Acute ventilatory restriction in children after weaning off inhaled nitric oxide: relation to rebound pulmonary hypertension.

Abstract

To assess the interaction between pulmonary hemodynamics and respiratory mechanics during acute pulmonary hypertension. Ventilated and paralysed children treated with inhaled nitric oxide because of post-operative pulmonary hypertension. Weaning of inhaled nitric oxide. Air flow and airway pressure, calculation of dynamic respiratory system compliance and respiratory system resistance for each breath by multiple linear regression. In four patients, increases in pulmonary arterial pressure from 26.1 to 56.7 mm Hg (p<0.001) during weaning off nitric oxide were associated with decreases in tidal volume (from 9.7-->8.2 ml/kg, p<0.01) and reductions in dynamic respiratory system compliance (from 0.52-->0.34 cm H20/ml/kg, p<0.001), while respiratory system resistance was unchanged. Impaired ventilation during acute pulmonary hypertension is predominantly related to a reduction in respiratory system compliance.