The classic teaching is that nobody is dead until they are warm and dead. But as discussed last week, knowing which patients are likely to survive (and thus warrant lifesaving efforts) is difficult to ascertain. Unlike the avalanche patient who is hypothermic, the non-trauma accidental hypothermia patient typically has better outcomes as well. It’s especially hard to stop (or not start) when you consider that the authors of this study had previously reported successful ROSC in a patient who had a core temp of 13.7◦C after 6 hours and 52 minutes of resuscitation.
The study was done in northern Norway, where data collection is easier for a hypothermia study. They had 28 years of data that they broke down into 3 “eras”; the early years, after moving to the new hospital, and post ECLS. Unfortunately, they only included 34 patients in their analysis, 9 of which survived. The authors did not find statistically significant difference in survival based on mechanism of cooling, season, initial ECG-rhythm, transport time, or distance from the medical center.
Similar to the French study, the potassium level was significantly different between survivors and non-survivors. Specifically, the highest level for survivors was 5.9 mmol/L, but a normal K did not predict survival. Survivors and non-survivors also differed in length of stay, as would be expected. However, the longest stay for a non-survivor was 218 days! This was twice the length of the longest survivor at 106 days, and calls into question their statement that non-survivors consumed only modest resources, even though median length of stay for non-survivors was 0.35 days. They also did not have any survivors until the last time period, after ECLS was incorporated into their treatment.
The authors do state that their study supports the use of K>12 mmol/L as a decision to stop resuscitation. While I don’t disagree, I would argue that it supports the use of a lower level, perhaps 10 or even 7 mmol/L. However, barring external trauma incompatible with life, packed snow in the airway, or physically being frozen, if they have a K lower than whatever cutoff you choose to use, you have to resuscitate them until they reach 34◦C. It is a retrospective study, and low patient numbers limit application of their data, but it’s unlikely that anyone can do a prospective trial on such a topic.
“Nobody is dead until warm and dead”: Prolonged resuscitation is warranted in arrested hypothermic victims also in remote areas – A retrospective study from northern Norway
Of note, volume 85 of the journal Resuscitation had quite a few articles about wilderness topics. This is the second one in two weeks, but people interested should look into the other articles.