Correspondence

Accidental Hypothermia

N Engl J Med 2013; 368:681-682February 14, 2013DOI: 10.1056/NEJMc1215158

Article

To the Editor:

In their review article on accidental hypothermia, Brown et al. (Nov. 15 issue)1 summarize very well the current understanding about this condition, along with triage and treatment.2,3 One cannot emphasize enough that advanced life support must be continued without interruption if the patient shows vital signs at rescue followed by hypothermic cardiac arrest (rescue death). In the absence of major trauma, there is a 47% chance of long-term survival after cardiopulmonary bypass rewarming, with total recovery 5 years after the accident.4 A recent study describes an unmatched result of 100% short-term survival of young female patients with hypothermic cardiac arrest after rewarming with extracorporeal membrane oxygenation (ECMO).5

In their conclusion, the authors mention the need for prospective studies and registries. The International Hypothermia Registry (IHR, https://www.hypothermia-registry.org) has been operational for more than a year and comprises more than 50 centers worldwide. With data gathered by the IHR from participating centers, we should be able to issue evidence-based recommendations on the rarely occurring cases of accidental hypothermia with cardiac arrest.6

Beat H. Walpoth, M.D.
Marie Meyer, M.D.
University Hospital, Geneva, Switzerland
beat.walpoth@hcuge.ch

No potential conflict of interest relevant to this letter was reported.

6 References

1. 1

   Brown DJA, Brugger H, Boyd J, Paal P. Accidental hypothermia. N Engl J Med 2012;367:1930-1938
   Full Text | Web of Science | Medline

2. 2

   2005 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care: hypothermia. Circulation 2005;113:IV-136
   

3. 3

   Soar J, Perkins GD, Abbas G, et al. European Resuscitation Council guidelines for resuscitation 2010. Section 8. Cardiac arrest in special circumstances: electrolyte abnormalities, poisoning, drowning, accidental hypothermia, hyperthermia, asthma, anaphylaxis, cardiac surgery, trauma, pregnancy, electrocution. Resuscitation 2010;81:1400-1433
   CrossRef | Web of Science | Medline

4. 4

   Walpoth BH, Walpoth-Aslan BN, Mattle HP, et al. Outcome of survivors of accidental deep hypothermia and circulatory arrest treated with extracorporeal blood warming. N Engl J Med 1997;337:1500-1505
   Free Full Text | Web of Science | Medline

5. 5

   Wanscher M, Agersnap L, Ravn J, et al. Outcome of accidental hypothermia with or without circulatory arrest: experience from the Danish Præstø Fjord boating accident. Resuscitation 2012;83:1078-1084
   CrossRef | Medline

6. 6

   Walpoth B. Implication of treatment and outcome of survivors of accidental deep hypothermia: the need for a hypothermia registry. In: Bierens JJLM, ed. Handbook on drowning. Berlin: Springer, 2006:520-1.
   

To the Editor:

Brown et al. state that 190 minutes is the longest reported duration of cardiopulmonary resuscitation (CPR) leading to survival without neurologic impairment in patients with hypothermic cardiac arrest.1 Recently, Mark et al. reported full neurologic recovery in a 41-year-old man after 273 minutes of manual CPR during transport in a remote arctic area.2 In this case, cardiac arrest occurred during transfer to the ambulance, and CPR was started immediately. Electrocardiography showed asystole followed by ventricular fibrillation after the administration of drugs used in advanced life support. Resuscitation was continued throughout ground transport to a local hospital and during air evacuation to a tertiary center. This case is an example of the adverse environmental, topographic, and logistic hindrances that occur in the management of cardiac arrest in the prehospital scenario. It also reinforces the fact that a good outcome is possible when hypothermia is not preceded by a hypoxic event. Despite the lack of evidence, such case reports show what is possible for human physiology and illustrate the importance of appropriate decisions regarding transportation.

Giacomo Strapazzon, M.D.
Giovanni Avancini, M.D.
EURAC Institute of Mountain Emergency Medicine, Bolzano, Italy
giacomo.strapazzon@eurac.edu

Marc Blancher, M.D.
University Hospital of Grenoble, Grenoble, France

No potential conflict of interest relevant to this letter was reported.

2 References

1. 1

   Husby P, Andersen KS, Owen-Falkenberg A, Steien E, Solheim J. Accidental hypothermia with cardiac arrest: complete recovery after prolonged resuscitation and rewarming by extracorporeal circulation. Intensive Care Med 1990;16:69-72
   CrossRef | Web of Science | Medline

2. 2

   Mark E, Jacobsen O, Kjerstad A, et al. Hypothermic cardiac arrest far away from the center providing rewarming with extracorporeal circulation. Int J Emerg Med 2012;5:7-7
   CrossRef

Author/Editor Response

Survival rates of 47 to 100% from hypothermic cardiac arrest (core temperature range, 15.5 to 25°C [60 to 77°F]) with extracorporeal rewarming seem reassuring.1,2 However, in seven survivors of cardiac arrest after an immersion incident, six had mild-to-moderate cognitive dysfunction and one had severe dysfunction.2 Thus, although medical progress has enabled us to save the hearts of patients with hypothermic cardiac arrest, we may still be losing more than necessary of their brains. Further studies are required to optimize the chain of survival and the ability to predict outcomes in these patients. The International Hypothermia Registry is a promising step in the right direction. More than 10 countries are now providing data, and additional contributors are welcomed.

Notably, in a small Norwegian hospital, a 42-year-old man with hypothermic cardiac arrest (23.2°C [73.8°F]) for 6.5 hours was rewarmed and successfully resuscitated with blankets, hot-water bottles, warm intravenous fluids, and peritoneal lavage.3 According to the patient's wife, his cerebral status was unchanged, although neurologic examination revealed “slow cerebration.” The longest documented time from rescue until the start of CPR followed by complete neurologic recovery appears to be 70 minutes.3 The same publication reported on three patients who underwent CPR for almost 4 hours with full neurologic recovery, two of them without the use of extracorporeal rewarming.3 The old advice that “No one is dead until warm and dead” still holds true, with few exceptions.

The International Commission for Mountain Emergency Medicine has published guidelines for avalanche resuscitation4 and termination of resuscitation.5 These guidelines recommend that in the absence of alternative causes of death, such as trauma or hypoxia, all patients with hypothermia who do not have vital signs should be considered for CPR, ideally with transport to a center capable of extracorporeal rewarming. The use of CPR is recommended until extracorporeal rewarming is complete, regardless of the duration of CPR. The guidelines acknowledge that CPR may be withheld or terminated if a patient is lethally injured or completely frozen, the airway is blocked (for avalanche victims buried >35 minutes), the risk to the rescuers is unacceptably high, or a valid do-not-resuscitate order exists.

Patients with asystole and deep hypothermia (<28°C [82.4°F]) should be given the benefit of the doubt. There is no reason to believe that the limits reported so far are definitive. We are just beginning to learn about successfully resuscitating “dead” victims of hypothermia.

Peter Paal, M.D.
University Hospital Innsbruck, Innsbruck, Austria

Hermann Brugger, M.D.
EURAC Institute of Mountain Emergency Medicine, Bolzano, Italy

Jeff Boyd, M.B., B.S.
Mineral Springs Hospital, Banff, AB, Canada

Since publication of their article, the authors report no further potential conflict of interest.

5 References

1. 1

   Walpoth BH, Walpoth-Aslan BN, Mattle HP, et al. Outcome of survivors of accidental deep hypothermia and circulatory arrest treated with extracorporeal blood warming. N Engl J Med 1997;337:1500-1505
   Free Full Text | Web of Science | Medline

2. 2

   Wanscher M, Agersnap L, Ravn J, et al. Outcome of accidental hypothermia with or without circulatory arrest: experience from the Danish Præstø Fjord boating accident. Resuscitation 2012;83:1078-1084
   CrossRef | Medline

3. 3

   Lexow K. Severe accidental hypothermia: survival after 6 hours 30 minutes of cardiopulmonary resuscitation. Arctic Med Res 1991;50:Suppl 6:112-114
   Medline

4. 4

   Brugger H, Durrer B, Elsensohn F, et al. Resuscitation of avalanche victims: evidence-based guidelines of the International Commission for Mountain Emergency Medicine (ICAR MEDCOM): intended for physicians and other advanced life support personnel. Resuscitation 2012 November 2 (Epub ahead of print).
   

5. 5

   Paal P, Milani M, Brown D, Boyd J, Ellerton J. Termination of cardiopulmonary resuscitation in mountain rescue. High Alt Med Biol 2012;13:200-208
   CrossRef | Medline