Study objective: Bystander cardiopulmonary resuscitation increases the likelihood of out-of-hospital cardiac arrest survival by more than two-fold. A common barrier to the prompt initiation of compressions is moving victims to the floor, but compression quality on a "floor" versus a "mattress" has not been tested among lay bystanders.
Methods: We conducted a prospective, randomized, cross-over trial comparing lay bystander compression quality using a manikin on a bed versus the floor. Participants included adults without professional health care training. We randomized participants to the order of manikin placement, either on a mattress or on the floor. For both, participants were instructed to perform 2 minutes of chest compressions on a cardiopulmonary resuscitation Simon manikin Gaumard (Gaumard Scientific, Miami, FL). The primary outcome was mean compression depth (cm) over 2 minutes. We fit a linear regression model adjusted for scenario order, age, sex, and body mass index with robust standard errors to account for repeated measures and reported mean differences with 95% confidence intervals (CIs).
Results: Our sample of 80 adults was 66% female with a mean age of 50.5 years (SD 18.2). The mean compression depth on the mattress was 2.9 cm (SD 2.3) and 3.5 cm (SD 2.2) on the floor, a mean difference of 0.58 cm (95% CI 0.18, 0.98). Compression depth fell below the 5 to 6 cm depth recommended by the American Heart Association on both surfaces. In the adjusted model, the mean depth was greater when the manikin was on the floor than the mattress (adjusted mean difference 0.62 cm; 95% CI 0.23 to 1.01), and mean depth was less for females than males (adjusted mean difference -1.42 cm, 95% CI -2.59, -0.25). In addition, the difference in compression depth was larger for female participants (mean difference 0.94 cm; 95% CI 0.54, 1.34) than for male participants (mean difference -0.01 cm; 95% CI -0.80, 0.78), and the interaction was statistically significant (P = .04).
Conclusion: The mean compression depth was significantly smaller on the mattress and with female bystanders. Further research is needed to understand the benefit of moving out-of-hospital cardiac arrest victims to the floor relative to the detrimental effect of delaying chest compressions.
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