METHODS: This was a simulated quasi-experimental study with a sample of 14 lifeguards and 13 laypersons. Each lifeguard performed 2 min single-rescuer CPR as baseline measurement. In three separate trials, a single lifeguard swam 50 m to perform a water rescue in a pool and returned with the manikin another 50 m. After each rescue, 10 min of CPR was performed by a single lifeguard, two lifeguards or a lifeguard with a layperson with no CPR training. Paired t-test and repeated analysis of variance were used to analyse CPR quality variables.
RESULTS: Baseline CPR quality was adequate for most measures except compression depth and re-expansion. After water rescue, the single lifeguard trial showed no significant differences compared with baseline. CPR score and ventilation score of the single-lifeguard trial was higher than that of the lifeguard-bystander trial (p=0.027, p<0.001). Both the two-lifeguard trial (p=0.025), and lifeguard-bystander trial (p=0.010) had a lower percentage of breaths with correct ventilation volume and higher percentage of breaths with excessive ventilation volume (p=0.007, p=0.011, respectively) than the single-lifeguard trial. No-flow time of the lifeguard-bystander trial was longer than other trials (p<0.001).
CONCLUSIONS: Although CPR given by the lifeguard was not optimal, fatigue generated by a water rescue has no impact on the quality of subsequent CPR performed by a trained lifeguard for 10 min. Untrained bystanders assisting in CPR in a drowning event is unlikely to be helpful.