Objective: Out aim is to study the effects of inhaling nitric oxide(NO) on the pulmonary ischemia/reperfusion injury during cardiopulmonary bypass surgery.
Methods: Cardiac valve replacement was performed on twenty patients with chronic rheumatic heart valve disease under cardiopulmonary bypass, and they were randomly divided into two groups: control group(n = 10) and NO group(n = 10). We monitored the following: mean pulmonary arterial pressure(MPaP), pulmonary vascular resistance(PVR), peak airway pressure (PAP), cyclic guanosine monophosphate(cGMP), inter-cellular adhesion molecule-1(ICAM-1), xanthinoxidase (XOD), malondialdehyde(MDA), PaO2 and the duration of post-operative mechanical ventilation.
Results: The PAP, MPaP and PVR in the control group were much higher than those in NO group after reperfusion(P < 0.05). The durations of postoperative mechanical ventilation in NO group were shorter than those in the control group(P < 0.01). The cGMP and PaO2 after reperfusion in NO group were higher(P < 0.01), and the ICAM-1, XOD, MDA were lower(P < 0.05) than those in the control group.
Conclusions: 1. If aortic clamp time is over 1 h, lung ischemia/reperfusion injury may occur during cardio-pulmonary bypass surgery. 2. Inhaling 20 ppm NO in the early phase of reperfusion has protective effects on the lung ischemia/reperfusion injury during cardio-pulmonary bypass surgery. 3. The mechanisms of the protective effects may be related with the increase of cGMP and the decrease of ICAM-1, XOD, MDA.