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Cryopreservation is usually discussed as a wager on the future. It is almost never discussed as what it is first: a technical act of post-mortem care, performed on a table, with hands, a vascular access and a clock. That is the part I know, and it is the part everything else depends on. 
Cryopreservation is usually discussed as a wager on the future. It is almost never discussed as what it is first: a technical act of post-mortem care, performed on a table, with hands, a vascular access and a clock. That is the part I know, and it is the part everything else depends on.
Quick answer
Cryoprotectant perfusion is a thanatopraxy procedure, performed by a practitioner trained in vascular access and circulatory anatomy. It progressively replaces the blood with a vitrification solution, so that cooling produces an amorphous solid — a glass — instead of ice crystals. It is inseparable from time. Once circulation stops, the most vulnerable neurons begin to die within about five minutes. Surface cooling on its own lowers core temperature by roughly 1 °C per hour. That difference in scale is why we travel ahead of a foreseeable death. Our protocol is measurable and verifiable. 40,000 units of heparin within the minute following the attestation of death, then — as a team of two, simultaneously — cardiac compressions to circulate it and cephalic cooling with iced water. Then a gravity perfusion at 170 cm, that is 2.2 to 2.5 psi, exactly the systolic pressure of a human heart, rising through three distinct steps of 10%, 30% and 70%, under continuous refractometric control. And it is inseparable from the trade. Choosing an injection site, recognising poor distribution, managing oedema, raising concentration in stages without causing osmotic shock: these are a thanatologist's acts, not a lab technician's. That is what this article is about. Why a thanatologist is writing about cryopreservationWriting on cryonics splits into two registers: the promise — you are being sold a second life — and the mockery — you are being told it is science fiction. Between the two, almost nobody describes the act. Yet that is where everything is decided. The liquid nitrogen vessels in Michigan are identical for every patient. What separates one case from another is what happened in the first few hours, in the hands of someone who either knew what they were doing or did not. I practise thanatopraxy and restorative art. I also perform cryoprotectant perfusion, in Quebec and Eastern Ontario. This article explains what the second borrows from the first, what separates them absolutely, and why a thanatologist's training is not a bonus here but a condition of feasibility. It does not set out to persuade you to choose cryopreservation. It sets out to give you what you need to judge whoever offers it to you. Ten numbers that shape the procedure
Embalming and cryopreservation: the same act, the opposite intentionAn embalming and a cryoprotectant perfusion begin the same way. You raise an artery. You raise the matching vein. You connect a pump. You inject on one side, drain on the other, and read the distribution off the body. A thanatologist who has performed hundreds of embalmings has acquired exactly what cryopreservation needs: recognition of anatomical landmarks under skin that no longer bleeds, the ability to judge distribution by eye, the reflex to change site when a territory does not fill. None of that is written in a protocol. It is built over years. What separates them: fixing or replacingThen the two diverge, and they diverge absolutely. Embalming fixes. Formaldehyde reacts with the amino and thiol groups of amino acids — cysteine, histidine, lysine, arginine, tryptophan — forming first methylol derivatives, then Schiff bases, then stable methylene bridges between residues. The result is a cross-linked protein network: the tissues become firm, aseptic, presentable, and biologically fixed for good. Cryopreservation replaces. The aim is not to harden proteins but to remove the water that would otherwise freeze into crystals and puncture the membranes. It is replaced by cryoprotectant agents, at rising concentration, so that cooling produces an amorphous solid. A precision that honesty requiresYou will often read that an embalmed body "can no longer" be cryopreserved. Technically that is inaccurate: there is a published method, aldehyde-stabilized cryopreservation, which fixes with glutaraldehyde first and then vitrifies with ethylene glycol, and which yields excellent anatomical preservation — the synapses remain crisp. But that method targets the connectome, the map of connections, not viability. No brain treated that way has ever been revived, and that is not what is asked of it. The exact formulation is therefore this one: formaldehyde embalming does not prevent a body from being vitrified; it permanently extinguishes any prospect of biological function returning — which is precisely what cryonics pursues. That is why the two do not combine in our practice. The clock: what happens in a brain deprived of circulationThe whole procedure is organised around a single constraint, and it is worth looking at closely, because it explains everything else.
One precision I insist on, because it is routinely caricatured: "five minutes" is not the point at which "the brain is destroyed". It is the point at which the most fragile neuronal populations — those of the hippocampus, notably — begin to die. The full course unfolds over days, and it is regionally heterogeneous. But for anyone trying to preserve a structure, it is the only number that matters. The countdown does not start when we arrive. It starts when death is pronounced. Why ice is not enough — and why we travel aheadThe first answer to ischaemia is cold. Its justification is measurable: cerebral metabolic demand falls by about 5 % per degree Celsius lost. To cool is to slow the cascade. The problem is speed. In a clinical series of post-cardiac-arrest patients, surface cooling achieved a rate of roughly 1.2 °C per hour, taking close to seven hours to reach target. Cold-induced vasoconstriction contributes: the body closes its peripheral vessels and shields itself from the cooling being applied. Set the two scales side by side. The ischaemic cascade runs in minutes. External cooling works in hours. Cold is not a race that can be won after the fact — only one that can be started earlier. That is the whole reason for bedside standbyWhere death is foreseeable — a known prognosis, palliative care, an end of life in view — we travel ahead and stand by at the bedside, equipment ready. Nothing whatsoever is done to the body until the attestation of death has been drawn up by a physician or nurse: the law is clear on that, and so are we. But the moment it is, cooling begins within the minute rather than in the third hour. No other decision in this entire file returns as much. And it is the only one a family retains full control over: call early. A premature call costs nothing. A late one cannot be undone. Our protocol, step by stepHere is what we actually do. I publish it because a protocol you cannot describe is a protocol you do not have. Minute 1 — heparinAs soon as the attestation of death is drawn up, we administer 40,000 units of heparin, an anticoagulant, within the minute. The aim is simple, and it governs everything that follows: keep the blood fluid and prevent clots from forming. Recall what the literature says about failed perfusions: post-mortem clots are abundant in human cases and directly limit perfusion quality. Every minute without anticoagulation is a vascular bed closing — and a closed vascular bed does not reopen. This is where bedside standby stops being a comfort and becomes the procedure itself. You do not inject heparin within the minute of a death if you are forty minutes away by road. Minutes 1 to 30 — two pairs of hands, two simultaneous actsHere a logistical constraint shapes everything: we always travel as a team of two. That is not comfort. The two acts that follow have to happen at the same time, and one person cannot do both. The first team member performs cardiac compressions. An anticoagulant injected into a static system is useless: the heart no longer beats, so it has to be replaced for the heparin to reach the territories that matter. Without that forced circulation, the drug stays at the injection point and the vascular bed closes anyway. The second cools the head with iced water. This is the direct application of the principle above: cerebral metabolic demand falls by about 5 % per degree lost. You cool first, and as a priority, what you are trying to preserve. The guitare: a nursing basin put to another useThe vessel the head is placed in is called a guitare, after its shape. Its original purpose has nothing to do with cryonics: it is a basin used to wash the hair of bedridden patients, in hospitals and long-term care homes. The head slides in, the hair is washed, the water drains through the neck without wetting the bed. We use it for what it does best: keeping a skull submerged in iced water, continuously, without tying up a third person and without obstructing the work being done on the chest. I mention it because this is exactly what real practice looks like: not science-fiction equipment, but a well-designed care object used with judgement. Competence rarely lies in what you buy. It lies in what you know how to do with it. Two pairs of hands, two acts, one objective: that the cold and the anticoagulant reach the brain while the window is still open. Then — the ice bath and the transferThe body is then placed in an ice bath for transfer to our facility. Cooling continues for the whole journey: nothing is paused because we happen to be driving. Vascular access: the heaviest technical decisionOnce cooling is under way, everything turns on one question: where does the solution go in, and where does it come out. The sites, and what distinguishes themIn thanatopraxy, six arterial injection sites are considered major, each paired with a venous drainage site:
The choice rests on three criteria: how accessible the vessel is, how close it lies to the aorta and right atrium, and its calibre. The common carotid is often treated as the reference. The femoral artery, approached in the femoral triangle below the inguinal ligament, has a diameter of 6 to 7 mm, comparable to the carotid; it leaves the neck intact, at the cost of an approach complicated by adipose tissue and of atherosclerotic lesions that can impede distribution to the upper body. Supporting vessels — brachial, radial, ulnar, popliteal, tibial, subclavian, iliac — are reserved for autopsy cases, donor cases and special situations. When a territory does not fill, that is where you turn. A practitioner who masters only one is a practitioner with only one answer. It is worth adding that the anatomical literature itself notes the lack of standardisation of embalming technique from one laboratory to another. This is not a field where you follow a recipe. It is a field where you decide. What makes a distribution failFour obstacles recur, and none of them is theoretical:
The clearest warning sign is oedema. Poor venous return, fluids escaping, the body gaining weight: in cases where ischaemia has been prolonged, a patient can gain up to 50 % in weight in fluid. Interstitial oedema then compresses the capillaries and produces heterogeneous cerebral perfusion — some regions receive the solution, others do not. Recognising that in real time, deciding to change site, adjusting pressure, stopping in time: that is the core of the trade. It is written in no protocol. Pressure: why we inject by gravity, at 170 cmA pump lets you inject fast. That is precisely the problem. Excessive pressure tears the vessel intima, forces fluid out of the vascular bed and worsens the very oedema you are trying to avoid — without improving distribution, since a ruptured vessel distributes nothing. So we inject by gravity, with the reservoir suspended 170 cm above the injection site. That height is not arbitrary. Do the arithmetic:
The 2.2 to 2.5 psi range corresponds exactly to the systolic pressure of a human heart. That is not a coincidence — it is the principle. We reproduce the pressure those vessels carried for a lifetime, no more and no less. The vascular bed was built for it. Gravity also brings a safety no pump has: it cannot exceed its setting. A pump drifts; a column of water never does. The height is the pressure, and it is visible across the room. The concentration curve: why you cannot go fasterThe vitrification solution is not injected as it comes. It is raised through steps of increasing concentration, over several hours. That is not excess caution: it is the answer to two distinct problems, which should not be conflated. First problem: osmotic stressInjecting a highly concentrated solution outright would create an abrupt osmotic gradient across the membranes. Cells would dehydrate violently, then, on returning towards isotonicity, swell beyond their normal volume until they lysed. Cryobiology established long ago that the harmful effect of certain cryoprotectants owes more to cell volume changes than to their own chemical action. Second problem: chemical toxicityPenetrating cryoprotectants become more toxic as concentration rises. Two distinct mechanisms add up: a non-specific toxicity — fewer water molecules available to hydrate macromolecules — and toxicities particular to each agent. Ethylene glycol is metabolised into glycolic acid; dimethyl sulfoxide disrupts cell membranes. Raising concentration in steps addresses both at once: it gives cells time to equilibrate, and it limits how long they are exposed to high concentrations. A published protocol on brain tissue illustrates the idea — five addition steps of ten minutes each, then removal in seven descending steps. There is another lever, less intuitive: higher concentrations can be introduced at lower temperature, toxicity being temperature-dependent. Every decision of that kind — rate, step, temperature — trades one form of damage against another. There is no setting without a cost. Our three stepsIn practice the rise happens in three stages. One distinction matters from the outset: the first two steps are not diluted vitrification solution. They are conditioning and pre-injection solutions, whose role is to prepare the circulatory system to receive the VM-1. Conflating the three would be conflating the preparation with the act.
Refractive index: how we know where we standYou do not perfuse blind and hope the concentration is rising. You measure it, continuously, on the venous effluent — the fluid coming back out — with a refractometer. The more concentrated in cryoprotectant a solution is, the more it refracts light. The refractive index is therefore a direct reading of the concentration actually reached in the tissues, not of the one that was injected. The target is 1.42: the value at which vitrification is complete enough that the risk of fracturing is minimised during the temperature descent. The trade-off every honest practitioner has to mentionReaching 1.42 is not always desirable. Pushing perfusion that far can cause cerebral oedema — the brain swells, compresses its own capillaries, and distribution degrades instead of improving. So we reserve the option of stopping perfusion before 1.42 is reached, when signs of oedema appear. It is a trade between two forms of damage, and there is no universally right answer: less cryoprotectant means more fracturing risk; more cryoprotectant risks an oedema that compromises distribution itself. The decision is made case by case, on one particular patient, by reading the signs in real time. That is why this act cannot be delegated to a protocol. A protocol gives you a target; it does not tell you when to abandon it. The solution we useThe protocol and the solution are supplied to us by the Cryonics Institute. Their formulation, known as CI-VM-1, was developed by the cryobiologist Yuri Pichugin and introduced to members in 2005. I do not publish its composition. Not out of mystery, but because I know of no description of it in a peer-reviewed journal — only secondary sources. On a subject where precision is the only currency that counts, I would rather state what I do not know. The temperature descent, and the problem nobody mentionsOnce perfusion is complete, the body is cooled. At a temperature called the glass transition — around −120 °C, give or take ten degrees depending on the solution — the cryoprotectant solution stops behaving as a liquid and becomes a glass, without the molecules having had time to organise into crystals. That is the intended outcome. Below that threshold, a phenomenon appears that brochures rarely mention: fracturing. The cryoprotectant glass and the tissues do not contract at the same rate. The resulting thermal stresses produce cracks. This is not hypothetical: autopsies conducted in 1983 on transferred patients described fractures through the skin and most internal organs, including a spinal cord fractured cleanly every six centimetres. Since 1997, acoustic detection during cooling has documented, case by case, between one and thirty-nine fracture events per patient. Volume makes it worse. A few millilitres of solution tolerate some twenty degrees below the glass transition before fracturing; beyond a litre, two degrees suffice. A whole human body is, in this respect, a very poor candidate. Countermeasures exist — annealing near the glass transition, storage at an intermediate temperature rather than at −196 °C. The practitioners who use them describe them themselves as fracture reduction techniques, not fracture avoidance. It would be dishonest to present them otherwise. Why tell you this, when I sell this service? Because a practitioner who does not mention fracturing either does not know about it, or does not want you to. Either way, the information is useful to you. What the law requires of the practitionerOne last dimension, and it is what separates a professional from an enthusiastic amateur: cryopreservation does not take place in a legal vacuum.
We drive the shipping container ourselves, overland, in our own specialised vehicles, from Montreal to Clinton Township. The container never changes hands and never passes through a freight terminal. An unbroken cold chain, and a chain of custody with no anonymous link in it. What an honest practitioner will not promise youI will end here, because this is what I would want to be told. No one has ever been revived. No human being, no whole mammal. Cryopreservation does not rest on a proven technique for returning to life, but on the wager that future medicine will be able to repair both the cause of death and the damage caused by preservation itself. That wager may never be won. The procedure leaves documented damage. Cryoprotectant toxicity, cellular dehydration, fracturing below the glass transition. These are not hypothetical risks; they are published findings. The outcome depends on circumstances we do not control. A death that occurs alone and is discovered hours later, or one followed by an autopsy, does not produce the same result as an anticipated death where we were able to stand by at the bedside. I cannot promise every family the same thing, because the situations are not the same. What I can guarantee comes down to little: a technically sound execution, performed by a trained and licensed professional, within the shortest delay the circumstances allow, with a frank account of what happened. That is less than a promise of immortality. It is considerably more than what you are offered elsewhere. Ten questions to ask any providerWhether you choose us or not, here is what to judge by.
A technical question? Ask it.Whether you are a family, a colleague in the funeral profession or a journalist, the conversation is free and carries no obligation. Technical glossary
Frequently asked questionsDo you have to be a thanatologist to perform cryoprotectant perfusion?Cryoprotectant perfusion rests on the same acts as an arterial injection in thanatopraxy: raising an artery and its matching vein, connecting a pump, judging distribution, changing site when a territory does not fill. In Quebec, offering a funeral service requires a funeral services business licence (s. 5, CQLR c. A-5.02), and removing a pacemaker requires a thanatopraxy licence (s. 54 of the regulation). Competence in vascular access and circulatory anatomy is not an extra here: it is the condition of feasibility. Can an embalmed body still be cryopreserved?Technically, yes: aldehyde-stabilized cryopreservation, published in Cryobiology in 2015, fixes with glutaraldehyde and then vitrifies with ethylene glycol, with excellent anatomical preservation. But it targets the connectome, not viability. Formaldehyde irreversibly cross-links proteins through methylene bridges: it permanently extinguishes any prospect of biological function returning, which is precisely what cryonics pursues. The two therefore do not combine in our practice. Why is the solution injected in steps rather than all at once?For two distinct reasons that should not be conflated. First, osmotic stress: a concentrated solution injected outright would violently dehydrate the cells, which would then swell beyond their normal volume until they lysed. Second, the cryoprotectants' own chemical toxicity, which rises with concentration — ethylene glycol is metabolised into glycolic acid, dimethyl sulfoxide disrupts membranes. Raising concentration in steps gives cells time to equilibrate and limits exposure to high concentrations. What do you do in the first minute after death?We administer 40,000 units of heparin, an anticoagulant, within the minute following the attestation of death, to keep the blood fluid and prevent clots — post-mortem clots are abundant in human cases and directly limit the quality of the later perfusion. We always travel as a team of two, because the two acts that follow have to happen simultaneously: one team member performs cardiac compressions to circulate the drug through the whole vascular network, while the other cools the head with iced water in a guitare — a basin normally used to wash bedridden patients' hair, which keeps the skull submerged without obstructing work on the chest. The body is then placed in an ice bath for transfer to our facility. This timetable is why we travel ahead of a foreseeable death: you do not inject heparin within the minute if you are forty minutes away by road. At what pressure is the solution injected?By gravity, with the reservoir suspended 170 cm above the injection site. A column of that height exerts about 2.4 psi, and our working range is 2.2 to 2.5 psi — that is 114 to 129 mmHg, exactly the systolic pressure of an adult human heart. That is not accidental: the vascular bed was built for that pressure, and reproducing it avoids tearing vessels and damaging organs. Gravity also brings a safety no pump has: it cannot exceed its setting. What is the 1.42 refractive index?It is the measurement that tells us where we actually stand. The more concentrated in cryoprotectant a solution is, the more it refracts light; by reading the refractive index of the venous effluent with a refractometer, we know the concentration reached in the tissues and not merely the one we injected. The target is 1.42, the value at which the risk of fracturing during the temperature descent is minimised. We do sometimes stop short of it, when cerebral oedema appears: it is a trade between two forms of damage, less cryoprotectant increasing fracturing risk, more of it risking compromise of the distribution itself. What concentration steps are used?Three, and they should not be conflated. A conditioning solution at 10 % first, which prepares the vascular bed and begins equilibration without an abrupt osmotic gradient. A pre-injection at 30 % next, where most of the replacement of intracellular water takes place. Then, and only then, VM-1 at 70 %, the vitrification solution proper. The first two steps are not diluted VM-1: they are distinct solutions whose role is to prepare the system to receive the third. Each step is held until equilibration, under continuous refractometric control. How much time is there after death?Less than people think. Cortical electrical activity ceases within seconds, ATP is depleted within minutes, and the most vulnerable neurons die about five minutes after complete interruption of cerebral blood flow. That does not mean the brain is destroyed in five minutes — the course unfolds over days and varies by region. But for anyone trying to preserve a structure, every minute of warm ischaemia is a permanent loss. That is why we travel ahead of a foreseeable death. Why is ice alone not enough to cool the body?Because the time scales do not match. Cerebral metabolic demand falls by about 5 % per degree Celsius lost, which makes cooling valuable — but surface cooling alone achieves only around 1 °C per hour in clinical series, and cold-induced vasoconstriction slows it further. The ischaemic cascade, meanwhile, runs in minutes. Cold is a race that cannot be won after the fact: it can only be started earlier. What makes a perfusion fail?Four main obstacles, all documented: post-mortem coagulation, abundant in human cases and directly limiting; the no-reflow phenomenon, where raised intracranial pressure prevents any cerebral perfusion — in one published series, two brains out of five showed no fixation at all; atherosclerosis, which narrows the vascular bed; and the post-mortem interval itself, autolysis setting in beyond roughly five hours. The main warning sign is oedema: poor venous return and weight gain, which can reach 50 % in cases of prolonged ischaemia. What is fracturing, and can it be avoided?These are cracks that appear in vitrified tissue when cooling below the glass transition temperature, around −120 °C, because the cryoprotectant glass and the tissues do not contract at the same rate. The phenomenon is documented in human patients: autopsies in 1983 described fractures through the skin and most organs, and acoustic detection during cooling records between one and thirty-nine events per patient. Volume makes it worse — beyond a litre of solution, two degrees below the glass transition suffice. Annealing and intermediate-temperature storage reduce the phenomenon, but their own proponents describe them as reduction techniques, not avoidance. Which vitrification solution is used?The Cryonics Institute formulation, known as CI-VM-1, developed by the cryobiologist Yuri Pichugin and introduced to members in 2005. The protocol and the solution are supplied to us by the organisation. We do not publish its composition, having found no description of it in a peer-reviewed journal — the only available sources are secondary, and on a subject where precision is the only currency that counts, we would rather state what we do not know. Does the statutory six-hour delay apply to cryopreservation?No. Article 48 of the Civil Code of Québec lists exhaustively three acts subject to the six-hour delay following the attestation of death: embalming, burial, cremation. Cryopreservation is not among them, and sections 60 and 114 of the regulation repeat that delay for thanatopraxy and cremation only. We note, however, that the question has never been tested before a Quebec court. Is the coroner's authorisation required to take a body out of Quebec?Yes. Section 43, second paragraph, of the Coroners Act (CQLR c. C-68.01) requires prior notice to the coroner of the place where the body was found, and section 78 makes transport outside Quebec conditional on their written authorisation where notice was due. We handle that step, and its very existence is a useful test: a provider who never mentions it has never taken a body out of Quebec. Does the body travel by air?No. We drive the shipping container ourselves, overland, in our own specialised transport vehicles, from Montreal to Clinton Township, Michigan. The container never changes hands and never passes through a freight terminal, which gives an unbroken cold chain and a chain of custody with no anonymous link in it. How much does cryopreservation cost in Quebec?There are two invoices. The local response by Online Funeral Services.ca runs from $22,430 CAD in Montreal and Laval up to $25,730 CAD for the furthest territories, with mileage added by administrative region. Cryopreservation and perpetual storage are billed separately by the Cryonics Institute: US$28,000 for a Lifetime Member. The full grid of 23 territories and the detail of the legal framework are on our cryopreservation in Quebec page. Our equipment, in picturesEverything above describes acts. Here are the objects they are performed with — the guitare, and the shipping container on arrival in Michigan. We publish them because a protocol you cannot show is a protocol you do not have. These are our own facilities, photographed as they are used. You will see equipment only. No photograph of a patient, no procedure in progress, no human silhouette — not even a mannequin. It is a rule we impose on ourselves, and we mention it because it is noticeable by its absence: demonstrating competence never justifies exposing anyone, or staging what should remain private. 
Scientific and legal sources, consulted 21 August 2026
Written by Pierre-Maxime Fugère, CFSP. Sources and statutory provisions last verified 21 August 2026. This text is informational and professional; it constitutes neither medical nor legal advice. For pricing, the legal framework and what to do first, see our cryopreservation in Quebec page. A French version of this article is available at Services Funéraires en ligne.com.
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AuteurPierre-Maxime Fugère 
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