CA2136286C - Portable infusion device - Google Patents
Portable infusion deviceInfo
- Publication number
- CA2136286C CA2136286C CA 2136286 CA2136286A CA2136286C CA 2136286 C CA2136286 C CA 2136286C CA 2136286 CA2136286 CA 2136286 CA 2136286 A CA2136286 A CA 2136286A CA 2136286 C CA2136286 C CA 2136286C
- Authority
- CA
- Canada
- Prior art keywords
- fluid pressure
- response
- base member
- bladder
- bag
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000001802 infusion Methods 0.000 title claims abstract description 25
- 239000012530 fluid Substances 0.000 claims abstract description 71
- 239000003814 drug Substances 0.000 claims abstract description 69
- 229940079593 drug Drugs 0.000 claims abstract description 64
- 238000004891 communication Methods 0.000 claims abstract description 7
- 230000007423 decrease Effects 0.000 claims description 20
- 239000002184 metal Substances 0.000 claims description 9
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 claims description 4
- 229920002554 vinyl polymer Polymers 0.000 claims description 4
- 238000005086 pumping Methods 0.000 abstract 2
- 238000005259 measurement Methods 0.000 description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- 230000005484 gravity Effects 0.000 description 4
- ODPOAESBSUKMHD-UHFFFAOYSA-L 6,7-dihydrodipyrido[1,2-b:1',2'-e]pyrazine-5,8-diium;dibromide Chemical compound [Br-].[Br-].C1=CC=[N+]2CC[N+]3=CC=CC=C3C2=C1 ODPOAESBSUKMHD-UHFFFAOYSA-L 0.000 description 3
- 239000005630 Diquat Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000010412 perfusion Effects 0.000 description 3
- 239000011521 glass Substances 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 101001110310 Lentilactobacillus kefiri NADP-dependent (R)-specific alcohol dehydrogenase Proteins 0.000 description 1
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 1
- 230000036772 blood pressure Effects 0.000 description 1
- 230000036760 body temperature Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011796 hollow space material Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
- 230000000276 sedentary effect Effects 0.000 description 1
- 239000008279 sol Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Landscapes
- Infusion, Injection, And Reservoir Apparatuses (AREA)
Abstract
An infusion device including a rigid accessible housing, a flexible air bag contained within the rigid housing in use, a space next to the flexible air bag for containing a drug bag in use, a line connected between the drug bag and patient in use, a pumping device connected to the air bag, a control unit for controlling the operation of the pump which includes a sensing mechanism in communication with the line or drug bag for sensing the fluid pressure therein without contaminating the medicament in the line to the patient and wherein the pumping device is activated when the pressure in the line or drug bag passes below a predetermined level.
Description
21362~6 ~, -91116-5 JWA:tm TITLE OF INVENTION
Portable Infuslon Devlce FIELD OF INVENTION
Thls lnventlon relates to lnfuslon devices for preclse admlnlsterlng of medlcaments to patients and flnds partlcular appllcatlon ln portable lnfuslon devlces.
BACKGROUND OF TH~ INVENTION
It ls known ln the art to whlch the present lnventlon pertalns, to provlde devlces whlch dellver a fluid medicament from a drug bag to a llne leadlng to an lnfuslng needle or catheter. Many such devlces utlllze mechanical pumplng means for dellverlng the fluld le. perlstaltic pumps, etc. As well, it ls known ln the art to provlde means for controlllng the rate at which the fluid ls dellvered.
For example, Australlan Patent Appllcatlon No. 61546/86 to Cannon et al. publlshed May 28, 1987 teaches an lnfuslon device whlch lncludes a perlstaltlc pump that ls used ln assoclatlon with a straln gauge assembly which monltors dlmenslonal changes in the outer dlameter of an I.V.
tube. The fluld flow through the lnfuslon tube ls motlvated by the pump whlch, through a serles of flngers which massage the I.V. tube, cause the fluld flow. The rate of fluld dellvery ls determlned from a readlng from the straln gauge.
From thls determlnatlon, a controller operates the pump to vary the rate of flow, lf necessary. There are dlsadvantages to the use of mechanlcal means such as perlstaltlc pumps to dellver fluids, lncludlng the costs assoclated wlth such fluld pumps whlch lnclude the costs of malntalnlng the pump.
, _ Further, the fluld to be delivered is gravity fed from a reservoir thereby lnterfering with the portabillty of the system.
Other references which lnclude dlrect displacement pumplng means include U.S. Patent No. 4,670,006 to Sinnett et al. and U.S. Patent No. 4,998,914 to Wiest et al.
U.S. Patent No. 4,670,006 teaches an lnfusion devlce whlch includes an electrlcally drlven fluld pump comblned with a pressure regulator and pressure detectlng means, as well as a motor control unit for the pump. The devlce monltors the fluld dellvery pressure and actlvates the fluld pump when the pressure falls below a predetermined level. As already stated above, the use of a pump assembly for pumplng a fluld dlrectly provldes certaln dlsadvantages ln both costs and malntenance.
Further, the configuratlon of detectlon and control means is not practical for use in a portable infusion unit.
U.S. Patent No. 4,998,914 descrlbes a perfuslon system whlch uses a perfuslon pump connected wlth a perfuslon llne having a pressure sensor for determinlng the flow rate of fluld to be dellvered. Thls device also provides for gravity feeding of the perfusion fluid to the pump. The perfusion system monitors the pressure within the body cavlty being perfused. This is useful ln such a perfusion system, but not necessary for use ln an infusion system. Again, the cost and maintenance of the fluid pump poses certain dlsadvantages, as does the gravity feed of the pump.
213628~
_ - 3 PCT appllcation W0 g0/07942 to Woicickl et al.
purports to teach a fluid dellvery system which includes a volumetrlc pump and a method of contlnuously monltorlng the operatlon of the dellvery system for controlllng the pump.
The control method of thls reference ls characterlsed by the measurement of actual pressure of dellvery of a fluid with every cycle of the volumetric pump. Such measurement requires certain electronic sensing and calculation means whlch add to the cost and complexity of the infusion system. Again, as stated above, volumetric pumps have disadvantages relating to both cost and malntenance.
European patent appllcatlon 277,518 to Heitmeier et al. discloses a pressure infuslon device, agaln in whlch an lnfuslon pump is used to control the rate of flow of the lnfused llquld. The lnfuslon pump ls operated by a control clrcult which measures the rate of flow of infused liquid between two sensors which are separated along the infusion tube. The volume of flow is calculated and the controller ad~usts the speed of the pump, lf necessary. Gravlty feed ls used to supply the pump thereby reduclng the portablllty of the system. Agaln, the use of an lnfuslon pump will add to the cost and malntenance dlsadvantages of the system, as wlll the electronics requlred to control the infuslon pump on the basis of measurements made between the two sensors. The gravity feed will limit the portabillty of the system.
It is also known in the art to which the present inventlon pertalns, to provlde lnfuslon devlces whlch transfer 21~6~6 a fluid medicament from a drug bag or reservolr using means to pressurize the drug bag or reservoir. The pressurizing means ls useful ln comblnatlon wlth a flow regulator whlch ls part of the dellvery line.
U.S. Patent No. 4,267,834 to Barger et al. dlscloses a devlce for flushlng a medlcal fluld through an lnfuslon llne used for monltorlng blood pressure fluctuatlons. The rate at which the fluid is lnfused to the patlent ls controlled in part through a compresslon sleeve connected to a pressure gauge and ad~ustable uslng a squeeze bulb. Although slmple to operate, the flowrate of fluld through the lnfuslon tube ls not preclsely controlled as the pressure to the drug bag must be monltored and ad~usted manually. Such an lnfusion system would not be practical for the infuslng of a drug at a constant flow rate.
U.S. Patent No. 5,059,182 to the present lnventor, describes a portable lnfusion device whlch lncludes an lnflatable bag carried in a container wlthin whlch a drug bag fllled wlth a fluld to be lnfused ls placed. The pressure imparted by the inflatable bag to the drug bag motlvates the fluld therein to flow through a tube to the patient to whlch the fluld ls belng delivered. Flow rate control ls achleved through the use of a flow regulator in combination wlth the monitoring the pressure imparted by the inflatable bag on the drug bag. Again, the flow rate control of infused fluid is not easily maintalned as constant monltoring and manual ad~ustment of the pressure of the lnflatable bag ls necessary.
' ..._ U.S. Patent No. 4,505,264 to Parmelee et al.
descrlbes a portable lnfuslon devlce ln whlch a drug bag contalnlng a fluld to be lnfused ls placed wlthin a rlgld contalner havlng a sprlng blased plate to lmpart a pressure on the drug bag to motlvate the fluld to flow lnto the connectlng tube. The flow rate ls controlled by regulators connected ln serles wlth the tube. The use of the sprlng blased plate results in a varlable pressure lmparted to the drug bag as the drug bag dralns (le. over the range of movement of the sprlng blased plate). As a result, hlgher flow rates wlll be experlenced lnltlally, compared to lower flow rates whlch wlll be experlenced when the drug bag nears depletlon. This varlable flow rate ls unacceptable ln a fluld lnfuslng devlce.
U.S. Patent No. 4,557,726 to Relnlcke descrlbes a medlcatlon dlspenslng system ln whlch a medlcatlon to be lnfused fllls a reservolr over whlch a constant pressure ls malntalned through the use of a fluld whlch has two-phases (gas and llquld) body temperature. The flow through the lnfuslon tube ls controlled by means of a regulator. The pressure of the fluld lnfusate ls not utlllzed or ad~usted to malntaln a constant flow rate of lnfusate to the patlent.
Slmllarly, Canadian Patent No. 1,152,823 to Dorman and Canadlan Patent No. 2,021,284 to Sampson both also utlllze regulator devices ln serles wlth an lnfusate llne malntalned at a constant pressure for controlllng the flow lnfusate to the patlent. Nelther reference dlscloses a manner of '_ 2136286 measurlng and thereby controlllng the pressure of lnfusate to regulate the flow to the patlent.
U.S. Patent No. 4,077,405 to Haerten et al.
dlscloses an apparatus for infusing llqulds whereln a supply reservolr of the lnfusate llquld is maintained at a pressure in excess of the pressure prevalllng at the point of llquld dlscharge to the patlent. Preselectable constant volumes of llquld are dlscharged at perlodlc lntervals ln accordance wlth a treatment program. Agaln the control of the flow rate of lnfusate ls not controlled by measurlng the pressure of the lnfusate.
U.S. Patent No. 4,443r218 to DeCant, Jr. et al.
dlscloses a lnfuslon apparatus ln whlch the flow of lnfusate ls controlled by the measurement of a dlfferentlal pressure across a flow path through whlch a hlgher vlscoslty fluld ls forced to flow as a result of the flow of the lnfusate. By respondlng to a measurement of the pressure drop across a flow restrlctlon, an electrlc motor may be used transmlt mechanlcal pressure to the lnfusate chamber to ad~ust the lnfusate flow rate. Agaln, the control of the flow of lnfusate ls not related to a dlrect measurement of the pressure of the lnfusate.
PCT appllcatlon WO 87/05225 to Kamen dlscloses a fluld dlspenslng system ln whlch a lnfusate ls transferred lnto a dlspenslng means contalned ln an lsolated reglon, the amount of lnfusate transferred lnto the dlspensing means determlned by measurlng the amount of a gas dlsplaced from the _ lsolated reglon surrounding the dlspenslng means. The lnfusate ls then transferred from the dlspenslng means and another measurement of the gas reenterlng the lsolated reglon ls made. By comparlng the amounts of dlsplaced and replaced gas, lt ls posslble to determlne the amount of lnfusate which has been dlspensed. Agaln, no measurement of the lnfusate pressure ls made to determlne the flow rate of lnfusate.
Nowhere ln the prlor art references ls there an lnfuslon device whlch overcomes many of the dlsadvantages of the prlor art and thereby provldes an lnfusion devlce whlch ls preferably portable and lncludes an lnfusate pressure monltorlng control loop ad~ustlng lnfusate flow.
As well, the prlor art does not dlsclose a means for respondlng to changes ln lnfusate pressure to control the deslred lnfusate flow rate, whlch ls both lnexpenslve and ln whlch the lnfusate ls not contamlnated.
It ls therefore a prlmary ob~ect of the present lnventlon to provlde an lnfuslon devlce whlch ls portable and allows the admlnlstratlon of fluld medlcaments to patlents wlthout the patlent needlng to be restrlcted to a hospltal or cllnlc.
It ls a further ob~ect of the present lnventlon to provlde an lnfuslon devlce whlch ls safe and rellable to use.
It ls yet a further ob~ect of the present lnventlon to provlde an lnfuslon devlce whlch monltors or responds to the lnfusate pressure and lncludes means to malntaln the lnfusate pressure at a deslred level.
21362~6 It ls another ob~ect of the present lnventlon to provlde an lnfuslon devlce whlch ls lnexpenslve.
Further and other ob~ects of thls lnventlon wlll become apparent to those skilled ln the art when consldering the followlng summary of lnventlon and the more detalled descrlptlon of the preferred embodlments lllustrated hereln.
SUMMARY OF THF INVRNTION
Accordlng to an aspect of the present lnventlon there ls provlded an lnfuslon devlce for flulds comprlslng a rlgld frame or houslng, the frame or houslng havlng dlsposed therewlth when assembled a space whereln ls dlsposed ln use a flexlble bag prevlously evacuated of alr and fllled wlth a fluld, the flexlble bag havlng an outlet and havlng a flrst tube havlng two ends connected thereto ln use for carrylng the fluld from the flexlble bag proxlmate one end of the flrst tube to the dlstal end of the flrst tube proxlmate the patlent ln use; the houslng contalnlng ln use means to press the fluld bag and cause flow of fluld through the flrst llne to the patlent; the lnfuslon devlce havlng means to change (such as lncrease/decrease) the ablllty of the means to press the fluld bag, to press the fluld bag, the lnfuslon devlce havlng senslng means to sense the pressure of the fluld ln the flrst llne; the lnfuslon devlce havlng control means havlng set polnts therewlth ln use for deslred fluld pressure ln the flrst llne and ln communlcatlon wlth the means to press the fluld bag and to recelve sensed fluld pressure from the senslng means and to respond to hlgh/low pressures sensed by ~ 2136286 g actlvatlng the means to lncrease/decrease the ablllty of the means to press the fluld bag to press the fluld bag, a second llne havlng two ends and connected wlth the flrst llne proxlmate one end of the second llne lntermedlate the ends of the flrst llne, and havlng dlsposed proxlmate the other end of the second llne lsolatlon means to present a pressure ln the fluld to the senslng means wlthout the senslng means contamlnatlng the fluld belng dellvered to the patlent ln use, whereln in use as the fluld bag ls pressed fluld passes to the patlent through the flrst llne depletlng the volume of fluld ln the fluld bag, whlch fluld communlcates a pressure ln the second llne to the lsolated senslng means wlthout contamlnatlng the fluld belng dellvered to the patlent, the control means respondlng to changes ln the fluld pressure by actlvatlng/deactlvatlng the means to change (such as lncrease/decrease~ the ablllty of the means to press the fluld bag to press the fluld bag.
Preferably, the lnfuslon devlce ls contalned wlthln a shoulder bag or the llke to lncrease the moblllty of the patlent. The means to press the fluld bag or the alr bag, and the fluld bag may be separated wlthln the frame or houslng of the lnfuslon devlce by a hlnged moveable plate whlch asslsts ln ensurlng equal pressure ls belng exerted over the length of the fluld bag.
A flow restrlctor may be placed before the needle of the second llne for preclse admlnlstratlon of the drug.
21~6~86 ~ ,~
The lsolatlon member may lnclude a sock or dlaphragm made from extremely thln flexlble lmpermeable materlal contalned ln a chamber attached at one end to the thlrd llne and to the senslng means at the other end thereof, the chamber S presentlng a llquld fllled sectlon withln the sock or on one slde of the dlaphragm and an alr fllled space on the other slde of the sock or dlaphragm, whereln the flexlble sock or diaphragm is contalned ln the chamber so that in use the fluld acts to produce a pressure readlng to the senslng means vla the alr space on the alr slde of the sock or dlaphragm.
Accordlng to another aspect of the present lnventlon there ls provlded a portable lnfuslon devlce comprlslng: (a) a rlgld houslng, the houslng havlng an lnterlor space; (b) a flexlble bag contalned withln the lnterlor space, the flexlble bag fllled wlth a fluld to be dellvered, the flexlble bag havlng an outlet; (c) a tube havlng a flrst end attached to the flexlble bag outlet ln flow communlcatlon wlth the fluld to be dellvered, the tube havlng a second end to whlch the fluld ls dellvered ln use; (d) an lnflatable bag contalned wlthln the lnterlor space, the lnflatable bag inflatable to press the flexlble bag thus creatlng a fluld pressure wlthln the flexlble bag causlng a tendency for the fluld to flow from the flexlble bag through the tube for dellvery to the second end of the tube; (e) means for lnflatlng the lnflatable bag ln response to a slgnal; (f) control means whlch responds to the fluld pressure wlthln the flexlble bag for generatlng the slgnal when the fluld pressure ln the flexlble bag ls less 2136~8B
. .
W_ than a desired fluld pressure, sald control means comprlslng:
(i) a substantlally lnflexlble base member; (11) a reslllent sprlng plate havlng a flrst end and a second end, sald plate attached to sald base member at sald flrst end, sald second end free to flex toward and away from sald base member, said second end blased toward sald base member; (111) a bladder ln flow communlcatlon wlth sald flexlble bag whereln sald bladder lnflates ln response to an lncrease ln sald fluld pressure and deflates ln response to a decrease ln sald fluld pressure, sald bladder compressed by sald plate between sald second end of sald plate and sald base member such that sald second end of sald plate flexes away from sald base member ln response to an lnflatlon of sald bladder and flexes toward sald base member ln response to a deflation of said bladder; and (lv) means to generate sald slgnal when sald plate flexes toward sald base member ln response to a deflatlon of sald bladder ln response to a decrease ln sald fluld pressure to less than sald deslred fluld pressure.
Preferably, (a) the reslllent sprlng plate comprlses a thln metal plate; (b) the lnflatlng means comprises an electrlc alr pump and an alr pump power supply, the alr pump lnflatlng the lnflatable bag ln repone to an electrlcal current from the alr pump power supply; and (c) the slgnal generatlng means comprlses a normally open swltch clrcult electrlcally connected ln serles between the electrlc alr pump and the alr pump power supply, the swltch clrcult closed by the second end of the metal plate when flexed toward the base 213628~
member ln response to a deflatlon of the bladder in response to a decrease ln the fluld pressure to less than the desired fluid pressure.
Accordlng to yet another aspect of the present lnventlon, there ls provlded for ln a portable lnfuslon devlce, means for controlllng dellvery of a fluld from a flexlble bag, sald dellvery caused by fluld pressure ln sald flexlble bag, said device having means for lncreaslng sald fluld pressure ln response to a slgnal generated when sald fluld pressure ls less than a deslred fluld pressure, sald control means comprlslng: (a) a substantlally lnflexlble base member; (b) a reslllent sprlng plate havlng a flrst end and a second end, sald plate attached to sald base member at sald flrst end, sald second end free to flex toward and away from sald base member, sald second end blased toward sald base member; (c) a bladder ln flow communlcatlon wlth sald flexlble bag whereln sald bladder lnflates ln response to an lncrease ln sald fluld pressure and deflates ln response to a decrease ln sald fluld pressure, sald bladder compressed by sald plate between sald second end of said plate and said base member such that sald second end of sald plate flexes away from sald base member in response to an inflation of sald bladder and flexes toward sald base member ln response to a deflatlon of sald bladder; and (d) means to generate sald slgnal when sald plate flexes toward sald base member ln response to a deflatlon of said bladder ln response to a decrease ln sald fluld pressure to less than sald deslred fluld pressure.
- 12a -According to a further aspect of the present invention, there is provided a portable drug infusion device comprising: (a) a flexible bag, said bag filled with a fluid to be delivered; said flexible bag having an outlet;
(b) fluid pressure increasing means, whereby fluid pressure is increased in response to a signal generated when said fluid pressure i8 less than a desired fluid pressure; c) control means for controlling delivery of said fluid, said - control means comprising (i) a substantially inflexible base member; (ii) a resilient spring plate having a first end and a second end, said plate attached to said base member at said first end, said second end free to flex toward and away from said base m~ber, said second end biased toward said base member; (d) a bladder in flow communication with said flexible bag; said bladder connected to inflating means;
wherein said bladder inflates in response to an increase in said fluid pressure and deflates in response to a decrease in said fluid pressure, said bladder compressed by said plate between said second end of said plate and said base member that said second end of said plate flexes away from said base member in response to an inflation of said bladder and flexes toward said base m~er in response to a deflation of said bladder; and (e) means to generate said signal when said plate flexes toward said base member in response to a deflation of said bladder in response to a decrease in said fluid pressure to less than said desired fluid pressure.
' ,~
7 ~
~RIEF D~ ON OF T~ DRAWINGS
The lnventlon wlll now be ~llustrated wlth respect to the followlng drawlngs lllustratlng embodlments of the lnventlon ln whlch:
Flgure 1 ls a slde perspectlve schematlc vlew of an lnfuslon devlce lllustrated ln a preferred embodlment of the lnventlon.
Flgure 2 ls a top plan schematlc vlew of the lnfuslon devlce of Flgure 1 lllustrated ln a preferred embodiment of the lnventlon.
Figure 3 i8 a schematic view of an infusion device illu~trated in a preferred embodiment of the invention.
Flgure 4 ls a partlally cutaway perspectlve vlew of the mechanlsm descrlbed ln relatlon to Flgure 3 lllustrated ln a preferred embodlment of the lnventlon.
Flgure 5 ls a general perspectlve vlew of the use of the lnfuslon devlce of Flgure 4 and lllustrated ln a preferred embodlment of the lnventlon.
Flgure 6 ls a clrcult dlagram for the operatlon of a control unlt of the lnfuslon devlce and lllustrated ln a preferred embodlment of the lnventlon. _ _ ~ v Figure 7 is a schematic view of an infusion d~vice illu~trated in a preferred embodiment of the invention.
Flgure 8 ls a slde elevatlonal vlew of the control -unlt of the embodlment l.llustrated ln Flgure 7 d~ vlewed along the llnes 8-8.
DETAILED DESCRIE~ON OF ~ KRED EMBODIMENTS OF THE
INVENTTON - _ Referring now to the flgures there is illustrated an lnfusion device 10 used for ~rlm1n1ctering drugs to a p~t1e~t- Typically the drug ls 10 provided in a pre-p~ck~ged flp~ihle cont~ er 40 which co~lt~ s up to 500 cm2 of mp~llr~mprlt to :be ~m1ntctered to the p~ti~pnt One of the advantages of thls inYention is that it uses st~n~ d s~zed "drug bags"
without the need for haYing to provide special casettes or the like which is found in t_e prior art. In using a standard drug bag in con~l~nctlon with 5 the present lnvent10n the App~ nt ls no longer required to remain sedentary at a hospital or a clinic wh11e the contPnt of the drug bag ls ~mm1ctered to the p:ltlPnt The i~f~sion device can therefore be provided ~n a comr~rt rlgid housing 20. whlch offers reslstance to the lnfl~t10rl of an alr bag 20 30 made from flPY~hle materials. Dlsposed below the air bag 30 is a space 29 which is filled subst~nt1~lty In use by the drug bag 40 which is made from fl~hhp mates~al and cont~1n~ up to 500 cm2 of the me~1r~m~nt being ~rlmi~i~tered to the p ~t~Prlt The ai~ bag 30 ls clamped to a llne 35 made of mP~r~l grade vinyl and clamped at 34 to a flttlng 30(a~ provided ..~
wlth the air bag 30. The llne 35 is connected wlth a diaphragm air pump proximate the other end thereof vla a clamp 36.
The drug bag 40 ls connected at a tapered end thereof 41 by conventlonal methods such as a clamp to a section of tubing 45 made of medical grade vlnyl whlch extends to the needle 49 and the patlent as best seen ln flgure 5. Located ad~acent the needle 49 ls a preclslon glass restrlctor 48 used to preclsely control the amount of drug admlnistered to the patient. A detalled descrlptlon of these preclslon restrictors is found ln my U.S. Patent 5,059,1B2 and speclflcally ln relatlon to the detailed descriptlon thereof at for example column 7 line 54 onward.
In order for the lnfusion device 10 to be of use to a patient lt ls preferred that the housing 20 be separable. No detalls as to the separatlon of the houslng is provlded as lt ls assumed that those skllled ln the art would appreclate the manner ln whlch a houslng may be separable lnto two halfs by a hlnge, by telescoplc relatlonshlp of one half being slightly larger than the other half and lnter-flttlng wlth that other half, or one portlon belng slldable in relation to the other portion. The important aspect ls that the housing be rlgld and lnclude a hollow space 29 so that a drug bag 40 may be placed in the posltion as shown and affixed to the tubing 45 at clamp 48A. Therefore if more than one type of fluid were being admlnlstered to a patlent sequentlally, for example a saline solution followed by a medlcament then the same apparatus may be used and may be easlly set up by the nurse or other medlcal attendant. The clamps 34 and 48A are known to those skllled ln the art and therefore no further descrlptlon ls necessary.
A second llne 46 ln communlcation wlth the first llne 45 at ~uncture 46a ls provided to allow for a dlrect pressure readlng to be taken from the llne 45 as the medlcament ls dellvered to the patient. At -- 16 -- ~ -the end 46b of line 46 there ls found an imperme~hle mpmhrane sock 65 contained within an isolation deYice 60 including a hollow glass rece~tacle 61 ha~ing two ends 61a and 61b. The sock 65 is the~efo~c ~m~.l at the end 61a at end of 65a of the sock ufith the end of 61a of the 5 giass r~Ce~LaCle. These two portlons are therefore clamped to the tube end 46b via clamp 47. Dlsposed ~thin the icol~t1rr~ device 60 is also an --~ alr space 64 which is- in comml-nlc~t10n w~th the end 61b of the .cce~tscle 61. End 61b is engaged wi~h a control module 50. which inri~rieS a transducer 55, by a luer lock fltting. Descriptlon of luer lock 10 fltting>e is found for PY~mple in U.S. Patent 4.369.781 ~eSlgJ~ed to Sherwood Medical ~ndustries Incorporated and describ~ng therein medic~l luer fltt1ne~, the te~rh~ngc thereof those skilled ln the art are referred to for a det~ile~l expI~n~t~on. such o~rpl~n~t~on being for a specific luer lock fitting and their parts, function, and use. Therefore end 61b of the isolation device 60 is fastened with the control module 50 via luer lock fitting 51 in direct relation with the transducer 55 80 that a~ fluid f~lls the line 46 and soc~c 65. the air space 64 Will experience a pressure above atmosphenc pressure direc~ly proportional to the pressure in the 20 line 45. as the me iir~mPnt is deliYered to the patient. The transducer 55 wlll therefore haYe available to It directly the pressure withln the section 64. Such re~r3ing of pressure will be communicated to the electronlc control unlt. such as a mlcroprocessor 56. haYing pre-est~hl~chefi set points therewith ln relatlon to the pressure In llne_45.
2S Should the pressure therefore in line 45 be below the set polnt. the mi~,ul.~ùcessor wlll comm--nir~te with the air pump 58 to pump air from the pump 58 through the line 3S into the air bag 30. The pump 58 is engaged with the air line 35 at end 35a to end 58a of the pump via clamp 36. Also end 35b of the line 35 is engaged with end 30a of the a~r bag 30 3628~
via cl~mp 34. As the yl~3s~ i8 increased in air bag 30 ~ 1t1nn~
pressure w~ll be exerted by the a~r bag 30 upon drug bag 40. since the housing 20 co~.t~ the air bag 30 ls a rlgld housing havlng very little resilience whatsoever resultlng in any 1nfl~tlnn of the bag 30 behg 5 e~ntirely (reciliPnrP~ exerted upon the drug bag 40 over ~llhst~nltl~lty all of lt~ lPn~th The re~s~lltlnE increased ~e3a~, from the air bag 30 wlll provide an increased flow of the Tr~ c~mPnt contained within the drug bag 40 through to the ~e 45 on to the p~tiPnt Fur~cher there will be an increase~ pressure in the line 45.
Importantly, the infuslon devlce 10 ls deslgned to provide a steady flow of medlcament to the patlent over the period of tlme during which the contents of the drug bag are to be delivered. For example, lf a drug bag contalnlng 500 cm2 of liquid is provided and it is desired to deliver this mP-l~c~mPnt to 15 the p~tiP-lt at the rate of 20 m11~ tPrs per hour. (although it is PXT'eCte~
for the a~aL~ls the range of 10 m1n~l~ters to 100 m1ll~l~ter5 per hour to be the expected range of o~,e,~,Uon), lt i8 also desirable to maintain the delivery of the 20 milliliters per hour uniformly over the 60 minutes represented by the hour. It would not be a~-iY~ Pous to the p~tl~Pnt to 20 deli~er an ~L~ e amount init~ally and ~ Ir~ off to a relatively small amount near the end of the ~rlm1n1stratlon cyc-ie. In order therefore to achieve this s~eady state LL '~s i~u~ t that tbe pressure ~: rnnnitr,re~i co~ti-~ually with~ ne 45, and yet the de~vice mon~tor~ng the pressure transducer 55, be ~sol~ted irom cr-~lz~ nE~ the mP~liC~mpnt delivered 25 to the p~t~Pn~, and yet provide L~ to the Ic,u~ cessor to control the flow to the patient within the desired range of de~riatlon. ~t ls therefore desirable for the ~l~ s~ rP~A~n~ at transducer 55 to be commtln~ te-l to the mic~o~l.,cr~sG. 56 wh~ch in turn compareS the pressure rP~ n~ to set points and based on the d~erence L,c1wc~l the 213628~
, -set point and the re~ n~ and whether the difference is positive or negative, will therefore allow the pump 58 to start or pr~vellt it from sts~ g until such t~me as the difference is negative for example. In this m~nner therefore a very precise control of the infusion rate can be 5 obt~lnP.l.
Referring to flgures 3 to 5 there is described the id~nt1c~l operation of the Wusion device 10a with the exception that the housing 20à~ of the Wusion device is shaped subst~nti~lly as shown in flgure 5 having a top 21a a bottom 23a and hinged member 22a resting between 10 the air bag 30 and the drug bag 40. The purpose of the plate 22a contained within the housing 20a is to provided a more uniform a pressure over the length of the drug bag 40 as the medicament is delivered to the patient. The plate 22a as best seen in flgure 4 is pivotally ~tt~(~hefl via pins 22al to the side of housing 20a all~wing motion thereof 15 in the directions D1 and D2 as best seen in flgure 3. The balance of this operation of the infusion device 10a is consistent with that as previously described, with the exception that in relation to flgure 5 the infusion device is provide with a convenience strap as in those manners which those skilled in the art would know. For example an opening may be provided at nange 22b of the housing for the strap to pass there through at both sides of the housing to form a shoulder bag type apparatus A which may be carried by perso~ "P" in an ambulatory fashion thus free~ , person "P" from havlng to be left in a se-~ont~ry positior~ at a hospital. taking up a hospital bed and the time of the medical professionals: wherein the 25 medication could equally be ~tlministered with the patient "P" going about his or her blls~ness at a moderate level of activity around the home for ~ mple.
Figure 6 describes one embodiment of many control units that would work with the instant invention. The following description ' -therefore is for the one specific circult design to accomplish the necessary tasks for operation of the infusion device. However any electronic circuit or device. or any combination of electronic and pneumatic devices which fllnfl~mpntally provides set points for the 5 expected pressure within llne 45 and a comparison therewith with the actual pressure being read from the line 45. Should the difference between the set point and the actual pressure be positive then the motor wlll turn on to drive the blower fan to inflate the bag 30 until there is no difference or negative difference. Should the pressure difference 10 between the set point and the actual pressure be negative than the motor will not turn on allowing the pressure in the line 45 to reduce toward the set point.
To accomplish this task therefore the circuit provided in hgure 6 as one embodiment only and without limitation provides a 15 transducer model number MPX 52DP which provides two outputs to a linear integrated circuit in chip form which 8 pin chip includes an or gate connected to input pins 2 and 3 and output pin 6 which flres only if output 2 is less than output 4 from the transducer. The input to pin 2 may be reduced in comparison to the value of the output of the 20 transducer by a potentiometer which may be adjusted so as to allow the value of output 2 to be less than the value of output 4. When this is the case the or gate will allow an output on pin 6 which passes through a diode to yrev~t any reverse current flow which would cause ri~m~e to the ~ntegrated circuit. Pin 7 ~s a return pin to the voltage Vl applied to 25 the transducer.
A signal would then carry on through a resister which would then lower the value of the voltage of the circuit p~csing through to the second linear integrated circuit which is also an 8 pin chip. Input pins 2 and 3 are provided for the or gate and output 6 is provided for the signal 2136~8G
. .,~,.,_ .~
once the or gate fires. The or gate of the second integrated circuit will fire only when the signal from the flrst integrated circuit is less than the signal resulting from the ad~ustment of the values of the second set of potPntiometers, one of the potPn~iometers including a diode to prevent 5 reverse current flow thereof and ~l~m~gin~ of the second integrated circuit. Therefore when the set points of the two potentiometers of the second integrated clrcuit are set at certain levels in a manner such that the input to pin 2 will be greater than the input to pin 3 until such a time as the pressure re~tling in line 45 is less than the set value set via the 10 ad~ustment provided in the circuitry. the or gate will fire and provide a signal on pin 6 which signal will then be reduced through a silicon controlled rectifier in parallel with an inductor coil which may be for P~mple a meter to obtain a read out convenient to the medical staff or the user so that if the meter is not working the silicon controlled 15 rectifier will not fire since no signal will be provide to the gate of the silicon controlled rectifier. The output of the silicon controlled rectifier will then pass through a transistor at the base thereof which will amplify the signal to a sufficient level to turn on the motor and light the LED to indicate that the motor is turned on when the conditions previously 20 described are present. The fan will than pump up the air bag 30 until such time as the pressure re~ing in line 45 is above the set point as established by the ad.~ustments in the circuitry and then the silicon controlled rectifier will not fire until such time as the pressure level passes below the set point aga~n.
The above circuit description is provided as an example only and no way limits the variations of circuitry or devices which would work based on advances in technology with the infusion device. It is sufficient that some electronic control unit or combination mechanical. pneumatic and/or electronic be provided which provides the features described above and the comparlson of the set point with the actual pressure readlngs.
Referring now to Figures 7 and 8, there is lllustrated another embodiment of the lnfusion device 210 constructed ln accordance with the present lnventlon. A drug bag 240 ls fllled wlth a fluid medicament to be dellvered to a patient. Drug bag 240 ls contained within rigid houslng 220 along wlth flexible alr bag 230. As descrlbed above, it is preferable that houslng 2Z0 be separable to allow access to the lnterior thereof to permlt replacement of drug bag 240 when depleted.
Drug bag 240 ls connected to tublng 245 by conventlonal means. Tublng 245 extends through houslng 220.
Tubing 245 ls ln flow communlcatlon wlth the contents of drug bag 240.
Alr bag 230 is connected to air llne 235. Air llne 235 also extends through rlgld housing 220. Air line 235 is in turn pneumatlcally connected to alr pump 258.
Preferably, alr pump 258 is a pneumatlc or dlaphragm air pum~.
Air pump 258 is drlven by electrlc motor 259 to lnflate alr bag 230 when electrlc motor 25g ls actlvated. Electrlc motor 259 ls actlvated when the electrlc clrcult 257 lS
closed. This will be further descrlbed below.
Tubing 245 is connected to dlaphragm or bladder 265 Z5 whlch is also connected wlth a further length of tublng 245a whlch ls at lts end connected to needle 249 through whlch the fluid medlcament of drug bag 240 ls administered to a patient.
Connected in serles wlth the further length of tubing 245a, ls flow restrictor 248. Tubing 245 or further tubing 245a may lnclude one-way valves 246 and 246a to prevent any back flow of fluids into drug bag 240.
Bladder 265 and tubing 245/245a are composed of a medical grade resillent flexlble materlal such as medlcal grade rubber or vinyl. Bladder 265 is lnflatable and deflatable in proportlon to the fluld pressure wlthln tublng 245/245a (which is proportionate to the fluid pressure wlthin drug bag 240).
- When lnflated, air bag 230, contained within rigid houslng 220 wlth drug bag 240, applies a direct pressure to drug bag 240 increasing the fluid pressure therein, thereby motlvatlng the fluld wlthln drug bag 240 to flow through tube 245 toward infusion needle 249. An lncreased pressure withln drug bag 240 results in an increased pressure wlthln tubing 245/245a. As a result of an lncreased pressure withln tubing 245/245a, bladder 265 will inflate.
With reference to Flgure 8, the pressure sensor assembly 280 of control module 250 may be descrlbed in ~reater detall. Pressure sensor 280 comprlses bladder 265 ln flow communication with tubes 245 and 245a (as previously described with reference to Figure 7). Bladder 265 ls sandwiched between a substantially rigld base 282 and a flexible plate 284 whlch is attached at one end 286 to base 282.
Plate 284 ls flexible, resilient and spring-like and is biased - 23 - 2 1 3-6 2 a 6 toward base 282 ln the dlrectlon of arrow F to compress bladder 265.
Gulde plns 288 and 290 lncluded ln base member 282 correspond to gulde holes 292 and 294 through plate member 284. Gulde plns 288 and 290 and gulde holes 292 and 294 guide the movement of plate 284 toward and from base member 282.
When lnflated as result of lncreased pressure in tublng 245/245a, bladder 265 wlll flex plate 284 agalnst lts blas ln the dlrection away from base 282. Conversely, when the fluld pressure ln tublng 245/245a decreases, bladder 265 wlll be compressed by plate 284 as it flexes in the directlon of lts blas toward base 282.
Swltch clrcult 296 is attached to end 298 of lS plate 284. Switch circuit 296 is preferably a microswitch whlch requires little force to trlgger actuator 299 when lt ls pressed agalnst base 282. Swltch 296 ls electrlcally connected ln series to electrical circuit 257 between power supply 300 and electric motor 259 (best deplcte~ irl rlgure 7).
Swltch 2g6 is normally open, meanlng that electrical clrcuit 257 ls not closed untll actuator 299 ls trlggered.
Wlth reference to both Flgures 7 and 8, when the circult between mlcroswltch 296, electrlc motor 259, power supply 300 and on~off switch 302 ls closed, electrlc motor 259 wlll be actlvated and pump 258 wlll pump air lnto air bag 230, thereby lncreaslng the space occupied by alr bag 230 wlthln rlgld ..
houslng 220 and wlll increase the fluld pressure wlthln drug bag 240.
Since swltch 296 ls normally open, when actuator 299 ls in the posltlon shown ln Flgure 8, electrlcal clrcult 257 lnterrupted (or open) and therefore alr pump 258 does not pump air lnto alr bag 230. Therefore, as fluld dralns from drug bag 240, the fluld pressure withln drug bag 240 ls decreased.
The decrease ln fluid pressure wlthln drug bag 240 (and tubes 245/245a) wlll cause a deflatlon of bladder 265 compressed by plate 284. At a polnt where the fluld pressure within drug bag 240 is less than a certaln deslred value, actuator 299 of swltch 296 will be depressed agalnst base 282, as a result of the movement of plate 284 ln the dlrectlon of lts bias as shown by arrow F, and will close clrcult 257 thus causlng alr pump 258 to lnflate alr bag 230 and lncrease the pressure in drug bag 240. The lnflatlon of alr bag 230 wlll continue untll clrcuit 257 ls agaln opened by the flexlng of plate 284 (and, therefore, swltch 296) from base 282. The lnflatlon of bladder 265 caused by the inflallon of alr bag 220 and the resultlng lncreased fluld pressure ln drug bag 23~ will cause the flexlng of metal plate 284 away from base 282 to cause actuator 299 to be agaln suspended above base 282, agaln opening clrcult 257. Thls cycle repeats ltself untll the drug bag ls depleted, at whlch tlme on/off swltch 302 may be used to open clrcult 257. Thls feedback control loop permlts accurate malntenance of a deslred fluld pres~ure ln the tubing leadlng from the drug bag.
..,_ Other conflguratlons of swltches, etc. may be used ln cooperatlon wlth plate 284 to cause the actlvation of alr pump 258. For example, a normally closed swltch ln serles with clrcult 257 may be lnterposed between plate 284 and another base member (not shown) above plate 284. Therefore, the clrcult wlll be opened when bladder 265 ls lnflated ln response to a fluld pressure at or above a deslred fluld pressure. The device may also lnclude a reverslble pump or other means to release pressure from or deflate the lnflatable bag lf necessary.
Referrlng to Flgure 8, lt wlll be understood that the deslred fluld pressure may be selected by ad~ustlng the extent to whlch swltch 296 extends upwardly or downwardly from plate 284.
An advantage of the lnventlon, partlcularly as embodled ln Flgures 7 and 8, ls that the portable lnfuslon devlce ls very lnexpenslve to manufacture and therefore may be dlsposed once used. The advantages of such an lnexpenslve, therefore dlsposable lnfuslon devlce wlll be apparent to those skllled ln the art.
As many changes can be made to the preferred embodlments of the lnventlon wlthout departlng from the scope of the lnventlon, lt ls lntended that all materlal contalned hereln be lnterpreted as lllustratlve of the lnventlon and not ln a llmltlng sense.
Portable Infuslon Devlce FIELD OF INVENTION
Thls lnventlon relates to lnfuslon devices for preclse admlnlsterlng of medlcaments to patients and flnds partlcular appllcatlon ln portable lnfuslon devlces.
BACKGROUND OF TH~ INVENTION
It ls known ln the art to whlch the present lnventlon pertalns, to provlde devlces whlch dellver a fluid medicament from a drug bag to a llne leadlng to an lnfuslng needle or catheter. Many such devlces utlllze mechanical pumplng means for dellverlng the fluld le. perlstaltic pumps, etc. As well, it ls known ln the art to provlde means for controlllng the rate at which the fluid ls dellvered.
For example, Australlan Patent Appllcatlon No. 61546/86 to Cannon et al. publlshed May 28, 1987 teaches an lnfuslon device whlch lncludes a perlstaltlc pump that ls used ln assoclatlon with a straln gauge assembly which monltors dlmenslonal changes in the outer dlameter of an I.V.
tube. The fluld flow through the lnfuslon tube ls motlvated by the pump whlch, through a serles of flngers which massage the I.V. tube, cause the fluld flow. The rate of fluld dellvery ls determlned from a readlng from the straln gauge.
From thls determlnatlon, a controller operates the pump to vary the rate of flow, lf necessary. There are dlsadvantages to the use of mechanlcal means such as perlstaltlc pumps to dellver fluids, lncludlng the costs assoclated wlth such fluld pumps whlch lnclude the costs of malntalnlng the pump.
, _ Further, the fluld to be delivered is gravity fed from a reservoir thereby lnterfering with the portabillty of the system.
Other references which lnclude dlrect displacement pumplng means include U.S. Patent No. 4,670,006 to Sinnett et al. and U.S. Patent No. 4,998,914 to Wiest et al.
U.S. Patent No. 4,670,006 teaches an lnfusion devlce whlch includes an electrlcally drlven fluld pump comblned with a pressure regulator and pressure detectlng means, as well as a motor control unit for the pump. The devlce monltors the fluld dellvery pressure and actlvates the fluld pump when the pressure falls below a predetermined level. As already stated above, the use of a pump assembly for pumplng a fluld dlrectly provldes certaln dlsadvantages ln both costs and malntenance.
Further, the configuratlon of detectlon and control means is not practical for use in a portable infusion unit.
U.S. Patent No. 4,998,914 descrlbes a perfuslon system whlch uses a perfuslon pump connected wlth a perfuslon llne having a pressure sensor for determinlng the flow rate of fluld to be dellvered. Thls device also provides for gravity feeding of the perfusion fluid to the pump. The perfusion system monitors the pressure within the body cavlty being perfused. This is useful ln such a perfusion system, but not necessary for use ln an infusion system. Again, the cost and maintenance of the fluid pump poses certain dlsadvantages, as does the gravity feed of the pump.
213628~
_ - 3 PCT appllcation W0 g0/07942 to Woicickl et al.
purports to teach a fluid dellvery system which includes a volumetrlc pump and a method of contlnuously monltorlng the operatlon of the dellvery system for controlllng the pump.
The control method of thls reference ls characterlsed by the measurement of actual pressure of dellvery of a fluid with every cycle of the volumetric pump. Such measurement requires certain electronic sensing and calculation means whlch add to the cost and complexity of the infusion system. Again, as stated above, volumetric pumps have disadvantages relating to both cost and malntenance.
European patent appllcatlon 277,518 to Heitmeier et al. discloses a pressure infuslon device, agaln in whlch an lnfuslon pump is used to control the rate of flow of the lnfused llquld. The lnfuslon pump ls operated by a control clrcult which measures the rate of flow of infused liquid between two sensors which are separated along the infusion tube. The volume of flow is calculated and the controller ad~usts the speed of the pump, lf necessary. Gravlty feed ls used to supply the pump thereby reduclng the portablllty of the system. Agaln, the use of an lnfuslon pump will add to the cost and malntenance dlsadvantages of the system, as wlll the electronics requlred to control the infuslon pump on the basis of measurements made between the two sensors. The gravity feed will limit the portabillty of the system.
It is also known in the art to which the present inventlon pertalns, to provlde lnfuslon devlces whlch transfer 21~6~6 a fluid medicament from a drug bag or reservolr using means to pressurize the drug bag or reservoir. The pressurizing means ls useful ln comblnatlon wlth a flow regulator whlch ls part of the dellvery line.
U.S. Patent No. 4,267,834 to Barger et al. dlscloses a devlce for flushlng a medlcal fluld through an lnfuslon llne used for monltorlng blood pressure fluctuatlons. The rate at which the fluid is lnfused to the patlent ls controlled in part through a compresslon sleeve connected to a pressure gauge and ad~ustable uslng a squeeze bulb. Although slmple to operate, the flowrate of fluld through the lnfuslon tube ls not preclsely controlled as the pressure to the drug bag must be monltored and ad~usted manually. Such an lnfusion system would not be practical for the infuslng of a drug at a constant flow rate.
U.S. Patent No. 5,059,182 to the present lnventor, describes a portable lnfusion device whlch lncludes an lnflatable bag carried in a container wlthin whlch a drug bag fllled wlth a fluld to be lnfused ls placed. The pressure imparted by the inflatable bag to the drug bag motlvates the fluld therein to flow through a tube to the patient to whlch the fluld ls belng delivered. Flow rate control ls achleved through the use of a flow regulator in combination wlth the monitoring the pressure imparted by the inflatable bag on the drug bag. Again, the flow rate control of infused fluid is not easily maintalned as constant monltoring and manual ad~ustment of the pressure of the lnflatable bag ls necessary.
' ..._ U.S. Patent No. 4,505,264 to Parmelee et al.
descrlbes a portable lnfuslon devlce ln whlch a drug bag contalnlng a fluld to be lnfused ls placed wlthin a rlgld contalner havlng a sprlng blased plate to lmpart a pressure on the drug bag to motlvate the fluld to flow lnto the connectlng tube. The flow rate ls controlled by regulators connected ln serles wlth the tube. The use of the sprlng blased plate results in a varlable pressure lmparted to the drug bag as the drug bag dralns (le. over the range of movement of the sprlng blased plate). As a result, hlgher flow rates wlll be experlenced lnltlally, compared to lower flow rates whlch wlll be experlenced when the drug bag nears depletlon. This varlable flow rate ls unacceptable ln a fluld lnfuslng devlce.
U.S. Patent No. 4,557,726 to Relnlcke descrlbes a medlcatlon dlspenslng system ln whlch a medlcatlon to be lnfused fllls a reservolr over whlch a constant pressure ls malntalned through the use of a fluld whlch has two-phases (gas and llquld) body temperature. The flow through the lnfuslon tube ls controlled by means of a regulator. The pressure of the fluld lnfusate ls not utlllzed or ad~usted to malntaln a constant flow rate of lnfusate to the patlent.
Slmllarly, Canadian Patent No. 1,152,823 to Dorman and Canadlan Patent No. 2,021,284 to Sampson both also utlllze regulator devices ln serles wlth an lnfusate llne malntalned at a constant pressure for controlllng the flow lnfusate to the patlent. Nelther reference dlscloses a manner of '_ 2136286 measurlng and thereby controlllng the pressure of lnfusate to regulate the flow to the patlent.
U.S. Patent No. 4,077,405 to Haerten et al.
dlscloses an apparatus for infusing llqulds whereln a supply reservolr of the lnfusate llquld is maintained at a pressure in excess of the pressure prevalllng at the point of llquld dlscharge to the patlent. Preselectable constant volumes of llquld are dlscharged at perlodlc lntervals ln accordance wlth a treatment program. Agaln the control of the flow rate of lnfusate ls not controlled by measurlng the pressure of the lnfusate.
U.S. Patent No. 4,443r218 to DeCant, Jr. et al.
dlscloses a lnfuslon apparatus ln whlch the flow of lnfusate ls controlled by the measurement of a dlfferentlal pressure across a flow path through whlch a hlgher vlscoslty fluld ls forced to flow as a result of the flow of the lnfusate. By respondlng to a measurement of the pressure drop across a flow restrlctlon, an electrlc motor may be used transmlt mechanlcal pressure to the lnfusate chamber to ad~ust the lnfusate flow rate. Agaln, the control of the flow of lnfusate ls not related to a dlrect measurement of the pressure of the lnfusate.
PCT appllcatlon WO 87/05225 to Kamen dlscloses a fluld dlspenslng system ln whlch a lnfusate ls transferred lnto a dlspenslng means contalned ln an lsolated reglon, the amount of lnfusate transferred lnto the dlspensing means determlned by measurlng the amount of a gas dlsplaced from the _ lsolated reglon surrounding the dlspenslng means. The lnfusate ls then transferred from the dlspenslng means and another measurement of the gas reenterlng the lsolated reglon ls made. By comparlng the amounts of dlsplaced and replaced gas, lt ls posslble to determlne the amount of lnfusate which has been dlspensed. Agaln, no measurement of the lnfusate pressure ls made to determlne the flow rate of lnfusate.
Nowhere ln the prlor art references ls there an lnfuslon device whlch overcomes many of the dlsadvantages of the prlor art and thereby provldes an lnfusion devlce whlch ls preferably portable and lncludes an lnfusate pressure monltorlng control loop ad~ustlng lnfusate flow.
As well, the prlor art does not dlsclose a means for respondlng to changes ln lnfusate pressure to control the deslred lnfusate flow rate, whlch ls both lnexpenslve and ln whlch the lnfusate ls not contamlnated.
It ls therefore a prlmary ob~ect of the present lnventlon to provlde an lnfuslon devlce whlch ls portable and allows the admlnlstratlon of fluld medlcaments to patlents wlthout the patlent needlng to be restrlcted to a hospltal or cllnlc.
It ls a further ob~ect of the present lnventlon to provlde an lnfuslon devlce whlch ls safe and rellable to use.
It ls yet a further ob~ect of the present lnventlon to provlde an lnfuslon devlce whlch monltors or responds to the lnfusate pressure and lncludes means to malntaln the lnfusate pressure at a deslred level.
21362~6 It ls another ob~ect of the present lnventlon to provlde an lnfuslon devlce whlch ls lnexpenslve.
Further and other ob~ects of thls lnventlon wlll become apparent to those skilled ln the art when consldering the followlng summary of lnventlon and the more detalled descrlptlon of the preferred embodlments lllustrated hereln.
SUMMARY OF THF INVRNTION
Accordlng to an aspect of the present lnventlon there ls provlded an lnfuslon devlce for flulds comprlslng a rlgld frame or houslng, the frame or houslng havlng dlsposed therewlth when assembled a space whereln ls dlsposed ln use a flexlble bag prevlously evacuated of alr and fllled wlth a fluld, the flexlble bag havlng an outlet and havlng a flrst tube havlng two ends connected thereto ln use for carrylng the fluld from the flexlble bag proxlmate one end of the flrst tube to the dlstal end of the flrst tube proxlmate the patlent ln use; the houslng contalnlng ln use means to press the fluld bag and cause flow of fluld through the flrst llne to the patlent; the lnfuslon devlce havlng means to change (such as lncrease/decrease) the ablllty of the means to press the fluld bag, to press the fluld bag, the lnfuslon devlce havlng senslng means to sense the pressure of the fluld ln the flrst llne; the lnfuslon devlce havlng control means havlng set polnts therewlth ln use for deslred fluld pressure ln the flrst llne and ln communlcatlon wlth the means to press the fluld bag and to recelve sensed fluld pressure from the senslng means and to respond to hlgh/low pressures sensed by ~ 2136286 g actlvatlng the means to lncrease/decrease the ablllty of the means to press the fluld bag to press the fluld bag, a second llne havlng two ends and connected wlth the flrst llne proxlmate one end of the second llne lntermedlate the ends of the flrst llne, and havlng dlsposed proxlmate the other end of the second llne lsolatlon means to present a pressure ln the fluld to the senslng means wlthout the senslng means contamlnatlng the fluld belng dellvered to the patlent ln use, whereln in use as the fluld bag ls pressed fluld passes to the patlent through the flrst llne depletlng the volume of fluld ln the fluld bag, whlch fluld communlcates a pressure ln the second llne to the lsolated senslng means wlthout contamlnatlng the fluld belng dellvered to the patlent, the control means respondlng to changes ln the fluld pressure by actlvatlng/deactlvatlng the means to change (such as lncrease/decrease~ the ablllty of the means to press the fluld bag to press the fluld bag.
Preferably, the lnfuslon devlce ls contalned wlthln a shoulder bag or the llke to lncrease the moblllty of the patlent. The means to press the fluld bag or the alr bag, and the fluld bag may be separated wlthln the frame or houslng of the lnfuslon devlce by a hlnged moveable plate whlch asslsts ln ensurlng equal pressure ls belng exerted over the length of the fluld bag.
A flow restrlctor may be placed before the needle of the second llne for preclse admlnlstratlon of the drug.
21~6~86 ~ ,~
The lsolatlon member may lnclude a sock or dlaphragm made from extremely thln flexlble lmpermeable materlal contalned ln a chamber attached at one end to the thlrd llne and to the senslng means at the other end thereof, the chamber S presentlng a llquld fllled sectlon withln the sock or on one slde of the dlaphragm and an alr fllled space on the other slde of the sock or dlaphragm, whereln the flexlble sock or diaphragm is contalned ln the chamber so that in use the fluld acts to produce a pressure readlng to the senslng means vla the alr space on the alr slde of the sock or dlaphragm.
Accordlng to another aspect of the present lnventlon there ls provlded a portable lnfuslon devlce comprlslng: (a) a rlgld houslng, the houslng havlng an lnterlor space; (b) a flexlble bag contalned withln the lnterlor space, the flexlble bag fllled wlth a fluld to be dellvered, the flexlble bag havlng an outlet; (c) a tube havlng a flrst end attached to the flexlble bag outlet ln flow communlcatlon wlth the fluld to be dellvered, the tube havlng a second end to whlch the fluld ls dellvered ln use; (d) an lnflatable bag contalned wlthln the lnterlor space, the lnflatable bag inflatable to press the flexlble bag thus creatlng a fluld pressure wlthln the flexlble bag causlng a tendency for the fluld to flow from the flexlble bag through the tube for dellvery to the second end of the tube; (e) means for lnflatlng the lnflatable bag ln response to a slgnal; (f) control means whlch responds to the fluld pressure wlthln the flexlble bag for generatlng the slgnal when the fluld pressure ln the flexlble bag ls less 2136~8B
. .
W_ than a desired fluld pressure, sald control means comprlslng:
(i) a substantlally lnflexlble base member; (11) a reslllent sprlng plate havlng a flrst end and a second end, sald plate attached to sald base member at sald flrst end, sald second end free to flex toward and away from sald base member, said second end blased toward sald base member; (111) a bladder ln flow communlcatlon wlth sald flexlble bag whereln sald bladder lnflates ln response to an lncrease ln sald fluld pressure and deflates ln response to a decrease ln sald fluld pressure, sald bladder compressed by sald plate between sald second end of sald plate and sald base member such that sald second end of sald plate flexes away from sald base member ln response to an lnflatlon of sald bladder and flexes toward sald base member ln response to a deflation of said bladder; and (lv) means to generate sald slgnal when sald plate flexes toward sald base member ln response to a deflatlon of sald bladder ln response to a decrease ln sald fluld pressure to less than sald deslred fluld pressure.
Preferably, (a) the reslllent sprlng plate comprlses a thln metal plate; (b) the lnflatlng means comprises an electrlc alr pump and an alr pump power supply, the alr pump lnflatlng the lnflatable bag ln repone to an electrlcal current from the alr pump power supply; and (c) the slgnal generatlng means comprlses a normally open swltch clrcult electrlcally connected ln serles between the electrlc alr pump and the alr pump power supply, the swltch clrcult closed by the second end of the metal plate when flexed toward the base 213628~
member ln response to a deflatlon of the bladder in response to a decrease ln the fluld pressure to less than the desired fluid pressure.
Accordlng to yet another aspect of the present lnventlon, there ls provlded for ln a portable lnfuslon devlce, means for controlllng dellvery of a fluld from a flexlble bag, sald dellvery caused by fluld pressure ln sald flexlble bag, said device having means for lncreaslng sald fluld pressure ln response to a slgnal generated when sald fluld pressure ls less than a deslred fluld pressure, sald control means comprlslng: (a) a substantlally lnflexlble base member; (b) a reslllent sprlng plate havlng a flrst end and a second end, sald plate attached to sald base member at sald flrst end, sald second end free to flex toward and away from sald base member, sald second end blased toward sald base member; (c) a bladder ln flow communlcatlon wlth sald flexlble bag whereln sald bladder lnflates ln response to an lncrease ln sald fluld pressure and deflates ln response to a decrease ln sald fluld pressure, sald bladder compressed by sald plate between sald second end of said plate and said base member such that sald second end of sald plate flexes away from sald base member in response to an inflation of sald bladder and flexes toward sald base member ln response to a deflatlon of sald bladder; and (d) means to generate sald slgnal when sald plate flexes toward sald base member ln response to a deflatlon of said bladder ln response to a decrease ln sald fluld pressure to less than sald deslred fluld pressure.
- 12a -According to a further aspect of the present invention, there is provided a portable drug infusion device comprising: (a) a flexible bag, said bag filled with a fluid to be delivered; said flexible bag having an outlet;
(b) fluid pressure increasing means, whereby fluid pressure is increased in response to a signal generated when said fluid pressure i8 less than a desired fluid pressure; c) control means for controlling delivery of said fluid, said - control means comprising (i) a substantially inflexible base member; (ii) a resilient spring plate having a first end and a second end, said plate attached to said base member at said first end, said second end free to flex toward and away from said base m~ber, said second end biased toward said base member; (d) a bladder in flow communication with said flexible bag; said bladder connected to inflating means;
wherein said bladder inflates in response to an increase in said fluid pressure and deflates in response to a decrease in said fluid pressure, said bladder compressed by said plate between said second end of said plate and said base member that said second end of said plate flexes away from said base member in response to an inflation of said bladder and flexes toward said base m~er in response to a deflation of said bladder; and (e) means to generate said signal when said plate flexes toward said base member in response to a deflation of said bladder in response to a decrease in said fluid pressure to less than said desired fluid pressure.
' ,~
7 ~
~RIEF D~ ON OF T~ DRAWINGS
The lnventlon wlll now be ~llustrated wlth respect to the followlng drawlngs lllustratlng embodlments of the lnventlon ln whlch:
Flgure 1 ls a slde perspectlve schematlc vlew of an lnfuslon devlce lllustrated ln a preferred embodlment of the lnventlon.
Flgure 2 ls a top plan schematlc vlew of the lnfuslon devlce of Flgure 1 lllustrated ln a preferred embodiment of the lnventlon.
Figure 3 i8 a schematic view of an infusion device illu~trated in a preferred embodiment of the invention.
Flgure 4 ls a partlally cutaway perspectlve vlew of the mechanlsm descrlbed ln relatlon to Flgure 3 lllustrated ln a preferred embodlment of the lnventlon.
Flgure 5 ls a general perspectlve vlew of the use of the lnfuslon devlce of Flgure 4 and lllustrated ln a preferred embodlment of the lnventlon.
Flgure 6 ls a clrcult dlagram for the operatlon of a control unlt of the lnfuslon devlce and lllustrated ln a preferred embodlment of the lnventlon. _ _ ~ v Figure 7 is a schematic view of an infusion d~vice illu~trated in a preferred embodiment of the invention.
Flgure 8 ls a slde elevatlonal vlew of the control -unlt of the embodlment l.llustrated ln Flgure 7 d~ vlewed along the llnes 8-8.
DETAILED DESCRIE~ON OF ~ KRED EMBODIMENTS OF THE
INVENTTON - _ Referring now to the flgures there is illustrated an lnfusion device 10 used for ~rlm1n1ctering drugs to a p~t1e~t- Typically the drug ls 10 provided in a pre-p~ck~ged flp~ihle cont~ er 40 which co~lt~ s up to 500 cm2 of mp~llr~mprlt to :be ~m1ntctered to the p~ti~pnt One of the advantages of thls inYention is that it uses st~n~ d s~zed "drug bags"
without the need for haYing to provide special casettes or the like which is found in t_e prior art. In using a standard drug bag in con~l~nctlon with 5 the present lnvent10n the App~ nt ls no longer required to remain sedentary at a hospital or a clinic wh11e the contPnt of the drug bag ls ~mm1ctered to the p:ltlPnt The i~f~sion device can therefore be provided ~n a comr~rt rlgid housing 20. whlch offers reslstance to the lnfl~t10rl of an alr bag 20 30 made from flPY~hle materials. Dlsposed below the air bag 30 is a space 29 which is filled subst~nt1~lty In use by the drug bag 40 which is made from fl~hhp mates~al and cont~1n~ up to 500 cm2 of the me~1r~m~nt being ~rlmi~i~tered to the p ~t~Prlt The ai~ bag 30 ls clamped to a llne 35 made of mP~r~l grade vinyl and clamped at 34 to a flttlng 30(a~ provided ..~
wlth the air bag 30. The llne 35 is connected wlth a diaphragm air pump proximate the other end thereof vla a clamp 36.
The drug bag 40 ls connected at a tapered end thereof 41 by conventlonal methods such as a clamp to a section of tubing 45 made of medical grade vlnyl whlch extends to the needle 49 and the patlent as best seen ln flgure 5. Located ad~acent the needle 49 ls a preclslon glass restrlctor 48 used to preclsely control the amount of drug admlnistered to the patient. A detalled descrlptlon of these preclslon restrictors is found ln my U.S. Patent 5,059,1B2 and speclflcally ln relatlon to the detailed descriptlon thereof at for example column 7 line 54 onward.
In order for the lnfusion device 10 to be of use to a patient lt ls preferred that the housing 20 be separable. No detalls as to the separatlon of the houslng is provlded as lt ls assumed that those skllled ln the art would appreclate the manner ln whlch a houslng may be separable lnto two halfs by a hlnge, by telescoplc relatlonshlp of one half being slightly larger than the other half and lnter-flttlng wlth that other half, or one portlon belng slldable in relation to the other portion. The important aspect ls that the housing be rlgld and lnclude a hollow space 29 so that a drug bag 40 may be placed in the posltion as shown and affixed to the tubing 45 at clamp 48A. Therefore if more than one type of fluid were being admlnlstered to a patlent sequentlally, for example a saline solution followed by a medlcament then the same apparatus may be used and may be easlly set up by the nurse or other medlcal attendant. The clamps 34 and 48A are known to those skllled ln the art and therefore no further descrlptlon ls necessary.
A second llne 46 ln communlcation wlth the first llne 45 at ~uncture 46a ls provided to allow for a dlrect pressure readlng to be taken from the llne 45 as the medlcament ls dellvered to the patient. At -- 16 -- ~ -the end 46b of line 46 there ls found an imperme~hle mpmhrane sock 65 contained within an isolation deYice 60 including a hollow glass rece~tacle 61 ha~ing two ends 61a and 61b. The sock 65 is the~efo~c ~m~.l at the end 61a at end of 65a of the sock ufith the end of 61a of the 5 giass r~Ce~LaCle. These two portlons are therefore clamped to the tube end 46b via clamp 47. Dlsposed ~thin the icol~t1rr~ device 60 is also an --~ alr space 64 which is- in comml-nlc~t10n w~th the end 61b of the .cce~tscle 61. End 61b is engaged wi~h a control module 50. which inri~rieS a transducer 55, by a luer lock fltting. Descriptlon of luer lock 10 fltting>e is found for PY~mple in U.S. Patent 4.369.781 ~eSlgJ~ed to Sherwood Medical ~ndustries Incorporated and describ~ng therein medic~l luer fltt1ne~, the te~rh~ngc thereof those skilled ln the art are referred to for a det~ile~l expI~n~t~on. such o~rpl~n~t~on being for a specific luer lock fitting and their parts, function, and use. Therefore end 61b of the isolation device 60 is fastened with the control module 50 via luer lock fitting 51 in direct relation with the transducer 55 80 that a~ fluid f~lls the line 46 and soc~c 65. the air space 64 Will experience a pressure above atmosphenc pressure direc~ly proportional to the pressure in the 20 line 45. as the me iir~mPnt is deliYered to the patient. The transducer 55 wlll therefore haYe available to It directly the pressure withln the section 64. Such re~r3ing of pressure will be communicated to the electronlc control unlt. such as a mlcroprocessor 56. haYing pre-est~hl~chefi set points therewith ln relatlon to the pressure In llne_45.
2S Should the pressure therefore in line 45 be below the set polnt. the mi~,ul.~ùcessor wlll comm--nir~te with the air pump 58 to pump air from the pump 58 through the line 3S into the air bag 30. The pump 58 is engaged with the air line 35 at end 35a to end 58a of the pump via clamp 36. Also end 35b of the line 35 is engaged with end 30a of the a~r bag 30 3628~
via cl~mp 34. As the yl~3s~ i8 increased in air bag 30 ~ 1t1nn~
pressure w~ll be exerted by the a~r bag 30 upon drug bag 40. since the housing 20 co~.t~ the air bag 30 ls a rlgld housing havlng very little resilience whatsoever resultlng in any 1nfl~tlnn of the bag 30 behg 5 e~ntirely (reciliPnrP~ exerted upon the drug bag 40 over ~llhst~nltl~lty all of lt~ lPn~th The re~s~lltlnE increased ~e3a~, from the air bag 30 wlll provide an increased flow of the Tr~ c~mPnt contained within the drug bag 40 through to the ~e 45 on to the p~tiPnt Fur~cher there will be an increase~ pressure in the line 45.
Importantly, the infuslon devlce 10 ls deslgned to provide a steady flow of medlcament to the patlent over the period of tlme during which the contents of the drug bag are to be delivered. For example, lf a drug bag contalnlng 500 cm2 of liquid is provided and it is desired to deliver this mP-l~c~mPnt to 15 the p~tiP-lt at the rate of 20 m11~ tPrs per hour. (although it is PXT'eCte~
for the a~aL~ls the range of 10 m1n~l~ters to 100 m1ll~l~ter5 per hour to be the expected range of o~,e,~,Uon), lt i8 also desirable to maintain the delivery of the 20 milliliters per hour uniformly over the 60 minutes represented by the hour. It would not be a~-iY~ Pous to the p~tl~Pnt to 20 deli~er an ~L~ e amount init~ally and ~ Ir~ off to a relatively small amount near the end of the ~rlm1n1stratlon cyc-ie. In order therefore to achieve this s~eady state LL '~s i~u~ t that tbe pressure ~: rnnnitr,re~i co~ti-~ually with~ ne 45, and yet the de~vice mon~tor~ng the pressure transducer 55, be ~sol~ted irom cr-~lz~ nE~ the mP~liC~mpnt delivered 25 to the p~t~Pn~, and yet provide L~ to the Ic,u~ cessor to control the flow to the patient within the desired range of de~riatlon. ~t ls therefore desirable for the ~l~ s~ rP~A~n~ at transducer 55 to be commtln~ te-l to the mic~o~l.,cr~sG. 56 wh~ch in turn compareS the pressure rP~ n~ to set points and based on the d~erence L,c1wc~l the 213628~
, -set point and the re~ n~ and whether the difference is positive or negative, will therefore allow the pump 58 to start or pr~vellt it from sts~ g until such t~me as the difference is negative for example. In this m~nner therefore a very precise control of the infusion rate can be 5 obt~lnP.l.
Referring to flgures 3 to 5 there is described the id~nt1c~l operation of the Wusion device 10a with the exception that the housing 20à~ of the Wusion device is shaped subst~nti~lly as shown in flgure 5 having a top 21a a bottom 23a and hinged member 22a resting between 10 the air bag 30 and the drug bag 40. The purpose of the plate 22a contained within the housing 20a is to provided a more uniform a pressure over the length of the drug bag 40 as the medicament is delivered to the patient. The plate 22a as best seen in flgure 4 is pivotally ~tt~(~hefl via pins 22al to the side of housing 20a all~wing motion thereof 15 in the directions D1 and D2 as best seen in flgure 3. The balance of this operation of the infusion device 10a is consistent with that as previously described, with the exception that in relation to flgure 5 the infusion device is provide with a convenience strap as in those manners which those skilled in the art would know. For example an opening may be provided at nange 22b of the housing for the strap to pass there through at both sides of the housing to form a shoulder bag type apparatus A which may be carried by perso~ "P" in an ambulatory fashion thus free~ , person "P" from havlng to be left in a se-~ont~ry positior~ at a hospital. taking up a hospital bed and the time of the medical professionals: wherein the 25 medication could equally be ~tlministered with the patient "P" going about his or her blls~ness at a moderate level of activity around the home for ~ mple.
Figure 6 describes one embodiment of many control units that would work with the instant invention. The following description ' -therefore is for the one specific circult design to accomplish the necessary tasks for operation of the infusion device. However any electronic circuit or device. or any combination of electronic and pneumatic devices which fllnfl~mpntally provides set points for the 5 expected pressure within llne 45 and a comparison therewith with the actual pressure being read from the line 45. Should the difference between the set point and the actual pressure be positive then the motor wlll turn on to drive the blower fan to inflate the bag 30 until there is no difference or negative difference. Should the pressure difference 10 between the set point and the actual pressure be negative than the motor will not turn on allowing the pressure in the line 45 to reduce toward the set point.
To accomplish this task therefore the circuit provided in hgure 6 as one embodiment only and without limitation provides a 15 transducer model number MPX 52DP which provides two outputs to a linear integrated circuit in chip form which 8 pin chip includes an or gate connected to input pins 2 and 3 and output pin 6 which flres only if output 2 is less than output 4 from the transducer. The input to pin 2 may be reduced in comparison to the value of the output of the 20 transducer by a potentiometer which may be adjusted so as to allow the value of output 2 to be less than the value of output 4. When this is the case the or gate will allow an output on pin 6 which passes through a diode to yrev~t any reverse current flow which would cause ri~m~e to the ~ntegrated circuit. Pin 7 ~s a return pin to the voltage Vl applied to 25 the transducer.
A signal would then carry on through a resister which would then lower the value of the voltage of the circuit p~csing through to the second linear integrated circuit which is also an 8 pin chip. Input pins 2 and 3 are provided for the or gate and output 6 is provided for the signal 2136~8G
. .,~,.,_ .~
once the or gate fires. The or gate of the second integrated circuit will fire only when the signal from the flrst integrated circuit is less than the signal resulting from the ad~ustment of the values of the second set of potPntiometers, one of the potPn~iometers including a diode to prevent 5 reverse current flow thereof and ~l~m~gin~ of the second integrated circuit. Therefore when the set points of the two potentiometers of the second integrated clrcuit are set at certain levels in a manner such that the input to pin 2 will be greater than the input to pin 3 until such a time as the pressure re~tling in line 45 is less than the set value set via the 10 ad~ustment provided in the circuitry. the or gate will fire and provide a signal on pin 6 which signal will then be reduced through a silicon controlled rectifier in parallel with an inductor coil which may be for P~mple a meter to obtain a read out convenient to the medical staff or the user so that if the meter is not working the silicon controlled 15 rectifier will not fire since no signal will be provide to the gate of the silicon controlled rectifier. The output of the silicon controlled rectifier will then pass through a transistor at the base thereof which will amplify the signal to a sufficient level to turn on the motor and light the LED to indicate that the motor is turned on when the conditions previously 20 described are present. The fan will than pump up the air bag 30 until such time as the pressure re~ing in line 45 is above the set point as established by the ad.~ustments in the circuitry and then the silicon controlled rectifier will not fire until such time as the pressure level passes below the set point aga~n.
The above circuit description is provided as an example only and no way limits the variations of circuitry or devices which would work based on advances in technology with the infusion device. It is sufficient that some electronic control unit or combination mechanical. pneumatic and/or electronic be provided which provides the features described above and the comparlson of the set point with the actual pressure readlngs.
Referring now to Figures 7 and 8, there is lllustrated another embodiment of the lnfusion device 210 constructed ln accordance with the present lnventlon. A drug bag 240 ls fllled wlth a fluid medicament to be dellvered to a patient. Drug bag 240 ls contained within rigid houslng 220 along wlth flexible alr bag 230. As descrlbed above, it is preferable that houslng 2Z0 be separable to allow access to the lnterior thereof to permlt replacement of drug bag 240 when depleted.
Drug bag 240 ls connected to tublng 245 by conventlonal means. Tublng 245 extends through houslng 220.
Tubing 245 ls ln flow communlcatlon wlth the contents of drug bag 240.
Alr bag 230 is connected to air llne 235. Air llne 235 also extends through rlgld housing 220. Air line 235 is in turn pneumatlcally connected to alr pump 258.
Preferably, alr pump 258 is a pneumatlc or dlaphragm air pum~.
Air pump 258 is drlven by electrlc motor 259 to lnflate alr bag 230 when electrlc motor 25g ls actlvated. Electrlc motor 259 ls actlvated when the electrlc clrcult 257 lS
closed. This will be further descrlbed below.
Tubing 245 is connected to dlaphragm or bladder 265 Z5 whlch is also connected wlth a further length of tublng 245a whlch ls at lts end connected to needle 249 through whlch the fluid medlcament of drug bag 240 ls administered to a patient.
Connected in serles wlth the further length of tubing 245a, ls flow restrictor 248. Tubing 245 or further tubing 245a may lnclude one-way valves 246 and 246a to prevent any back flow of fluids into drug bag 240.
Bladder 265 and tubing 245/245a are composed of a medical grade resillent flexlble materlal such as medlcal grade rubber or vinyl. Bladder 265 is lnflatable and deflatable in proportlon to the fluld pressure wlthln tublng 245/245a (which is proportionate to the fluid pressure wlthin drug bag 240).
- When lnflated, air bag 230, contained within rigid houslng 220 wlth drug bag 240, applies a direct pressure to drug bag 240 increasing the fluid pressure therein, thereby motlvatlng the fluld wlthln drug bag 240 to flow through tube 245 toward infusion needle 249. An lncreased pressure withln drug bag 240 results in an increased pressure wlthln tubing 245/245a. As a result of an lncreased pressure withln tubing 245/245a, bladder 265 will inflate.
With reference to Flgure 8, the pressure sensor assembly 280 of control module 250 may be descrlbed in ~reater detall. Pressure sensor 280 comprlses bladder 265 ln flow communication with tubes 245 and 245a (as previously described with reference to Figure 7). Bladder 265 ls sandwiched between a substantially rigld base 282 and a flexible plate 284 whlch is attached at one end 286 to base 282.
Plate 284 ls flexible, resilient and spring-like and is biased - 23 - 2 1 3-6 2 a 6 toward base 282 ln the dlrectlon of arrow F to compress bladder 265.
Gulde plns 288 and 290 lncluded ln base member 282 correspond to gulde holes 292 and 294 through plate member 284. Gulde plns 288 and 290 and gulde holes 292 and 294 guide the movement of plate 284 toward and from base member 282.
When lnflated as result of lncreased pressure in tublng 245/245a, bladder 265 wlll flex plate 284 agalnst lts blas ln the dlrection away from base 282. Conversely, when the fluld pressure ln tublng 245/245a decreases, bladder 265 wlll be compressed by plate 284 as it flexes in the directlon of lts blas toward base 282.
Swltch clrcult 296 is attached to end 298 of lS plate 284. Switch circuit 296 is preferably a microswitch whlch requires little force to trlgger actuator 299 when lt ls pressed agalnst base 282. Swltch 296 ls electrlcally connected ln series to electrical circuit 257 between power supply 300 and electric motor 259 (best deplcte~ irl rlgure 7).
Swltch 2g6 is normally open, meanlng that electrical clrcuit 257 ls not closed untll actuator 299 ls trlggered.
Wlth reference to both Flgures 7 and 8, when the circult between mlcroswltch 296, electrlc motor 259, power supply 300 and on~off switch 302 ls closed, electrlc motor 259 wlll be actlvated and pump 258 wlll pump air lnto air bag 230, thereby lncreaslng the space occupied by alr bag 230 wlthln rlgld ..
houslng 220 and wlll increase the fluld pressure wlthln drug bag 240.
Since swltch 296 ls normally open, when actuator 299 ls in the posltlon shown ln Flgure 8, electrlcal clrcult 257 lnterrupted (or open) and therefore alr pump 258 does not pump air lnto alr bag 230. Therefore, as fluld dralns from drug bag 240, the fluld pressure withln drug bag 240 ls decreased.
The decrease ln fluid pressure wlthln drug bag 240 (and tubes 245/245a) wlll cause a deflatlon of bladder 265 compressed by plate 284. At a polnt where the fluld pressure within drug bag 240 is less than a certaln deslred value, actuator 299 of swltch 296 will be depressed agalnst base 282, as a result of the movement of plate 284 ln the dlrectlon of lts bias as shown by arrow F, and will close clrcult 257 thus causlng alr pump 258 to lnflate alr bag 230 and lncrease the pressure in drug bag 240. The lnflatlon of alr bag 230 wlll continue untll clrcuit 257 ls agaln opened by the flexlng of plate 284 (and, therefore, swltch 296) from base 282. The lnflatlon of bladder 265 caused by the inflallon of alr bag 220 and the resultlng lncreased fluld pressure ln drug bag 23~ will cause the flexlng of metal plate 284 away from base 282 to cause actuator 299 to be agaln suspended above base 282, agaln opening clrcult 257. Thls cycle repeats ltself untll the drug bag ls depleted, at whlch tlme on/off swltch 302 may be used to open clrcult 257. Thls feedback control loop permlts accurate malntenance of a deslred fluld pres~ure ln the tubing leadlng from the drug bag.
..,_ Other conflguratlons of swltches, etc. may be used ln cooperatlon wlth plate 284 to cause the actlvation of alr pump 258. For example, a normally closed swltch ln serles with clrcult 257 may be lnterposed between plate 284 and another base member (not shown) above plate 284. Therefore, the clrcult wlll be opened when bladder 265 ls lnflated ln response to a fluld pressure at or above a deslred fluld pressure. The device may also lnclude a reverslble pump or other means to release pressure from or deflate the lnflatable bag lf necessary.
Referrlng to Flgure 8, lt wlll be understood that the deslred fluld pressure may be selected by ad~ustlng the extent to whlch swltch 296 extends upwardly or downwardly from plate 284.
An advantage of the lnventlon, partlcularly as embodled ln Flgures 7 and 8, ls that the portable lnfuslon devlce ls very lnexpenslve to manufacture and therefore may be dlsposed once used. The advantages of such an lnexpenslve, therefore dlsposable lnfuslon devlce wlll be apparent to those skllled ln the art.
As many changes can be made to the preferred embodlments of the lnventlon wlthout departlng from the scope of the lnventlon, lt ls lntended that all materlal contalned hereln be lnterpreted as lllustratlve of the lnventlon and not ln a llmltlng sense.
Claims (10)
- THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS.
l. A portable infusion device comprising:
(a) a rigid housing, said housing having an interior space;
(b) a flexible bag contained within said interior space, said flexible bag filled with a fluid to be delivered, said flexible bag having an outlet;
(c) a tube having a first end attached to said flexible bag outlet in flow communication with said fluid to be delivered, said tube having a second end to which said fluid is delivered in use;
(d) an inflatable bag contained within said interior space, said inflatable bag inflatable to press the flexible bag thus creating a fluid pressure within said flexible bag causing a tendency for said fluid to flow from said flexible bag through said tube for delivery to said second end of said tube;
(e) means for inflating said inflatable bag in response to a signal;
(f) control means which responds to said fluid pressure within said flexible bag for generating said signal when said fluid pressure in said flexible bag is less than a desired fluid pressure, said control means comprising:
(i) a substantially inflexible base member;
(ii) a resilient spring plate having a first end and a second end, said plate attached to said base member at said first end, said second end free to flex toward and away from said base member, said second end biased toward said base member;
(111) a bladder in flow communication with said flexible bag wherein said bladder inflates in response to an increase in said fluid pressure and deflates in response to a decrease in said fluid pressure, said bladder compressed by said plate between said second end of said plate and said base member such that said second end of said plate flexes away from said base member in response to an inflation of said bladder and flexes toward said base member in response to a deflation of said bladder; and (iv) means to generate said signal when said plate flexes toward said base member in response to a deflation of said bladder in response to a decrease in said fluid pressure to less than said desired fluid pressure. - 2. The portable infusion device of claim 1 wherein said inflation means comprises a diaphragm air pump pneumatically coupled with said inflatable bag.
- 3. The portable drug infusion device of claim 1 wherein:
(a) said resilient spring plate comprises a thin metal plate;
(b) said inflating means comprises an electric air pump and an air pump power supply, said air pump inflating said inflatable bag in reponse to an electrlcal current from said air pump power supply; and (c) said signal generating means comprises a normally open switch circuit electrically connected in series between said electric air pump and said air pump power supply, said switch circuit closed by said second end of said metal plate when flexed toward said base member in response to a deflation of said bladder in response to a decrease in said fluid pressure to less than said desired fluid pressure. - 4. The portable drug infusion device of claim 3 wherein said control means further comprises:
(d) a second switch circuit electrically connected in series between said electric air pump and said air pump power supply, said second switch circuit opened by said second end of said metal plate when flexed away from said base member in response to an inflation of said bladder in response to an increase in said fluid pressure to greater than a maximum desired fluid pressure, said second switch circuit interrupting said electrical current to said air pump when opened. - 5. The portable drug infusion device of claim 3 wherein said bladder, said flexible bag and said tube are composed of a medical grade vinyl.
- 6. In a portable infusion device, means for controlling delivery of a fluid from a flexible bag, said delivery caused by fluid pressure in said flexible bag, said device having means for increasing said fluid pressure in response to a signal generated when said fluid pressure is less than a desired fluid pressure, said control means comprising:
(a) a substantially inflexible base member;
(b) a resilient spring plate having a first end and a second end, said plate attached to said base member at said first end, said second end free to flex toward and away from said base member, said second end biased toward said base member;
(c) a bladder in flow communication with said flexible bag; said wherein said bladder inflates in response to an increase in said fluid pressure and deflates in response to a decrease in said fluid pressure, said bladder compressed by said plate between said second end of said plate and said base member such that said second end of said plate flexes away from said base member in response to an inflation of said bladder and flexes toward said base member in response to a deflation of said bladder; and (d) means to generate said signal when said plate flexes toward said base member in response to a deflation of said bladder in response to a decrease in said fluid pressure to less than said desired fluid pressure. - 7. A portable drug infusion device comprising:
(a) a flexible bag, said bag filled with a fluid to be delivered; said flexible bag having an outlet;
(b) fluid pressure increasing means, whereby fluid pressure is increased in response to a signal generated when said fluid pressure is less than a desired fluid pressure;
(c) control means for controlling delivery of said fluid, said control means comprising (i) a substantially inflexible base member;
(ii) a resilient spring plate having a first end and a second end, said plate attached to said base member at said first end, said second end free to flex toward and away from said base member, said second end biased toward said base member;
(d) a bladder in flow communication with said flexible bag; said bladder connected to inflating means; wherein said bladder inflates in response to an increase in said fluid pressure and deflates in response to a decrease in said fluid pressure, said bladder compressed by said plate between said second end of said plate and said base member that said second end of said plate flexes away from said base member in response to an inflation of said bladder and flexes toward said base member in response to a deflation of said bladder; and (e) means to generate said signal when said plate flexes toward said base member in response to a deflation of said bladder in response to a decrease in said fluid pressure to less than said desired fluid pressure. - 8. The portable drug infusion device of claim 7 wherein:
(a) said resilient spring plate comprises a thin metal plate;
(b) said fluid pressure increasing means comprises an inflatable bag inflated by inflating means, said inflatable bag adapted to press against said flexible bag to increase said fluid pressure in said flexible bag;
(c) said inflating means comprises an electric air pump and an air pump power supply, said air pump inflating said inflatable bag in response to an electrical current from said air pump power supply; and (d) said signal generating means comprises a normally open switch circuit electrically connected in series between said electric air pump and said air pump power supply, said switch circuit closed by said second end of said metal plate when flexed toward said base member in response to a deflation of said bladder in response to a decrease in said fluid pressure to less than said desired fluid pressure. - 9. The portable drug infusion device of claim 8 wherein said control means further comprises:
(e) a second switch-circuit electrically connected in series between said electric air pump and said air pump power supply, said second switch circuit opened by said second end of said metal plate when flexed away from said base member in response to an inflation of said bladder in response to an increase in said fluid pressure to greater than a maximum desired fluid pressure, said second switch circuit interrupting said electrical current to said air pump when opened. - 10. The portable drug infusion device of claim 8 wherein said bladder, said flexible bag and said tube are composed of a medical grade vinyl.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/155,220 US5399166A (en) | 1992-11-23 | 1993-11-22 | Portable infusion device |
| US08/155,220 | 1993-11-22 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2136286A1 CA2136286A1 (en) | 1995-05-23 |
| CA2136286C true CA2136286C (en) | 1999-05-04 |
Family
ID=22554547
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2136286 Expired - Lifetime CA2136286C (en) | 1993-11-22 | 1994-11-21 | Portable infusion device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2136286C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115957393B (en) * | 2022-12-07 | 2023-12-15 | 香港大学深圳医院 | Chemotherapy pump |
-
1994
- 1994-11-21 CA CA 2136286 patent/CA2136286C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2136286A1 (en) | 1995-05-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |
Effective date: 20141121 |