肺表面活性物质和吸入一氧化氮治疗家兔胎粪吸入性肺损伤

目的　观察在应用肺表面活性物质 (Surf)和吸入一氧化氮 (NO)预防性治疗家兔胎粪吸入性急性肺损伤 (ALI)并机械通气时的疗效。方法　将 3 3只成年家兔随机分为 5组进行治疗 :即对照组 (C ,n =8)、NO组 (n =6)、Surf组 (n =7)、NO +Surf组 (SNO ,n =6)、正常组 (N ,n =6)。前四组用胎粪生理盐水混悬液滴入气道内经机械通气造成ALI并随机分四组治疗 ;N组气道内滴入生理盐水替代 ;NO组连续吸入NO 1× 10 - 6 、10× 10 - 6 、2 0× 10 - 6 、40× 10 - 6 各 1h ,间隔停用 3 0min ;Surf组气道内滴入猪肺Surf10 0mg/kg ;SNO组联合NO吸入及Surf组治疗 ,各组均治疗 6h ,同时测定血气、肺呼吸力学判断疗效。化学发光法检测吸入气NO浓度。结果　在C组胎粪滴入 3 0min后动脉血氧合 (PaO2 /FiO2 )及呼吸顺应性 (DynamicCompliance ,Cdyn)显著变差 ,治疗后血氧合、Cdyn在SNO组显著改善 ,Surf和NO组略有改善。在湿化器前持续接入NO可在供气管道“Y”近端测得较为稳定的吸入NO浓度 ,受呼出气的影响最小 ,( 10～ 2 0 )× 10 - 6 NO吸入有较好的效果。结论　Surf联合NO治疗在有效预防ALI上优于单独应用Surf或NO。从呼吸机供气管路持续接入NO测定到稳定NO浓度与接入气和监测部位有关

Effects of combined surfactant and inhaled nitric oxide in ventilated rabbits with meconium aspiration-induced acute lung injury

OBJECTIVE: To evaluate dose response of inhaled nitric oxide (iNO) for surfactant-treated rabbits with meconium aspiration-induced acute lung injury (ALI) and hypoxemic respiratory failure (HRF), and variation of measured iNO by continuous NO delivery in pressure support ventilation (PSV). METHODS: Adult rabbits (2.0 - 3.5 kg, n = 33) were randomized to receive intratracheal meconium instillation for 30 min and subjected to following treatment (n = 6 - 8). There were 4 groups: Control (C); NO, iNO at 1, 10, 20 and 40 x 10(-6) each for 60 min at 30 min interval of disconnection; Surf, intratracheal instillation of porcine lung surfactant phospholipids (100 mg/kg); SNO, both iNO and surfactant as in the NO and Surf groups; and a normal group (N), which did not undergo meconium aspiration but received sham deliveries of normal saline. All the animals were treated with PSV for 6 h. iNO levels at different input and sampling sites in the NO and SNO groups were detected by on-line chemiluminescent technique. The blood gas and lung mechanics were measured during the experiments every 2 h. RESULTS: (1) Meconium aspiration induced ALI and severe HRF (PaO(2)/FiO(2) < 200 mmHg) and depressed dynamic compliance of respiratory system (Cdyn) and airway resistance (Raw). In both Surf and NO groups modestly improved oxygenation was observed. In the SNO, values for PaO(2)/FiO(2) were improved from (185 +/- 39) mmHg at baseline to (301 +/- 123) mmHg at 6 h, while moderate or transient improvement was observed in both Surf and NO groups. Cdyn and Raw were only improved for short time in the Surf, NO and SNO groups. iNO had a mild response at 1 x 10(-6) to good response at 10 and 20 x 10(-6), but no further improvement occurred at 40 x 10(-6). The response of iNO in NO group was relatively transient compared to the SNO group. (2) When iNO was connected to the ventilator circuit, the connected site should be placed before humidifier to minimize fluctuation of iNO concentration, and sampling site for iNO monitoring should be placed adequately to eliminate artifact. CONCLUSIONS: iNO synergistically improved surfactant effects on oxygenation and lung mechanics. Continuous supply of iNO with non-continuous flow ventilator provided stable NO within accepted target range with least variation.