Repeated remote ischaemic preconditioning can prevent acute mountain sickness after rapid ascent to a high altitude

Abstract

Background:The aim of the present study was to assess the effectiveness of 4 different remote ischaemic preconditioning (RIPC) protocols varying in duration and frequency for preventing acute mountain sickness (AMS). Methods: The participants in the four RIPC groups received different RIPC treatments in the arms at a low altitude; the control group did not receive a specific sham treatment. The participants were then flown to a High Altitude (3650 m). The primary outcome was the incidence and severity of AMS evaluated by the Lake Louise score (LLS) after arrival; vital signs were collected simultaneously. We performed an intention-to-treat analysis. Results: A total of 250 participants were included with 50 participants in each group. The total AMS incidence in all participants was 26.4%. A total of 20 AMS cases (40%) occurred in the control group, whereas 15 AMS cases (30%) occurred both in the RIPC A and RIPC B groups (relative risk 1.3; 95% confidence interval 0.8 -2.3; χ2 = 1.099; p = 0.29), and 8 AMS cases (16%) occurred both in the RIPC C and D groups (RR 2.5; 95% CI 1.2 -5.2; χ2 = 7.143, p < 0.01), with significantly lower LLSs in the RIPC C and D groups (F = 6.51, p <0.001). Conclusion: This study demonstrated that a four-week RIPC intervention but not a one-week regimen reduced AMS incidence and severity; however, a placebo effect might have contributed to the results of this study. Methods: The participants in the four RIPC groups received different RIPC treatments in the arms at a low altitude; the control group did not receive a specific sham treatment. The participants were then flown to a High Altitude (3650 m). The primary outcome was the incidence and severity of AMS evaluated by the Lake Louise score (LLS) after arrival; vital signs were collected simultaneously. We performed an intention-to-treat analysis. Results: A total of 250 participants were included with 50 participants in each group. The total AMS incidence in all participants was 26.4%. A total of 20 AMS cases (40%) occurred in the control group after arrival at high altitude, whereas 15 AMS cases (30%) occurred both in the RIPC A and RIPC B groups (relative risk 1.3; 95% confidence interval 0.8 -2.3; χ 2 = 1.099; p = 0.29), and 8 AMS cases (16%) occurred both in the RIPC C and D groups (RR 2.5; 95% CI 1.2 -5.2; χ 2 = 7.143, p < 0.01), with significantly lower LLSs in the RIPC C and D groups (F = 6.51, p <0.001). Conclusion:This study demonstrated that a four-week RIPC intervention but not a one-week regimen reduced AMS incidence and severity; however, a placebo effect might have contributed to the results of this study.

Effects of acetazolamide combined with remote ischemic preconditioning on risk of acute mountain sickness: a randomized clinical trial

“…Results of peripheral venous blood gas [ 34 , 35 ] suggested that acetazolamide induced mild metabolic acidosis, which led to hyperventilation and an improvement of the oxygen supply under hypoxic conditions [ 10 , 36 ]. On the other hand, our study, as well as a previous clinical trial [ 15 ], showed that RIPC had a limited role in improving SpO 2 , despite its ability to enhance tissue oxygen exchange in mouse models [ 37 ]. Given that the combination of acetazolamide and RIPC performed the most potent clinical effect, the efficacy of Combined group was not limited in increasing oxygen saturation.…”

“…The incidence of AMS at 4000 m altitude without any intervention was about 40% [ 2 , 3 ]. A study on RIPC for the prevention of AMS showed that a 1-week course of RIPC reduced the incidence of AMS at 3650 m by 25%, from 40 to 30% [ 15 ]. In addition, systematic reviews showed that acetazolamide could decrease the incidence of AMS by 47% [ 6 ], which corresponded to an incidence of 21% at 4000 m altitude.…”

“…In this context, newly developed non-pharmacological approaches, such as remote ischemic preconditioning (RIPC), have emerged to prevent AMS while avoiding the side effects of the drug [ 14 ]. RIPC involves applying brief periods of ischemia and reperfusion to the upper arm, and it has been shown to reduce the incidence of AMS [ 15 ], improve oxygen saturation, attenuate the increase in pulmonary artery pressures, and ameliorate attentional function in individuals exposed to high altitude [ 16 – 18 ]. Since acetazolamide and RIPC are both effective in preventing AMS, whether the combination of the two can intensify the effectiveness of AMS prevention deserves further investigation.…”

Examination of novel diagnostic approaches and contemporary strategies for preventing acute mountain sickness

“…The results from individual centers are divergent, although the discrepancies are explained by unsystematized treatment patterns. [3,4] Limper and colleagues evaluated the use of the 30°elevated sleep method.…”

Remote ischemic preconditioning enhances aerobic performance by accelerating regional oxygenation and improving cardiac function during acute hypobaric hypoxia exposure

“…Then, VO 2 max and SmO 2 were measured when they were taking a graded exercise test. Thereafter, the RIPC intervention, an effective method to prevent acute mountain sickness (Wang et al, 2021) and enhance sports performance (Lisboa et al, 2017;Richard and Billaut, 2018), began and was performed continued for 8 days. On the eighth day, after the last RIPC intervention, physiological variables were measured under normoxia and then the 24 participants underwent a 30-min ascent profile from the 400-4,000 m in a hypobaric chamber.…”