Question: I need some further clarification on the question "Seeking Clarification" from March 1 2012 regarding hypothermia. It has been my understanding that we DO NOT give medications to hypothermic VSA patients. I have clarified this before, unless this rule has changed since, so could you please readdress this part of the question for me?
Thanks for your question. The posting you are referring to on March 1 2012 states that once "transport is initiated, yes, it is completely acceptable to attempt procedures you describe (IV, epi, advanced airway etc) en-route but NOT on scene. Same rules apply to the hypothermic cardiac arrest."
With that said, hypothermic cardiac arrests are rare. It will also be extremely challenging with your often limited number of responding paramedics to establish IV access and administer meds while on transport following the one analysis. If you are able to accomplish this that would be terrific however it is not our expectation. Rather, rapid scene time and transport for early active core rewarming is the preferred strategy.
We base this decision upon the 2010 AHA Guidelines (Vanden Hoek et al Part 12: Cardiac Arrest in Special Situations) which state:
"ACLS management of cardiac arrest due to hypothermia focuses on aggressive active core rewarming techniques as the primary therapeutic modality. Conventional wisdom indicates that the hypothermic heart may be unresponsive to cardiovascular drugs, pacemaker stimulation, and defibrillation; however, the data to support this are essentially theoretical. In addition, drug metabolism may be reduced, and there is a theoretical concern that medications could accumulate to toxic levels in the peripheral circulation if given repeatedly to the severely hypothermic victim. For these reasons, previous guidelines suggest withholding IV drugs if the victim's core body temperature is _30°C (86°F).
In the last decade a number of animal investigations have been performed evaluating both vasopressors and antiarrhythmic medications that could challenge some of this conventional wisdom. In a meta-analysis of these studies, Wira et al found that vasopressor medications (ie, epinephrine or vasopressin) increased rates of return of spontaneous circulation (ROSC) when compared with placebo (62% versus 17%; P_0.0001, n_77). Coronary perfusion pressures were increased in groups that received vasopressors compared with placebo. But groups given antiarrhythmics showed no improvement in ROSC when compared with control groups, although sample sizes were relatively small (n_34 and n_40, respectively).
Given the lack of human evidence and relatively small number of animal investigations, the recommendation for administration or withholding of medications is not clear. It may be reasonable to consider administration of a vasopressor during cardiac arrest according to the standard ACLS algorithm concurrent with rewarming strategies (Class IIb, LOE C)".