CN117083096A - Myocardial jet perfusion device - Google Patents

Abstract

The invention relates to the following hardware and method: it uses a 14-18 gauge cannula, typically equipped with a retractable trocar, to inject a sufficient amount of frozen saline or cryoprotectant solution directly into the left ventricle of the heart of a patient or animal undergoing cardiac arrest or early cardiac arrest to create a frozen blood stream through the two carotid arteries, two vertebral arteries, and the brain, thereby cooling the brain or other vital organs. Typically, sufficient saline or cryoprotectant solution is injected at a sufficiently high pressure to produce a baseline common carotid blood flow of 30%. The cannula device with the cooperating sharp-tipped retractable trocar, in combination with its surrounding flexible and rigid shield, septum and stopcock, provides a sterile, self-sealing system suitable for use in a "field" or hospital environment.

Description

Myocardial jet perfusion device

Cross Reference to Related Applications

This patent application claims priority to each of the following four U.S. provisional patent applications, which are incorporated herein by reference: U.S.63/126,119 submitted on 12/16 2020; U.S.63/126,130 submitted on 12/16/2020; U.S.63/132,165 submitted on 12/30 2020; U.S.63/132,192 submitted on 12/30 of 2020.

Technical Field

The present invention is a method and apparatus for inhibiting tissue metabolism in a brain region, and more particularly, for inducing localized therapeutic hypothermia or systemic therapeutic hypothermia or both.

Background

Systemic hypothermia can significantly delay the deterioration of neurological function in hypoxic or anoxic tissues, and hypothermia has long been recognized as preventing brain damage during cardiac arrest. Although originally thought to be due to reduced metabolism, low temperature inhibition of triggering events during ischemia and reperfusion injury are now considered to be the cause of hypoxia injury, since oxygen reserves are depleted in the early stages of low temperature cardiac arrest. Thus, low temperatures are now known to reduce oxygen demand of tissues and inhibit pathological processes that occur during cardiac arrest and after recovery of blood circulation. For example, accidental immersion in cold water, and the corresponding systemic hypothermia resulting therefrom, always contributes to the survival of the nervous system of accident victims who would otherwise suffer from irreparable brain damage. Observations of this phenomenon have prompted physicians to induce systemic hypothermia during various surgical procedures that produce hypoxia and anoxia to reduce the patient's systemic metabolism and associated global oxygen requirements, and to inhibit deleterious processes.

In particular, low temperatures have been widely used in cardiac and neurosurgical procedures where cardiac arrest must be induced to safely perform the procedure. Low temperature is also used to alleviate brain damage after spontaneous blood circulation is restored after cardiac arrest. Although the low temperatures induced before cardiac arrest are more effective than those induced after cardiac arrest, clinical trials have shown that in some cases there are some benefits even to post cardiac arrest low temperatures, and some EMS systems do employ prior art post-arrest low temperatures when writing this document. The low temperature induced by external means during cardiac arrest has produced positive results in bench top studies, which has now been done in some centers as an additional treatment with cardiopulmonary resuscitation (cardiopulmonary resuscitation, CPR). It should be noted that while cardiopulmonary resuscitation is beneficial during cardiac arrest, it only produces about 10% of normal blood flow, which is insufficient to prevent brain damage for any period of continuous cardiopulmonary resuscitation (perhaps 20 minutes or more). At normal temperature, it is believed that about 30% of normal blood flow is required to prevent brain damage. While external cooling may be beneficial during cardiac arrest and CPR, it is widely recognized that only superficial brain structures may benefit from external cooling while deep structures will remain normothermic. Long-term cardiac arrest and cardiopulmonary resuscitation for hours still produce good neurological effects in cases where the asystole patient is subjected to low temperatures, typically in cold water drowning. Thus, rapid induction of cooling, particularly of the brain, has proven promising barriers to prolonged current 20 minutes of cardiopulmonary resuscitation at ambient conditions.

One of the current methods of improving the effect, relative to CPR, is the treatment of cardiac arrest using venous arterial extracorporeal circulation or VA ECMO. Recent studies on early use of VA ECMO have significantly improved cardiac arrest effects and improved neurological effects. In such patients, cardiopulmonary resuscitation is replaced by blood flow from VA ECMO devices that mimic normal cardiac output and tissue perfusion. Once placed on the VA ECMO, the patient can be brought to the cardiac catheterization laboratory, where the coronary artery occlusion (and possibly stent insertion) is opened so that the heart can "stand alone" again. Placing the patient on VA ECMO is a very technically intensive procedure, requiring 10 minutes of surgery even in the most excellent hands, severely limiting downtime and transportation to the center where such treatment can be performed. The time required to perform VA ECMO surgery also limits the use of VA ECMO in hospitals to a small extent, as delays of only a few minutes can have a serious negative impact on the neurological effects. Thus, VA ECMO is an important technique for treating cardiac arrest patients, but VA ECMO itself does not provide any similar "time-to-purchase" benefit that would be achieved if low temperatures were induced in similar circumstances.

Currently, there is less difficulty in inducing systemic hypothermia in a hospital environment, but currently it is difficult or nearly impossible to induce systemic hypothermia in an emergency in a non-hospital environment. Thus, while such hypothermia would provide beneficial metabolic inhibition, and such effects have been well known and demonstrated, induction of systemic hypothermia currently does not form part of, for example, pre-hospital emergency cardiac arrest care (e.g., cardiopulmonary resuscitation (CPR)). To date, similar emergency procedures that have not induced hypothermia include pre-hospital emergency care for severely shocked or stroke patients. As mentioned above, cooling after cardiac arrest is sometimes performed by caregivers through the use of cold packs and non-regular infusion of cold intravenous fluids at will, but these do not provide adequate systemic cooling in an arbitrarily controlled manner.

In addition, induction of localized hypothermia has been widely used for non-hospital or pre-hospital treatment of various physiological conditions. Some type of cold pack is the standard equipment in first aid kits for reducing peripheral blood flow and corresponding swelling in the event of bruise, insect bites or stings, nose bleeding, sprains, etc. Of course, cold head dressing has long been the standard symptomatic relief of headache and fever. However, in addition to these common treatments, three less well known uses of topical cold compress are described in U.S. Pat. nos. 2,438,643, 3,175,558 and 4,552,149.

U.S. patent No.2,438,643 discloses a bag for local frozen anesthesia that includes a plurality of waterproof compartments containing saline and an absorbent material (e.g., wood chips). The pack may be cooled in any suitable refrigeration device and then used as a partial cold pack. Because the bag must be refrigerated, its use to induce localized hypothermia is limited to areas where refrigeration is available.

U.S. patent No.4,552,149 also discloses a refrigerant-dependent cold pack containing a coolant, more specifically a head coolant device. The device comprises a main body composed of cooling elements for covering the top of the head and a plurality of cooling elements arranged radially around the main body for covering the front, side and rear of the head. Such head cooling caps are designed to inhibit hair loss during administration of drugs or chemotherapeutics where hair loss is a known side effect. As with all cold packs requiring refrigeration, the head coolant apparatus is most suitable for hospital and home applications and is less suitable for pre-hospital emergency care types where traditional (powered) refrigeration is not common.

U.S. patent No.3,175,558 discloses a thermal treatment pack designed for post-partum application to the female perineum containing unreacted components of the endothermic reaction. Unreacted components are separated by frangible barriers, time release capsules, or both and remain separated until a cold pack is needed. In use, the reactants are mixed by, for example, manually breaking the frangible barrier between the reactants, thereby initiating the endothermic reaction and lowering the overall temperature of the cold pack and its contents. The pack is placed on the patient as needed to cool the application area by reverse conduction heating of the pack by the body.

In several prior art devices, cooling of the liquid in the device is achieved by an endothermic reaction between water and ammonium nitrate, which typically appears as a group of precipitates. The amount and form of the reactants are generally selected to be liquids that do not fall below freezing to prevent freezing of the tissue and subsequent damage. This condition may produce sub-optimal cooling of the patient while avoiding tissue damage.

As mentioned above, prior art patents and techniques for localized cooling have only drawbacks that prevent their effective use in emergency treatment of cardiac arrest or severe shock in this area. The inventions disclosed in U.S. patent nos. 4,750,493 and 4,920,963 address and overcome some of these deficiencies at an earlier time by providing deep header cooling that can drive systemic cooling somewhat more effectively than localized cold packs. Even so, the device disclosed therein is still relatively bulky, preferably of size 2'x 2'. In combination with their typically considerable weight (around 25 lbs.), these devices are limited in the area that can be stored and deployed, let alone the inherent limitations in the ability of external cooling applications to produce deep internal cryogenic temperatures of optimal precision and accuracy.

Accordingly, there remains an unresolved need in the medical community for a portable device with a limited physical profile that provides controlled cryogenic temperatures for induced cooling of the skull and extracranial regions. Furthermore, there remains an unresolved need for rapid deep cooling of patients, particularly brain tissue, while avoiding tissue damage caused by icing. While such emergency methods and systems may require training for use by persons with care and treatment expertise, at a minimum, the system is preferably simple, easy to deploy, and easy to monitor even in "on-site" and off-site situations.

Disclosure of Invention

To meet the unresolved needs, the present invention pertains to: the brain is cooled by injecting a sufficient amount of frozen physiological saline or cryoprotectant solution directly into the left ventricle of the heart of a patient or animal that is cardiac arrest or early cardiac arrest, using a 14-18 gauge cannula typically equipped with a retractable trocar, creating a frozen blood flow through the two carotid arteries, the two vertebral arteries, and the brain. Since injection of frozen saline or cryoprotectant solution prevents heart restart, the present invention also includes the use of VA ECMO in animals or patients, as described above, as a complete cardiopulmonary bypass device providing respiratory and hemodynamic support, which can be used in the field and in any medical setting. Any respiratory and hemodynamic support equivalent to VA ECMO may be substituted for VA ECMO. Typically, sufficient saline or cryoprotectant solution is injected at a sufficiently high pressure to produce a baseline common carotid blood flow of 30% (as opposed to CPR which typically produces only 10% of the same blood flow), typically 1-2 liters for patients of average height and weight, never exceeding 2 liters in practice. The cannula device with cooperating sharp-tipped retractable trocar for selectively piercing the skin directly into the left ventricle of the heart, in combination with its surrounding flexible and rigid shield and stopcock, provides a sterile self-sealing system suitable for use in a "field" or hospital setting, in combination with VA ECMO or even simpler electric or even manual pumps for continuous or pulsatile liquid injection.

Drawings

Fig. 1A is a schematic diagram showing features of the present system, including but not limited to a trocar, stopcock, septum, flexible sheath, and elastomeric sheath, all in a closed sterile arrangement.

Fig. 1B is a perspective view of the trocar of the present invention in place through a cooperating stop cock valve.

Fig. 2 is a line graph showing the results of a preliminary study that will be compared and contrasted with a baseline with respect to blood flow (in CC/min) during cardiopulmonary resuscitation during left ventricular infusion.

FIG. 3A is a perspective view of an embodiment of the present trocar in which the cutting tip is solid and a partially hollow center terminates in a "bird's eye" hole near the cutting tip, the trocar being tightly mounted within a surrounding cannula, the trocar being free to move back and forth through the cannula and free to pass back and forth.

Fig. 3B is a perspective view of another geometric configuration of the cutting tip of a trocar, wherein the cutting tip is roof-shaped and solid, with a partially hollow center terminating in an eyelet near the cutting tip, the trocar being tightly mounted within a surrounding cannula, the trocar being free to move back and forth and pass back and forth through the cannula.

FIG. 3C is a perspective view of a trocar fitted with an external recess instead of an internal hollow center, tightly fitting within a surrounding cannula;

FIG. 3D is a cross-sectional view taken along line IIID-IIID of FIG. 3C;

FIG. 3E is a perspective view of an alternative configuration of a trocar with an external groove disposed within a surrounding cannula; and

fig. 3F is a perspective view of another configuration of a trocar with external grooves within a surrounding cannula.

Detailed Description

As described above, the present invention is directed to injecting an appropriate amount of a cryoprotectant or cryoprotectant directly into the left ventricle of the heart and using a 14-18 gauge catheter or equivalent thereof to create a flow of frozen blood through both the carotid and vertebral arteries and into the brain, thereby cooling the brain. Continuous injection of frozen saline or cryoprotectant for longer periods of time may produce more general hypothermia when needed, for example during emergency treatment of cardiac arrest or severe shock. Systemic hypothermia for a limited period of time is often suitable for ameliorating the negative consequences of stroke. Since injection of frozen saline or cryoprotectant prevents heart restart due to low temperature, the present invention also includes the use of VA ECMO (or its equivalent), a well-established (known in the art) portable cardiopulmonary bypass device that provides support for both respiratory and hemodynamic support, and can be used in both field and healthcare environments. Any respiratory and hemodynamic support device or protocol equivalent to VA ECMO may be substituted in connection with the inventive concepts described herein. Typically, sufficient saline or cryoprotectant is injected at a sufficiently high pressure to produce 30% baseline carotid blood flow, whereas CPR typically produces only 10-20% carotid blood flow. As described in detail below, a cannula device with a cooperating sharp-tipped retractable trocar for selectively penetrating through the skin directly to the left ventricle of the heart, along with its surrounding shield and stopcock, provides a sterile self-sealing system suitable for use in a "live" or hospital environment.

Direct left ventricular puncture is the optimal injection site for cold saline for several reasons. When using the left ventricle, only one puncture is needed to perfuse the entire cerebral vascular system. The left ventricle is thicker and typically self-seals, unaffected by small diameter punctures (e.g., trocars/14-18 gauge cannulas may be created or removed). Even if leakage occurs, the normal aortic valve restricts bleeding when VA ECMO is used, which can provide rapid transfusion and continuous infusion. Alternatively, if desired, the use of alternative guidewire embodiments (see fig. 1, modules F, G and H) would allow for percutaneous closure. In the case of cardiac arrest, the left ventricle is easily found. In contrast, a single artery is smaller, is more difficult to locate and manipulate in the event of cardiac arrest, is more difficult to cannulate than the left ventricle, is not as self-sealing as the left ventricle, and is often plaque, which can be inadvertently bumped and released, resulting in potentially catastrophic embolism. For these reasons, attempts to cannulate blood vessels, rather than left ventricle, are left unattended for injection of cooling fluid. By using high pressure infusion into the left ventricle, additional flow can be created by the venturi effect induced by the high pressure flow. These high infusion pressures will be better tolerated than any thin walled vessel given the left ventricular wall thickness. Thus, in the context of the present technology, it is preferred to inject and infuse a cold liquid into the left ventricle and not any other veins or arteries. The liquid itself may be cold physiological saline, cold protective liquid or any other cold solution suitable for infusion into the circulatory system of an animal or patient in need of cooling.

More particularly, therapeutic brain and whole body hypothermia can be achieved quickly and easily by the following techniques and hardware. The protective/therapeutic hypothermia state can be rapidly induced upon cardiac arrest by percutaneous left ventricular catheterization with a small diameter cannula (14-18 gauge) typically fitted with a retractable trocar for initial cutting and perforation, and high pressure infusion of cooled cardioplegic fluid into the left ventricle. Preliminary studies have shown that this technique can achieve 30% baseline cerebral blood flow in a short period of time (fig. 2). Thus, rapid brain cooling can be achieved quickly. Although it is speculated that a similar effect can be achieved by inserting a cannula in the carotid artery, this is technically much more difficult than intraventricular infusion as described above, because the need to insert in both carotid arteries, the need to place the cannula in a smaller target, and the risk of dislodging the arteriosclerotic plaque, can lead to stroke in the patient. When fluid is introduced into the left ventricle, positive flow is created by increasing the pressure of the left ventricle, causing the mitral valve to close and the aortic valve to open. By using high pressure jets, blood is generated within the circulatory system, thereby increasing the effective volume of perfusate. Left ventricular assist devices (left ventricular assist device, LVAD) require open surgical implantation of a cannula in the left ventricle on a semi-permanent/permanent basis, extending the replacement of cardiac output. In contrast, the present device is designed as a temporary (provisional) measure to achieve brain and organ protection, possibly re-cardiopulmonary resuscitation after infusion is completed. Only a limited amount (typically not more than 2 litres) of liquid can be infused in this way, since no liquid is returned to the pump and if allowed to continue indefinitely, a volume overload will occur in the patient. The blood flow of cardiopulmonary resuscitation, although insufficient at normal temperature, becomes sufficient to protect tissues, especially fragile brain substances, due to the reduced temperature of the brain and body. By using pulsatile flow (discussed further below), it is also believed that more filling between the jets in the left ventricle will occur with the patient's own blood, thereby increasing the volume of perfusate and allowing perfusion to occur at more effective levels than typical CPR. The cold cardioplegia solution is kept at a relatively low temperature because each jet requires cooling of a larger volume of the patient's own blood.

As described in more detail below in connection with the figures, a stiff (possibly metallic) trocar/cannula insertion device is required to penetrate into the left ventricle as compared to a simpler percutaneous intravascular device, because a powerful penetration device is required to penetrate through all tissue layers (including the wall of the left ventricle) to access the left ventricle. The use of a more powerful, stiffer cannula will prevent kinking and curling during and after insertion. (a more flexible, less solid cannula is more prone to migration after insertion and is affected by "catheter pull", which may be detrimental to the left ventricle.) a stiff cannula will also allow the jet to better point to the left ventricular outflow tract/aortic valve. Small diameter cannulas are also known to be removable from the left ventricle at high percentages without requiring surgery to close the ventricular insertion tract. Since the patient will normally be placed on the VA ECMO anyway and the perfusion from the VA ECMO device will reach the aorta from the opposite direction upwards, the aortic valve will prevent any loss of blood from any continuously open channel in the left ventricle until spontaneous circulation is restored. Since it is thought that a brain and whole body maintenance state can be achieved, immediate restarting of the heart in the field is not a concern, as in case of unexpected low temperatures, cardiopulmonary resuscitation limits without brain damage may extend to several hours, depending on clinical data. In one simulation, as shown in FIG. 1A (see modules F-G-H), a guidewire may be inserted into a channel extending from the puncture site to the left ventricle. By holding the guidewire in place, commercially available occlusion materials can be passed through the guidewire and used to occlude the left ventricular tract when needed. In addition, if reinsertion of the cannula is desired, it can also be passed through the guidewire. The guidewire is uniquely configured to: the outer member is made of a malleable pre-treated sheath that can be folded/accordion folded to prevent the guidewire from being lost in the passageway. A simple sterile dressing may be placed over the outer section of the guidewire to maintain its sterility.

The device also has a number of features to verify optimal positioning. If an ultrasound device is available, the optimal location can be determined by this technique if the clinician is skilled in using ultrasound. In order to make it possible to verify the cannula position, the construction of the trocar must allow blood to be aspirated from the left ventricle after it has been pierced. When the cannula is inserted "blindly", that is, without ultrasound or any other imaging guidance, this will confirm whether placement is appropriate. Typical trocars are solid in construction, but current trocars are either hollow or cooperate with side channels that allow blood flow, as discussed in more detail below (although the cutting tip of the trocar must be solid). The need for the robustness of the trocar cutting tip is that if the trocar is configured similar to an IV catheter with a hollow-centered stylet (a substantially hollow trocar) throughout the tip, the cutting tip may create coring that penetrates tissue. This coring may lead to embolism after the current infusion begins. A completely hollow trocar tip may also interfere with attempts to aspirate blood from the left ventricle to confirm positioning of the present cannula. Thus, several embodiments of any cutting shape of the current trocars ("pencil point", hexagon, etc.) are contemplated. These all require a solid or mostly solid sharp trocar tip with a different geometry, however, the central portion of the trocar (rather than the tip itself) will be hollow starting from the "bird's eye" near the cutting tip. The bird's eye creates a conduit that can "pull back" the fluid (including blood) flow to ensure that the trocar/bird's eye/conduit is indeed properly positioned in the left ventricle. If ultrasound is used, the confirmed localization can be further verified or optimized by visualized blood flow generated within the left ventricle. As further explained with respect to the figures, rather than completely removing the trocar after initial deployment, the trocar may be retracted within the sealing system to allow reinsertion of the trocar, drawing blood/fluid back through the bird's eye to establish left ventricular positioning to reconfirm cannula positioning by "aspiration" without introducing external contamination or accidental introduction of air. Furthermore, instead of containing a hollow center, the trocar may advantageously be externally grooved in a manner that allows aspiration from the left ventricle, and this groove creates a virtually hollow channel when the trocar is in place in its tightly fitting cannula. For practical reasons, grooved trocars are generally easier and stronger to manufacture than hollow trocars, mainly due to the narrower gauge of the trocars. Such a grooved trocar may be used in other medical areas where a cannula or catheter is placed, and it is desirable to sample or even inject fluid prior to removal of the trocar. When an obturator is used during insertion, a slotted trocar, that is, a trocar with a substantially rounded tip, may also be used. In particular, insertion of an intraventricular catheter may be one application of the slotted trocar of the present invention because the obturator needs to be removed and replaced repeatedly in order to determine whether the cannula tip is within the ventricular space of the brain. As modified below and discussed further below, the trocar may be removed upon successful placement of the cannula within the left ventricle and contained within the sterile field of the present device while the needle is shielded to prevent inadvertent penetration by the needle by the patient, operator or bystanders. This is also an option if it is desired to remove the trocar entirely from the device, considering the positioning of the stopcock through which the trocar passes. The transparent sheath material will be easily torn off of the above-described plug valve and the septum into which the trocar tip is initially inserted may and should be made of a self-sealing polymer. There is an additional port (D) (see fig. 1A) that can be repeatedly aspirated during infusion as needed to re-verify cannula position.

Optimally, the device consists of a fully sealed percutaneous myocardial puncture cannula/trocar device, used in association with a cardioplegia fluid reservoir/pump (fig. 1, items a-E, I and J), and with optional Seldinger guidewire features (fig. 1, items F, G and H) to mark the insertion tract of the left ventricle. All of these features are further disclosed and explained in connection with the accompanying drawings.

Referring now to fig. 1, module a contains the main cannula 10 of the present invention. It is inserted using a specially designed trocar as shown in module B and designed to be used in conjunction with the main cannula 10. The main cannula 10 is in the range of 14 to 18 gauge or equivalent conduit sizes. The main casing is connected to the casing joint 12 via a casing joint connector 14. The cannula connector is typically a threaded male/female connector, but may be any connector (snap-in, press-fit, etc.) that is capable of similarly maintaining a liquid tight, sterile system. Adjacent the cannula hub connector 14 is a distal plug valve 16. The distal plug valve 16 is directly connected to a distal plug valve rigid housing 18, which distal plug valve rigid housing 18 is a hollow tube connected to the plug valve at the distal end of the tube, while the proximal end of the hollow tube is completely covered by a rigid housing septum 20 (the housing is rigid, rather than the septum 20 itself, the septum 20 itself being flexible and generally self-sealing permeable). The rigid housing septum 20 is made of a flexible, resilient polymer that can be broken (pierced) by the present trocar, but optimally self-seals when the trocar is retracted. As shown in FIG. 1A, the trocar 22 has been pushed through the rigid housing membrane 20 and the trocar cutting tip 24 is shown in a proximal position of the distal stop cock valve 16, wherein the trocar cutting tip 24 is fully covered and unable to puncture any operators, patients or bystanders.

With respect to fig. 1A, it will be appreciated that the linear connection of the trocar base 26, trocar 22 and trocar cutting tip 24, all of which represent a long, continuous structure, is much longer than that shown in fig. 1A, and therefore has a break at block B. The trocar 22 needs to be long enough to extend away from the cannula distal tip 11 as it passes through the main cannula 10 to act as a cutting edge from the chest skin, through the patient's tissue and down into the left ventricle of the heart. After positioning the trocar 22 and its associated main cannula 10, the trocar 22 may be retracted to the position shown in FIG. 1A where the trocar is unobstructed but still contained within a sterile, enclosed environment, as will be further described below.

The sterility (pre-sterilization) of the pre-assembled structure of fig. 1A, particularly the main cannula 10 and its associated structures shown in paragraphs a and B, is likely to be largely achieved by the flexible sheath 29. The flexible sheath 29 may be made of any flexible polymeric material, typically much longer than shown in fig. 1A, possibly from 4 to 12 inches or more, up to about 20 to 24 or 30 inches. The flexible sheath 29 allows the trocar 22 to pass through the main cannula 10 to exit the cannula distal tip 11 because there is enough slack in the flexible sheath to allow this to be done, and the trocar can then be retracted without affecting the enclosed environment within the flexible sheath 29. As shown in fig. 1A, a flexible sheath 29 extends from and encloses the region between the distal and proximal stopcocks of the distal stopcock rigid housing (in a sterile region created by means known in the art), but the flexible sheath need only actually extend from the proximal end of the distal stopcock rigid housing to the trocar connector 28, so long as the interior of the flexible sheath is sealed and held so that it is free of a breach (except for a breach introduced into septum 20 by the cutting end of trocar 22 itself). In this manner, if the trocar 22 is inserted into a patient, then retracted, and then subsequently reinserted into the patient, the sterile field of the insertion site will remain, particularly when the distal stopcock 16 is selectively closed as desired.

In fig. 1A, the trocar base 26 is firmly anchored in the trocar connector 28, but anywhere else along the length of the trocar 22, the trocar 22 is free to move forward (distally) and rearward (proximally) through the main cannula 10, assuming the distal stopcock 16 is in the open position.

The liquid flow eventually entering the main cannula 10 is introduced by a liquid injector 32 or a functional or structural equivalent thereof, a manual pump, a hand pump or other liquid injection device. When the main cannula 10 is placed in position, the proximal plug valve 30 is maintained in the closed position. When cold liquid injection is initiated, the proximal stopcock should be manually opened and held in the open position throughout the introduction of liquid into the system.

During placement of the main cannula 10, particularly in the field, and without any guidance from the ultrasound waves to place the trocar cutting tip 24 and the main cannula 10 into the left ventricle of the patient to be treated, a method is needed to confirm proper cannula placement. (of course, ultrasound or fluoroscopic guidance may be used to place the main cannula 10, but such guidance may not be available in the field.) one way to confirm proper placement of the cannula distal tip 11 is to open the suction stopcock 40 and "pull back" the suction syringe 36 to ensure that blood is returned from the cannula distal tip 11 in place in the left ventricle (and associated left ventricular blood supply). This return can be optimally returned while the trocar is still in the initial insertion position, with blood drawn back into the trocar 22 through the bird's eye 35 and then back into the aspiration syringe 36 where the blood return can be seen at the aspiration syringe 36. Of course, even after the trocar is retracted, blood can be confirmed to be returned to the aspiration syringe 36 through the cannula tip 11. Thus, the aspiration syringe 36 has the advantage of providing a simple, mechanically confirming that the cannula distal tip 11 is indeed in the correct position in the left ventricular chamber of the heart. Of course, the aspiration syringe 36 is fitted with its own aspiration cannula 38 interconnected with an aspiration stopcock 40. After initial placement of the trocar 22 into the patient, while positioning the cannula distal tip 11 within the left ventricle, the only stopcock in the system that is initially in the open position is the aspiration stopcock 40 to allow the user to "pull back" to confirm flashback. When it is confirmed that blood has been returned, the suction stopcock 40 is closed and both the distal stopcock 16 and the proximal stopcock 30 are opened to allow a cold fluid passage from the fluid syringe 32 into the main cannula 10 and then into the left ventricle of the patient (in some cases assisted by the module C reservoir and pump connected thereto).

An optional feature shown in FIG. 1A is the provision of modules F-G-H for placement of an auxiliary Seldinger guidewire. Seldinger guidewires are known in the art, although never before used in a system according to the invention. If it is desired to remove the entire main cannula 10 (not just the trocar 22), but also to reinsert the cannula at a later time, the Seldinger guidewire may be inserted down the cannula and into the left ventricle to maintain the insertion path. The Seldinger guidewire has a flexible removable flange that allows for advancement through the infusion cannula. Upon exiting the tip of the infusion cannula, the program will deploy, preventing the guidewire from being lost in the patient, that is, the deployed configuration shown in module G will hold the guidewire in place in the patient so that the guidewire will not be inadvertently pulled out or dislodged. This module G option would allow another catheter or cannula than the initial cannula to be reinserted if desired or needed, or would facilitate the introduction of a left ventricular wall closure device if desired or needed.

Referring again to the trocar 22, with the trocar 22 in the fully inserted position within the patient, the tip of the trocar, its trocar cutting tip 24, is shown in the loaded (extended) position in the block labeled I, for puncturing the chest wall in an optimized orientation for successful access to the left ventricle. As described above, the trocar is a dedicated hollow or slotted trocar having at least one bird's eye such that the trocar is not hollow (or slotted) throughout its entire procedure to its distal tip. After confirming that the cannula/trocar is considered to be within the left ventricle, then the proximal stopcock 30 is opened and the trocar is flushed with ultrasound in doppler mode (if available) to verify that it is positioned within the left ventricle and that it has been flushed well. If fluoroscopy is used, the IV contrast agent is contained within the flush syringe, or within saline with doppler, but as described above, the aspiration syringe 36 may be used to aspirate back blood for verification when fluoroscopy or doppler guidance is not available, as blind insertion of the left ventricle using only anatomical landmarks is possible (although not optimal). The main cannula 10 is preferably composed of steel and the trocar 22, however, equivalent materials may be substituted. Considering that the trocar/cannula device needs to penetrate multiple hard tissue layers, plastic cannulas may be difficult to insert and may "fold" while steel does not. Steel will also be more readily visible upon ultrasonography or fluoroscopic observation, although a sufficiently strong plastic cannula may be impregnated with ultrasonographic or radiological marking material, as desired. After the cannula/trocar is considered in place within the left ventricle, the cannula may be attached to the skin by an attachment means, labeled J, which will also keep the puncture site sterile. Module J is not necessarily required if the cannula is expected to be removed immediately or quickly after the initial jet infusion. The trocar is then withdrawn to a length limited by the flexible sheath 29. If deemed necessary, the trocar 22 may be completely removed from the system by tearing the flexible sheath 29 and closing the illustrated stopcock to prevent air from leaking back into the system.

After being ready to begin jet infusion, the proximal stopcock 30 may be opened and additional flushing may be performed as a final verification of position. Proximal stopcock 30 will be turned to the closed position, module C-cardioplegia fluid reservoir and pump will be turned to the open position (including stopcock 46) -and the cardioplegia solution, which may or may not be cold in general (but is not necessarily), may be infused under high pressure with an electric pump, mechanical pump, or even a manual pump. In other words, if in field use, liquid pumping can be achieved by an electric motor or any manual pumping mode (fig. 1A, module C). The reservoir requires a capacity of about two liters. After the start of jet infusion, particularly when the distal stopcock valve 16 is also closed, the flexible sheath 29, with the trocar 22 retracted, will prevent air from entering the system via the venturi effect.

As described in the previous section, modules G and H are optional modifications as are modules F and represent additional features of a standard guidewire that are also contained within a transparent hermetic package. If it is desired to hold the guidewire in place but to remove the cannula, the guidewire will be advanced in a standard manner, with the attached flange G preventing the proximal tip of the guidewire from being lost within the cannula device-module a. Once the cannula device-module a is removed, the distal end of the guidewire can be manually secured to the now retracted cannula at the puncture site above the skin. To completely remove the cannula, the flange G will be broken off from the specially designed proximal module H of the guidewire. This will allow the guidewire to pass through the cannula module a so that the jet infusion device can be completely removed from the site. To prevent the guidewire from being lost in the patient, the proximal portion of the guidewire is typically specially constructed of a plastic substance having a "memory," suggesting that an optional folding point be provided within the proximal guidewire. These multiple fold points, once folded, will prevent the guidewire from being lost through the puncture site and into the patient where it would not be easy to retrieve the guidewire.

A sterile dressing may be placed over the outside of the guidewire to maintain sterility. Such a guidewire is placed for multiple uses. First, if reinsertion of the perfusion cannula is desired, the guidewire may be used. The fold point may be straightened and the catheter passed through the guidewire back into place. In addition, left ventricular puncture may result in sustained bleeding at the puncture site. Percutaneous insertion puncture sealing devices, such as those used in non-invasive VSD closures, may be passed along such a guidewire and may be used to non-surgically close the leaking puncture site.

The diagram in fig. 1A shows a completely closed system of left ventricular high pressure "jet" infusion of "cerebral palsy" solution, primarily for the brain, but also to facilitate protection of other organs during cardiac arrest, primarily as a bridge for VA ECMO. The figure shows the components of a fully implemented device. It is a closed system because introducing air into the left ventricle at any time can produce catastrophic results, leading to bubble embolism of critical organs (more specifically, coronary arteries/heart and brain). The device of the present invention is also a closed system with high infusion pressure tolerance to prevent detachment during high pressure infusion and to cause infusion fluid leakage and potentially air ingress into the left ventricle. The system is also closed to maintain sterility. The accompanying data (fig. 2) show that in animal models, the infusion pressure of the left ventricle through a 16-18 gauge catheter (for testing) allows the brain to achieve good flow rates, thereby enabling rapid cerebral palsy. By rapid cardioplegia, the brain and other organs, especially the heart, are protected, as the left ventricular infusion will rapidly cool the heart. Also as described above, the heart is more accessible than attempting to infuse through a single artery supplying the brain. Also as described above, individuals at risk may suffer from arteriosclerotic disease, and fragments of plaque may flow upstream into the brain when the needle is inserted, and may cause irreparable damage. The four arteries supply the brain, the right carotid artery, the left vertebral artery, and the right vertebral artery. By left ventricular infusion, all four arteries are involved in the infusion of cerebral palsy solution to the brain. Furthermore, small diameter punctures of the left ventricle are known to be mostly self-sealing. By using a small diameter piercing device, the likelihood of tissue damage due to imperfect insertion techniques may be minimized. The use of high pressure infusion would require existing blood within the cardiovascular system to aid in the perfusion of vital organs. By using an infusion solution that is extremely cold, the resulting mixed blood and infusion solution reaches therapeutic temperatures low after mixing.

Referring again to fig. 1, module a is an infusion cannula; module B is a trocar; the module C is an infusion reservoir and an infusion pumping device; module D is an infusion cannula position check device; the module E is a guide wire inserting module; module F is a sterile trocar retraction module; module G is a trocar positioning verification module; module H provides the optional guidewire hardware described above. From all of the above, it will be apparent that the present cannula device will be percutaneously inserted into the left ventricle through the left chest or upper abdomen, wherein the trocar is fully extended within the infusion cannula. By aspiration over the syringe shown in block G, since the trocar is a hollow trocar with bird-sized tip, once the tip is within the vascular structure, flashback will be obtained through the bird's eye when the trocar is in the correct position.

All of the above are briefly reviewed below. The syringe will be partially filled with a commonly used intravenous solution (e.g., physiological saline) or cardioplegic solution (e.g., a solution known in the art for open heart surgery). In the context of the present invention, a "cerebral cardioplegia solution" is any solution including, but not limited to, cardioplegia solutions of the prior art, which can be frozen and suitable for introduction into the blood circulation system of an animal or patient in need of the hyperthermia of the present invention. Ultrasound using the doppler mode can then be used to verify good location within the left ventricle by detecting flow resulting from injection into the hollow trocar and flow exiting through the bird's eye into the left ventricle. The tip of the infusion cannula and trocar may also be composed of a special echogenic material, which may additionally or alternatively be used to verify the position of the infusion cannula and trocar within the left ventricle. The serial trocar retraction module is composed of transparent plastic to visualize the procedure and includes a specific length that does not allow the tip of the trocar to leave the system when fully retracted (which can lead to potential puncture problems) but remains within the unused portion of the infusion cannula system. It is also a security feature for the provider. By maintaining sterility, the trocar may be reinserted into the infusion cannula if desired, so that the cannula may be repositioned. Both the trocar and the infusion cannula are rigid, strong metallic structures. This will better withstand high pressure infusion, including reduced catheter whip. Plastic catheters do not safely allow re-introduction of the trocar as such devices are known to cause the catheter to shear. The tip of the trocar is not hollow so as not to create a tissue core within the trocar nor to accidentally embolize during any infusion. Once the catheter position is verified within the left ventricle, the retracted trocar may begin infusion at high pressure. Then, various solutions can be injected using current data and practices, suggesting that any such liquid should also be cooled. Module C is an infusion reservoir and an infusion device. The solution may be cooled by various means and kept cold by suitable insulation. An electric infusion pump may be used, or a pneumatic pressure device may be used in high pressure intravenous infusion, or even a mechanical piston device may be incorporated. If it is desired to verify the position of the infusion cannula further after the trocar is retracted, module D may be used to aspirate blood or injection solution to verify the cannula position by doppler. Module G is a guidewire that can be inserted along the cannula into the left ventricle, which can remain inserted into the channel if one wishes to withdraw all infusion cannulas. The guidewire has a flexible removable flange that allows for advancement through the infusion cannula. Upon exiting the tip of the infusion cannula, a plan will be deployed that prevents the guidewire from being lost in the patient. This option would enable the Seldinger technique to reinsert another catheter or cannula after removal of the flange, or to facilitate introduction of the left ventricular wall closure device after re-straightening the "folded" outer portion of the guidewire.

Referring now to fig. 1B, an alternative embodiment of the trocar 22 has a trocar base 26 attached to an inner plunger portion of a trocar syringe 27 so that the trocar can be extended and retracted through the trocar syringe 27 without having to rely on the flexibility of the flexible sheath 29. The trocar 22 extends through the distal stop cock valve 16 (in the open position), similarly to that shown in fig. 1A, also through the hollow center of the cannula hub connector 14, and thence through and to the cannula distal tip (not shown).

Figures 3A-3F illustrate various embodiments of a trocar in combination with its adjacent cannula, including the shape of the cutting tip, and whether the passage to the vicinity of the trocar tip is a hollow inner tube within the trocar or a recess in the trocar that forms a hollow liquid tube within the cooperating cannula. In all of these figures, the trocar/cannula combination 300 has a trocar 322, an associated cannula 324, a trocar cutting tip 326, and a trocar hollow center 330 or trocar recess 332, through which the trocar 322 may pass in either direction within the associated cannula 324. Fig. 3A and 3B contain bird's eye holes 328. All of these structures and their functions have been discussed above.

While liquid may be injected into the system at a constant flow rate, a preferred cold liquid injection will be a pulsed injection, for example, 60 to 100 pulses per minute. Such pulsed injections may be performed manually or using a manual or computer controlled electric or other pump (see block C of fig. 1A). When a pulsating flow is introduced, about 30-50% of the pulse time will be the actual liquid injection, balancing "recovery". Thus, for a pulsatile flow injection of 60 pulses per minute, about.3-5 seconds will be a liquid injection and the rest of the time will be a recovery period during which the left ventricle may contract and refill or otherwise equilibrate. Pulsating flow enhances cooling by promoting faster mixing of cold liquid into the liquid flow in the patient, while direct uninterrupted flow is also considered detrimental to mixing.

While the invention has been particularly described hereinabove, it is limited only by the scope of the invention as set forth in the following claims.

Claims (15)

1. A percutaneous myocardial jet perfusion apparatus, comprising: a co-trocar and cannula device for perforating and cannulating the left ventricle of the heart of a patient or animal in need of such treatment; a liquid reservoir; a quantity of liquid that fills the liquid reservoir and test syringe, wherein all cooperating elements are contained within a sterile closed system within which the trocar can be advanced and retracted.

2. The device of claim 1, wherein the cooperating trocar has a solid cutting tip.

3. The device of claim 2, wherein the co-trocar has a solid cutting tip and a bird eye aperture adjacent the solid cutting tip.

4. The device of claim 3, wherein the bird eye aperture is connected to a hollow tube within a trocar.

5. The device of claim 3, wherein the bird's eye aperture connects to a groove in the cooperating trocar that forms a fluid passageway with the cannula.

6. The device of claim 3, wherein the cooperating trocar is retractable through the cannula.

7. The device of claim 3, wherein the co-trocar and cannula are controlled by at least one stopcock or syringe.

8. The device of claim 3, wherein the cannula contains an associated guidewire.

9. A device according to claim 3, wherein the cannula contains an associated aspiration syringe.

10. A device according to claim 3, wherein the cannula contains an associated reservoir and pump.

11. The apparatus of claim 10, wherein the pump is a manual pump.

12. The apparatus of claim 10, wherein the pump is an electric pump.

13. The apparatus of claim 10, wherein the pump is configured to provide a pulsating liquid flow.

14. The apparatus of claim 10, wherein the pump is configured to provide a pulsating liquid flow of between 60 pulses per minute and 100 pulses per minute.

15. The apparatus of claim 10, wherein the pump is configured to provide a pulsating liquid flow, wherein pulses generated by the pump have a duty cycle, wherein 30-50% of the periodicity of the pulsating flow is actively pumping.