Is the Perfusion Index an Accurate Predictor of Return of Spontaneus Circulation in Out-of-hospital Cardiac Arrest

The purpose of this pilot feasibility study is to evaluate the ability of the Perfusion Index to predict the return to spontaneous circulation of the out-of-hospital cardiac arrest patient during cardiopulmonary resuscitation. The performance of the perfusion index will also be compared to the current gold standard, end-tidal CO2 (EtCO2).

The aim of this observational research is to measure the predictive performance the perfusion index to predict a return of a spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR). The research focuses on patients in out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest (IHCA) treated by the mobile intensive care unit of Saint Pierre University Hospital. The study will be a pilot observational study during cardiac arrest. During the study period a non-invasive sensor will be connected to the patient's finger to measure continously and non-invasively the perfusion index. This non-invasive measurement is done by means of an infrared light which has no known risks for the health of the patient and which is usually used for the measurement of arterial oxygen saturation (SatO2). No intervention is planned as no decision will be taken on treatment based on the collected values of perfusion index during the arrest and post-arrest care of the participants. The study will therefore be conducted during conventional advanced life support procedures without rescuers having access to the ongoing measurements. The study will end when the participant returns to spontaneous circulation (RACS) or when patients is admitted to the emergency ward, whichever comes first in a time frame of maximum two hours. The decision to stop resuscitation procedures will be made in accordance with the European Resuscitation Council (ERC) recommendations and the Resuscitation Termination Rules (TOR) for cardiac arrest. Pulsatility index values will be sampled at a 0.5 Hertz frequency. These values will be tested for their ability to predict ROSC within 2 minutes. Similarly, EtCO2 values (as a gold standard) will be analyzed from the time of first measure. The sensitivity and specificity of the collected values of EtCO2 in the prediction of ROSC will be compared, at the end of the study to the diagnostic sensibility and specificity of different thresholds of the perfusion index. The patient's consent will be requested at the moment when he/she recovers consciousness allowing the comprehension and signature of a consent after the cardiac arrest.