From Cryonics, May 1992
The responsibility of suspending members can be overwhelming at times. After all, if medical personnel err and kill someone, they have cost that patient the remaining years of his or her life, at most a few decades, more commonly a few years. If we fail, we could be costing our patients (who are often our friends) a chance at near immortality. Worse yet, if we don't do it (given the current state of cryonics), they will have no chance at all. Thus, cryonics is a stressful occupation (or whatever you think it should be called), and much of this article will be illustrating this point. The oversights are reported for the usual reason: so we can learn and do better next time.
A few weeks ago, patient A-1260 was one of that growing number of people well acquainted with cryonics, but not signed up. He had been to a number of Alcor functions over the years and was friends with several Alcor members. Because of his desire to remain anonymous, he will be known as "Nick" in this article.
Nick had been diagnosed with HIV from the time tests became available in 1987. As is common with HIV infection, he remained symptom-free and clinically well for a number of years following diagnosis of his HIV-positive status. However, as is almost inevitable with this disease, his T-cell count began to decline and he began treatment with zidovudine (AZT) and other chemotherapeutic agents to slow the progression of the disease, and to ward off opportunistic infections.
Like many patients on AZT, he stayed relatively free of symptoms until the last five months of his illness. At that point he began developing multiple problems starting with a cytomegalovirus (CMV) infection of his gallbladder which was treated by surgical removal and medication with the antiviral drug ganciclovir. And again, as is typical of patients on AZT, he responded poorly to treatment. This infection was followed by another, this time cryptosporidium. (It now appears that patients on AZT do not live appreciably longer than those not taking the drug. However, they have a course which is characterized by more "well" time followed by a rapid decline, with the opportunistic infections which cause death being unresponsive to treatment. The reason for this difference is not yet understood.)
While the decision to join Alcor came late as a result of the usual mix of denial and funding problems (insurance is not available to HIV-positive people), once he and his lover "Jim" decided to make suspension arrangements, the sign-up process was completed in about two weeks.
It is worth pointing out that while Nick and Jim had long considered making suspension arrangements, it was their perception that it was not possible to do so given Nick's terminal status and his uninsurability. Due in large measure to the intervention and encouragement of Alcor member Steve Harris, this misunderstanding was cleared up and financing was put in place with a mixture of some up-front cash and a second mortgage on their home. Alcor does not encourage this kind of last-minute preparation for cryonic suspension, for the obvious reason that last-minute can very quickly become too late. It is very important to point out that flexible financial arrangements are available, and can be made well in advance, and that Alcor will work with anyone to facilitate their cryonic suspension. This case also points out how the thoughtful intervention of a friend can make the difference between someone's getting suspended and not getting suspended. This is not an easy subject to broach with someone you care about who is dying, and Steve is to be commended for his courage and caring in doing this.
One of us (Mike Darwin) has had extensive experience both in-hospital and in cryonics-related situations in caring for terminal patients. Pain and discomfort are the handmaidens of death, and at best dying is not a pleasant business. However, even Mike was unprepared for the degree of misery Nick was in. Nick suffered from pancreatitis (perhaps as a result of his treatment with the new anti-retroviral drug didanosine, and perhaps as a result of CMV infection of his pancreas), which caused him severe abdominal pain, unrelenting (day and night) hiccoughing, and near-constant nausea and vomiting.
In addition, he had frequent diarrhea as a result of cryptosporidium infection. (Cryptosporidium is an organism that normally infects sheep and occasionally infects humans, causing a one-time illness similar to a case of "tourista" from which the patient recovers uneventfully. It causes severe diarrhea in immunocompromised humans, and there is currently no effective treatment. Experimental treatment with the newly available antibiotic azithromycin — which had been anecdotally reported to be effective against cryptosporidium — failed to control Nick's infection.) Any one of these would have been a misery; together, the infections had him in a constant nightmare.
The constant nausea and vomiting had prevented Nick from eating or drinking for several months; his food and fluid requirements were being met by intravenous feedings with total parenteral nutrition (TPN). Nick had been on every anti-nausea medication available in the U.S., including Marinol, the FDA-approved version of marijuana. Unfortunately, Marinol is not nearly as effective at suppressing nausea as its natural counterpart. It was a source of some frustration that due to the U.S. drug laws Jim was unable to secure any marijuana in an attempt to relieve Nick's nausea. Mike has known several patients suffering intractable nausea secondary to cancer chemotherapy (including a lady in her late 60s!) who found that the only thing that relieved their nausea was pot. The misery that Nick suffered as a result of this law is unconscionable. Since both Jim and Nick are libertarians, the irony of this situation was not lost on them even in the midst of their suffering. Compounding this stupidity is the recent ruling by the FDA that no further applications for releases will be accepted for the legal medical use of marijuana.
Nick's suspension arrangements were completed by March 14th, so the next day Hugh Hixon and Keith Henson went to Nick and Jim's home in the Los Angeles area to set up for the initial stages of the suspension at their home. Hugh had already scouted out the situation, which was about as poorly set up for a MALSS-supported stabilization as could be imagined. Nick's bedroom was up a staircase with three turns in it, and the twists and turns at the entrance of the house made it impossible to get the MALSS (Mobile Advanced Life Support System) cart inside. The only feasible location for set-up was a garage located about 60 feet from the front door up a steep street. Considering that it took us over two minutes to move the last patient about six feet, there was concern over the ischemic time such a move would cause if Nick were pronounced in his bed.
That day, with Jim's assistance, Hugh and Keith cleaned out the garage, moved in several oxygen bottles, built a plastic enclosure large enough to hold the MALSS cart by stapling plastic sheeting to the ceiling beams, and installed 2000 watts of lighting. Typically, this would not be necessary, since most houses have at least one doorway that will admit the MALSS cart. So, while it was kind of rough and ready, the nurse who pronounced Nick when the time came commented that he had certainly seen worse set-up's used for operating rooms in Vietnam. Keith and Hugh also restocked the cart and ambulance, refilled the MALSS cart oxygen cylinders, and for practice ran through as much of the process as they could manage.
Keith Henson surveys preliminary work of turning a garage into a field operating room. By cutting cords, suspended plastic sheets drop down to form walls. Photo by Hugh Hixon.
With the whole team present, work continues on the garage/O.R. L to R: Paul Wakfer, Hugh Hhixon, Leonard Zubkoff. Photo by Carlos Mondragon.
While the patient's name will not be given here, his name and the fact that he had made suspension arrangements circulated among his friends, and word of this reached Mike Darwin. Mike (who knew Nick personally) offered his services, and, though the team thought they could manage without him, the offer was gladly accepted. Mike came in and found a number of oversights and deficiencies and he worked most of the afternoon and evening of March 15th with Hugh Hixon to remedy these shortcomings. One of the most glaring was Keith's failure to clean out (or even remember) the vacuum system on the MALSS cart from the last suspension. This is one of the side effects of doing things while 20 hours short of sleep. Well, that one goes on a checklist.
Earlier in the day (on the 15th), Mike had participated in a call from Steve Harris and conference with the Alcor Staff regarding Nick's medical situation and prognosis. Nick had decided to end his misery by dehydration, and had stopped all food and fluids (with the exception of a morphine infusion) the previous Thursday (March 12th). (As with previous similar situations, we point out that in terminal cases such as Nick's, dehydration is the only means of hastening death that will not result in an autopsy. Legal initiatives such as Thomas Donaldson's have yet to ameliorate this barbaric necessity.) Both Steve and Mike expressed concern over this since with Nick's large fluid losses as a result of his diarrhea and vomiting, he was liable to dehydrate very quickly. Both Steve and Mike expressed surprise that Nick was even still alive. The Alcor staff related that they had been told by Nick's treating physician that death from dehydration would take a week to ten days. Unfortunately, this physician was probably not charting fluid intakes and outputs and was thus speaking in general rather than specific terms.
(Since Nick was still alert enough on Sunday to sit up and hold a conversation, Keith went back to San Jose, knowing that dehydration cases typically last a week or sometimes more, and not being aware of the conversation between Steve and Mike. He was home for less than 24 hours when the call came through that Nick was near death, having dehydrated much faster than expected. Keith now has a rather different view of dehydration times when a patient has large fluid losses from diarrhea or other causes. In spite of the cost involved, he has become a champion of being on site and ready based on the shortest estimate.)
Early on the morning of the 16th a call came in to Alcor from Jim and the Registered Nurse attending Nick. They reported that Nick's condition was very grave and that death seemed imminent. Mike was put in touch with Jim and the attending RN. At that time Nick was unconscious and in deep shock with a blood pressure of 40/0, a respiratory rate of 3-4 a minute, and pupils which were only sluggishly responsive to light. Since the suspension team could not be on location for at least two hours and additional preparation to the MALSS cart and ambulance were needed, Mike asked the attending nurse if he could pour what prescribed IV fluids they had available into Nick to reverse his shock and give Alcor more time to set up. Without this timely intervention, it is almost certain that Nick would have suffered hours of ischemia before an Alcor team could arrive. As we know from previous unlucky patients, this would have resulted in a very poor quality suspension.
Since it was by no means certain that Nick would respond to fluid resuscitation, it was decided that Mike should come into the lab, and assist finishing up preparation of the MALSS and setting up the operating room as quickly as possible. Mike and Hugh worked throughout the night to get this done. At about 8:00 a.m. a call came through that after he had stabilized, Nick was again deteriorating and that the transport team should come at once. By this time the equipment and team were almost ready to depart, although several critical items were still not in place. They were delayed approximately another 45 minutes to an hour before they could depart.
On hearing the news, Arel, Leonard Zubkoff, and Keith flew into the Los Angeles area. The available staff members drove the ambulance with MALSS cart and the Cryovita van full of support supplies over to Jim and Nick's home, and Max More was recruited from his university job for the standby. By 11 a.m. on Tuesday we were on site and ready to go. However, nearly 2 liters of IV fluids had reversed Nick's shock and yanked him a good ways back from death's door. He even got out of bed for short times that day. It seemed we were in for an indeterminate wait, but after the scare, nobody was about to complain. Keith used a little of the time to check the calculations Max and Tanya had worked out on the transport medications against a medication spread sheet he had created the week before, and all were right on.
The team used the time to check over readiness, make final preparations, and to upgrade our safety precautions to reduce the risk of transmitting Nick's HIV and/or associated infections to the Alcor team that would be caring for him.
Mike sent out for puncture-resistant nitrile rubber gloves and fluid-barrier Tyvek jumpsuits with integral shoe covers. These were added to surgical masks, full plastic face shields, and conventional latex surgical gloves which we normally use for suspensions. (The nitrile rubber gloves were discovered to work well as "liners" under conventional surgical or exam gloves, which could be discarded as they got dirty). Much credit goes to Paul Wakfer who took the initiative to run down these items at the last minute. Paul also took the Cryovita van (backup for the ambulance) out and located a replacement tire for a blown spare.
Nearly at the last minute, Keith suggested adding pool chlorine to the MALSS ice bath to reduce the infectivity of the ice water which is pumped over the patient. The ice water, contaminated with body fluids, invariably splashes on anyone standing close to the cart. Paul went out and found some at about 8:00 p.m. the night before the suspension began.
If these precautions seem excessive, let us assure you they are not — especially three months later when you are getting your HIV status checked! Those on the team with medical backgrounds are comfortable working with AIDS patients giving day-to-day care without gloves or masks except when handling body fluids (when gloves are required). However, a MALSS-supported transport is not your normal day-to-day situation. We are performing invasive procedures under field conditions using sharp instruments and in the presence of many gallons of splashing contaminated fluids. We are also working with volunteers, and few of them have extensive medical training. A high level of precautions is in order to safely conduct these suspensions. Incidentally, we used the new sample collection method inspired by the last suspension when a team member got stuck (not an HIV-positive case). This greatly reduced the number of contaminated sharps to which team members were exposed.
An added precaution we took was the prophylactic administration of AZT to the entire suspension team during the period of potential exposure. While chronic administration of AZT to health care workers at risk for exposure to HIV is not warranted because of the serious side effects of long-term use, it is acceptable to use it for an acute situation where risk of exposure may be high. AZT is used as a prophylaxis against HIV for health care workers with known exposure. It is even more effective if the drug is already present when the exposure occurs. Fortunately, our precautions were effective and we were lucky. We had no incidents of exposure and there was no need for anyone to continue the AZT prophylaxis for the recommended 30 days following a needle stick or conjunctival (eye) exposure. (Whew.)
By Tuesday evening it seemed unlikely that Nick was going to be in dire straits for the next 12 hours or so. We were very short of bed space, so half the crew went back to Riverside that night, and the rest of us found places to spend the night. NOTE to transport team members: consider adding an air mattress to your overnight kit!
Early the next morning we reassembled to move Nick to a downstairs bedroom which could be accessed by a gurney, but that was called off because he was in too much discomfort to be moved. Nick continued a slow decline in vital signs all day Wednesday, and by that evening it seemed likely that he would not make it through the night. All of us tried to get a little sleep that evening, but not many were successful at it. About midnight Jim and the nurse on duty decided Nick (who was again in deep shock and completely unresponsive) had under an hour to go, and (to minimize ischemic time) we were gathered to move him near the MALSS cart.
The logistics of moving our patient downstairs resulted in more discussion, arguments, and testing than any other aspect of the whole transport. (Mike missed this because he was in the garage priming the MALSS cart.) Keith's suggestion of using a gurney was tried with an empty gurney, but the required 70-degree angle looked so scary that nobody was willing to be a test subject. Hugh`s suggestion of a fireman's carry was ruled out because a slip on the carpeted stairs might seriously hurt both the patient and the carrier. We finally tried and settled on Carlos's proposal, with Max on one arm, Paul on the other, Hugh taking Nick's feet under his arms, and Keith holding his head. We got him downstairs without any problems (good suggestion, Carlos), onto the gurney, and (in our white Alcor lab coats) wheeled him up the street into the garage. Then we all got into face shields, double gloves, and the Tyvek "bunny suits." Tyvek, incidentally, is the tough, water-resistant material used for floppy disk sleeves and Federal Express envelopes.
The time is drawing near. Tanya draws up some last minute medications. Photo by Carlos Mondragon.
The nurse, who was extremely supportive and competent, had called it close. Nick (with Jim holding his hand to the end) quit breathing and experienced cardiac arrest about half an hour after we got him into the garage. We used a standard hospital sheet carry, picking him up on the bottom bed-sheet and going in over the foot end of the MALSS cart. HLR support was begun on him within less than 60 seconds. Unfortunately, although circulation was promptly restored, Nick had vomited (without it being evident) a small amount of blood-derived material looking much like coffee grounds. This blocked Arel's attempt at placing the PTL airway (a device which had been purchased some time ago by Mike for evaluation, but which had never been used). Seeing her difficulty, Mike cleared Nick's airway of vomitus, tried to position the PTL airway, failed, and then managed to get a backup Esophageal Obturator Airway (EOA) in place. Unfortunately we did not have an Esophageal Gastric Tube Airway (EGTA) in the emergency response kit. A disadvantage of the (older) EOA is that it has no passageway for a tube to neutralize stomach acid with Maalox or to place a temperature probe.
A disadvantage of both the EOA and the EGTA is that they both require a mask. The relatively high airway pressures generated by Heart-Lung Resuscitators makes holding the mask on (in a spray of ice cold water) a very painful task, mostly borne by Arel who was spelled by Max and Paul. Added practice with the PTL might help to solve this problem, since it does not require a mask.
Arel suggested that next time we have a large bore-suction line available to handle respiratory emergencies, and Mike adds that the bag-valve respirator should be set up with a conventional mask to facilitate prompt respiratory support in the event there is trouble placing an EGTA, ET-tube, or PTL airway. Early airway management has turned out to be a major problem in several cases. Arel was sore up to the shoulders for several days from holding the mask on, but after the quickly-solved initial problems, the patient was well oxygenated, with the end-tidal CO2 monitor showing a 3% to 5% reading on each breath: the best obtained so far. (About 5% CO2 is expired by a normally perfusing and respiring person!)
The initial procedures are underway. Keith Henson and Tanya Jones continue work on medications, while Max More takes notes. Photo by Carlos Mondragon.
Tanya administered the transport medications through a central venous catheter which had been left in place for this purpose. After administrating the initial medications, Tanya went back to taking notes, with Mike dealing with the IV drips. Mike was having difficulty getting the dextran into the patient, and wanted to proceed with the femoral cutdown as soon as possible, so he asked Leonard if he would administer the remaining dextran. Since Leonard had no experience with this, Mike quickly explained the procedure of first filling the syringe through a 3-way valve, then turning the valve the opposite way and squeezing the plunger (more sore muscles) to force the dextran into the patient. He also explained to watch carefully for air in the IV line; Leonard thought he was pointing to the opposite (mannitol) bag from the correct one, and began watching the wrong bag.
When he completed the dextran and shut off that line, Leonard reported that the dextran was complete. Mike asked him to start the other bag, which was apparently already hooked up. Leonard checked and found that it was already started, and reported this to Mike, assuming that someone else had started it, and was responsible for watching it. Because Leonard had not had training on this subject (not to mention that he was busy watching and changing oxygen cylinders), he missed understanding that the responsibility for the medications was being handed off to him, and nobody noticed at first when a pneumatically compressed IV bag started to pump air into the patient. Fortunately Tanya had removed most of the air from the bag prior to its being hung up, so at most a few cc's of air got into the patient. However, this experience reinforces the opinion that note-taking is too complex to combine with any other task, and that IV medications must be monitored by a trained person until they are turned off.
Although the intent was for Hugh and Keith to do the femoral cutdown, their inexperience with the prep and drape phase (inadequately practiced on pigs) slowed them down so much that they turned it over to Mike. Mike went on to do the femoral cutdown with Hugh assisting and Keith handing off instruments. (The first thing they ran into was a set of arterial branches gnarled like tree roots.) Several sessions working with pigs made it possible for Keith to anticipate when instruments, suture, or heparinized saline would be needed next, and had also sharpened up Hugh's surgical skills. From arrest to going on bypass required 80 minutes, not as fast we'd like, but better than last time (105 minutes) and the record so far. Oxygenation and perfusion during HLR support was excellent, and the patient had a strong femoral (groin) pulse (as a result of the Heart-Lung Resuscitator support), which made it easier to do the cutdown. The patient's temperature was 22.3°C at the time bypass on the MALSS was started. This works out to a drop in temperature of 0.18°C per minute — excellent for HLR-supported surface cooling, though this is largely a function of patient mass/surface ratio.
Work on the femoral cutdown is proceeding well. Mike Darwin is performing the surgery, with Hugh Hixon assisting. Photo by Carlos Mondragon.
The cutdown is drawing to a close. Transport to Riverside is about to begin. Photo by Carlos Mondragon.
Cooling to washout temperature went both smoothly and rapidly. Mike had installed an extra heat exchanger in the bypass circuit (in addition to the one on the Bentley hollow fiber oxygenator), and switched to a higher output pump for delivering the ice water to the heat exchangers. This resulted in a cooling rate of 0.47°C/min. When Nick's temperature reached 10°C, washout with Viaspan began. This procedure took about 7 minutes and (with large bore lines for the Viaspan this time) went very smoothly. Blood washout was deemed excellent in the field and confirmed upon arrival at the Alcor facility: Nick's hematocrit was 1%, indicating that about 98% of his blood had been washed out.
At 5:01 a.m. we shut down the pump/oxygenator on the MALSS in order to safely load it and Nick into the ambulance. At that time Nick's esophageal temperature was 3.5°C (he could have been kept off bypass safely for hours); he had cooled approximately 34°C in 3 hours and 20 minutes — a powerful testimony to the effectiveness of the portable ice bath and MALSS-supported cooling. Within a few minutes after Nick was loaded into the ambulance, clean-up in the garage was completed, all the support gear was loaded into the Cryovita van and assorted personal vehicles, and transport to Riverside was begun. The ambulance arrived at the lab at about 7:00 a.m. Keith and Arel (who had dropped off Max and picked up breakfast) made it by about 8:00 a.m.
Since there would be about a six-hour gap before the contract surgeon could get there, most of the team headed off to get some badly needed sleep. Even though Keith had not slept at all the previous night, he did not feel like trying to sleep, so he remained awake to monitor and operate the MALSS. By that time Nick was on intermittent (10 minutes on, 20 minutes off) low-flow bypass to minimize the risk of cold-perfusion-associated-edema. Intermittent circulation of the Viaspan has been found to be important to supply tissues with needed oxygen and glucose, remove wastes, and control pH. Initially Hugh was going to operate and monitor the MALSS cart, but he was in worse shape than Keith, so he headed for bed. This was Hugh's first transport-team leadership, and he had gotten little sleep since days before it started from worrying about all the things which are needed and which can go wrong.
Mike left Keith with instructions to check pH once an hour and adjust with bicarbonate as required. Keith decided to check glucose as well, located a test kit, found the level to be low, and (following the directions in the transport manual) adjusted the glucose level. This was keeping Keith as busy as a one-armed paper hanger, so it was a great relief to him when Paul came back in to help after a quick trip home for a wake-up shower. About the time Paul came in, Keith stuck a clamp on the wrong line (no harm to the patient, thank goodness) and opened a seam on the oxygenator, spraying a couple of hundred cc's of perfusate on the floor. Arel later made a suggestion of taping the lines with stripes of narrow-gauge tape: red for arterial, blue for venous, and green for the bypass line. It might not prevent all accidents, but it would sure help dead-tired people. After cleaning up the mess, Paul and Keith checked with each other when they changed the clamps.
Paul and Keith had problems both with measurements and with keeping the ice water flow ice-cold in temperature. Near the end of the MALSS support they moved the esophageal probe, and the reading dropped from 2.2° to 1.5°, more likely representing the patient's core temperature. The arterial probe must have been off by about 5°, because the arterial temperature (after going through the heat exchanger) had to be lower than the patient's core temperature. The readings were still very useful: they could see small rises in arterial temperature and take steps to correct it. The heat-exchanger water flow kept channeling between the pump and the return line, and required constant stirring and fiddling to keep the right level of water and enough ice in the cooler chest they were using. They kept at it for about 6 hours, until the rest of the crew returned, both rested and fed, and the contract surgeon showed up.
Three problems should be mentioned. First, the glucose test kit was missing the calibration strip for the meter, so the test strips had to be roughly read by hand. Second, due to unfamiliarity with procedures, and a failure of communication (side effect of a lack of sleep), no analysis samples were taken during the long period of low flow. Last, we ran one oxygen cylinder out, and while it did not hurt the patient, it was not noticed for some tens of minutes. Oxygen flow should be read with each temperature check.
Nick was moved from the MALSS cart to the operating room table. With Hugh assisting, surgery to access the heart was seemingly uneventful. Arterial and venous cannulas were placed, Mike did a burr hole using the DuPuy pneumatic burr-hole tool. This time he did not open the dura. Brain swelling or shrinking was assessed by depressing the dura with a blunt instrument to "sound" the cortical surface, and observing the dura in the burr-hole for being flaccid or bulging. It seems that the profuse leaking of perfusate observed in previous well-supported cases was due to cutting nearly invisible vessels in the dura, not (as Keith had speculated) from the brain surface itself. This was the first time the DuPuy was used in a suspension and it worked very well, making a small hole in the skull in a fraction of the time it took to open a hole with a conventional hand drill. Observations of intracranial pressure were consistent with low injury patients: low pressure and some shrinkage of the brain during perfusion.
Hugh Hixon, Keith Henson, and Leonard Zubkoff complete preparations in the O.R., just prior to surgery. Photo by Carlos Mondragon.
Our contract surgeon begins the median sternotomy, with Hugh Hixon (left) assisting. Photo by Carlos Mondragon.
The surgery complete, Tanya Jones begins the periodic drawing of fluid samples for analysis. Photo by Carlos Mondragon.
While all of this was going on, Arel made a food run. Later she and Keith got busy cleaning out the MALSS cart. They used a lot of Clorox, and this time the vacuum system got checked.
With surgery completed, Carlos took the surgeon back to the airport, and Ralph started the perfusion ramp. After a quick lesson, Keith was put on measuring perfusate refractive index — which converts to a measurement of the level of cryoprotective agent going into and coming out of the patient. From the start, the computer model and the measured results were not agreeing. Dr. Perry was called over to see if anything odd was going on with his program, but it seemed to be okay — reality was out of adjustment. Early measurements indicated that the glycerol concentration was not increasing as rapidly as predicted and that we might not reach target.
The cryoprotective perfusion ramp has begun. Perfusionist Ralph Whelan monitors pressure in the perfusion circuit. Photo by Carlos Mondragon.
Keith Henson, having forgotten to look as busy as he was, gets nabbed for aglycerol concentration analysis. Photo by Carlos Mondragon.
The reason for this was not apparent until the conclusion of perfusion, and after cephalic isolation. At that time we discovered that the umbilical tape that the contract surgeon had used to tie off the aorta (so that the body did not perfuse) had not completely closed off flow — with the result that the patient's body had partially perfused! This was a potentially serious problem, in that the perfusate volume for neurosuspension patients is less than that used in whole body cases. We now know better, and in the future only metal (Satinsky) occlusion clamps specially designed for closing large vessels will be used for neurosuspension isolation.
Fortunately we came very close to the minimum target glycerol concentration of 4.0 M (the final venous reading was 3.86 M or 27.84%). We just reached this concentration with the last drop of glycerol. Hugh was running blood gases, and we were pleased to see that Nick was using oxygen (as determined by the arterial-to-venous oxygen differences) at levels comparable to those observed in our canine total-body-washout animals cooled to similar temperatures and subsequently resuscitated!
About an hour before ending the cryoprotective ramp, an inquiry by Mike led to the realization that nobody had been assigned to get dry ice. The only source at that time in the night was forty-five minutes, so Carlos took off to get some. He made it back in time, but in the meantime Mike and Leonard had rigged a way to get cooling with the Silcool oil started using liquid nitrogen.
During our efforts to reach the target glycerol concentration another problem surfaced, one which really requires an immediate fix. During early cryonic suspensions it was discovered that when glycerol concentrate is added to the recirculating system (the perfusate being pumped through the patient), it tends to stratify; i.e., it sinks to the bottom of the reservoir and ends up being pumped into the patient without being adequately diluted. (Glycerol is the very best available cryoprotectant, but very high glycerol concentrations are used to dissolve some tissues!) This problem was solved (we thought!) by continuous mixing of the perfusate with a magnetic stirring bar.
Unfortunately, if the reservoir level drops too low, the stir bar creates a vortex which sucks in air and fills the perfusate with micro-bubbles. This happened during Nick's perfusion, though — fortunately — the in-line arterial filter/bubble trap caught the air. However, we cannot rely on this in the future and several (patentable?) suggestions have been put forth on how to eliminate this problem. A decision has also been made to acquire (as soon as we can locate one) an air-bubble detector for use on the circuit. Operating room perfusionists have had bubble detectors for so long that few of them would willingly pump a case without one.
Cephalic isolation has been greatly improved due to the introduction of new tools by Keith and Mike. We now have this procedure down to a fraction of Jerry Leaf's best time. After trying umbilical tape (which proceeded to untie itself), Mike found cable ties to be an efficient way to occlude (tie off) the esophagus and trachea. This goes a long way toward maintaining a clean surgical field during cephalic isolation.
Cooling to -79°C was started at about 11:00 p.m. After cooling was started, the grueling and seemingly endless process of cleaning up began. About this time Mark Connaughton came in and calibrated the blood-gas machine so we could try to make better sense out of pH data that did not agree between two machines. Cleanup was fairly well completed by about 2:30 a.m., though there would be a lot of work done over the next few days in restocking, re-ordering, and of course patient cooldown and subsequent transfer to liquid nitrogen storage.
The final result was that this suspension ranks among our very best to date. And while there were plenty of new surprises and problems of every imaginable sort, it is fairly clear that the most serious problem (nearly having the patient deanimate with us hours away) was more the result of inadequate pre-suspension medical evaluation than lack of preparation.
Organization and attention to detail need a lot more work, and we are really going to have to train some of the suspension team members (in addition to Mike) as backups to do the cardiac surgery. Emotionally, suspensions are about as rough on people as can be imagined, but there was great (and effective) effort by all concerned to be more supportive of each other. Sadly, we have to expect to be doing more HIV cases as time goes on and Alcor grows.