Miniaturized mechanical chest compressor: A new option for cardiopulmonary resuscitation

Aim of study: After cardiac arrest, uninterrupted chest compressions with restoration of myocardial blood flow facilitates restoration of spontaneous circulation. We recognized that this may best be accomplished with a mechanical device and especially so during transport. We therefore sought to develop a lightweight, portable chest compressor which may be carried on the belt or attached to the oxygen tank typically carried on the back of the first response rescuer. A miniaturized pneumatic chest compressor (MCC) weighing less than 2 kg was developed and compared with a currently marketed "Michigan Thumper^®", which weighed 19 kg. We hypothesized that the 2 kg, low profile, portable device will be as effective as the standard pneumatic Thumper^® for restoring circulation during CPR. Material and methods: Ventricular fibrillation was electrically induced in 10 domestic male pigs weighing 39 ± 2 kg, and untreated for 5 min. Animals were then randomized to receive chest compressions with either the MCC or the Thumper^®. After 5 min of mechanical chest compression, defibrillation was attempted with a 150 J biphasic shock. Coronary perfusion pressure (CPP) and end tidal PCO₂ (EtPCO₂) were measured by conventional techniques together with right carotid artery blood flow (CBF). Results: Four of five animals compressed with the Thumper^® and each animal compressed with the MCC were successfully resuscitated. No significant differences in CPP, EtPCO₂, CBF and post-resuscitation myocardial function were observed between groups. Resuscitated animals survived for more than 72 h without neurological impairment. Conclusion: The low profile, 2 kg miniaturized chest compressor is as effective as the conventional Thumper^® in an experimental model of CPR.