[Changes of pulmonary diffusing capacity in subjects with acute mountain sickness].
OBJECTIVE
The study was conducted to investigate whether the changes in the pulmonary diffusing capacity found in individuals with acute mountain sickness (AMS) reflect the early stage of high-altitude pulmonary edema (HAPE).


METHODS
According to international definition of AMS (Lake Louise Consensus) thirty-two subjects were divided into AMS and non-AMS group. The pulmonary diffusion capacity for carbon monoxide (DLco) by the single-breath method, arterialized capillary blood gas were measured in all subjects at an altitude of 2,260 m and after ascent to 4,700 m.


RESULTS
All subjects exhibited an increase in DLco from 2,260 m to 4,700 m, the degree of increase in DLco in the AMS group was significantly lower than that of the non-AMS group, delta DLco (1.3 +/- 1.7) ml.min-1.mm Hg-1 vs (10.7 +/- 1.3) ml.min-1.mm Hg-1 (P > 0.01). The AMS group showed a greater alveolar-arterial oxygen pressure difference at 4,700 m compared with the non-AMS group. DLco showed a significantly negative correlation with AMS score (r = -0.885 P < 0.01).


CONCLUSIONS
These results suggest that the decreased pulmonary diffusing capacity has an important role in the incidence of acute mountain sickness, it reflects the presence of pulmonary gas exchange abnormality, which is probably due to subclinical interstitial edema of the lung.
Chen
Q
Q
Qinghai High Altitude Medical Science Institute, Xining 810012, China.
Ge
R
R
Ruan
Z
Z
D000208:Acute Disease; D000532:Altitude Sickness / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D011653:Pulmonary Diffusing Capacity