Original ContributionThe physiological effects and quality of chest compressions during CPR at sea level and high altitude☆,☆☆,☆☆☆
Introduction
A growing number of people visit mountainous areas worldwide. While ascending to high altitude, a number of acute physiological changes occur [1]. Cardiac arrest is the second most common cause of death in the mountains [2].
If a time-sensitive rescue operation is necessary, usually, no acclimatization time is available for rescuers. Prolonged cardiopulmonary resuscitation (CPR) at high altitude presents a significant physical challenge to rescuers. After continuous single-operator CPR at high altitude for 5 minutes, the rescuer’s arterial blood oxygen saturation (Spo2) decreases; and the rescuer’s Borg scale score, a subjective score of fatigue, becomes higher than that at sea level [3], [4]. Although a comprehensive review by Chalkias et al [1] addressed several important issues and proposed reasonable recommendations for CPR and the considerations of rescuers at high altitude, most guidelines for resuscitation do not provide specific recommendations for CPR at high altitude [1], [5]. Nonetheless, physiological changes during exercise at high altitude have been studied extensively, which, in conjunction with results indicating quality changes, should able to provide a rationale for modifying current guidelines regarding CPR performed at high altitude.
The quality of CPR is paramount to advanced cardiac life support. Previous studies have demonstrated that the return of the spontaneous circulation in patients experiencing an out-of hospital cardiac arrest is dependent on the quality of the CPR they receive [6], [7], [8]. Several investigations have also shown that improved outcomes are associated with greater chest compression depth [9], [10]. The quality of chest compressions during CPR has been demonstrated to decline rapidly after a short period [11], [12]. A number of simulations have shown that rescuers develop immediate fatigue during CPR and that chest compression depth declines after 1 to 3 minutes of CPR [12], [13], [14]. During continuous chest compression CPR (CCC-CPR), chest compressions are minimally interrupted; but the depth of compressions decreases more rapidly than in conventional CPR [15]. Data regarding the quality of CPR performed by rescuers and the acute physiological effects of CCC on rescuers at high altitude are still limited. Therefore, this pilot study aimed to compare the time-dependent deterioration of CCC-CPR quality and the acute physiological effects of CPR on rescuers at sea level and high altitude. We provide recommendations on how to best perform CPR at high altitude.
Section snippets
Data collection
Thirty-eight volunteers 18 years of age or older who had completed a basic life support and CPR training course in accordance with the 2010 American Heart Association (AHA) guidelines were recruited for this study. All of the participants were health care providers, including medical staff of a tertiary medical center and emergency medical technicians. The participants were also enrolled to establish a rescue team. Comprehensive demographic data were collected for all participants. This
Results
The baseline characteristics of the study participants are shown in Table 1. Thirty-eight volunteers were enrolled in this study, and 33 participants completed the 5-minute CCC-CPR at high altitude (3100 m). Five participants did not complete the 5-minute CCC-CPR at high altitude because they were tired and asked to cease the test.
Before CPR, the participants’ SBP and DBP were not significantly different between sea level and high altitude (Table 2). The pre-CPR LLS and Borg scores at high
Discussion
Our study showed a difference in the quality of chest compressions performed at sea level and high altitude. The results demonstrated that, at high altitude, the depth of chest compressions declined rapidly, reaching statistical significance at 60 seconds after the initiation of CCC-CPR. At high altitude, the average depth of chest compressions decreased to less than 5 cm and approached statistical significance after CCC-CPR for 2 minutes. Furthermore, prior to the observed decline in depth,
Conclusion
This is the first study to assess the quality of CPR performed by health care providers at high altitude using a real-time monitoring device. The quality of chest compressions rapidly declined at high altitude. In addition, the average number of effective chest compressions decreased after CCC-CPR was performed for 1 minute; and the average depth of chest compressions decreased to less than 5 cm after CCC-CPR was performed for 2 minutes. More research is needed to evaluate the appropriate
Acknowledgments
We gratefully acknowledge Kaz Hanamura and all members of KISSEI COMTEC CO, LTD, for their instruction in the operation of the Chest Compression Coach System. We also thank all of the ED staff at Tri-Service General Hospital for volunteering to participate in the study.
References (27)
- et al.
Recommendations for resuscitation after ascent to high altitude and in aircrafts
Int J Cardiol
(2013) - et al.
Effects of cardiopulmonary resuscitation at high altitudes on the physical condition of untrained and unacclimatized rescuers
Wilderness Environ Med
(2012) - et al.
Rescuer fatigue during actual in-hospital cardiopulmonary resuscitation with audiovisual feedback: a prospective multicenter study
Resuscitation
(2009) - et al.
Quality of out-of-hospital cardiopulmonary resuscitation with real time automated feedback: a prospective interventional study
Resuscitation
(2006) - et al.
Effects of compression depth and pre-shock pauses predict defibrillation failure during cardiac arrest
Resuscitation
(2006) - et al.
Effect of rescuer fatigue on performance of continuous external chest compressions over 3 min
Resuscitation
(2002) - et al.
The effect of rescuer fatigue on the quality of chest compressions
Resuscitation
(1998) - et al.
Quality of chest compressions during continuous CPR; comparison between chest compression-only CPR and conventional CPR
Resuscitation
(2010) - et al.
Chest compression depth and survival in out-of-hospital cardiac arrest
Resuscitation
(2014) - et al.
Characteristics and management of acute ST-segment elevation myocardial infarctions occurring in ski resorts in the French Alps: impact of an acute coronary care network
Arch Cardiovasc Dis
(2010)
The benefits of a simplified method for CPR training of medical professionals: a randomized controlled study
Resuscitation
High-altitude illness
N Engl J Med
The effect of hypoxemia and exercise on acute mountain sickness symptoms
J Appl Physiol
Cited by (24)
Physiological demands of quality cardiopulmonary resuscitation performed at simulated 3250 meters high
2020, American Journal of Emergency MedicineCitation Excerpt :Therefore, when engaged in rescue activities, they have to take into account the involved factors like the reduction of air oxygen content, low temperature, difficulties to access to hospitals and to transport of victims and the rescue resource limitations. In some conditions, rescuers should consider the use oxygen delivery devices as well as mechanical compression devices to reduce their effort and fatigue and maintain Q-CPR along the time [2,3,6,10,11]. In addition, CPR with chest compressions and ventilation would permit some time to rest during the ventilation cycles [12].
Reduction of Arterial Oxygen Saturation Among Rescuers During Cardiopulmonary Resuscitation in a Hypobaric Hypoxic Environment
2020, Wilderness and Environmental MedicineCitation Excerpt :Scores on the Borg scale were high at 3700 m, where SpO2 decreased and HR increased. This is consistent with previous findings.4 The latest guidelines recommend switching the personnel applying chest compressions every 2 min, based on findings of fatigue and an accompanying loss of CPR quality.8
Cardiorespiratory dynamics of rescuers during cardiopulmonary resuscitation in a hypoxic environment
2018, American Journal of Emergency MedicineCitation Excerpt :Immediate cardiopulmonary resuscitation (CPR) is required in patients with cardiac arrest [4,5]. However, performance of CPR is effort-intensive even at sea level, and CPR at altitude is even more exhausting [6-8]. We encountered a case of prolonged CPR at high altitude, in which a rescuer performed prolonged CPR in an out-of-hospital setting on an individual following a suspected cardiac or neurological event, with an unsuccessful outcome.
Randomized trial of the chest compressions effectiveness comparing 3 feedback CPR devices and standard basic life support by nurses
2016, American Journal of Emergency Medicine
- ☆
The authors declare that they received no financial support and have no disclosures.
- ☆☆
Grants: DV101-04 and DV102-02 from the Ministry of National Defense–Medical Affairs Bureau and Taipei Veterans General Hospital.
- ☆☆☆
Conflict of interest statement: There are no conflicts of interest to declare.