Abstract 224: Effective Chest Compressions Are Related to Gender and Body Mass Index

Abstract

Introduction: The outcome after cardiopulmonary resuscitation (CPR) depends on effective chest compressions. This prospective, single-center study examined the relationship between a provider's gender and body mass index (BMI) to chest compression depth and rate during CPR. Method: After informed consent, 84 medical students were tested for a continuous period of 2 minutes on a simulator (Laerdal Advanced Resusci Annie with PC Skills Reporter) that automatically measured depth and rate of chest compressions. Data collected included average rate and depth and the rate and depth for the first and last 30 seconds of 2 minutes of CPR. Statistical analysis was performed using a Two-Sample T-test, Wilcoxon Mann-Whitney test, Pearson and Spearman correlations. Adequate depth (38-51 mm) and rate (90-110 compressions/minute) were based on 2005 AHA guidelines. Results: During the first 30 seconds of CPR, males were more effective than females in administering sufficient compression depth (p=0.0006); a positive correlation was found between compression depth and height (p=0.0203), weight (p=0.0002) and BMI (p value < 0.0001). Similar positive correlations were also found between average adequate depth of chest compressions with BMI (p=0.0039) and weight (p=0.0176). During the last 30 seconds of CPR there was a positive correlation between compression depth and BMI (p=0.0256); however males were 3.58 times more likely than females to continue administering chest compressions for the full 2 minutes and those who completed had a higher median BMI, height and weight. All providers achieved an adequate compression rate. Conclusion: BMI and gender have a significant effect on initial chest compression depth and on the duration of continued CPR, but not on compression rate. Smaller people may have a more difficult time achieving adequate depth of compressions during CPR and may require more frequent rotations to maintain good cardiac output. The new AHA Guidelines may exaggerate this difference due to deeper compression recommendations. Further studies are needed to determine the effect on different patient or provider sizes.