目的　观察一氧化氮 (NO)吸入复合呼气末正压 (PEEP)通气对羊感染性急性呼吸窘迫综合征 (ARDS)血流动力学、肺气体交换和机械力学的影响。方法　静脉注入小剂量内毒素诱导的羊感染性ARDS模型 12只 ,随机均分为两组 ,NO组 :吸入 40ppmNO ;复合组 :PEEP(6cmH2 O)通气复合吸入 40ppmNO。通过肺动脉导管和动脉血气分析 ,测定基础、ARDS和治疗 3 0min后肺气体交换和血流动力学参数 ,记录相应时点的气道峰压 (PIP)、平均气道压 (Pm)。结果　NO组和复合组治疗期间平均肺动脉压较ARDS时显著降低 (P <0 0 1) ,动脉血压和心输出量则无明显变化 ;治疗 3 0min后 ,两组ARDS的PaO2 均明显升高 (P <0 0 1) ,肺泡动脉氧分压差 (P(A -a)O2 )和肺内分流 (Qs/Qt)显著减少 (P <0 0 1) ,复合组比NO组更为显著 (P<0 0 5 ) ;NO组各监测时点PIP、Pm均无明显变化 ,复合组的PIP、Pm较治疗前明显增高 (P <0 0 5 )。结论　吸入NO复合PEEP通气协同改善ARDS肺氧合 ,不影响体循环 Objective To observe the effects of inhalation of nitric oxide (NO) combined with positive end expiratory pressure (PEEP) on hemodynamics, pulmonary gas exchange and mechanical mechanics in sheep with acute respiratory distress syndrome (ARDS). Methods A total of 12 ARDS models of sheep induced by low dose of endotoxin were randomly divided into two groups. NO group: inhaled 40ppmNO; composite group: PEEP (6cmH2O) inhaled 40ppmNO. Baseline, ARDS and pulmonary gas exchange and hemodynamic parameters after 30 min were measured by pulmonary arterial and arterial blood gas analysis. Peak airway pressure (PIP) and mean airway pressure (Pm) were recorded at the corresponding time points. Results Compared with ARDS, the mean pulmonary arterial pressure was significantly lower in NO group and combination group than that in ARDS group (P <0.01), while there was no significant change in arterial blood pressure and cardiac output. After 30 minutes of treatment, the PaO2 in ARDS group was significantly higher than that in ARDS group P <0.01), P (A-a) O2 and Qs / Qt were significantly decreased in the alveolar artery (P <0.01), and the composite group was more significant than the NO group P <0.05). There was no significant change of PIP and Pm in NO group at each monitoring point. The PIP and Pm of compound group were significantly higher than those before treatment (P <0.05). Conclusions Inhalation of NO combined with PEEP ventilation can improve pulmonary oxygenation of ARDS and does not affect systemic circulation