Objective: To determine the safety and clinical efficacy of prolonged NO administration in patients with pulmonary hypertension.
Method: Clinical efficacy of prolonged treatment (28 days) with NO (20 ppm) in 17 patients with pulmonary hypertension was observed by chest X-ray film, ECG, Doppler echocardiography, analysis of arterial blood gases and the other laboratory investigations.
Results: After prolonged treatment with NO, regurgitation velocity and peak pressure gradient across tricuspid valves during systole reduced by 11.8% and 22.6%, respectively (P < 0.0001). Ejection fraction of right ventricle, stroke volume and cardiac output of left ventricle, partial oxygen pressure and oxygen saturation of arterial blood increased by 29.9%, 60.3%, 37.8%, 21.7% and 3.8% (all statistics; P < 0.0001), respectively. The class of heart function by New York Heart Association (NYHA) was improved dramatically (P < 0.01). Heart rate also reduced from 96 +/- 12 bpm to 83 +/- 10 bpm (P < 0.0001). But systemic artery pressure and the concentration of blood methemoglobin which reflected NO toxicity did not change obviously (P > 0.05).
Conclusion: Clinical efficacy of prolonged treatment with NO is satisfied in patients with pulmonary hypertension. Significant clinical side effects and toxicities are not seen during prolonged treatment with NO.