Inhaled nitric oxide, oxygen, and alkalosis: Dose-response interactions in a lamb model of pulmonary hypertension

Autor: Janine M. Bekker, Michael J. Johengen, R. Scott Heidersbach, Jeffrey R. Fineman
Rok vydání: 1999
Předmět:
Zdroj: Pediatric Pulmonology. 28:3-11
ISSN: 1099-0496
8755-6863
DOI: 10.1002/(sici)1099-0496(199907)28:1<3::aid-ppul2>3.0.co;2-s
Popis: Inhaled nitric oxide (NO) is currently used as an adjuvant therapy for a variety of pulmonary hypertensive disorders. In both animal and human studies, inhaled NO induces selective, dose-dependent pulmonary vasodilation. However, its potential interactions with other simultaneously used pulmonary vasodilator therapies have not been studied. Therefore, the objective of this study was to determine the potential dose-response interactions of inhaled NO, oxygen, and alkalosis therapies. Fourteen newborn lambs (age 1–6 days) were instrumented to measure vascular pressures and left pulmonary artery blood flow. After recovery, the lambs were sedated and mechanically ventilated. During steady-state pulmonary hypertension induced by U46619 (a thromboxane A2 mimic), the lambs were exposed to the following conditions: Protocol A, inhaled NO (0, 5, 40, and 80 ppm) and inspired oxygen concentrations (FiO2) of 0.21, 0.50, and 1.00; and Protocol B, inhaled NO (0, 5, 40, and 80 ppm) and arterial pH levels of 7.30, 7.40, 7.50, and 7.60. Each condition (in randomly chosen order) was maintained for 10 min, and all variables were allowed to return to baseline between conditions. Inhaled NO, oxygen, and alkalosis produced dose-dependent decreases in mean pulmonary arterial pressures (P 5 ppm, alkalosis induced further dose-independent decreases in mean pulmonary arterial pressure, while oxygen did not. We conclude that in this animal model, oxygen, alkalosis, and inhaled NO induced selective, dose-dependent pulmonary vasodilation. However, when combined, a systemic arterial pH >7.40 augmented inhaled NO-induced pulmonary vasodilation, while an FiO2 >0.5 did not. Therefore, weaning high FiO2 during inhaled NO therapy should be considered, since it may not diminish the pulmonary vasodilating effects. Further studies are warranted to guide the clinical weaning strategies of these pulmonary vasodilator therapies. Pediatr Pulmonol. 1999; 28:3–11. © 1999 Wiley-Liss, Inc.
Databáze: OpenAIRE
Externí odkaz: