Patients in cardiac arrest due to severe hypothermia benefit from extracorporeal rewarming, and it is often recommended that they are treated at centres capable of providing cardiopulmonary bypass or extracorporeal membrane oxygenation (ECMO).
But what if they’re brought to a centre that doesn’t have those facilities?
If you work in such a centre do you have a plan, and are you familiar with what equipment you could use?
One option if you have an ICU is to provide extracorporeal warming using a haemofiltration machine used for renal replacement therapy(1). A double lumen haemofiltration catheter is inserted into a central vein and an ICU nurse can often do the rest, although some variables have to be set by the intensivist, often aided by a standard renal replacement therapy prescription chart. The machines are mobile and can be wheeled into the resus room (I have practiced this set up in resus). It might be worth discussing and practicing this option with your ICU.
Another extracorporeal option is to rig up a rapid infusion device such as a ‘Level 1’ to connect to arterial and venous catheters so that blood from the patient flows through and is warmed by the machine before being returned to the patient(2). Rapid rewarming has been achieved by this method but it requires some modification to the usual set up and so is much less likely to be a realistic option for most teams doing this on very rare occasions.
Less technical options are the traditionally taught warm saline lavage of body cavities such as the thorax and the peritoneal cavity. These can be achieved with readily available catheters and of course should be combined with ventilation with warmed gas and administration of warm intravenous fluid.
Thoracic lavage can be achieved with open thoracotomy or tube thoracostomy. One or two chest tubes can be placed on each side. One technique was described as:

Two 36 French chest tubes were placed in each hemithorax. One tube was placed in the fourth intercostal space in the mid-clavicular line. Another tube was placed into the sixth intercostal space in the mid-axillary line. Sterile saline at 39.0◦C was infused by gravity into each superior chest tube and allowed to drain passively through each inferior tube.(3)

Rapid rewarming at a rate of 6.8◦C per hour was achieved in an arrested hypothermic man using peritoneal lavage. It was done in the operating room with peritoneal lavage (saline 40◦C) with a rapid infusion system (Level 1) through two laparoscopic access sites. It was combined with external forced air rewarming and warm intravenous infusions(4).
Finally some devices manufactured for inducing hypothermia in post-cardiac arrest patients can also be used to rewarm patients, which might be endovascular devices, such as the Cool Line® catheter(5), or external, such as the Arctic Sun® Temperature Management System(6). It’s definitely worth finding out what your critical care services have as far as this equipment goes.
In summary, although the ‘exam answer’ for cardiac arrest due to profound hypothermia is often ECMO/cardiopulmonary bypass, in most centres that’s not an option. It’s helpful to remind ourselves that (1) other extracorporeal rewarming options exist and (2) non-extracorporeal techniques can provide rapid rewarming.
 
1. Spooner K, Hassani A. Extracorporeal rewarming in a severely hypothermic patient using venovenous haemofiltration in the accident and emergency department. J Accid Emerg Med. 2000 Nov;17(6):422–4. Full text
2. Gentilello LM, Cobean RA, Offner PJ, Soderberg RW, Jurkovich GJ. Continuous arteriovenous rewarming: rapid reversal of hypothermia in critically ill patients. The Journal of Trauma: Injury, Infection, and Critical Care. 1992 Mar;32(3):316–25 PubMed
3. Plaisier BR. Thoracic lavage in accidental hypothermia with cardiac arrest — report of a case and review of the literature. Resuscitation. 2005 Jul;66(1):99–104. PubMed
4. Gruber E, Beikircher W, Pizzinini R, Marsoner H, Pörnbacher M, Brugger H, et al. Non-extracorporeal rewarming at a rate of 6.8°C per hour in a deeply hypothermic arrested patient. Resuscitation. 2014 Aug;85(8):e119–20. PubMed
5. Kiridume K, Hifumi T, Kawakita K, Okazaki T, Hamaya H, Shinohara N, et al. Clinical experience with an active intravascular rewarming technique for near-severe hypothermia associated with traumatic injury. Journal of Intensive Care. BioMed Central Ltd; 2014;2(1):11. link to abstract
6. Cocchi MN, Giberson B, Donnino MW. Rapid rewarming of hypothermic patient using arctic sun device. Journal of Intensive Care Medicine. 2012 Mar;27(2):128–30. PubMed