Relationship between oxygen delivery and its compensatory factors and acute mountain sickness
- Author:
Ming LI
1
Author Information
1. Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University
- Publication Type:Journal Article
- Keywords:
Altitude sickness;
Middle cerebral artery resistance units;
Middle cerebral artery velocity;
Stroke volume
- From:
Medical Journal of Chinese People's Liberation Army
2013;38(3):245-248
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the changes in oxygen delivery (D02) to the body and brain and its compensatory factors to acute hypoxia and their relation to acute mountain sickness (AMS). Methods One hundred and forty-seven participants were recruited from Chinese young men who had lived in plain all along arrived in Tibet by flight. All of them were asked to complete an AMS questionnaire within 48h after arrival. The resting heart rate (HR), blood pressure (BP), cardiac output (CO), oxygen saturation (Sa02), stroke volume (SV) and blood flow velocity in the middle cerebral artery (MCAv) were measured one week before departure from the plain and within 48h after arrival in Tibet. AMS was diagnosed according to Louis Lake Score System (LLS), and the results were then statistically analyzed. Results AMS was diagnosed in eighty-six subjects (58.5%). After exposure to hypoxia, Sa02 was decreased by 10% and was negatively correlated with AMS score. Systemic D02, CO and HR were increased by 19%, 32.5% and 31.7%, respectively, and were positively correlated with AMS, while the SV remained unchanged. MCAv accelerated by 10%, and that of AMS subjects was higher than of non-AMS ones. The cerebral D02 (D02C) was maintained because the MCAv matched with Sa02 changes. The middle cerebral artery resistance units (RMCA) decreased obviously with an increase in MBP, and RMCA in AMS subjects was lower than that in non-AMS ones. HR and MCAv, the key compensation factors of D02, were used as the objective evaluation indices, in collaboration of HR≥85 beat/min and MCAv≥66cm/s, could be a better means to evaluate AMS, with a positive predictive value of 82.4% and specificity of 90.2%. Conclusions D02 and its compensatory factors may play a key role in the regulation response to acclimatize to acute hypoxia. Among them, HR and MCAv may relate to the mechanism of AMS development, and indirectly reflect the compensation level to oxygen debt, implying that HR and MCAv are helpful in the assessment of AMS.
