It is known that providing basic life support (BLS) may be limited by the physical capabilities of rescuers. The other factor that may affect BLS quality is its energy expenditure. Therefore, we decided to compare the energy expenditure of standard BLS with a compression-ventilation ratio of 30:2 (S-BLS) and compression-only BLS (CO-BLS) and assess the sensation of fatigue and perceived exertion associated with these activities.
Methods. We conducted a simulation study on 10 healthy volunteers using a resuscitation manikin. Participants were randomly assigned to start with CO-BLS or with S-BLS, in accordance with recent guidelines. Later, every individual provided the other type of BLS. BLS was terminated in the event of exhaustion, impossibility to retain high-quality BLS or after 30 minutes of BLS. Energy expenditure was expressed as relative oxygen consumption (VO2/kg) and area under the curve of all VO2/kg measurements during each BLS procedure indexed to one minute (AUCVO2/kg min). All participants completed a survey to assess perceived intensity of exertion by Borg, and sensation of general fatigue by visual analogue scale.
Results. Maximal VO2/kg (23.16±3.94 vs. 20.17±2.14 ml/kg/min, p=0.049) and AUCVO2/kg min (18.90±3.13 vs. 15.91±2.07 ml/min3; p=0.021) during S-BLS were significantly higher compared to CO-BLS. Conversely, a more intense rate of perceived exertion (16.6±2.0 vs. 13.8±1.2, p=0.001) and sensation of general fatigue (86.5±10.8 vs. 75.0±14.3, p=0.058) were associated with CO-BLS. Neither sensation of general fatigue, nor perceived exertion correlated with energy expenditure.
Conclusions. Energy expenditure of S-BLS was higher than of CO-BLS in our study, while sensation of fatigue and perceived exertion reflected the opposite association.
Key words: basic life support, energy expenditure, general fatigue