High-dose inhaled NO for the prevention of nosocomial pneumonia after cardiac surgery under cardiopulmonary bypass: A proof-of-concept prospective randomised study

Abstract

Objective: This study aimed to assess the safety and potential efficacy of high-dose inhaled nitric oxide therapy for the prevention of postoperative pneumonia in cardiac surgery patients.

Methods: A prospective randomised controlled pilot study included 74 patients with moderate risk of postoperative pneumonia after elective cardiac surgery under cardiopulmonary bypass. Patients were randomised into two groups. The main group (NO-group) (n = 37) received inhaled nitric oxide at a dose of 200 ppm for 30 minutes 2 times a day for 5 days or until pneumonia developed. The control group received conventional postoperative care (n = 37). The primary endpoint was the incidence of postoperative pneumonia during in-hospital stay.

Results: Preventive nitric oxide inhalations were associated with a reduced incidence of postoperative nosocomial pneumonia (2 (5.4%) cases in the main group (NO-group) vs. 9 (24.3%) cases in the control group, p = 0.046; OR = 0.178, 95% CI = 0.036-0.89)). There was no decrease in either peak expiratory flow, or peak inspiratory flow in comparison with the preoperative values in the NO-group. Inhaled nitric oxide therapy is safe. It did not lead to an increase in the incidence of acute kidney injury.

Conclusions: High-dose inhaled nitric oxide therapy is safe and effective for the prevention of postoperative nosocomial pneumonia in cardiac surgery.

Keywords: Nitric oxide; cardiac surgery; cardiopulmonary bypass; nosocomial pneumonia; spirometry.