Cardiac arrest in the operating room: Do we need to check the carotid pulse?

Abstract

To the Editor, We read this interesting report by Charapov et al. about a case of prolonged cardiopulmonary resuscitation (CPR) in the operating room. The authors stated that ‘‘The quality of the chest compressions was continuously assessed by palpation of the carotid pulse... ’’, and ‘‘One of the anesthesiologists checked the patient’s carotid pulse every minute throughout resuscitation.’’ The 2010 American Heart Association guidelines for CPR state that ‘‘No studies have shown the validity or clinical utility of checking pulses during ongoing CPR’’, and ‘‘Carotid pulsations during chest compressions do not indicate the efficacy of myocardial or cerebral perfusion during CPR.’’ The left ventricle is perfused only during diastole; therefore, its perfusion pressure is determined by the arterial relaxation ‘‘diastolic’’ pressure and not by the systolic pressure. Furthermore, blood pressure is only a surrogate measurement of cardiac function and does not necessarily correlate with flow. Additionally; a measurable cardiac output does not mean that tissue oxygen delivery and uptake at the cellular level are adequate. Physiological measures, such as end-tidal carbon dioxide concentration (ETCO2) and diastolic blood pressure, are much more reliable than palpation of a carotid or femoral arterial pulse to assess the quality of chest compression and to predict the return of spontaneous circulation (ROSC). During CPR, if ventilation is constant, ETCO2 values are directly correlated with cardiac output. Persistent ETCO2 values \ 10 mmHg suggest that ROSC is unlikely; therefore, it would be reasonable to try to improve the CPR quality by optimizing chest compressions (i.e., increasing the compression rate or depth and allowing a better chest recoil). It has also been observed that healthcare providers may take longer than expected to check for a pulse and have difficulty determining if a pulse is present or absent, causing unnecessary interruptions during CPR. The authors in this case identified that the upward curvature in the capnography trace observed at the end of the pulseless period could have predicted the ROSC, but they did not use this information to judge the effectiveness of the CPR. This case exemplifies a very valuable teaching point, as all patients under general anesthesia have continuous monitoring of ETCO2. In case of cardiac arrest during general anesthesia, ETCO2 values can be used as real-time feedback of the quality of the chest compressions and as a prognostic value for ROSC. Femoral artery and carotid artery pulsations are not necessarily good indicators of the effectiveness of chest compressions, and so we suggest that presence or absence of palpable pulses should be used in conjunction with ETCO2 measurements in monitoring cardiac arrest when these rare and unfortunate events occur in the intraoperative setting.