AimCardiopulmonary resuscitation (CPR) quality is associated with survival outcomes after out-of-hospital cardiac arrest. The objective of this study was to evaluate the effectiveness of simplified dispatcher CPR instructions to improve the chest compression (CC) quality during simulated pediatric cardiac arrest in public places. MethodsAdult bystanders recruited in public places were randomized to receive one of two scripted dispatcher CPR instructions: (1) “Push as hard as you can” (PUSH HARD) or (2) “Push approximately 2 inches” (TWO INCHES). A pediatric manikin with realistic CC characteristics (similar to a 6-year-old child), and a CPR recording defibrillator was used for quantitative CC data collection during a 2-min simulated pediatric scenario. The primary outcome was average CC depth treated as a continuous variable. Secondary outcomes included compliance with American Heart Association (AHA) CPR targets. Analysis was by two-sided unpaired t-test and Chi-square test, as appropriate. Results128 out of 140 providers screened met inclusion/exclusion criteria and all 128 consented. The average CC depth (mean (SEM)) was greater in PUSH HARD compared to TWO INCHES (43 (1) vs. 36 (1) mm, p<0.01) and met AHA targets more often (39% (25/64) vs. 20% (13/64), p=0.02). CC rates trended higher in the PUSH HARD group (93 (4) vs. 82 (4) CC/min, p=0.06). More providers did not achieve full chest recoil with PUSH HARD compared to TWO INCHES (53% (34/64) vs. 75% (48/64), p=0.01). ConclusionsSimplified dispatcher assisted pediatric CPR instructions: “Push as hard as you can” was associated with lay bystanders providing deeper and faster CCs on a simulated, 6-year-old pediatric manikin. However, percentage of providers leaning between CC increased. The potential effect of these simplified instructions in younger children remains unanswered.