Abstract 84: Relationship Between Chest Compression Rate and Depth During Cardiopulmonary Resuscitation

Abstract

Background The 2010 AHA guidelines for healthcare providers encourage rescuers to focus on the delivery of high quality cardiopulmonary resuscitation (CPR). For adults, guidelines recommend chest compressions at a rate of at least 100 compressions per minute (cpm) with a depth of at least 51 millimeters (mm). Continuously pushing the chest hard and fast can be difficult and the compression depth may drop if the rescuer increases the compression rate. Objective Determine the distributions of and relationship between chest compression rate and depth during CPR in out-of-hospital cardiac arrest (OHCA) patients. Methods Recordings from a convenience sample of 234 OHCA patients with compression waveforms collected from 2006 to 2010 from a single EMS agency using the Philips HeartStart MRx defibrillator. Real-time audio and visual feedback was available to EMS personnel based on the 2005 depth guidelines (38 to 51 mm). Compression depth and rate were calculated based on the waveforms recorded by the Q-CPR TM measurement and feedback tool. The continuous distributions of rate and depth were generated using only the segments with good signal quality (total of 42 hours). Results The figure shows the distributions of and relationship between the rate and depth. In this dataset, 69% of the time the compression rate was at least 100 cpm and 48% of the compressions had a depth between 38 and 51 mm. Only 10% were performed slower than 90 cpm, and only 12% were less than 30 mm deep. With the compression rates between 73 to 88 cpm, the depth increased at a rate of 0.3 mm/cpm. However, at compression rates faster than 88 cpm, the depth decreased at almost the same rate of -0.3 mm/cpm. Conclusion Chest compressions at rates faster than 88 cpm are associated with a reduction in depth. The practical balance between compression rate and depth deserve consideration in the Guidelines process.