Serial changes in nasal potential difference and lung electrical impedance tomography at high altitude.
Recent work suggests that treatment with inhaled beta(2)-agonists reduces the incidence of high-altitude pulmonary edema in susceptible subjects by increasing respiratory epithelial sodium transport. We estimated respiratory epithelial ion transport by transepithelial nasal potential difference (NPD) measurements in 20 normal male subjects before, during, and after a stay at 3,800 m. NPD hyperpolarized on ascent to 3,800 m (P < 0.05), but the change in potential difference with superperfusion of amiloride or isoprenaline was unaffected. Vital capacity (VC) fell on ascent to 3,800 m (P < 0.05), as did the normalized change in electrical impedance (NCI) measured over the right lung parenchyma (P < 0.05) suggestive of an increase in extravascular lung water. Echo-Doppler-estimated pulmonary artery pressure increases were insufficient to cause clinical pulmonary edema. There was a positive correlation between VC and NCI (R(2) = 0.633) and between NPD and both VC and NCI (R(2) = 0.267 and 0.418). These changes suggest that altered respiratory epithelial ion transport might play a role in the development of subclinical pulmonary edema at high altitude in normal subjects.
Mason
Nicholas P
NP
Department of Physiology, Free University of Brussels, B1070 Brussels, Belgium. nmason@ulb.ac.be
Petersen
Merete
M
Melot
Christian
C
Imanow
Bakyt
B
Matveykine
Olga
O
Gautier
Marie-Therese
MT
Sarybaev
Akpay
A
Aldashev
Almaz
A
Mirrakhimov
Mirsaid M
MM
Brown
Brian H
BH
Leathard
Andrew D
AD
Naeije
Robert
R
D000293:Adolescent; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000328:Adult; D000531:Altitude; D000584:Amiloride / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D004232:Diuretics / Q000494:pharmacology; D004452:Echocardiography; D017097:Electric Impedance; D004848:Epithelium / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008168:Lung / Q000000981:diagnostic imaging / Q000502:physiology*; D008297:Male; D009297:Nasal Mucosa / Q000502:physiology*; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D011652:Pulmonary Circulation / Q000502:physiology; D014797:Vital Capacity / Q000187:drug effects / Q000502:physiology
D000318:Adrenergic beta-Agonists; D004232:Diuretics; D000584:Amiloride; D007545:Isoproterenol