Metabolic demands and perceived exertion during cardiopulmonary resuscitation

Emergency situations often require continuous execution of one-person cardiopulmonary resuscitation (CPR) for periods of time in excess of 30 minutes. The limited research which has examined the demands of the procedure has focused on central physiological measures, despite (1) the use of a subjective end-point for termination of CPR (i.e., exhaustion) as stated in professional guidelines, and (2) significant peripheral involvement in the form of muscular exertion, a phenomenon more closely linked to Ratings of Perceived Exertion (RPE) than to central factors. To examine subjective responses to performing CPR, 8 healthy, sedentary subjects [M age = 20.8 (yr) +/- .4; weight (kg) 82.6 +/- 7.1; height (cm) 183.7 +/- 2.8] reported differentiated Ratings of Perceived Exertion (RPE) following 10 minutes of one-person CPR testing. While metabolic data observed during CPR support previous research suggesting that the energy demands of performing CPR are relatively low, both peripheral and over-all RPE were significantly higher than central (respiratory-metabolic) RPE. Over-all RPE was also significantly greater than peripheral RPE. The data suggest research investigating CPR demands based on central measures may underestimate actual as well as perceived demands of performing the procedure. In addition, the considerable interindividual variability in the relative energy cost (% VO2 max) of performing one-person CPR suggests that the fitness level of the individual may be a limiting factor in the ability to perform CPR for extended periods of time.