Pulmonary vascular responses during acute and sustained respiratory alkalosis or acidosis in intact newborn piglets. Pediatr Res 1999 Dec;46(6):735-41
Date
12/10/1999Pubmed ID
10590032DOI
10.1203/00006450-199912000-00013Scopus ID
2-s2.0-0032731295 (requires institutional sign-in at Scopus site) 27 CitationsAbstract
Acute alkalosis-induced pulmonary vasodilation and acidosis-induced pulmonary vasoconstriction have been well described, but responses were generally measured within 5-30 min of changing pH. In contrast, several in vitro studies have found that relatively brief periods of sustained alkalosis can enhance, and sustained acidosis can decrease, vascular reactivity. In this study of intact newborn piglets, effects of acute (20 min) and sustained (60-80 min) alkalosis or acidosis on baseline (35% O2) and hypoxic (12% O2) pulmonary vascular resistance (PVR) were compared with control piglets exposed only to eucapnia. Acute alkalosis decreased hypoxic PVR, but sustained alkalosis failed to attenuate either baseline PVR or the subsequent hypoxic response. Acute acidosis did not significantly increase hypoxic PVR, but sustained acidosis markedly increased both baseline PVR and the subsequent hypoxic response. Baseline PVR was similar in all piglets after resumption of eucapnic ventilation, but the final hypoxic response was greater in piglets previously exposed to alkalosis than in controls. Thus, hypoxic pulmonary vasoconstriction was not attenuated during sustained alkalosis, but was accentuated during sustained acidosis and after the resumption of eucapnia in alkalosis-treated piglets. Although extrapolation of data from normal piglets to infants and children with pulmonary hypertension must be done with caution, this study suggests that sustained alkalosis may be of limited efficacy in treating acute hypoxia-induced pulmonary hypertension and the risks of pulmonary hypertension must be considered when using ventilator strategies resulting in permissive hypercapnic acidosis.
Author List
Gordon JB, Rehorst-Paea LA, Hoffman GM, Nelin LDAuthor
George M. Hoffman MD Chief, Professor in the Anesthesiology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Acidosis, RespiratoryAcute Disease
Alkalosis, Respiratory
Animals
Animals, Newborn
Lung
Oxygen
Pulmonary Circulation
Swine
Vasoconstriction
