To compare OHCA outcomes in patients managed with mechanical versus manual CPR in an EMS system with a “pit crew” approach to resuscitation and a scripted sequence for the initiation of mechanical CPR.

Through a year-long quality improvement effort we standardized the initial resuscitative efforts for OHCA, prioritizing a “pit crew” approach to high quality manual CPR, early defibrillation and basic airway management ahead of a scripted sequence for initiating mechanical CPR. We then analyzed outcomes for adult, non-traumatic OHCA attended in the following year (2016). We used a propensity score matched analysis to compare ROSC, survival to discharge, and neurologic status among patients managed with manual versus mechanical CPR while controlling for patient demographics and arrest characteristics.

Of 444 eligible OHCAs, 217 received manual and 227 received mechanical CPR. Crude ROSC (39.2% vs. 29.1%) and survival to discharge (13.8% vs. 5.7%) were higher with manual CPR. In the propensity matched analysis (n = 176 manual CPR; 176 mechanical CPR), both ROSC (38.6% vs. 28.4%; difference: 10.2%; CI: 0.4% to 20.0%) and survival to discharge (13.6% vs. 6.8%; difference: 6.8%; CI: 0.5% to 13.3%) remained significantly higher for patients receiving manual CPR.

In this EMS system with a standardized, “pit crew” approach to OHCA that prioritized initial high-quality initial resuscitative efforts and scripted the sequence for initiating mechanical CPR, use of mechanical CPR was associated with decreased ROSC and decreased survival to discharge.