Department of Anaesthesiology and Intensive Care Medicine, Hospital Scheibbs, Eisenwurzenstraße 26, 3270, Scheibbs, Austria.
Mountain Rescue Service Austria, Baumgasse 129, 1030, Vienna, Austria.
Scand J Trauma Resusc Emerg Med. 2023 Oct 24;31(1):59. doi: 10.1186/s13049-023-01132-7.
Performing cardiopulmonary resuscitation (CPR) inevitably causes significant physical, as well as psychological stress for rescuers. Physical activity at high altitude, a hypobaric and hypoxic environment, similarly adds to the level of stress and causes multiple physiological changes. Continuous measurement of pulse rate serves as an objective measure of fatigue during CPR. We therefore aimed to investigate rescuers' heart rates as a measure of physical strain during CPR in a high-altitude alpine environment to provide a better understanding of the physiological changes under these very special conditions.
Twenty experienced mountaineers performed basic life support (BLS) on a manikin for 16 min, both at baseline altitude and at high altitude (3454 m) following a quick and exhausting ascent over 1200 m. Sequence of scenarios was randomised for analysis. Heart rate was continuously measured and compared between baseline and high altitude by absolute differences and robust confidence intervals.
During CPR at baseline, the average heart rate increased from 87 bpm (SD 16 bpm) to 104 bpm [increase 17 bpm (95% CI 8.24-24.76)], compared to an increase from 119 bpm (SD 12 bpm) to 124 bpm [increase 5 bpm (95% CI - 1.59 to 12.19)] at high altitude [difference between two groups 32 bpm (95% CI 25-39)]. Differences between periods of chest compressions and ventilations were very similar at baseline [19 bpm (95%CI 16.98-20.27)] and at high altitude [20 bpm 95% CI 18.56-21.44)], despite starting from a much higher level at high altitude. The average heart rates of rescuers at high altitude at any point were higher than those at baseline at any other point.
Performing BLS CPR causes exhaustion both at base level and at a high altitude. A further increase during CPR might imply a physiological reserve for adapting to additional physical exertion at high altitude. Phases of ventilation are much needed recovery-periods, but heart rates remain very high. Subjective measures of exhaustion, such as the BORG-scale, might lead to rescuers' overestimation of their own performance.
进行心肺复苏术（CPR）不可避免地会给施救者带来身体和心理上的巨大压力。在高海拔地区进行体力活动时，由于低气压和缺氧环境，压力水平同样会增加，并导致多种生理变化。连续测量脉搏率可作为 CPR 期间疲劳的客观衡量标准。因此，我们旨在研究救援人员的心率，以作为在高海拔高山环境下进行 CPR 时身体压力的衡量标准，以便更好地了解这些特殊条件下的生理变化。
20 名经验丰富的登山者在高原和平地（3454 米）两种环境下对模拟人进行了 16 分钟的基本生命支持（BLS），随后在海拔 1200 米的高度进行了快速且费力的攀爬。场景的顺序是随机分析的。通过绝对差值和稳健置信区间，比较基线和高原时的连续心率测量值。
在基线进行 CPR 时，平均心率从 87bpm（SD 16bpm）增加到 104bpm（增加 17bpm，95%CI 8.24-24.76），而在高原时从 119bpm（SD 12bpm）增加到 124bpm（增加 5bpm，95%CI-1.59-12.19）[两组之间的差异为 32bpm（95%CI 25-39）]。在基线[19bpm（95%CI 16.98-20.27）]和高原[20bpm 95%CI 18.56-21.44]时，胸部按压和通气之间的差异非常相似，尽管高原时的起始心率水平较高。在任何时候，高原时救援人员的平均心率都高于任何其他时间的基线心率。
在基础水平和高海拔地区进行 BLS CPR 都会导致疲劳。在 CPR 期间进一步增加可能意味着在高海拔地区适应额外体力消耗的生理储备。通气阶段是非常需要的恢复期，但心率仍然非常高。疲劳的主观衡量标准，如 BORG 量表，可能导致救援人员高估自己的表现。
