Perfusion Index not better predictor of cardiac arrest compared to EtCO2 Monitoring: Study

Globally, cardiac arrest is one of the major causes of mortality; nonetheless, hospital survival and release rates with favourable neurological outcomes are still quite low. 9.0% of out-of-hospital cardiac arrests (OHCAs) and 23.3% of in-hospital cardiac arrests (IHCAs) resulted in hospital discharges, according to the American Heart Association (AHA). Parameters like intraarterial pressure monitoring and end-tidal carbon dioxide (EtCO2) are utilised during cardiopulmonary resuscitation (CPR) to track the efficacy of the procedure and estimate the prognosis. Low EtCO2 levels are indicative of subpar CPR, however sharp rises might be a sign of the spontaneous circulation returning (ROSC).

In addition to hemodynamic monitoring in the form of pulse oximetry, additional monitoring methods used in medicine include photoplethysmography (PPG) and perfusion index (PI). PPG is rapid, affordable, objectively repeatable, and simple to test. There is, however, little data about PI's usefulness in cardiac arrest patients. Recently published research assessed how well PI and EtCO2 predict ROSC in individuals who have had cardiac arrest.

From November 1, 2018, to April 30, 2019, the research was carried out in the emergency department of Hacettepe University Hospital utilising the advanced cardiac life support protocol (ACLS), in accordance with the guidelines provided by the American Heart Association and the International Liaison Committee on Resuscitation (ILCOR). Both resuscitations revolve on providing excellent CPR and defibrillation. Using the LIFEPAK® 15 monitor/defibrillator and the Masimo Signal Extraction Technology (SET®) Radical 7 pulse device, patients were grouped based on ROSC and monitored.

The purpose of this investigation was to evaluate how well the Perfusion Index (PI) predicted cardiac arrest patients' restoration of spontaneous circulation (ROSC). The ability of end-tidal carbon dioxide (ETCO2) to predict ROSC in individuals undergoing cardiac arrest as well as the correlation between PI and EtCO2 levels were the secondary outcomes. A total of 162 instances of cardiac arrest were recorded; the patients' mean age was 70.4 ± 13.4, and 65% of them were men. Of the patients, 29 (29%) obtained the ROSC.

To forecast the ROSC, the values of PI and EtCO2 were looked at. The PI values did not vary statistically across the groups. But beginning in the fifth minute, the ROSC (+) group's EtCO2 readings were noticeably greater than those of the ROSC (-) group. After the 25th minute, the sample size significantly decreased, making comparison and further analysis impossible.

To investigate the relationship between the EtCO2 concentrations and PI, Spearman correlation analysis were carried out. Between the PI and ETCO2 at0,5,10,15, 20, and 25 minutes, there was no association. The research emphasises how crucial it is to comprehend how PI and EtCO2 readings relate to one another in order to anticipate the ROSC in individuals who have had cardiac arrest.

The usage of PI and EtCO2 in cardiac arrest patients was compared in the research since hemodynamic monitoring depends on these measures. The PI values of the groups with and without the ROSC did not significantly change, according to the data. Nevertheless, from the fifth minute on, the ROSC group's EtCO2 readings continued to be considerably higher, indicating that EtCO2 could provide insights into the outcomes of cardiac resuscitation. This implies that monitoring hemodynamic parameters—particularly those related to the use of EtCO2—may be essential for assessing the efficacy of resuscitation and formulating focused treatment plans in the context of cardiac arrest care. The lack of a significant correlation between PI readings and the ROSC suggests that PI may not be a very reliable predictor of cardiac arrest. The single-center design, the inclusion of only intubated patients, and the exclusion of non-intubated patients are among the limitations of this research. Nonetheless, the study projects that as technology advances, EtCO2 will become more widely used. Appropriate techniques will be used to do more research on individuals who are not intubated.

Reference –

Dogan B, Kudu E, Danış F, et al. (December 20, 2023) Comparative Analysis of Perfusion Index and End-Tidal Carbon Dioxide in Cardiac Arrest Patients: Implications for Hemodynamic Monitoring and Resuscitation Outcomes. Cureus 15(12): e50818. doi:10.7759/cureus.50818