The evaluation of physiological responses during the performance of external chest compressions in simulated hypo and microgravity

Abstract

This study aimed to evaluate physiological responses during cardiopulmonary resuscitation (CPR) in hypogravity (hypoG) and microgravity (microG) simulations, and to compare these with 1G (Earth’s gravity). A CPR training manikin was used with an indicator for depth and frequency of compressions, along with surface electromyography (EMG), a mobile heart rate (HR) monitor, and the Borg Scale. A body suspension device was used to reduce body weight during CPR in hypoG and microG simulations. Thirty male volunteers (21.97 ± 2.94 years) performed 3 sets of 30 chest compressions, with a 6-s interval between sets to allow for ventilation, for each of the three gravity scenarios. Everyone achieved compression rates and depths within the expected values. The data for maximum HR, variation in HR and perceived exertion were higher for performances in microG (146.50 ± 26.56 bpm; 73.30 ± 24.53 bpm; 16.07 ± 2.29 points) and hypoG (109.40 ± 19.62 bpm; 36.20 ± 17.19 bpm; 11.60 ± 2.59 points) than observed at 1G (101.37 ± 20.47 bpm; 28.17 ± 15.36 bpm; 9.57 ± 2.19 points). The EMG showed greater activation of the rectus abdominis muscle (0.07 ± 0.18 uv) at 1G when compared to the pectoralis major (0.06 ± 0.04 uv) and triceps brachii (0.04 ± 0.03 uv) muscles. In hypoG, the activation of the pectoralis major muscle was greater (0.16 ± 0.40 uv) than that of the triceps brachii (0.11 ± 0.27 uv). No significant difference in EMG was seen between 1G and hypoG. A lower activity was observed for the triceps brachii (0.09 ± 0.07 uv) in microG in comparison to the pectoralis major (0.16 ± 0.11 uv) and rectus abdominis (0.35 ± 0.68 uv) muscles. However, all the muscles studied showed increased activity during the microG simulation. The results of this study suggest that the rescuer expends more effort and requires greater muscle recruitment to maintain adequate CPR performance in microG.

BibTeX

@article{russomano2012evaluation,
  title={The evaluation of physiological responses during the performance of external chest compressions in simulated hypo and microgravity},
  author={Russomano, Thais and Baptista, Rafael and Corr{\^e}a, Nicholas and Dias, Mariana},
  journal={Resuscitation},
  volume={83},
  pages={e55},
  year={2012},
  publisher={Elsevier}
}