Manual versus Mechanical Chest Compressions on Surfaces of Varying Softness with or without Backboards: A Randomized, Crossover Manikin Study

Abstract

BackgroundChest compression quality is decisive for overall outcome after cardiac arrest. Chest compression depth may decrease when cardiopulmonary resuscitation (CPR) is performed on a mattress, and the use of a backboard does not necessarily improve compression depth. Mechanical chest compression devices may overcome this problem. ObjectivesWe sought to investigate the effectiveness of manual chest compressions both with and without a backboard compared to mechanical CPR performed on surfaces of different softness. MethodsTwenty-four advanced life support (ALS)–certified rescuers were enrolled. LUCAS2 (Physio-Control, Redmond, WA) delivers 52 ± 2 mm deep chest compressions and active decompressions back to the neutral position (frequency 102 min−1; duty cycle, 50%). This simulated CPR scenario was performed on a Resusci-Anne manikin (Laerdal, Stavanger, Norway) that was lying on 3 different surfaces: 1) a concrete floor, 2) a firm standard mattress, and 3) a pressure-relieving mattress. Data were recorded by the Laerdal Skill Reporting System. ResultsManual chest compression with or without a backboard were performed correctly less often than mechanical chest compressions (floor: 33% [interquartile range {IQR}, 27–48%] vs. 90% [IQR, 86–94%], p < 0.001; standard mattress: 32% [IQR, 20–45%] vs. 27% [IQR, 14–46%] vs. 91% [IQR, 51–94%], p < 0.001; and pressure-relieving mattress 29% [IQR, 17–49%] vs. 30% [IQR, 17–52%] vs. 91% [IQR, 87–95%], p < 0.001). The mean compression depth on both mattresses was deeper with mechanical chest compressions (floor: 53 mm [range, 47–57 mm] vs. 56 mm [range, 54–57 mm], p = 0.003; standard mattress: 50 mm [range, 44–55 mm] vs. 51 mm [range, 47–55 mm] vs. 55 mm [range, 54–58 mm], p < 0.001; and pressure-relieving mattress: 49 mm [range, 44–55 mm] vs. 50 mm [range, 44–53 mm] vs. 55 mm [range, 55–56 mm], p < 0.001). In this ∼6-min scenario, the mean hands-off time was ∼15 to 20 s shorter in the manual CPR scenarios. ConclusionsIn this experimental study, only ∼30% of manual chest compressions were performed correctly compared to ∼90% of mechanical chest compressions, regardless of the underlying surface. Backboard use did not influence the mean compression depth during manual CPR. Chest compressions were deeper with mechanical CPR. The mean hands-off time was shorter with manual CPR.