Helium ventilation for treatment of post-cardiac arrest syndrome: A safety and feasibility study

Besides supportive care, the only recommended treatment for comatose patients after cardiac arrest is target temperature management. Helium reduces ischaemic injury in animal models, and might ameliorate neurological injury in patients after cardiac arrest. As no studies exist on the use of helium in patients after cardiac arrest we investigated whether this is safe and feasible. The study was an open-label single arm intervention study in a mixed-bed academic intensive care unit. We included 25 patients admitted after circulatory arrest, with a presenting rhythm of ventricular fibrillation or pulseless tachycardia, return of spontaneous circulation within 30min and who were treated with hypothermia. Helium was administrated in a 1:1 mix with oxygen for 3h. A safety committee reviewed all ventilation problems, complications and causes of mortality. Helium ventilation was started 4:59±0:52 (mean±SD)h after circulatory arrest. In one patient, helium ventilation was discontinued prematurely due to oxygenation problems. This was caused by pre-existing pulmonary oedema, and imposed limitations to PEEP and FiO2 by the study protocol, rather than the use of helium ventilation. Sixteen (64%) patients had a favourable neurological outcome. We found that helium ventilation is feasible and can be used safely in patients treated with hypothermia after cardiac arrest. No adverse events related to the use of helium occurred during the three hours of administration