Chapter 9: Blood Substitution
Alcor 1997 Stabilization and Transport Manual
Table of Contents
Most patients will be transported to Alcor Headquarters from distances of more than a few hours’ drive away, and transport preparations will include washing out the patient’s blood and replacing it with an organ preservation solution. Any mortician will be able to carry out a blood washout using a solution provided by Alcor. Only the most experienced transport team members will have the necessary training and experience to execute this step independently. However, local team members may be responsible for setting up a site for the washout, and a rudimentary understanding of the reasons for this step is necessary to explain it to a mortician.
During ischemia, many components of the blood will settle, making it more difficult to circulate fluids once external cardiopulmonary support is initiated. Further, some of the things which settle on the blood vessels walls will eventually break through the wall, leaving holes in the vessel. One example of cells which do this is leukocytes.
Leukocytes are white blood cells which scavenge for bacteria and combat infection. There are trillions in the body. During ischemia, 80% of them will be damaged. If these leukocytes aren’t removed from the blood, they will hinder attempts to restore metabolic stability after a short period of oxygen deprivation.
In the case of cryonic suspension patients, it becomes easier to restore the semblance of balance by completely replacing the degrading blood with a fresh solution that closely mimics the healthy composition of blood. Cryonic suspension patients will not be going home after the application of the cryonic suspension procedure, and therefore somewhat more extreme (and effective) measures may be taken in their care which are not available to conventional emergency medical personnel.
Washing out the patient’s blood will serve to remove many of the damaged cells and cellular components and replace them with robust counterparts.
For patients whose death involved massive bleeding, it may not be possible to perform a washout. Contact Alcor Headquarters if there is any doubt.
Mechanics
Basically, this part of the transport preparations requires performing surgery to expose the femoral arteries and veins, opening those vessels, inserting tubes into the channels, displacing the blood with another fluid on one side, and letting the blood drain on the other. This may be done by a mortician, if the organ preservation solution is on-hand.
If trained Alcor personnel and equipment are available, a more complex washout may be attempted. The blood replacement may then also be used to cool the patient quickly through the introduction of a heat exchanger into the washout circuit. Alcor’s Remote Emergency Response Kit (“remote kit”) and the ambulance (with the MRC III) are both equipped for this level of washout.
The remote kit contains a surgical kit, a blood pump, a pressure monitor, a heat exchanger, and a tubing pack which allows for the venting of air from the lines. In addition, it contains various drapes which enable the transport team to create a sterile environment which duplicates that of an operating room. It also carries a few devices which, if the team is allowed to use them, may help predict the time of death.
Footnote: One example of a device which may be useful in predicting time of death is the pulse oximeter. The pulse oximeter measures the oxygen-carrying capacity of arterial blood. A sensor is secured (the sensor has been designed to grip, but may also be taped as needed) to the patient’s earlobe, fingertip, or other well-vascularized area. The monitor will register the patient’s pulse and a percentage. Normal percentages are between 95%-98%. Anything below 80% is cause for serious alarm. Most people will not survive this for long. A consistently dropping oximetry reading will allow the transport team to be prepared before the reading reaches 80%. Alcor currently has one pulse oximeter, and it is kept in the central remote kit. Pulse oximeters are used before the patient is pronounced, therefore it may only used in cases where the patient and physician agree to its use.
If appropriately trained team members and equipment are available, the remote kit will be used during the blood washout. If they are not available, a cooperating mortician will be needed to implement this part of the stabilization.
Mortician Assistance
A mortician won’t have the necessary equipment to both remove the patient’s blood and circulate the substitute down to 3-5°C (the desired transport temperature). This is unfortunate, but does not prevent the goal of this aspect of the protocol — to remove the patient’s blood and its damaging elements. The mortician does have the personnel and equipment to do this.
Any mortician who agrees to assist with this step will be properly compensated. Any expenses incurred should either be invoiced or paid-in-full prior to departure, depending on the mortician’s preference.
In order to carry out this step, the mortician or transport team members must have a replacement solution, which Alcor will supply. Either DuPont’s Viaspan or Alcor’s MHP-1 will be used. A mortician will generally assist with the surgery for circulatory system access. Femoral vessels will usually be used to provide access to the circulatory system, since they are large and near the surface. Morticians have a great deal of experience in accessing vessels, and can usually cannulate the femoral arteries and veins in little time.
These professionals are capable of providing support in excess of simply filling out paperwork. If they offer their assistance, accept.
Gravity Flush
The “gravity flush” is the simplest of all forms of blood washout. It involves no pumps and little tubing. It involves cannulating a femoral artery, pushing fluid into the patient, and draining blood from a small hole in the femoral veins. Gravity provides the necessary pressure to flush the circulatory system.
Gravity provides less pressure than either a conventional medical pump or an embalmer’s pump. It will be less effective at overcoming the problem of sludging and clotting than the alternatives. A gravity flush is only to be used if there are no pumps available, as would be the case only if the remote kit or ambulance wasn’t on-site and the mortician was uncooperative.
Pressure may be calculated at 23mmHg per foot of height that the solution bladders are raised above the patient.
Gravity Flush Circuit
Pack the Loading bags in ice water until use. |
Embalming Method
This method does not refer to the fluid perfused into the patient, as that won’t change. It refers instead to the pump used in the blood wash-out. It is to be used only if the ambulance and remote kit are unavailable.
The embalmer’s pump is connected to the inlet end of the tubing, and the blood still drains out the opposing side. These pumps usually have knobs which allow for some control of the pressures exerted on the blood substitute. Generally, these pumps are calibrated in terms of pounds per square inch. Normal metabolic pressures range from 116-144mmHg mean arterial pressure (MAP). Use the patient’s normal blood pressures to determine the rate of flow for the embalming pump, if they are known. Typical washout pressures are usually at the low end of the normal range.
Several cautions must be emphasized:
- Using perfusion pressures significantly higher than are advised may result in the capillaries exploding. Without a complete vascular bed, there will be no chance of the patient receiving an adequate cryoprotective perfusion in Scottsdale.
- The mortician’s embalming pump will almost invariably be dirty. Transport team members must examine the pump and tubing, clean, and rinse them before allowing them to be used on the patient. Every attempt must be made to duplicate a medical environment, and this demands cleanliness of the highest standards possible.
| Caution: If a mortician’s embalming pump is used during washout, it must be thoroughly cleaned and rinsed before use.
Pressure must be adjustable to within 1-3 pounds per square inch. |
Do not allow the mortician to perfuse the blood substitute through any vessels other than the femorals. For example, if the carotids are used, the vessels must be repaired prior to the start of cryoprotective perfusion. Currently, cryoprotective perfusion begins once cannula (basically, the medical-grade tubes which are inserted into the circulatory system for perfusion) have been inserted into the heart and connected to the perfusion solution. Since the heart is used, the carotids (the primary vessels feeding the brain) must be intact for perfusion if the brain is to receive flow. Repairing damaged blood vessels is a delicate task, at best. Have the mortician use the femorals, and make certain that these vessels are securely tied off once the blood washout is complete. In the past, these vessels have occasionally been left open, and during the subsequent cryoprotective perfusion, much of the cryoprotectant was lost through these breaches in the circuit.
Because the fluid cannot be recirculated to thoroughly cool the patient (as is the case with cardiopulmonary bypass), the blood substitute must be as cool as possible prior to beginning the washout. Keep the solution on ice until it is needed. These solutions do not cool quickly, so holding up the washout for a few more minutes’ cooling time usually won’t make a significant difference. In these cases, it is best to replace the blood as quickly as possible and get the patient, on ice, to Scottsdale.
It may be possible to gather samples of the patient’s blood at the point where it drains. (At a mortuary, blood generally drains into the sink.) If so, be careful to gather the samples before they become contaminated by the sink or drain. If non-sterile tubing is used, there will be no hope of collecting uncontaminated samples. Keep any samples gathered on ice, and then tape them to the patient’s forearm and surround them with ice for shipment.
All samples should be labeled with the patient’s Alcor number and time, as a minimum.
One final caution. Using an embalming pump will increase the possibility of introducing air into the circulatory system. Many embalming pumps contain a rotor at the bottom which stirs the solution prior to introduction. If the fluid level gets sufficiently low, a vortex will form in the bottom of the fluid container. There is little that can be done for microbubbles, but introducing the large bubbles of a vortex can be avoided. Stop the perfusion before any of these bubbles enter the tubing.
Cardiopulmonary Bypass
This is the most effective and controllable type of blood washout available to Alcor personnel. It requires a complex array of tubing which is carried primarily in the ambulance and remote kit.
During a transport, the ambulance, specifically the Mobile Rescue Cart (MRC III), provides the most efficient arrangement for implementing cardiopulmonary bypass. All of the equipment needed is contained within or is part of the MRC III. The MRC series was initially designed by Jerry Leaf, Hugh Hixon, and Mike Darwin and was a tremendous advance in emergency medical care. The MRC enabled a transport team to initiate cardiopulmonary by-pass and then move a patient to the Alcor facility for cryoprotective perfusion while still maintaining circulatory flow and cooling.
Both the ambulance and the remote kit contain the necessary equipment to cool the patient effectively to 3-5°C, and are used for that purpose.
For the purpose of illustration, the MRC III will be used in this description of cardiopulmonary bypass. The remote kit contains identical elements, and the equipment must be assembled to specifications which match those of the MRC.
The Mobile Rescue Cart, Past and PresentAlcor’s local response capability hinges on the ambulance and the mobile rescue cart (formerly referred to as the “mobile advanced life support system”). The primary purpose of the mobile rescue cart (MRC) is to allow for field cardiopulmonary support through mechanical means and through extracorporeal perfusion. It was first discussed in Cryonics magazine (March, 1987):
Jerry Leaf, then Alcor’s suspension team leader and President of Cryovita, initiated the project after seeing professional perfusionist literature discussing custom perfusion carts. Estimates for the prototype ranged from $150,000 to $250,000 and were well beyond what Alcor and Cryovita were able to spend on this project. Jerry, Mike Darwin, and Hugh Hixon decided to build one independently. Jerry and Mike found a Travenol Life Support Litter, a folding, aluminum gurney which accommodated a Brunswick HLR “Thumper”, a cardiac monitor-defibrillator, two small oxygen cylinders, and three storage drawers. These acquisitions were turned over to Hugh, who then remounted the drawers and built support frames for the tubing pump, two 12-volt batteries, a battery charger, a tubing (roller) pump, a noisy vacuum pump, a water pump, and vacuum distribution pump. Once struts were added to mount an oxygenator and monitoring instruments, the gurney no longer folded and was bowed in the middle. Jerry replaced the bottom struts with steel tubing, and brought the weight to about 450 pounds. At this weight, the original design specification of “easily transportable” eluded the team, and ultimately resulted in a lift gate being installed on the ambulance (much to the delight of the transport team members). Over the years, the Brunswick HLR was replaced with a Michigan Instruments HLR, which was both more reliable and more effective, the cardiac monitor was removed, a portable ice bath was mounted on top, and a circuit for circulating ice water was added. Modification to the perfusion circuit was also required, especially after the suspension of Jerry Leaf in 1991. Original tubing packs for the MRC I consisted of assorted tubing components, which were assembled by Jerry in the field. He was an experienced perfusionist and fully capable of stringing a pump on the fly and often raided other sources for missing pieces, but this meant that no one else (unless they were also a perfusionist) would be able to string the pump. After Jerry’s suspension, responsibility for the perfusion circuits fell to Hugh Hixon, who has implemented a simpler system. Hugh’s system includes all necessary circuit components, an assembly diagram, and tubing labeled for assembly. There are also training packs available for practice. Keith Henson accepted the challenge of designing the MRC II and began fabrication with a gas welder and steel tubing. Although the MRC II was never completed, it demonstrated the utility of steel framing. When Keith’s project was delayed, Hugh picked up the ball and ran with it. After purchasing enough equipment to furnish a small welding shop, Hugh built the MRC III. This one weighs 625 pounds and cost about $6,500 to construct. It took about four months and has incorporated many improvements over the original design.
Hugh Hixon was the prime force behind the improvements to this critical aspect of Alcor’s emergency response infrastructure. He did most of the work himself, with assistance from Tanya Jones, Scott Herman, and Keith Henson. He advanced Alcor the funds to complete the project and purchased all of the necessary welding equipment, and he was able (even happy) to apply knowledge he’d gained in an adult education class in welding to significantly Advance Alcor’s emergency response capability at a time when Alcor’s options were limited. |
Circuits
To obtain perfusion results near to the metabolic norm, some information is needed about the bypass circuit. Perfusion pressures are critical, and a pressure monitor is connected to gather this information. Flow rates will affect perfusion pressures, and the medical-grade pumps have a display with this data.
Ideally, the blood substitute is oxygenated before it is introduced to the circulatory system, and a device to do this is part of the circuit. This device actually serves a dual purpose. It is a heat-exchanger and oxygenator, and will simultaneously cool and oxygenate the blood substitute. A gas flow meter is included to provide information on the oxygen flow rate.
Medical-grade tubing, cannula, and filters are combined into an array that provides a sterile path between the blood substitute and the patient’s circulatory system. It also is configured to allow sterile samples to be taken easily.
Both the remote kit and the MRC III also contain surgical equipment and protective garments for the transport team. An independent source of oxygen is carried in the ambulance, but there is none in the remote kit. It is illegal to transport oxygen cylinders by commercial airline, and so, oxygen must invariably be acquired locally. (If in an unfamiliar town, check the phone book under Welding Supplies, Medical Equipment and Supplies, or Gas Cylinders.) If medical-grade oxygen is unavailable, use welding oxygen.
Simplified MRC III Washout Circuit
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Surgery
Surgery is something that only trained personnel may initiate, and in the absence of a trained transport team member, is done by a mortician with the assistance and direction of the untrained team member.
Current Alcor protocol is that the femoral veins are both cannulated for perfusion, one femoral artery is cannulated for perfusion, and the other for pressure monitoring. Cannulating vessels requires incising the skin, and proceeding to dissect away all intervening fat, tissue, and muscle which pre-vent the placement of the cannula and pressure monitoring line. The vessels are then cleared of the external sheath which binds them. Once cleanly exposed, sutures are placed around the extreme ends of each artery and vein. The distal ends are tied off with suture, and the proximal ends are double-looped and left loose.
A clamp is then placed as high up on the proximal end as possible. An atraumatic clamp is best, as it will not injure the delicate tissue. Once clamped, the vessels may be raised slightly and carefully cut open for the placement of the cannula.
The cannula should be clamped at the far end and completely filled with heparinized saline. All air bubbles should be tapped out of the cannula prior to the end being clamped. Once the vessel is cut and the cannula ready, insert the cannula as far into the vessel as it will go. Then, the proximal clamp can be removed to allow full insertion of the cannula. Be certain that the pump is off and the perfusion lines are clamped. Use the suture to secure the cannula in place.
Once everything is in place and secure, the washout can begin.
| Caution: Wear gloves, face masks, and hair covers! For individuals handling sharp objects, like needles or scalpels, puncture-resistant nitrile gloves should be worn underneath the exam gloves. For the surgeon, perfusionist, and their assistants, face shields or goggles are also required. |
Circuit Volume
The volume of fluid perfused into the patient is important. Approximately two liters of fluid are used to prime the circuit, and around twelve liters of organ preservation will be introduced. Once that volume has been introduced into the circulatory system, the fluid introduction ports are clamped, as is the drain line, and the remaining fluid in the patient and the circuit is allowed to recirculate until the patient’s temperature drops to 3-5°C.
If the circuit appears to be loosing volume once the fluid introduction ports have been clamped be certain to check the surgical area for leakage. If there are no obvious breaches in the circuit, there may be a leak inside the patient. Evidence of this may surface prior to the loss of volume during re-circulation. If the patient’s abdomen appears to be expanding, there may be a tear in the gastric (stomach) lining. If bloody, frothy fluid begins coming out of the patient’s mouth, the capillary beds of the lungs may have burst. There is little which can be done to repair these forms of damage, and in the past, each have been sufficiently severe to halt perfusion.
Safety Precautions
Alcor is often told when a patient harbors an infectious disease, and in fact, such diseases are usually contributing factors in the dying processes. Infectious diseases pose a serious health risk for transport team members if suitable precautions are not taken during the stabilization. However, there are few quick tests for determining whether or not a person has been infected with a virus, and some diseases have incubation times extending years before any symptoms of infection surface. Basic precautions, like those below, are very effective and easily implemented and should be used for every patient. The surgeon and the perfusionist should be especially careful to observe these guidelines.
Any transport team member coming into contact with a patient’s body fluids must wear latex exam gloves. Face masks and hair covers are also required. For individuals handling sharp objects, like needles or scalpels, puncture-resistant nitrile gloves should be donned underneath the exam gloves. For the surgeon and perfusionist, or anyone assisting them, face shield or goggles are also required.
Quality Control
Quality control is primarily accomplished during the perfusion by means of maintaining pressures and flow rates near the metabolic norms, and after the perfusion by means of sample analysis and ease of cryoprotective perfusion. Observation of the patient during the blood washout will also provide valuable information.
A patient who is perfusing well will undergo some observable changes. Skin color will change toward a more healthy color. Bruises may form on the patient’s limbs. The color of the fluid coming out of the patient will begin to lighten from a dark maroon and become increasingly transparent. The patient’s core temperature, as evidenced by esophageal and rectal temperature readings, will begin to drop quickly. (Rectal temperatures will drop more slowly than the esophageal readings, as the rectal probe is deep within a muscle mass, and might be imbedded in feces.)
If all these changes occur, the pressures and flow rates are properly maintained, and the patient is cooled to the appropriate temperatures, the patient will be in good shape for the cryoprotective perfusion.
Samples should be taken at fifteen minute intervals, beginning from the initiation of cardiopulmonary bypass. Begin sample collection as soon as possible (before bypass would be unusual but highly desirable). Samples will provide data which may be analyzed long after the cryonic suspension of the patient to help evaluate the quality of the transport.
Conclusion
A successful blood washout and cooling will provide a window of metabolic stabilization of about twelve hours. Within this time, the patient may be transported to Scottsdale, Arizona. Once the washout is complete, the patient should be packed in ice and transported by the fastest means possible to Alcor Headquarters.
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