ABSTRACT
Inhaled nitric oxide (INO) has been shown to improve oxygenation and decrease intrapulmonary shunt and pulmonary hypertension in various lung diseases. In this study we report a patient with end-stage idiopathic pulmonary fibrosis and pulmonary hypertension who received INO after coronary artery bypass surgery, with significant improvement in arterial oxygenation and pulmonary arterial pressure. Using a pulsing delivery system, the patient continued to receive outpatient INO for 30 months while waiting for lung transplantation. Exercise study and two-dimensional echocardiogram, after 3 months of inhaled NO, demonstrated continued benefits of INO for improvement of arterial oxygenation, pulmonary arterial pressure and exercise tolerance.
Subject(s)
Lung Transplantation , Nitric Oxide/administration & dosage , Pulmonary Fibrosis/therapy , Administration, Inhalation , Ambulatory Care , Coronary Artery Bypass , Humans , Hypertension, Pulmonary/therapy , Male , Middle Aged , Postoperative ComplicationsABSTRACT
BACKGROUND: Inhaled nitric oxide (NO) has been shown to be a selective pulmonary vasodilator in certain patients with primary pulmonary hypertension (PPH). OBJECTIVES: The purpose of this study was to design and test a system for delivery of NO to awaken, ambulatory patients with PPH and to evaluate this system in the home setting. METHODS: The ambulatory delivery system consisted of a tank of 80 ppm of NO (balance N2), a modified gas-pulsing device, and nasal cannulas. The pulsing device was set to deliver NO for 0.1 s at the beginning of each inspiration. RESULTS: Using this system, eight patients with PPH were studied with pulmonary artery catheters in place. Inhalation of NO led to significant reductions in both mean pulmonary arterial pressure (PAPm) (51 +/-12 to 43 +/- 10 mm Hg; p=0.001) and pulmonary vascular resistance (PVR) (790 +/- 285 to 620 +/- 208 dyne x s x cm-5; p=0.01). Three of the eight patients had both greater than 20% and greater than 30% decreases in PAPm and PVR, respectively. No exhaled NO or N02 was detectable in any of the eight patients. One patient was discharged home from the hospital on a regimen of inhaled NO. At 9 months, no adverse effects were noted and the system was working well. CONCLUSIONS: Pulsed delivery of inhaled NO to ambulatory patients with PPH, via nasal prongs, is feasible and, in some patients, leads to significant improvement in pulmonary hypertension. Inhaled 09NO, therefore, may have a role in the long-term treatment of patients with PPH.
Subject(s)
Hypertension, Pulmonary/drug therapy , Nitric Oxide/administration & dosage , Administration, Inhalation , Blood Pressure , Cardiac Output , Home Care Services , Humans , Hypertension, Pulmonary/physiopathology , Pulmonary Artery/physiopathology , Pulmonary Wedge Pressure , Vascular ResistanceABSTRACT
Nitric oxide (NO) is a potent dilator of vascular smooth muscle that likely represents an important endothelium-dependent relaxing factor. Recent interest has focused on inhaled NO as a pulmonary vasodilator. The purpose of this study was to design a reliable NO delivery system with on-line monitoring of NO and nitrogen dioxide (NO2) concentrations, and to test the effects of inhaled NO in a dog model of acute hypoxic pulmonary vasoconstriction (HPV). Six canines were studied. Marked HPV was induced using a hypoxic gas mixture. Using a standard blender. NO was delivered through a volume-cycled ventilator. We were able to rapidly adjust the delivered NO concentration using this system. An on-line chemoluminescence analyzer was used to continuously measure NO and NO2 concentrations. Inhaled NO at 40 and 80 ppm for 30 min rapidly reversed HPV in all animals (PVR 502 +/- 154 dynes.s.cm-5 with hypoxia, 244 +/- 52 with 40 ppm NO, 227 +/- 47 with 80 ppm NO). No significant NO2 or methemoglobin production was noted during the study. We conclude that inhaled NO can be easily delivered through a ventilator and the dose rapidly adjusted, NO and NO2 concentrations can be monitored continuously on-line, inhaled NO rapidly reverses HPV in dogs, and with short-term NO inhalation, there is no significant NO2 or methemoglobin formation. Inhaled NO may, therefore, have a future clinical role as a new agent in the diagnosis and treatment of other forms of pulmonary hypertension.
Subject(s)
Hypoxia/drug therapy , Nitric Oxide/therapeutic use , Pulmonary Artery/drug effects , Pulmonary Veins/drug effects , Respiratory Therapy/instrumentation , Ventilators, Mechanical , Administration, Inhalation , Animals , Dogs , Equipment Design , Luminescent Measurements , Nitric Oxide/administration & dosage , Nitric Oxide/analysis , Nitrogen Dioxide/analysis , Vasoconstriction/drug effectsABSTRACT
A patient with severe interstitial pulmonary fibrosis, hypoxemia, pulmonary hypertension, and cor pulmonale was given inhaled nitric oxide (NO) followed by intravenous PGE1 to assess the reversibility of pulmonary hypertension. During NO inhalation, there was marked reduction in pulmonary vascular resistance, increased cardiac output, and dramatic improvement in arterial oxygenation. There was no effect on systemic vascular resistance. In contrast, intravenous PGE1 led to rapid arterial oxygen desaturation and worsened dyspnea. The beneficial responses to inhaled NO in this patient suggest that, even in severe chronic lung disease, reversible pulmonary vasoconstriction is present. Inhaled NO thus has a potential therapeutic role as a selective pulmonary vasodilator in patients with interstitial pulmonary fibrosis and cor pulmonale.
