Exhaled Nitric Oxide Changes During Acclimatization to High Altitude: A Descriptive Study.
Summerfield, Douglas T., Kirsten E. Coffman, Bryan J. Taylor, Amine N. Issa, and Bruce D. Johnson. Exhaled nitric oxide changes during acclimatization to high altitude: a descriptive study. High Alt Med Biol. 19:215-220, 2018.


AIMS
This study describes differences in the partial pressures of exhaled nitric oxide (PeNO) between subjects fully acclimatized (ACC) to 5300 m and those who have just arrived to high altitude.


METHODS
PeNO was determined in eight subjects newly exposed and nonacclimatized (non-ACC) to high altitude and compared with that in nine subjects who had ACC to high altitude for 1 month. In addition, systolic pulmonary artery pressure (sPAP) and arterial oxygen saturation (SaO2) were measured in all participants. These measurements were repeated in the non-ACC group 5 and 9 days later.


RESULTS
PeNO levels on day 1 were significantly higher in the non-ACC versus ACC cohort (8.7 ± 3.5 vs. 3.9 ± 2.2 nmHg, p = 0.004). As the non-ACC group remained at altitude, PeNO levels fell and were not different when compared with those of the ACC group by day 9 (5.9 ± 2.4 vs. 3.9 ± 2.2 nmHg, p = 0.095). Higher sPAP was correlated with lower PeNO levels in all participants (R = -0.50, p = 0.043). PeNO levels were not correlated with SaO2.


CONCLUSIONS
As individuals acclimatized to high altitude, PeNO levels decreased. Even after acclimatization, PeNO levels continued to play a role in pulmonary vascular tone.
['Summerfield|Douglas T|DT|', 'Coffman|Kirsten E|KE|', 'Taylor|Bryan J|BJ|', 'Issa|Amine N|AN|', 'Johnson|Bruce D|BD|']
D000064:Acclimatization D000531:Altitude D062186:Arterial Pressure D001944:Breath Tests D045853:Exhalation D005260:Female D006801:Humans D008297:Male D009569:Nitric Oxide D010100:Oxygen D010313:Partial Pressure D011651:Pulmonary Artery D013997:Time Factors
exhaled nitric oxide acclimatization systolic pulmonary artery pressure high altitude populations