Influence of Intercompression Cycle Rest Period Duration on CPR Quality

Introduction: Cardiopulmonary resuscitation (CPR) has been the keystone of cardiac arrest care since its creation in the early 1900s. CPR quality, however, decreases drastically, in some cases over 60%, in just a few minutes. Limited research has investigated rest periods that providers may need in order to provide another full and effective two minutes of CPR following their previous cycle.

Objective: To explore whether rest periods of varying durations influence provider fatigue and CPR compression quality. 

Methods: Participants volunteered their time, were active prehospital providers, and were tasked with performing four continuous two-minute cycles of CPR compressions. Participants were randomly assigned to one of four groups. Each group had a specified rest period between cycles: two, four, six, or eight minutes. Chest compression rate, depth, hand placement, and recoil were recorded by proprietary CPR manikins. Following each CPR cycle, the participant also self-reported his/her fatigue level on a 0–10 scale. Linear regression models utilizing robust standard errors were estimated and controlled for the participant’s age, sex, years of EMS experience, level of EMS certification, and BMI. 

Results: Sixty-two volunteers participated and were equally split among the four rest duration groups. Using the two-minute rest duration group as the referent, there were no statistically significant differences in compression rate, depth, hand placement, or recoil among groups. There was, however, a statistically significant difference in self-reported fatigue among the groups. Following the fourth compression cycle, participants in the eight-minute rest group reported a fatigue level nearly  three points lower than the two-minute rest group (β=[-2.94], p<0.000). The six-minute (β=[-1.75], p=0.013) and four-minute (β=[-1.48], p=0.037) rest groups also reported lower fatigue after four cycles. 

Conclusions: Previous research has shown that compressor rotation is an important contributor to CPR quality. Although a two-minute cycle is now the standard, there are no recommendations on the length of rest between cycles for each provider. Using rest duration as a proxy for the number of available providers, this study may suggest that increasing the number of responders decreases fatigue but does not improve the quality of CPR compressions.