Efficiency and safety of a noninvasive therapeutic hypothermia protocol in cardiac arrest

Abstract

Objectives: Therapeutic hypothermia (TH) is part of the treatment strategy for comatose survivors of cardiac arrest (CA). The aim of our study was to evaluate the efficiency and the safety of a noninvasive and affordable cooling procedure applied to all types of CA in an ICU.

Study design: This was a retrospective, observational, monocenter study.

Patients and methods: In all patients remaining unconscious after CA, irrespective of their initial cardiac rhythm, TH was induced with a rapid intravenous infusion of 30 ml/kg ice-cold (4°C) saline fluid associated with external surface cooling involving ice packs and wet sheets. The body temperature was maintained between 32 and 34°C during 24 h using external surface cooling only. The patients were then passively rewarmed.

Results: Of 200 eligible patients, 145 were treated by TH; 104 patients completed the 24-h TH treatment. The primary cause of noninclusion or secondary exclusion was severe hemodynamic impairment. From induction, the median time to reach the target temperature was 167 min (47-300 min). During the protocol, 24 patients did not remain within the targeted temperature range. Adverse events included hypokalemia (44%), severe arrhythmia (13.8%), bleeding (4.8%), and seizure (1.4%). All patients presented hyperglycemia. The oxygen partial pressure to oxygen fractional concentration (PaO2/FiO2) ratio remained constant after initiation and throughout the procedure, even in patients with poor systolic function.

Conclusion: This noninvasive TH procedure seems efficient and safe in all patients remaining comatose after CA. Thanks to its simplicity, it could allow prehospital cooling to reach the target temperature more rapidly.