Ventilatory parameters at rest after months of stay at 3300 m: A comparison between acclimatized lowlanders and natives at Leh.

BACKGROUND

Increased pulmonary ventilation helps lowlanders and natives to maintain arterial oxygenation at high altitudes. Natives of Ladakh have been shown to have similar ventilatory parameters as Tibetans at 3300 m. But there is limited literature comparing these parameters in Ladakhi natives with acclimatized lowland sojourners.

METHODS

End-tidal carbon dioxide partial pressure (EtCO), blood oxygen saturation (SpO) and hemoglobin concentration (Hb) were measured in 276 participants, 126 native highlanders (NHL - 40 females, 86 males) and 150 acclimatized lowlanders (ALL - 60 females, 90 males).

RESULTS

EtCO was greater in the NHL compared to the ALL, (33.8 ± 3.3 vs 31 ± 2.5 mmHg) although SpO was lower (90.9 ± 2.4 vs 91.7 ± 2.3%). When grouped by sex, NHL males had significantly greater EtCO than NHL females, ALL males and ALL females. Hb and calculated arterial oxygen content was similar in Ladakhis and acclimatized lowlanders, although greater in males compared to females. Systemic blood pressure, heart rate and the proportion of hypertensives was significantly greater in the ALL.

CONCLUSION

Native Ladakhis, have a significantly greater resting EtCO (especially in males) and lower SpO than acclimatized lowlanders. Blood Hb concentration and oxygen content is, however, similar in natives and acclimatized lowlanders of the same sex.