Use of nitric oxide inhalation in chronic obstructive pulmonary disease

Abstract

Background-Inhalation of nitric oxide with oxygen could be a promising treatment in patients with chronic obstructive pulmonary disease (COPD) and pulmonary hypertension. However, the current methods of delivery of NO are cumbersome and unsuitable for long term use. The present study was undertaken to investigate the safety and eYcacy of a mixture of nitric oxide (NO) and oxygen administered via a nasal cannula for 24 hours in patients with oxygen dependent COPD. Methods-Twenty five parts per million (ppm) of NO was administered by inhalation combined with supplemental oxygen at a flow rate of 2 l/min via a nasal cannula for 24 hours to 11 ambulatory men with stable, oxygen dependent COPD. Room air with supplemental oxygen at 2 l/min was administered in an identical manner for another 24 hours as control therapy in a randomised, double blind, crossover fashion to all patients. Pulmonary function tests, exercise tolerance, dyspnoea grade, and lung volumes were measured at baseline, 24, and 48 hours. Pulmonary artery pressure (PAP), cardiac output (CO), pulmonary vascular resistance (PVR), arterial blood gas tensions, and minute ventilation were measured at baseline, after 30 minutes and 24 hours of breathing NO and oxygen. Venous admixture ratio (Qs/Qt) and dead space ratio (Vd/Vt) were also calculated. Concentrations of nitrogen dioxide (NO 2 ) and NO in the inhaled and ambient air were monitored continuously. DiVerences in pulmonary function, arterial blood gas tensions, pulmonary haemodynamics, exercise tolerance, and dyspnoea between oxygen and NO breathing periods were analysed for significance using paired t tests.

Nitric oxide, nitrotyrosine, and nitric oxide modulators in asthma and chronic obstructive pulmonary disease

“…Currently, prostacyclin derivatives, endothelin antagonists, and NO donors [30] have been effectively used in patients with primary pulmonary hypertension. We speculate that iNOS inhibitors may also be effective in the treatment of secondary pulmonary hypertension by reducing or reversing arterial wall and airway remodeling in COPD.…”

Pulmonary hypertension in chronic obstructive pulmonary disease

“…Whereas the haemodynamic effects of combined NO and oxygen appear to be related to the NO dose, the amelioration in gas exchange seems to have a ceiling effect at a concentration of 5 ppm [110]. ASHUTOSH et al [111] showed that inhaled NO can be safely administered to COPD patients for 24 h. Nevertheless, the long-term administration of NO combined with oxygen is not easy and there is no evidence that it ameliorates pulmonary hypertension in COPD. …”

Pulmonary hypertension in patients with chronic obstructive pulmonary disease: Recent advances in pathophysiology and management

“…86,87 Moreover, this combined use lowers PVR in such patients. Since there are inconsistent results with inhaled NO in patients with COPD, the therapeutic use of NO for PH in COPD patients needs further research.…”