Figure 1. a, Time to asytole represented as absolute time ± standard error (SE). The 1:4 group time to asystole (*) was significantly prolonged compared to control (21.2 vs 17.6 minutes, P < 0.05). b, Time to apnea represented as absolute time ± SE. There was no significant difference between control and intervention groups. c, Baseline heart rate with 95% confidence interval (CI). There was no significant difference between control and intervention groups. d, Baseline respiratory rate with 95% CI. There was significant variability between control and intervention groups 2 (mean difference 18.2, 95% CI 4.7–31.7, P < 0.05) and 4 (mean difference 21.5, 95% CI 7.9–35, P < 0.05).