Abstract 17983: Optimal Chest Compression Rate During CPR: The Importance of Filling Time
Introduction: AHA 2015 Guidelines for cardiopulmonary resuscitation (CPR) recommended an upper rate limit of 120 compressions per minute (cpm) based on observational data showing optimal survival with rates between 100 and 120 cpm. Higher rates are accompanied by decreased compression depth, but CPR efficacy at high rates may also be limited by reduced filling time.
Hypothesis: Refilling time may limit optimal CPR rates as much or more than depth
Methods: Accelerometry and force waveform recordings during CPR from Philips MRx monitors were examined in a convenience sample of 21 cases from an existing OHCA registry. Custom software measured 31,681 compression waveforms, defined by force minima. Depths were calculated by double integration of accelerometry. Depth waveforms were modeled as trapezoidal, with compression and release periods defined as time spent within 10% of either extreme.
Results: Maximum depths and release durations were both independent predictors of rate in a generalized linear model (p < 0.001). Depths and release times both declined at highest rates. Depth decreased only at rates in excess of 140 cpm, while release time declined monotonically through most of the range. Release time in the recommended range averaged 153 ms, declining to 121 for rates of 120-130 and further thereafter. These shorter periods may be insufficient to support refilling during CPR.
Conclusions: Release time and compression depth are both compromised at high compression rates. Depth had an “inverted U” distribution, declining only at highest rates. Decline in release time is nearly monotonic, and may limit CPR efficacy at lower rates than does compression depth.
Author Disclosures: J.K. Russell: None. D. Zive: None. M.R. Daya: None.
- © 2016 by American Heart Association, Inc.