Effect of nitric oxide inhalation on neutrophil CD11b expression and postoperative function in patients undergoing cardiac valve replacement with CPB

Objective To investigate the effects of sustained nitric oxide (NO) inhalation during operation on neutrophil CD11b expression and postoperative lung function in patients undergoing cardiac valve replacement with cardiopulmonary bypass(CPB) .Methods Forty-two ASA Ⅱ or Ⅲ patients aged 35-53 yr weighing 47-69 kg undergoing cardiac valve replacement with CPB were randomly divided into 2 group:NO group(n = 21) and control group(n= 21) .In NO group the patients inhaled 40 ppm NO through the lungs and oxygenator after tracheal intubation during operation before the chest was closed. Anesthesia was induced with fentanyl 20 μg·kg-1 and pipeceuronium 0.2 mg·kg-1 maintained with isofluarane inhalation and intermittern i.v. boluses of fentanyl and pipecuronium. A total of 5 000 000 IU aprotin was given during operation. Arterial blood samples were taken before induction of anesthesia (T0, baseline), immediately before CPB (T1 ) 10 rain after CPB was started (T2 ), immediately before aortic unclamping (T3 ) ,10 min after aortic unclamping (T4 ), at the end of operation (T5 ) , 12 h and 24 h after operation (T8 ,T9) for polylmorphonuclear(PMN) counts and determination of neutrophil CD11b expression . Blood gas analysis was performed PA-a O2 was calculated and dynamic compliance of respiratory system (Cdyn) was measured before induction of anesthesia, at the end of operation and at 4 and 8 h after operation. Results PMN count significantly decreased at T2 compared to baseline and then gradually increases ( P 0.05) , whereas in NO group there was no significant decrease in PMN count at T2. The PMN count was significantly greater in NO group than in control group at T2-5 ( P 0.05) . CPB significantly upregulated neutrophil CD11b expression which reached at peak at T3 both groups but CD11b expression was significantly lower in NO group than in control group at T2-5 ( P 0.05) .There was no significant change in Cdyn after operation in both group but PA-a O2 was smaller at the end of and 4h after operadon in NO group than in control group( P 0.05). Conclusion Continuous NO inhalation during operation can significantly inhibit neutrophil CDllb expression upregulation induced by CPB and improve postoperative lung function.