Biomechanical analysis of force distribution in one-handed and two-handed adult chest compression: a randomised crossover observational study.

Introduction: The standard method of chest compression for adults is a two-handed procedure. One-handed external chest compression (ECC) is used in some situations such as during transport of patients who had an out-of-hospital cardiac arrest, but the quality of one-handed ECC is still not well known. The distribution of force is related to the quality of chest compression and may affect the risk of injury. This study aimed to determine the differences in the quality and potential safety concern between one-handed ECC and two- handed ECC.

Methods: In this randomised crossover study, participants recruited from National Cheng Kung University Hospital and the ambulance team from the fire bureau were asked to perform one-handed and two-handed ECC on the Resusci Anne manikin according to standard 2015 ECC guidelines. The MatScan Pressure Measurement system was used to investigate the compression pressure and force distribution.

Results: Two-handed ECC had better results than one-handed ECC in terms of the median (IQR) depth (51.00 (41.50-54.75) mm vs 42.00 (27.00-49.00) mm, p=0.018), the proportion of depth accuracy (82.05% (13.95%-99.86%) vs 11.17% (0.00%-42.13%), p=0.028) and the proportion of incomplete recoil (0.23% (0.01%-0.44%) vs 2.42% (0.60%-4.21%), p=0.002). The maximum force (45.72 (36.10-80.84) kgf vs 35.64 (24.13-74.34) kgf, p<0.001) and ulnar-radial force difference (7.13 (-16.58 to 21.07) kgf vs 23.93 (11.19-38.74) kgf, p<0.001) showed statistically significant differences. The perceived fatigue of two-handed ECC versus one-handed ECC was 5.00 (3.00-6.00) vs 6.00 (5.00-8.00), p<0.001.

Conclusion: The quality of one-handed ECC, based on depth and recoil, is worse than that of standard two-handed ECC. The pressure and force distribution of one-handed ECC result in greater ulnar pronation of the hand than that of two-handed ECC. One-handed ECC more easily causes operator fatigue. Acknowledging these findings and adjusting training for one-handed ECC would potentially improve the quality of cardiopulmonary resuscitation during transport.