Relation Between Chest Compression Rate And Depth: The Enfonce Study

Introduction Chest compressions are the cornerstone of cardiopulmonary resuscitation. The recent International Liaison Committee on Resuscitation guidelines recommend increasing the rate and the depth of chest compressions, to 100-120/min and 5-6 cm, based on theoretical arguments and observational studies. We hypothesized that an increased chest compressions rate could decrease chest compressions depth. Methods Operators were asked to perform continuous chest compressions on a mannequin. Chest compressions rate and depth were collected. The ratio of chest compressions compliance to the guidelines, that is rate 100-120/min and depth 5-6 cm, was calculated. Results In total 951 sequences of chest compressions were studied. Median chest compressions rate: 114 (104-130)/min. Median chest compressions depth: 4.5 (3.4-5.3) cm. Correlation between rate and depth: low (R-2 = 0.12). Chest compressions in compliance with the recommended rate: 434 (46%). Rate >120/min in 285 (30%) cases and <100/min in 223 (23%) cases. Chest compressions in compliance with the recommended depth: 286 (30%). Depth >6 cm in 50 (5%) cases and <5 cm in 621 (65%) cases. Finally, chest compressions were in compliance with the guidelines for both rate and depth in 141 (15%) cases. The ratio of chest compressions in compliance with the recommended depth significantly decreased with the increase of the rate: 40% for a rate <100/min, 32% for a rate in the target (100-120/min) and 18% for a rate >100/min (P < 0.0001). Discussion The ratio of chest compressions in compliance with the recommended rate and depth was as low as 15%. The rate of chest compressions in compliance with the recommended depth significantly decreased when the chest compressions rate increased. To reach both recommended rate and depth seems illusive.