Rewarming From Hypothermic Cardiac Arrest Applying Extracorporeal Life Support: A Systematic Review and Meta-Analysis

Area of Science:

• Critical Care Medicine
• Cardiology
• Emergency Medicine

Background:

• Accidental hypothermic cardiac arrest (HCA) presents unique resuscitation challenges.
• Rewarming techniques, including cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO), are crucial for survival.
• Comparative outcome data for different rewarming strategies in HCA are limited.

Approach:

• Systematic review and meta-analysis of 23 case observation studies involving 464 patients.
• Primary outcome: survival to hospital discharge.
• Secondary outcomes: neurological outcome, relative risks of survival based on rewarming technique, sex, asphyxia, and witnessed/unwitnessed HCA.

Key Points:

• Overall survival to hospital discharge was 37% (172/464 patients).
• Survival rates were higher with ECMO (44%) compared to CPB (31%).
• ECMO use was associated with a 41% higher chance of survival (P=0.005).
• Witnessed HCA and male sex were associated with better survival odds with ECMO.
• Avalanche victims had the lowest survival probability.
• Factors associated with reduced survival included asphyxia, unwitnessed HCA, male sex, high initial body temperature, low pH, and high serum potassium.

Conclusions:

• Rewarming with ECMO offers significantly higher survival chances than CPB in accidental HCA.
• Witnessed HCA is a critical factor for improved survival outcomes.
• Identifying and mitigating risk factors like asphyxia, low pH, and high serum potassium is vital for enhancing patient survival.