Electromyography activity of selected trunk muscles during cardiopulmonary resuscitation.

BACKGROUND: Understanding trunk muscle activity during chest compression may improve cardiopulmonary resuscitation (CPR) training strategies of CPR or prevent low back pain. This study investigates the trunk muscle activity pattern of chest compression in health care providers to determine the pattern alternation during chest compression. METHODS: Thirty-one experienced health care providers performed CPR for 5 minutes at a frequency of 100 compressions per minute. An electromyography (EMG) system was used to record muscle activity in the first minute, the third minute, and the fifth minute. Electrodes were placed bilaterally over the pectoralis major, latissimus dorsi, rectus abdominis, erector spinae, and gluteus maximus. We calculated the root mean square (RMS) value and maximal amplitude of the EMG activity, median frequency, and delivered force. RESULTS: The maximal amplitude of EMG of the pectoralis major, erector spinae, and rectus abdominis showed large muscle activity above 45% of maximal voluntary contraction under chest compression. There were no significant differences in the RMS value of one chest compression cycle (RMS100%) and median frequency for all muscles at the first, third, and fifth minutes. Only gluteus maximus showed significant imbalance. The EMG ratios (erector spinae/rectus abdominis; erector spinae/gluteus maximus) increased significantly over time. The delivered force, compression depth, and number of correct depth decreased significantly over time. CONCLUSION: We suggest that the muscle power training for the pectoralis major, erector spinae, and rectus abdominis could be helpful for health care providers. Keeping muscle activity balance of bilateral gluteus maximus and maintaining the same level of EMG ratios might be the keys to prevent low back pain while performing CPR.

Push-fast recommendation on performing CPR causes excessive chest compression rates, a manikin model.

BACKGROUND: Increasing chest compression rate during cardiopulmonary resuscitation can affect the workload and, ultimately, the quality of chest compression. This study examines the effects of compression at the rate of as-fast-as-you-can on cardiopulmonary resuscitation (CPR) performance. METHODS: A crossover, randomized-to-order design was used. Each participant performed chest compressions without ventilation on a manikin with 2 compression rates: 100 per minute (100-cpm) and "push as-fast-as you-can" (PF). The participants performed chest compressions at a rate of either 100-cpm or PF and subsequently switched to the other after a 50-minute rest. RESULTS: Forty-two CPR-qualified nonprofessionals voluntarily participated in the study. During the PF session, the rescuers performed CPR with higher compression rates (156.8 vs 101.6 cpm), more compressions (787.2 vs 510.8 per 5 minutes), and more duty cycles (51.0% vs 41.7%), but a lower percentage of effective compressions (47.7% vs 57.9%) and a lower compression depth (35.6 vs 38.0 mm) than they did during the 100-cpm session. The CPR quality deteriorated in numbers and percentile of effective compression since the third minute in the PF session and the fourth minute in the 100-cpm session. The percentile of compressions with adequate depth in the 100-cpm sessions was higher than that in the PF sessions during the second, third, and fourth minutes of CPR. CONCLUSION: Push-fast technique showed a significant decrease in the percentile of effective chest compression compared with the 100-cpm technique during the 5-minute hand-only CPR. The PF technique exhibited a trend toward increased fatigue in the rescuers, which can result in early decay of CPR quality.