal shunt-ing. (Induction of Controlled Hyperther~nia in Treatment of Cancer, Henderson, M.A. and Pettigrew, R.T. Lancet, 1:1275, 1971 and Cancer Therapy by Whole Body Heating, Pettigrew, R.T. Proce~edings, p. 282). The P~ttiqrew Lancet article characterized the reyional perfusion ~ork of Cavaliere et al. ("Selective Heat Sensiti~ity of Cancer Cells", Cancer, 1967, 20-1351) as having "achieved very satis~actory tem-peratures in the malignancies using an arteriovenous shunt and a heat exchangar, but since ~his requires surgery it cannot be repeated indefinitely and can only be applied easily to peripheral malignancy."
It is of significance, however t to note that the recognized practitioners of regional perf~lsion, namely Cavaliere et al. and Stehlin et al., have both indicated that the regional perfusion pract.ices utilizing a shunt and an extracorporeal heat exchanger are limited to regional extremity applications and both have utilized other pro-cedures for inducing total body hyperthermia.
On page 135 of the cancer article Cavaliere et al.
state:
"This method of high temperature treatment obviously has limitations and at pre~ent is indicated ln patients with primary or recurrent malignant tumors of the limbs for whom the only alternative therapy would be amputation, which often does not prevent me~astases~
... It is evident that future progress in this field will come ~rom total-body high-temperature treatment~ We are now in the process of developing tech-niques towards this end, which are considerably different from those now being used."
The last paragraph of the Stehlin article in the Proceedings publication, page 271, sets forth the ~ollowing:
.~ 3~7 "As a result of our experience with regional perfuslon with heat, we are currently, and have for the past five years been investlgating the possi-bility that syqtemic hyperthermia induced with bacterial toxins will enhance the antitumor effects of various chemotherapy agents on melanomas and sarcomas~"
~ preferred minimum flow rate in accordance with the principles of the present invention, is approxi-mately 1 liter per minute. Such flow rate can be achieved by following the procedures of the present invention with-out affecting the femoral areas from which the blood i~
withdrawn, Thus, with the present procedure, there is no systemic femoral isolat~on as by a clamp or tourniquet occluding the main femoral artery and vein, but rather, a preerred procedure is to effect communication of the extracorporeal flow path between the famoral artery and the femoral vein through a side wall of each, so that systemic circulation in the femoral areas can continue.
The pumping proceduxe undertaken to effect flow of the withdrawn blood through the temperature control zone of the extracorporeal flow path achieves an adequate con-trolled flow rate while permitting adequate systemic cir-culatory flow through the femoral areas sufficient to prevent the type of adverse e~fects over extended periods of time which will occur in the aforesaid regional per-fusion techniques.
. ~
~4~ 7 The present invention also contemplates an improved implantable de~ice for facllitating the connection of the ex~racorporeal flow circuit with the blood system of the patient. Devices for establishing an extracorporeal blood flow path for the purposes of kidney dialysis as distinguished from systemic hyperthermic treatments are well-known. These devices, known as shunts, are made commercially available by several manufacturers. Typically, these shunt devices are implanted in the patient and include tubes which extend extracorporeally. ~hese exterior-ized tubes have caused considerable dif~iculty.
A good discussion of the difficulties encountered in the practice3 relating to such exteriorized shunt de~
vices is contalned in UOS. patent No. 3,998,222. In the opening paragraphs of the specification, one type of shunt device is described as a U-shaped loop, one end of which is connected to a vein and the other end of which is con-nected to an artery. The loop itself is implanted sub-cutaneously but outlet conduits extending from the sides o the loop protrude through open holes in the skin to outlet terminals on the outside of the body. Removable plugs fit in the outlet tubes and block the flow through these tubes during normal conditions. When the patien~ is sub-jected to dialysis, the plugs are removed and the out-let terminals are connected to inlet fittings for a dialysis machine~ (See 3,826,257).
83~
One of the problems enunciated in the opening paragraphs o the specification attributable to this type of exteriorized shunt is the ri~k of infection in the location where the outlets protrude ~hrough the opening holes in the skin~ While there is considerable reference to problems relating to blood clotting in shunt devices of the prior art, there is proposed in the patent a shunt arrangement which would at least have the effect of al-leviating the infection problem~ in that the shunt device of the invention is arranged to be implanted in a com-pletely interiorized or totally subcutaneous condition:
In order to effect communication of the totally interiorized shunt device with the extracorporeal flow path, the im-planted device is provided with mechanically movable valve members. These valve members are normally retained in a position within housings provided by the shunt device which maintain the valve members out of communicating re-lation with the blood flow through the shunt device. The valve members are provided with cooperating surfaces such as square apertures or threads which are operable to initially establish a fluid~tight communication with a hollow needle. The hollow needle is thus capable of being inserted through the skin into fluid contact with the ' valve member and then after such fluid coupling has been effected, the hollow needle is capable of effecting the ;, :
83~
movement of the valve member into flo~ communicating re-lation with the bloodstream.
While the patent describes the utili~ation of a Fogarty catheter for effecting the cleaning and declotting 5 o the device, no provision is made for preventing the clotting of the blood within the central flow passages of the valve members when they are disposed in their normal closed positions. Moreover, while provision is made for circulating blood between the periphery of the valve membexs and the housing retaining the same when the valve members are in their opened position, no such provision is made or the - valve members when they are in closed position and, indeed, the peripheral passages provided for continued ~low when the valve members are open are themselves closed when the valve member is closed, thus presenting, along with the interior passages o the valve members, spaces where blood would be trapped and become clotted.
While it is recognized to be desirable to overcome the disadvantages of the commercially available exteriori~ed shunt device, the arrangement disclosed in ~he aforesaid patent would ~ppear to present clotting problems equal to, if not worse than the clottiny problems noted in the prior art. When it is considered that it is quite usual for cancer patients to be hypercongulable, the clotting problems of the prior art assum~ greater proportions .
3~7 when contemplatillg the utilizatlon of such shunts for hyperthermic treatment of a patient for anti-cancer pur-poses. Moreover, effective hypert~,~rmic treatments in accordance l~ith the principles of ~he present invention require flow rates considerably in excess o that normally provided for kidney dialysis.
Accordingly, it is a further object of the pxesent invention ~o provide a shunt device of the totally sub-cutaneous type which is particularly suitable for use in hyperthermic treatment of a patient for anti-cancer pur-poses in accordance with the present invention, which device overcomes, or at least substantially alleviates, the clot',ing problems of the prior art heretofore noted.
This objecti.ve is obtained by providing a totally lS subcutaneous implant for use with the apparatus provi~ing the extracorporeal blood flow path~ including both a blood withdrawing and a blood returning percutaneous cannula, each of which is cooperable with a trocar for effecting the percutaneous disposition thereof, which cannulas co-operate with the implant ~o achieve the extrac rporealblood flow. The implant comprises a body of elastomeriC
material adapted to be implanted totally subcutaneously in a femoral extremity, the body having an arterial pas-sage therein, a spaced venous passage, and a bypass conduit extendil~ ~rom one end of the arterial passage to one end of the venous passage. An arterial tube and a venous tube of vascular prosthesis material are provided, each having one end connected in commw~icating relation with the other end of the respective ar~erial or venous passage anA an opposite end ad~ted to be connecte: with a respective main ~emoral artery or vein side wall in communicating relation respectively with the respective interior of the femoral artery or vein.
The elastomeric body is provided with means extend-ing from two spaced positions exterior of said elastomeric body inwardly thereof to two positions in communicating relation respectively with the arterial and venous pas~
;~ sages operable to move in response to the insertion of a cannula-trocar assembly from (1) a closed condition ex-cluding fluid containing space within the body between the ~, respective two positions so that blood flowing ~rom the arterial tube through,the arterial passage will pass there-~rom through the bypass conduit into the venous passage and out of said venous tube into (2) an open condition 2~ excluding fluid receiving space within the body from the exterior periphery of the.portions of the respective cannula extending between the two respective positions each of which also extends percutaneously and in com-municating relation with the respective arterial or : 25 venous passage so that blood flowing from the arterial i 337 tube throu~h the arterial passage ~ill flow through the bypass conduit as aforesaid and, in addition, will also ~low into the blood withdrawing cannula (with its trocar re-moved), through the ex~racorporeal flow path, through the blood retw ning cannula (with its trocar removed), back into the venous passage.
A further object of the present invention is the provision of an implant device of the type described which is simple in construction, economical to manufacture and eff~ctive in operation.
Another object of the present invention is the provision of cannula-trocar assemhlies particularly con-structed to cooperate with such implant, which cannula-trocar assemblies are simple in construction, economical to manufacture and effective in operation.
These and other objects of the present invention will become more apparent during the course of the follow-ing detailed description and appended claims.
The invention may best be understood with refer-ence to the accompanying drawings, wherein an illustrativeembodiment is shown.
In the drawings:
Figure 1 is a perspective view illustrating the method and apparatus embodying the principles of the present invention;
- ~6 -3~
~igure 2 is an enlarge~ v~rtical sectlonal view taken along the line 2-2 of Figure ~;
Figure 3 is a plan view ~ the implant part of the apparatus;
5Figure 4 is a longitudinal section taken along :~ the line ~-4 of ~igure 3;
Figure 5 is an end view of the implant shown in ~igure 3;
~igure 6 is an enlarged, fragmentary sectional view illustrating the entry of the blood withdrawing can~
nula with its cooperating trocar assembled therein into cooperating relation with the implant and specifically the arterial passage thereof;
~igure 7 is an enlarged fragmentary sectional view taken along the line 7-7 of Figure l;
Figure B is a top plan view of the blood with-drawing cannula with its cooperating trocar assembled therein;
Figure 9 is a side view of the cannula shown in ~igure 8;
Figure 10 is an end view of the cannula shown in Figure 8; and ~ igure 11 is a perspective view of the trocar shown in Figure 8.
33~
Referrin~ now more particularly to the drawings, there is shown therein a preferred apparatus 10 ernbodying the princi~les o~ the present invention ~or practicing the method of the present invention. ~hile it is posslble to utilize other apparatus in pract~cing the present method, since the apparatus 10 is preferred the principles of the present invention can best be understood by first consider ~ ing the pre~erred apparatus 10 ancl then considering the - me~hod pxocedures involved ln utilizing the preferred ap-paratus.
~; In its broadest aspects, the apparatus 10 includes sterile tubing, generally indicated at 12, which defines an : extracorporeal blood flow path. A pump mechanism prefer-a~ly in the form of a peristaltic roller pumpl generally ~ 15 indicated at 14, is provided for pumping blood along the :. extracorporeal flow path at a controlled rate from the inlet tubing end to the outlet tubing end. In addition, there is provided a temperature control zone preferably in the form of a heat exchanger assembly 16 through which the blood flowing along the extracorporeal flow pa~h has its temperature controlled, pre~erably both by heatins and cooling, through a control device, generally indicated at 18, ~or the liquid circuit of the heat exchanger assembly 16. Finally, the apparatus 10 includes means, generally indicated at 20, fox communicating the inlet end of the ;~ .
. .
3~
tubing 12 defining the extracorporeal flow path with the bloodstream of a patient and the outlet end of thc tubilly 12 defining the extracorporeal flow path with the bloodstream of the patient, so that the returning blood is systemically distributed without adversely affecting the blood depleted areas frorn which the blood is withdrawn.
The tubing 12 may be formed of any suitable plastic material, as, for example, vinyl polymer ~e.g. Tygon~), polytetraflouroethylene (e.g. Teflon~), or other plastic materials having known uses in medical applications (e.g.
Silastic~). An exemplary tubing size is 1/4" i.d., with a convenient length being from 3 - 5'. The pump assembly 14, as previously indicated, pre~erably embodies a peristaltic roller type pump driven by a variable speed electric motor.
peristaltic pump is preferred because it can utilize the replacement sterile tubing 12 for blood contact and does not provide pump part which must be maintained in a sterile condition. An exemplary pump is manu~actured by Sarns, having a 1-2 liter per minute capacity.
A preferred embodiment of the heat exchanger assembly 16 is available commercially under the tradename Travenol Mini-Prime, 5MO 337, which has a 57 cc capacity and rated flow of 1-3 liters per ~inute.
3~7 r~'ith reference ~o Figure 2, the ccntrol device 1~ is made up of individually known components. As shown, there is p~ovided a cooled liquid reservoir 22 and a heated liquid reservoir 24 each containing a bo~y of liquid. While any liquid may be utilized a preferred e~..bodiment is water.
Each reservoir is provided with a stirring or agitating means 26 for purposes of mixing the liquid contained therein so as to render the temperature thereof more uniform throughout. The cool liquid reservoir 22 is provided with a coolinq unit, schematically indicated at 28, while the heated liquid reservoir 24 is provided with a heating unit 30. A liquid circulating system is provided in cooperating relation between the cooled liquid reservoir 22 and heated . liquid reservoir 24 and the liquid side of the heat ex-changer 16. Such circulating system includes the utili~ationof two pump assemblies, schematicaily indicated in the drawings at 32 and 34.
As shown in ~igure 2, the pump assembly 32 is associated with the cooling liquid reservoir 22 and includes an inlet or suction pipe 36 extending from ~he reservoir 22 to one side of the pump 32 and an outlet pipe 38 extending therefrom. Similarly, an inl~t pipe 40 ex-tends from the heated liquid reservoir 24 to one side of the pump 34 which side has an outlet pipe 42 extending therefrom. Outlet pipes 38 and 42 are interconnected by a 83~7 T-connector 44 which has a pipe 46 extending therefrom to the liquid inlet side of the heat exchanger 16. A pipe 48 ~xtends from the outlet of the liquid side of the heat : e~changer 16 which by means of a Y-connection 50 coiNmuni-ca~es with two branch conduits 52 dnd 54 extending respec-tively to the opposi~e sides of the pumps 32 and 34. The : circuit is completed by pipes 56 and 58 connected respec-tively to the outlet of the opposite sides of pumps 32 and 34 and the cooled liquid reservoir 22 and heated liquid reservoir 24 respectively. As shown, an overflow pipe 59 is connected between the reservoirs.
The cooling unit 28 is of conventional nature and is adapted to maintain the liquid in the reservoir 22 at a substantially constant temperature as, for example, 30C.
Likewise, the heating unit 30 is of conventional construc-tion and is adapted to maintain ~he liquid within the heated liquid reservoir 24 at a substantially constant temperature as, for example, 45C. Pump 32, when operated, serves to meter from the reservoir 22 through pipe 36 an amount of 2~ liquid which is equal to the amount of liquid returned through pipe 56. In a similar manner, pump 34 when operated serves ~o meter an amount of flow from the reservoir 24 which is always equal to the amount returned through return pipe 58. A control, schematically indicated at 60, for varying the rate of movement of the pumps 32 and 33~
34, e.g. electrical controls for the variable speed elec-trical motors driving the same which form a part of the pump assemblles schematically illustrated is operable so that the total output of the two pumps is adjusted to and maintained at a substankially constant rate, as for example, approximately 10 liters per minute. The control 60 is also operable to effect a proportional variation in the rates which each of the two pumps assume of this total output from 0 10 to 10-0.
Control of the pump assemblles 32 and 34 is undertaken in accordance with the readout of three tem-perature recording de~ices 62/ 64 and 66 placed respectively to sense the core temperature of the patient's body (e.g. a rectal probe or isophageal probe), the temperature ~f ~he blood leaving the heat exchangex 16 being returned to the patient and the temperature of the liquid enteriny the heat exchanger, A pressure sensing device 68 is also provided in the liquid inlet line 46. It will be understood that the temperature sensing devices and pressure sensing devices are of any conventional design, pre~erably of the type providing a remote readout, as schematically indicated by corres-ponding primed numerals.
For illustrative purposes it is suf~icient to note that control 60 can be manually operated to determine .
4~3~
the proportion of the total liquid ~low through ~he heat exchanger which is provided by the ~ooled liquid at 30C and the heated liquid at 45C. Control 60 thus serves to directly vary the liquid temperature sensed by device 66 between the low limit of 30~C and upper limi' of 45~C, which in turn will vary the temperature of the blood sensed by : device ~4 which in ~urn will affect the patient's systemic blood temperature and hence the temperature sensed by device 62. It will be understood that while the operation of control 60 is set forth for illustrative purposes as being manual, the control 60 may be rendered automatic and pro-grammable if desired.
Referring now more particularly to Figures 3-11, the communicating means 20 preferably comprises a totally su~cutaneous implant device, generally indicated at 70, which serves as the means communicating with the patient's bloodstream and a pair of percutaneous cannula-txocar assem-blies, generally indicated at 72 and 74, which serve as the means for operatively communicating the implant de-vice 70 with ~ubing 12 defining the extracorporeal flowpath. As best shown in Figures 3 7, the implant device includes a ~ody 76 of elastomeric material such as Silastic~, molded so as to provide an arterial passage 78, a spaced venous passage 80 and a by-pass conduit 82 connect~d between the inner end of the passage 78 and .
: - 23 -; .
.f~ 33~7 the inner end of the passage 80. ~s best shown in Fisure 3, the passage, 78 and 80, together with the by-pass conduit 82, are of generally ~-shaped configurationO
Each of the passages 78 and 80 has a peripheral cross-sectional configuration which is elongated in one direction; namely, the direction in which they are spaced apart, wi~h sharp points defining opposi~e ends in the directio~ of elongation. The preferred configuration shown is further characterized by a pair of convexly curved lines extendinq between the sharp points, the distance between the central portions of the convex lines being appro~imately one-half the distance between the two end points~ While the by-pass conduit may be of other cross-sectional configura-tion, as shown, it too is of similar cross-sectional con-lS fiyuration. This preferred cross-sectional configuration for the passages 78 and 80 is provided for the purpose of cooperatively receiving the correspondingly shaped exterior peripheries of the cannulas of the assemblies 72 and 74, which assemblies are so shaped for the purpose of co-operating with a pair o~ slits 84 and 86 formed in thebody 76 in operative association with the passages 78 and 80 respectively.
As shown, each slit 84 and 86 extends from a position exterior of the body 76 to a position of com-munication with the innex end of the associated passage ~ 4~837 78 or 80. The width of each slit is generally equal to the distance between the end points of the associated passaye and is ori nted in its closed condition, as best shown in Figure 4, in longitudinal alignment with a plane passing between th~ end points of the associated passage.
In the closed condition shownl the two planar interior surfaces of the body 76 which dcfine the respective slit 84 or 86 are resiliently urged into engagement by the elastomeric characteristics of the body material. ~he engagement o the surfaces serves to exclude any spaces which could contain fluid such as blood between the two positions of extent of the slit as aforesaid.
The resiliency of the elastomeric material of the body 76 also permits each slit 84 and 86 to be moved by its lS respective cannula-trocar asscmbly 72 and 74 into an open condition where the planar body surfaces definin~ the slit are spread arcuately so that the profile thereof coincides with the peripheral configuration of the associated passage 78 or 80.
To aid the entry and insertion of each cannula-trocar assembly through its associated slit, there is molded in embedded relation within the body 76 a pair of metallic guide structures 88 and 90. Each ~uide structure is pre~
ferably made of a medically acceptable interior use metal, such as stainless steel (e.g~ Vitallium Metal manufactured by Howmedica~. The guide structures include similar ~ t7 inwardly tapering annular parts 92 and 94 respectively fixed to the exterior end face of the body 76 and similar parallel spring finger parts 96 and 98 respectivel~ em-bedded in the exterior of the body on opposite sides of S associated slit. The tapered part~ 92 and 94 provide the guide assist function previously noted while the spring finger parts 96 an~ 98 provide a spring assist function for the slits of the elastomeric body serving ~o resiliently urge the slit defining sur~aces toward one another i~
addition to the spring function provided by the elasto-meric characteristics of the material of the body 76.
The implant device 70 also includes a pair o~
tubes 100 and 102 made of vascular prosthesis material.
A preferred vascular prosthesis material is woven Dacron~
marketed commercially by Meadox Medicals although any other acceptable vascular prosthesis material may be utilized. As best shown in Figure 1, the tube 100 has one end thereof fixed in communicating relation with the outer end portion of the arterial passage 78, as by being molded in embedded relation. The opposite end of the tube 100 is adapted to be connected, as by suture, to a surgical openiny formed in the side wall of a femoral artery so that the interior o~ the tube 100 is in com-municating relation with the interior of the femoral artery. In a like manner, one end oE the tube 102 is Z3~
embedded in communicating relation wi~h the outer end por-tion of the venous passage ~0 and its opposite end is adapted to be sutured to a surgical side wall opening in the associated femoral vein so that its interior is in com-munica~ing relation with the interior of the femoral vein.
The implant device 70 also includes a layer offabric 104 which is fixed to the inner side wall of the elastomeric body as by Silastic~ glue or the like. The fabric 104 includes marginal portions extending laterally outwardly from the operative inner side wall of the body 76 to which it is fixed. The fabric layer 104 and particularly the marginal portions thereof provide for initial fixation by suture of the body 76 during implant and for subsequent semi-permanent ~ixation by tissue ingrowth. A preferred fabric material is Dacron~ double velour which is marketed commercially by Meadox ~edicals.
For identification purposes directly from the implant device itself, radiopaque identification (not shown) is provided on the operative outer side wall of the elastomeric body 76. Such identification insules that the proper cooperating cannula-trocar assemblies 72 and 74 will always be used since such assemblies can be ascer-tained from the implant itself after total implantation has been effected through X-ray identification.
~5 ReferrincJ now more particularly to Figures 8-11 3~
of the drawings, the details of con~truction of the car~nula-trocar assemblies 72 and 74 are sho~n therein. It will be unders~ood that since the assemblies 72 and 74 are left and right hand mirror images of one another, a description of one of the assemblies will suffice to give an understanding of both. The assembly 74 is shown in assembled condition in ~igure 8 and includes a percutaneous cannula, generally indicated at 106 and a cooperating trocar, generally indi-cated at 108.
1~ The cannula 106 includes a tubular body which includes a straight section 110 defining the subcutaneous end portion of the cannula and an angular section 112 which, together with an adjacent part of the straight section 110, defines the extracorporeal end portion of the cannula. The cannula 106 is preferably molded o~ radiopaque plastic material having sufficient rigidity to preven~
interior collapse when in operative pOsition within the implant device 70. Thermoset plastics are preferred al-though thermoplastic materials with sufficient functional rigidity and heat stability for sterilization can be used.
An exemplary material is ethylehe-propylene-terpolymer te.g.
where the third monomer is norbornadiene) impregnated with a radiopa~ue material such as barium sulfate.
As shown, the entire straight section 110 of the cannula 106 has its exterior periphery for~ed with a cross-sectional configuration which conforms with and engages - 2~ -33~
within the interior periphery of the body 76 defining the artery passaye 78 or venous passage 80. Such configuxa-tion, however, is required only in the extent o~ the sub-cutaneous end portion which is disposed within the passage and associated slit of the implant body during operation.
The cannula 106 includes an interior passage 114 which extends through the angular sec~ion 112 into the straight section 110 and out of the extremity thereof.
In order to maximize the interior passage cross-sectional area for an optimum exterior cross-sectional size, the cross-sectional configuration of the interior passage 114 at least in the straight section 110, conforms to the exterior cross-sectional configuration.
In this regard it will be noted that the trocar 108 consists essentially of a molded body o~ plastic ma-terial, similar to the plastic material of the cannula 106, which provides a blade part 116 and a handle part 118. The blade part 116 is of a longitudinal extent generally equal to the longitudinal extent of the straight 2~ section 110 of the cannula 106. T~.e main extent of the blade part 116 has an exterio~ peripheral cross-sectional configuration conforming wi~h the interior cross-sectional con~iguration of the portion of the interior passage 119 extending through the straight cannula sec-~5 tion 110. The blade part 11~ includes a sharpened tip - 29 ~
3~
portion 120 whic~ tapers gradually in cross-sectional con-figuration outwardly from the aforesaid configura~ion to a pointO
It will be noted that the extracorporeal end of the straight section 110 of the cannula 106 is closed as by a diaphragm or plug of elastomeric material 122 which pref-erably is preslit (although may be imperforate) to permit .the passage of the trocar 108, pointed end 120 first, therethrough.
The exterior periphery of the outer end of the angular section 112 is provided with gripping flanges.124 operakle to efect a fluid-tight connection with the in-terior of the tubi~g 12. When the trocar lOB is withdrawn, the elas~omeric plug slit, which has expanded to receive the trocar, contracts to close the end of the straight section of the cannula and insure that all of the blood will flow outwardly through the angular section 112 and into the tubing 12.
Formed on the exterior periphery of the straight 2~ section 110 of the cannula is an annular shoulder 126 which forms a stop sur~ace facing in a direction ~oward the open extremity of the straight cannula section operable to engage the guide part 92 or 94 of the implant device when the cannula is in its fully inserted operative position, as shown in Figure 7. The straigh~ cannula section 110 is 483~
~ormed with an opening 128 which extends inwardly from one exterior end point into communication with the interior passage 114 at a posi~ion to register with the by-pass conduit 82 of the implan~ body 76 when the cannula is fully inserted, as aforesaid. Formed on the e~terior pexiphery of the extracorporeal portion of the straight cannula section 110 is a stabilizing shield 130 which facilitates main-tenance of the cannula on the patient when in operative position.
A preferred procedure is to coat all of the blood contacting surfaces o~ the cannulas 106 ~i.e. interior passages 114) tubiny 12 and elastomeric body 76 (passages 78 and 80, conduit 82 and slits 84 and 86) with an anti~
coagulant coating. A suitable coating material for this purpose is marketed commercially under the tradename TDMAC~.
The manner in which the device 70 is surgically implanted is in accordance with usual implant procedures well ~nown to those s~illed in the art. ~or present pur-poses suffice it to say that the elastomeric body 76 isimplanted in an arterior femoral region spaced downwardly fxom ~he position o~ bending at the hip approximately the distance o~ the width of a normal-sized palm ~ap-proximately 4") as is clearly shown in ~igure 1. The large area faces of the body 76 are preerably disposed parallel with the skin with the face having the fabric ~ ~ 4~ 3~
104 ~ixed thereto in~ermost. The arterial and venous tubes 100 and 102 extend upwardly and the free ends are tapered and sutured to surgical openings i~ the side walls o~ the ~emoral artery and vein respecti~ely so as S to extend there~rom at an angle of approximately 45.
This procedure is accomplished in accordance with usual practices relating to the use of vascular prosthesis material.
The marginal edge portions of the fabric 104 are 5utured to tlle adjacent tissue to provide initial body 76 fixation, as aforesaid. ~11 of the exterior surfaces of the implant device 76 are contacted with tissue includ-ing tapered guide parts 92 and 94 (~ith fat).
AQ previously indicated, it is possible to use known shunt devices (e.g. U.S. pa~ent No. 3,713,441) in lieu of the device 70 so long as they provide the neces-sary capacity which is ordinarily not the case without modi~ication.
The advantages of the use of the implant device 2J 70 is that it is specifically intended for long-term surgical implantation in the thig}l of cancer patients t whereby its anastomosis to the femoral artery and vein, creates a high~low (1-2 liters per minute) arterio-venous conduit which may be repeatedly entered by per-cutaneous insertion of the cannula assemblies 72 and7~. , .~ .
4~3~7 As compared with other prosthetic partially exteriorized A-V Shunt devices as ~sed for renal hemo-dialysis the implant device 70 red~lces ~he risk of in-fection, reduces the risk of throm~osis, reduces the ris~ of disruption and improves the esthetics of normal usage. The renal dialysis experience indicates that partially exteriorized lower extremity shunts frequently develop infection along the tract of the shunt tubing.
The incidence and severity of this type of infection would be increased in cancer patients by the immunosup-pressive effects of malignancy, and the che~otherapy and radiotherapy they frequently receive. The implantable device '0 greatly diminishes the risk of infection and requires no increase in the amount of surgery needed ~or insertion. Cancer patients have a state of hypercoagul-ability or increased tendency to form blood clots in their normal and any arti~icial circulations. Ordinary A-V
shunts last only 2-6 months in hypocoagulable dialysis patients, and likely will clot much sooner in those with the "Stic~y blood" of disseminated malignancy The im-plantable device 70 has a shorter fluid path, much o~
which will be covered by a patient's own intravascular tissues, and hence will be less likely to thrombose.
Partially exteriorized shunts have press connections which ~,.ay be inadvertently loosened or disconnected.
Such events have caused deaths in dialysis patients but, in general, those shunts are small and a patient can contro.l.
a bleeding shunt before exsanguination occurs. However, disruption of the large shunt necessary for hyperthermia would result in massive bleeding, which could render a patient unconscious even before the shunt could be reached through normal clothing. This cannot happen with the de-vice 70 as the connections are permanent, as well as totally prvtected.
Unlike commercially known shunts, there is no external tubing associated with the device 70. A nor~al bath or shower could be taken by the implanted patient, whereas those with partially exteriori~ed shunts cannot submerge them and must resort to ~ess hyyienic methods, lS a probable factor in their increased incidence of in-fections. Furthermore, the device 70 does ~ot interfere with clothing or require any sort of dressing, leaving a patient's appearance unimpaired, an important asset to the depressed cancer patient.
The manner in which each cannula assembly 72 or 74 i5 inserted into cooperating relation to the im-planted device 70 should be apparent from the above. It is of significance to note the advantages of the utili-~ation of a main implant body 76 which provides increase~
palpation facility during cannulation. Moreover, cannu-lation is effected in a straight line relationship f ,.~
.
resulting in a straight line percutaneous communication with the extracorporeal flow path. The preferred cross~
sectional con~iguration of the cannula enables simple but effective alignment to be accomplished during insertion.
Such cross-sectional configuration ~lso provides optimal cooperation with the slits 84 and 86 of the elastomeric body 76 both in expandinc3 the slits during insertion and in contracting the peripheral portion of the cannula extending therethrough to insure a gsod fl-lid-tight con-nection. The extension of this cannular cross-sectional configuration with the elastomeric body passages 78 and 80 also insures non-distortion of these passages and a full flow area o~ 4 mm or larger.
The flow capacity provided is of extreme im-portance since it is a critical determining factor in the time re~uired to bring the patient's blood up to the desired treatment temperature and to the sensitivity of the temperature control available. The approximate 1 liter minute capacity provided is based upon the aver-2 age size of an average adult patient and, of course, shou~d be varied to suit the particular size of the patient being treated. The term approximately 1 liter per minute is there~ore intended ~o comprehend within i~s meaning such variation to suit the patient size.
It will be understood that once the inlet and 3'7 outlet ends of the tubing 12 are con~ected over the ~langes 124 of the .~annula of the assemblies 72 and 74 and the associated trocars 108 of the assemblies are withdrawn, pump 14 can be started to commence the flow of blood along the extracorporeal flow path at the approximate 1 liter per minute as aforesaid and through the tem2erature control zone thereof. In~tially, control 60 is set to pass 100~ 45C water through the heat exchanger 16. During this initial trea~ment phase withdrawn blood temperatures measured a~ 62' will show a gradual increase from the initial normal reading of approximately 37C. The cap-acity and effectiveness of the heat exchan~er 16 is such that readings of the re~urning blood taken at 64 closely approximate the 45C maximum water temperature utilized.
As the heated blood is returned to the femoral vein through the blood receiving percutaneous cannula 106, venous passage 80 and tube 102, it is distributed systemically which in turn, has the effect of increasing the total systemic tempera~ure. As the patient's core body tem-perature increases to~ard the 91.SC level control 60 must be operated to lower the liquid reading at 66 to a value below 45C as, for example, 42.5C. The liquid temperature level stabilized at 42.5C, the patient core body tempera-ture readings at 6~, and returning blood readings will stabilize at a desired level of approximately 41.5C and ~0.0C
respectively. This critical phase wherein the patient's 83}~
systemic temperature is increased and stabilized should, as aforesaid, normally be completed within one hour, al-though here again, variation because of patient size will occur.
O~ce temperature stabilization is achieved as aforesaid, treatment is continued for a time period ef-fective ~or the particular cancer which the patient has.
A preferred minimum time for all types including simple carcinomas is six hours although treatment times of 20 hours and longer will be re~uired for more complex ca~cer situationsO
.. Preferably, a third phase of the present method involves utilizing the continued blood flow through the temperature control zone o~ the extracorporeal flow path to reduce the blood temperature to normal and, hence, the patient's systemic temperature to normal. This phase is initiated by turning control 60 to pass predominately 3~C
; water through the heat exchanger 16. This has the effect of substantially lowering the readings of the returning blood taken at 64. ~gain, this cooler blood is distributed systemically, causing the systemic temperature to lower until a normal of 37C is reached. The decreasing tem-perature phase normally will require a time period ap-proximately the same as the initial increasing temperature phase although usually somewhat less.
83~
Preferably, the patient is maintained during treatment il a skin contacting environment approximating that of an intensive care room. While it is within the contemplation of the invention to provide a skin insulat-S ing environment and even compaxable elevated temperaturesto inhaled gases, the intensive care like environment is preferred because the temperature level o~ the skin and respiratory system does not vary significantly from the induced hyperthermia systemic level and access to the patient is much more readily obtained. Moreover, the ap-plication of radiation or chemotherapy treatments can be carried on simultaneously if desired.
I~ thus will be seen t.hat the objects of this invention have been fully and effectively accomplished.
It will be realized, however, that the foregoing preferred specific embodiment has been shown and described for the purpose of illustrating the functional and structural principles of this invention and is subject to ch~nge without departure from such principles. Therefore, this inYention includes all modifications encompassed within the spirit and scope of the following claims.
-.38 -
Claims (8)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An assembly for use in establishing percutaneous communica-tion with a flow passage of a totally subcutaneous implant com-prising an elongated percutaneous cannula having a subcutaneous end portion and an extracorporeal end portion, said subcutaneous end portion having an exterior peripheral cross-sectional con-figuration elongated in one direction with sharp points defining opposite ends thereof in the direction of elongation, said can-nula having an interior passage extending from the extracorporeal end portion thereof to the extremity of said subcutaneous end portion and an elongated trocar including a pointed end, said trocar having an exterior periphery extending from said pointed end of a shape to enable said trocar (1) to be inserted pointed end first through said interior passage of said cannula in a direction and to an extent sufficient to position the pointed end thereof outwardly of the extremity of said subcutaneous end portion thereof and (2) to be withdrawn from said interior passage in the opposite direction.
2. An assembly as defined in claim 1 wherein said cross-sectional configuration is further characterized by two convexly arcuate lines extending between said end points.
3. An assembly as defined in claim 2 wherein the central dis-tance between said convexly arcuate lines measured in a direction perpendicular to the direction of elongation is approximately one-half the distance between said points.
4. An assembly as defined in claim 1 wherein the interior peri-phery of said cannula defining said interior passage has a cross-sectional configuration similar to said exterior cross-sectional configuration, the exterior peripheral cross-sectional configura-tion of said trocar closely approximating said interior con-figuration.
5. An assembly as defined in claim 1 wherein the subcutaneous end portion of said cannula has an opening therein spaced from said extremity extending from the exterior periphery thereof through one end point thereof into communication with said interior passage.
6. An assembly as defined in claim 5 wherein the subcutaneous end portion of said cannula is formed with a stop surface on the exterior periphery facing toward said extremity and spaced therefrom a distance greater than the spacing of said opening.
7. An assembly as defined in claim l wherein the extracorporeal end portion of said cannula has a stabilizing shield portion formed on the exterior periphery thereof.
8. An assembly as defined in claim 1 wherein said interior passage includes a straight portion and an angularly related outlet portion, the extracorporeal end portion of said cannula including means disposed in longitudinal alignment with the straight portion of said interior passage for (1) enabling the insertion of said trocar pointed end first therethrough and into said interior passage (2) enabling the trocar to be removed thereform and (3) for preventing fluid flow therethrough after said trocar has been removed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000399706A CA1144837A (en) | 1977-05-31 | 1982-03-29 | Method and apparatus for effecting hyperthermic treatment |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/802,033 US4181132A (en) | 1977-05-31 | 1977-05-31 | Method and apparatus for effecting hyperthermic treatment |
| US802,033 | 1977-05-31 | ||
| CA303,444A CA1127033A (en) | 1977-05-31 | 1978-05-16 | Method and apparatus for effecting hyperthermic treatment |
| AU53195/79A AU518660B2 (en) | 1977-05-31 | 1979-11-26 | An elongate percutaneous cannula |
| CA000399706A CA1144837A (en) | 1977-05-31 | 1982-03-29 | Method and apparatus for effecting hyperthermic treatment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1144837A true CA1144837A (en) | 1983-04-19 |
Family
ID=27423444
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000399706A Expired CA1144837A (en) | 1977-05-31 | 1982-03-29 | Method and apparatus for effecting hyperthermic treatment |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1144837A (en) |
-
1982
- 1982-03-29 CA CA000399706A patent/CA1144837A/en not_active Expired
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