Inter-individual differences in control of alveolar capillary blood volume in exercise and hypoxia.
We compared by non-invasive technique the adaptive response of alveolar capillary network to edemagenic conditions (exercise and high altitude [HA, PIO2 107mmHg] in subjects with different resting sea level (SL) capillary blood volume (normalized to alveolar volume, Vc/Va): Group 1 (N=10, Vc/Va=16.1±6.8ml/L- mean±SD) and Group 2 (N=10, Vc/Va=25±7.7). In Group 1 Vc/Va remained unchanged in HA at rest and increased during exercise at SL (26.3±8.6) and HA (28.75±10.2); in Group 2 Vc/Va significantly decreased in HA (19±6) and did not increase in exercise at SL and HA. We hypothesize that Group2 exerts a tight control on Vc/Va being more exposed to the risk of lung edema due to inborn greater microvascular permeability. Conversely, Group 1 appears more resistant to lung edema given the large capillary recruitment in the most edemagenic condition. The 4-fold increase in frequency dependence of respiratory resistance in Group2 in HA stems for greater proneness for lung water perturbation compared to Group 1.
Laboratory of Clinical Physiology and Exercise, Department of Health Sciences, University of Milano Bicocca, Via Cadore 48, 20900 Monza, Italy.
Manuela
M
Bartesaghi
Egidio
E
Beretta
Luca
L
Pollastri
Valentina
V
Scotti
Gaia
G
Mandolesi
Francesca
F
Lanfranconi
Giuseppe
G
Miserocchi
D000328:Adult; D002196:Capillaries / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D007206:Individuality; D008297:Male; D011650:Pulmonary Alveoli / Q000098:blood supply*; D011652:Pulmonary Circulation / Q000502:physiology*; D011653:Pulmonary Diffusing Capacity / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012044:Regression Analysis; D015656:Respiratory Mechanics / Q000502:physiology; D013997:Time Factors; D014463:Ultrasonography
High altitude pulmonary edema; Lung diffusion; Lung ultrasound; Microvascular filtration; Respiratory impedance