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Cryonic Suspension Protocol

We are frequently asked just what we do during a cryonic suspension. Below we outline the major procedures used to place a patient into cryonic suspension. There are four main steps:

I) Stabilize, cool, and transport the patient.

II) Perfuse the patient with cryoprotective solutions.

III) Lower the patient's temperature to -79C.

IV) Lower the patient's temperature to -196C.

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Step I

Follow these guidelines when the patient is pronounced dead:

  • Maintain blood flow and respiration of the patient (with caution).
  • Cool the patient by surrounding with ice bags, especially the head
  • Inject 500 IU/kg of heparin.
  • Use sterile technique if possible.

This procedure should be performed in conjunction with a physician, nurse, or paramedic.

1) At the time of death maintain blood flow (using sternal compression) and oxygenation (using a bag resuscitator or other positive pressure device) to limit ischemic injury. Administer the oxygen through a face mask, or preferably an endotracheal tube. Avoid mouth-to-mouth resuscitation, because of the danger of infection. Do cardiopulmonary resuscitation manually until a mechanical heart-lung resuscitator (with 100% O2) can be employed.

Note: The chest compression rate affects hemodynamics, and it has been recommended that one apply 120 compressions/minute and 12 breaths/minute (Circulation 74:63, 1986). CPR (cardiopulmonary resuscitation) predisposes the patient to gastric insufflation due to the unprotected airway. Thus while using CPR it is advisable to intersperse abdominal compressions. It should be noted that chest compressions may not be efficient enough to maintain adequate blood flow. A thoracotomy can be performed to expose the heart, which can be pumped manually.

2) Establish venous cannulation in the forearm, employ a 3-way stopcock and tape securely, before the time of death if possible, for the administration of pharmacological agents. Keep the pathway open until death using normal saline. Upon death, administer heparin: 500 IU/kg.

3) Place the patient on a cooling blanket, if available, and circulate coolant. Surround the patient with Ziploc ice bags, paying particular attention to cooling the head. Lower the body temperature toward 0C.

4) Insert thermocouple probes in the esophagus and in the rectum, and monitor temperature throughout the protocol.

5) Tape the eyelids closed to prevent dehydration.

6) Inject 300 mg Tagamet (cimetidine HCl), or administer 20 ml Maalox through a gastric tube, to prevent HCl production by the gastro-intestinal tract.

7) When suitable, use a Foley catheter to drain the bladder.

8) While continuing to apply CPR, transport the patient to the facility where the patient will be prepared for bypass, perfusion, and extracorporeal oxygenation. The sooner the patient is on bypass the better, due to superior cooling and oxygenation.

...

Step II

This perfusion step should be performed with the guidance of a surgeon, perfusionist, and medical technician.

Expose and cannulate the carotid artery and jugular vein. Secure the cannulas and attach them to the tubing of the bypass circuit.

Alternatively, one can use the femoral approach. Expose and cannulate the femoral vein and artery. Secure the cannulas and attach them to the tubing of the bypass circuit. The cannula in the femoral vein should be pushed up toward the right atrium of the heart.

Arterial and venous pressure should be monitored throughout perfusion to limit edema. Catheters should be inserted into the radial vein and radial artery or a femoral artery. These catheters should be coupled to pressure sensors. Monitor pH, O2, CO2, and cryoprotectant concentration by using a refractometer.

The reservoir should initially contain ice-cold cryoprotective; solution. Begin total body washout and replace the blood with 4 to 6 liters of cryoprotective solution (one blood volume or 5 L / 70 kg). Discard the venous effluent into containers holding Clorox bleach.

After perfusion is complete, decannulate and suture the surgical wounds.

...

Step III

Place thermocouples on the skin surface, and in the esophagus and rectum (if not already done). Cool the patient in an insulated chest using dry ice. Monitor the patient's temperature and freeze gradually. Temperature lowering should ideally be between 0.01 and 0.1 degrees C per minute, with slower preferred especially after the patient has solidified.

...

Step IV

Place the patient in a container, and suspend the container above the (low) level of liquid nitrogen in a dewar, to begin vapor phase cooling to -196C. Cooling should continue slowly at about 0.01C per minute if possible. Rapid cooling may cause stress fractures.

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