From the Research
In hypothermic cardiac arrest, continue standard ACLS protocols as usual when the patient's core temperature is above 30°C (86°F). For patients with temperatures below 30°C, modifications to ACLS are necessary. When the core temperature is below 30°C, limit defibrillation attempts to a maximum of three shocks until the patient is warmed above this threshold. Medications should be withheld or administered at longer intervals, as drug metabolism is significantly slowed in severe hypothermia. CPR should be continued without interruption while active rewarming measures are implemented. The rationale for these modifications is that hypothermia below 30°C causes significant physiological changes including decreased drug metabolism, myocardial irritability, and altered pharmacokinetics that reduce the effectiveness of standard ACLS interventions. The heart becomes increasingly resistant to both electrical defibrillation and medications at lower temperatures, making rewarming the priority while maintaining circulation through continuous CPR. Once the patient is rewarmed above 30°C, resume normal ACLS protocols including standard medication administration and defibrillation sequences.
Some key points to consider in the management of hypothermic cardiac arrest include:
- The use of extracorporeal life support (ECLS) has revolutionized the management of hypothermic cardiac arrest, with survival rates approaching 100% in some cases 1.
- Delayed or intermittent CPR may be appropriate in hypothermic arrest when continuous CPR is impossible 2.
- Modern post-resuscitation care should be implemented following hypothermic arrest, including structured protocols for pre-hospital triage, transport, and treatment, as well as in-hospital management 1.
- The application of ACLS protocols in severe hypothermic cardiac arrest remains controversial, but there is evidence to suggest that they can be effective in certain cases 3.
It is essential to prioritize rewarming and maintain circulation through continuous CPR in hypothermic cardiac arrest patients. The most recent and highest quality study 4 supports the use of active rewarming measures, such as the ZOLL Icy catheter, to rapidly increase the patient's core temperature. By following these guidelines and prioritizing rewarming and circulation, healthcare providers can improve outcomes in hypothermic cardiac arrest patients.