摘要Background:Hypoxia is a significant risk factor of hypertension.However,no studies have used transcutaneous tissue partial pressure of oxygen(TcPO2)and partial pressure of carbon dioxide(TcPCO2)monitors to measure the respective partial pressures in healthy indi-viduals.Oxygen saturation(SpO2)is often used for traditional monitoring of vital signs.This study investigated the changes in TcPO2 and SpO2 values during rapid changes in altitude.The trial was registered at ClinicalTrials.gov(registration no.NCT06076057).Methods:Healthy adult volunteers were instructed to sit vertically in a hypobaric oxygen chamber,which ascended from 0 m to 2500 m at a uniform speed within 10 min.The Danish Radiometer TCM4 was used to measure TcPO2 and TcPCO2 with the ventral side of the upper arm as the measure-ment site.The Shenzhen Kerokan P0D-1 W pulse oximeter was used to measure heart rate and SpO2,with values recorded once every 500 m.Results:Altogether,49 healthy volunteers were recruited between March 2023 and August 2023.With increasing altitude,TcPO2 and SpO2 decreased significantly(P＜0.01).During the ascent from 0 m,TcPO2 began to change statistically at 500 m(P＜0.05),whereas SpO2 began to change statistically at 1000 m(P＜0.05).At the same altitude,the difference in TcPO2 was greater than the difference in SpO2.At 1000 m,there were statistically significant changes in TcPO2 and SpO2(P＜0.001).At altitudes＞500 m,statistical significance was identified between TcPO2 in both sexes(P＜0.05).Statistical significance in TcPCO2 and heart rate was observed at the different elevations(P＜0.05).Conclusion:In acutely changing low-pressure hypoxic environments,TcPO2 changed more dramatically than SpO2.