[Changes in oxygen saturation can not help diagnose acute mountain sickness (AMS): ascending to Lhasa on the Qinghai-Tibet train]

Abstract

Objective: Acute mountain sickness (AMS) is a common condition in individuals who ascend to altitudes over 2 500 m. There is no measurements that can reliably predict or diagnose this condition. We therefore determined whether pulse oximetry data are associated with the development of AMS and can help diagnose AMS.

Methods: We studied 58 young male undergraduates who traveled from Chongqing (300 m) to Lhasa (3 658 m) by train. We collected data on the ascent profiles and AMS symptoms based on the Lake Louise Score (LLS). The resting arterial oxygen saturation (R-SpO₂) and pulse rate were then measured using finger pulse oximetry.

Results: In Golmud(2 800 m) and Tanggula(5 200 m), R-SpO₂ was significantly lower in the AMS group than in the group without AMS (P<0.05). However, upon arrival in Lhasa (3 658 m), the R-SpO₂ was higher in the AMS group than in the non-AMS group (P<0.05). In Tanggula, the change in the SpO₂ (CR-SpO₂) in the AMS group was higher than that in the non-AMS group (P<0.05). But in Lhasa, the CR-SpO₂ in the AMS group was lower than that in the non-AMS group (P<0.05). We also monitored heart rate (HR) throughout the study. In Xining(2 200 m) and Golmud, the HRs in the AMS group were higher than those in the non-AMS group. However, the HRs in the AMS group were lower than those in the non-AMS group in Tanggula and Lhasa.

Conclusions: Based on the results of this study, the R-SpO₂ graph was not consistent. We can thus conclude that the utility of SpO₂ remains limited in the diagnosis of AMS. The results suggest that using pulse oximetry to diagnose AMS is not valuable in people ascending to Lhasa on the Qinghai-Tibet train.

Keywords: acute mountain sickness; altitude; heart rate; oxygen saturation.