Question 16from the first paper of 2012 asks about the advantages and disadvantages of various cooling methods. I have assembled these advantages and disadvantages into a massive table. This table is based on an even better table from a 2009 article by Kees Polderman and Herold Ingeborg, which is almost identical to the college answer for Question 16.

Methods of Inducing Therapeutic Hypothermia
METHOD ADVANTAGES DISADVANTAGES
Air cooling by skin exposure

Easy, cheap, and without procedural risk

Cooling rate is around 0.5°C per hour

Not very effective.

And you cannot rewarm them this way.

Air cooling with electric fans

Easy, cheap, and without procedural risk

Cooling rate is around 1.0°C per hour

As you fan the patient, you blow aerosolised pathogens all around your ICU, which is a potential infection risk. And you cannot rewarm them this way.

Evaporative air cooling by skin exposure with alcohol, water, sponge baths etc

Easy, cheap, and without much procedural risk. Cooling rate is around 1.0°C per hour

Labour intensive.

The patient ends up wet - that may be a major problem for patients with wounds.

Alcohol is not benign, it may absorb into eroded skin areas and it may irritate.

Electrical safety becomes a concern with exposed transvenous or epicardial pacing wires. And you cannot rewarm them this way.

Air cooling with an inflatable blanket

Easy, cheap, and without procedural risk

Frequently the ICU will already have one.

Cooling rate is around 0.5°C per hour.

One can change the air temperature, and rewarm the patient in this fashion.

Not any more effective effective than cooling by passive air-skin exposure.

Specially designed air-cooling beds (with an air-pumped inflating mattress)

Without procedural risk, and potentially offering a protection against pressure areas.

Cooling rate is around 1.0°C per hour.

One can change the air temperature, and rewarm the patient in this fashion.

Expensive and noisy.

Not available everywhere

Surface cooling by ice packs

Easy and cheap.

Cooling rate is around 1.0°C per hour

Labour intensive.

Uneven cooling - some areas may have little cooling while other areas may develop frostbite or pressure areas.

Surface cooling by immersion in cold water

Rapid cooling rate: around 8-10°C per hour

Cold water is inexpensive.

It may be possible to rewarm the patient this way by changing the bath temperature.

Impractical for large patients - this technique may only be suitable for infants and children.

The patient ends up wet - that may be a major problem for patients with wounds.

Unusual problems arise with attempting to ventilate a partially submerged patient.

Electrical safety becomes a concern with exposed transvenous or epicardial pacing wires.

Surface cooling by skin contact with circulating cold water in a cooling blanket

Good cooling rate: around 1.5°C per hour

Cold water is inexpensive.

Changing the water temperature can be used to rewarm the patient.

Some systems can be coupled in feedback with a temperature probe for more accurate temperature maintenance

Labour-intensive

Initially, takes some time to reach he desired temperature

Surface cooling by skin contact with circulating cold water in a cooling vest

Rapid cooling rate: around 8-10°C per hour

Cold water is inexpensive.

Changing the water temperature can be used to rewarm the patient.

Some systems can be coupled in feedback with a temperature probe for more accurate temperature maintenance

The cooling blankets may be reusable, but the jackets are not -and these can be expensive.

The jackets may leave marks on the skin, and theoretically could cause pressure areas

Infusion of cold fluids

Easy and cheap.

Good cooling rate: 2.5-3.0°C per hour

A large volume of fluid needs to be infused;

this may result in electrolyte derangement and fluid overload. The patient cannot be rewarmed in this way.

Also, there is little control over the temperature which is achieved in this way.

Lastly, exposure of the myocardium to a jet of cold fluid may result in arrhythmias and asystole.

Peritoneal lavage with cold fluids

Potentially, a good cooling rate

Invasive, requires some surgical expertise. Infused cold fluids will be absorbed to some extent, giving rise to electrolyte abnormalities.

The patient cannot be rewarmed in this way.

Intravascular cooling catheters: baloons filled with cold saline, metal catheters for heat exchange,

Good cooling rate: around 2.0°C per hour

Most of these double as central lines, offering central venous access and central temperature monitoring

Invasive, expensive, and disposable.

Catheter-related thrombosis may be an issue.

Extracorporeal circuit cooling

Rapid cooling rate: around 4-6°C per hour

Convenient if the patient is already on ECMO or CVVHDF; little additional workload.

The patient can also be rewarmed in this way.

Very invasive. Major disadvantage due to the need for anticoagulation.

Antipyretic drugs

Easy and cheap.

Poor cooling rate: 0.1-0.5°C per hour

References

Polderman, Kees H., and Ingeborg Herold. "Therapeutic hypothermia and controlled normothermia in the intensive care unit: Practical considerations, side effects, and cooling methods*." Critical care medicine 37.3 (2009): 1101-1120. This article is ideal, but not available without institutional access.