Chapter 5: Surface Cooling
Alcor 1997 Stabilization and Transport Manual
Table of Contents
One of the first things which will be done for a patient is surface cooling. Cooling is important because it reduces the metabolic demands of the body at a known rate: more than 50% for every 10°C temperature reduction . This means that the amount of cellular deterioration drops with the temperature. For a transport patient, time is critical to the stabilization procedures.
Ice bag placement, when limited supplies are available
Cooling is one of the easiest, inexpensive, and more effective methods for reducing ischemic damage. Surface cooling is to begin immediately after the patient is released to Alcor personnel, if not sooner. Hospital staff may, even after adopting a position of noninterference or noncooperation, allow ice to be placed around the patient in cases where release of the patient will not occur immediately after pronouncement (as when the transport team is awaiting the arrival of the mortician).
Without ice or alternative cooling methods, ambient temperature will be the only thing cooling the patient until additional measures are taken. When exposed to air, a patient will cool at approximately 1°C per hour . This is slow, compared to the efficiency of other cooling methods, and to be avoided if at all possible.
If a limited supply of ice is available, or if the hospital staff limits access to the patient until release is secured, concentrate cooling around the entire head (back, sides, and face) and the neck, axilla, and groin. Ice, crushed or cubed, should be placed into sealable bags (e.g. Ziploc). All of the air should be removed from the ice bags, to enable better heat removal.
If the supply of ice is not limited, surround the patient completely with bags of ice — be certain to place ice underneath the patient’s body as well as on top.
Keep in mind, that ice bags can be messy and difficult to keep in position around the patient. Bags may become wet from condensation and slide from their original positions. Ice bags will carry the patient’s bodily fluids in addition to condensation. Contact with these fluids poses potential health risks.
|Caution: Wear gloves! Ice bags may carry infectious material if they come into contact with patient fluids or are allowed to accumulate condensation and slide around the patient or to the floor. Such condensation is also an electrical hazard.|
Patient Ice Bath
A patient ice bath (PIB) is essentially a lightweight bathtub on wheels. A patient can be placed into a PIB and completely surrounded in ice. When placing a patient into the PIB, transport team members should take care to have a layer of ice underneath the patient. If the undersides of a patient are neglected, over 33% of the patient’s entire surface area is wasted, and the patient will not cool as quickly. When placing ice in the PIB, do not put ice over the heart lung resuscitator baseboard or on the patient’s chest directly. As the ice will quickly melt, which will mean that the HLR will have to be repositioned (see Chapter 6) and causes a delay in the application of other stabilization procedures. Ice bags may be placed around the chest once the cardiopulmonary support has begun, but care must still be to keep this area relatively dry.
Removing the patient’s clothing will be essential to rapid cooling, and should be done at the earliest opportunity. (Paramedic shears may be used to quickly cut off the patient’s clothing.) Once the clothing has been re-moved and the patient is in the PIB, cover the patient’s genitals with a privacy drape. This activity has no effect upon the quality of a stabilization, yet demonstrates respect and care for the patient, which are essential to maintaining cordial relations with the patient’s family, friends, and health care providers.
The basic design of the patient ice bath has seen considerable modification and improvement over the past few years, and two primary models are used in transports. Alcor Headquarters has a compact and easily assembled prototype PIB, which is of a radically different design to the ones found in most local groups. This PIB needs only to be opened, bolted in four places, and the liner snapped in place to be operational during an emergency. It is quite sturdy.
Most of the patient ice baths are made of polyvinylchloride tubing (PVC) with a naugahyde liner, and a stabilizing baseplate made of plywood. They must be assembled. Tubing sections must be connected, the PVC frame connected to the baseplate, and the liner snapped to the frame.
To assemble a PVC PIB, gather the necessary components (refer to the illustration) and follow the assembly instructions. (A copy of the assembly instructions should be kept with each unit.) Once these steps have been completed, your PIE should be ready for ice and the patient. However, several cautions must be emphasized for those using a PVC PIB. The PVC may become brittle when cold and snap under weight. In general, they will be extremely difficult to lift; they are also large. When a mortician’s transport vehicle is being used, the mortician should be asked to remove the gurney usually carried in the back before departing for the patient’s location.
Patient Ice Bath Components
1 bath base
Assembly instructions for the PIB
The first step in assembling the portable ice bath is to lay out all of the components (which should have labels: left, right, head, and foot) in an orderly fashion.
Open the wooden base plate.
Attach the foot section to the two bottom connecting sections.
Join the two top connecting section to the foot section.
Attach the head section.
Use the bolts and wing nuts to attach the assembled frame to the base plate. Wing nuts should go on top.
Insert IV pole into the appropriate hole in the PVC.
Snap the naugahyde liner in place.
Add the pouches to each end.
Improving Cooling Rates
At least one device has been invented to improve the cooling rates of cryonic suspension patients. This device is a submersible pump-and-tubing array, called a “Squid” (named for its arms of tubing). This device was initially developed by Fred Chamberlain during the cryonic suspension of Arlene Fried and later improved by other Alcor members.
A Squid is used to circulate ice-cooled water around the patient. It improves the heat exchange capacity of the portable ice bath and results in faster cooling. Water circulates from the PM; through the tubing; around the patient, exiting the tubing via cuts in the flexible arms; and back into the bath, where the cycle begins again.
To use the Squid, surround the patient with loose ice. Then, add about five gallons of water. Position the submersible pump at one end of the bath and connect it to the appropriate power source. The intake port and pump must be completely covered with water before the Squid will be able to circulate cooled water. Add more water to the bath, as needed.
The Squid’s flexible arms should be strategically placed near areas where main blood vessels rise near the surface of the patient (at least the head, neck, axilla, and groin). Driven by the submersible pump, cold water constantly circulates around the patient and cools faster than the ice bags or ice bath alone. During times where a mechanical cps device is being used, none of the arms should be placed directly on the chest. The mechanical piston will not function when wet. Avoid splashing, where possible. These should be removed from the groin area before the start of surgery to wash out the patient’s blood.
An innovation to the Squid design was provided by Robert Cardwell. He recommended placing sheaths over the tubing segments (from which water sprays) to act as diffusers. By cutting these sheaths horizontally (with cuts about a quarter inch apart), the water won’t spray as forcefully or splash as widely as with the previous design.
In addition to providing improved cooling capacity, the FIB has been designed to allow for cardiopulmonary support once the patient ii in the ice bath, . It will accommodate a heart-lung resuscitator (HLR). Using an HLR to circulate the patient’s blood will enable faster core cooling of the patient (blood near the skin will be cooled and circulated throughout the body). A graph later in the Chapter provides a visual reference for judging the improvement to the cooling rate provided by the Squid.
As a safety precaution against the transmission of infectious diseases, 5% sodium hypochlorite (common bleach) may be added to the water in a portable ice bath. Bleach has been shown to kill many infectious viruses, and can even neutralized the AIDS virus (although it needs 20 minutes to do so). Household bleach (in liquid form) is acceptable, and one or two cups will reduce the potential for infection. If pool bleach is used, the concentrated crystals must be dissolved (in water) before adding them to the PIB. One or two capfuls is sufficient.
|Caution: Be certain to dissolve all bleach crystals before adding them to the patient ice bath. Undissolved crystals may become lodged in the heat exchanger during washout and breach the circuit. This could result in bleach being pumped into the patient.|
|Caution: Wear gloves! Splashing water from the ice bath may carry infectious material. Avoid splashing the HLR piston. When wet, it will seize and no longer function.|
Monitoring Cooling Rates
Collecting data during a transport can be difficult, but it must be done. Temperature data, for example, provides precise information about a patient’s condition which may be factored into damage estimates and later transport evaluations.
Temperature-monitoring devices are a standard component of Alcor’s emergency response equipment. Temperature monitors and probes are currently available from Alcor, and data recording devices may be soon. The equipment varies slightly between groups, so transport team members should take a few moments to familiarize themselves with the equipment at hand before it is needed.
The placement of probes, however, remains the same for each patient. Flexible wire makes the temperature probes relatively easy to insert. Temperature probes should be placed in either the esophagus or nasopharyngeal passages and in the rectum. A transport team member should gently pass the probe into the appropriate passage. If the probe is inserted less than 3 inches, temperature readings may be inaccurate. Probe depths of 3-6 inches are desirable. If the probe becomes lodged before reaching these depths, wiggle the probe and try to insert it further. Each should be inserted as far as possible for maximum accuracy. (Lubricating jelly may be used for difficult placements, as when inserting the rectal probe.) A transport team member must wear gloves when placing these probes.
Probes should be securely taped in place once they have been inserted the appropriate distance. This should prevent accidental shifting of the probes during the transport. Shifting probes is usually discovered when temperature readings appear inconsistent with the protocol being administered. For example, normal body temperature hovers around 37°C and a patient surrounded by ice and circulating water should have a temperature drop of about 10°C per hour. Cooling rates should appear consistent with this rate. Increasing temperatures are a sign that a probe is probably being exposed to the air.
Replace and resecure any probes which become dislodged during the transport procedures. Probes are connected to the monitoring device immediately after they are securely in place.
Temperature readings should be recorded regularly (every few minutes if possible) in the data collection sheets contained in the Emergency Response Manual. All notes should be kept together to prevent loss.
Surface Cooling Rates
The cooling of a patient should begin immediately after the pronouncement of legal death, if possible. With a cooperative hospital, hospice, or home situation, this is usually what will happen. If the release of a patient to Alcor personnel is to be delayed, for whatever reason, cooling should still be implemented immediately if possible.
The method for cooling a patient should be selected based upon the optimal rate of cooling and the availability of equipment. A freestanding body will cool at the rate of 1°C per hour. This is unacceptable in all cases. Surrounding the patient with ice bags will provide cooling at about 5°C per hour. Adding the portable ice bath will increase that rate to about 10°C per hour, and in conjunction with the Squid, that rate rises to about 15°C per hour. Using both a portable ice bath and a Squid (or similar device) provides the fastest external cooling.
No matter what the method of surface cooling is implemented, transport team members should take all required precautions for preventing the spread of infectious diseases.
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