不同机械通气方式对外源性肺表面活性物质治疗大鼠呼吸机相关性肺损伤效果的影响

目的 探讨不同机械通气方式对外源性肺表面活性物质(PS)治疗大鼠呼吸机相关性肺损伤(VILI)效果的影响.方法 雄性Wistar大鼠42只,体重310～356 g,随机分为6组(n=7):CVT6组、SVT6组、CVT10组、SVT10组、CVT14组和SVT14组.VT分别为6、10、14 ml/kg,通气频率分别为75、45、32次/min.采用高气道压机械通气(HPV,气道峰压为40 cm H20,PEEP为0)制备大鼠VILI模型.于HPv前(T0,基础值)及通气15～25 min,在呼气末经气道注入4 ml/kg空气,测定气道压力,计算胸肺顺应性,当其降至基础值50%时,PEEP升高至7.5 cm H2O.吸除气道内水肿液后,SVT6组、SVT10组和SVT14组给予PS 100 mg/kg,CVT6组、CVT10组和CVT14组给予等容量空气,并按不同VT和通气频率行机械通气.于T0、HPV后5 min(T1)、给予PS后15、30、60、90及120 min(T2-6)时测定MAP,采集股动脉血样行血气分析,于T1,6时收集气道内水肿液,于T6时处死大鼠取肺组织,观察病理学结果.结果 相同机械通气方式下,给予Ps后大鼠呼吸机相关性肺损伤较对照组减轻;不同机械通气方式下,SVT10组大鼠呼吸机相关性肺损伤较其余组均减轻.SVT10组肺组织病理损伤较其余组减轻.结论 采用VT10 ml/kg、通气频率45次/min行机械通气时PS治疗大鼠VILI的效果较好.

Effects of different ventilation modes on efficacy of exogenous pulmonary surfactant for treatment of rats with ventilator-induced lung injury

Objectlve To investigate the effects of different ventilation modes on the efficacy of exogenous pulmonary surfactant(PS)for the treatment of rats with ventilator-induced lung injury(VILI).Methods Forty-two male Wistar rats weighing 310-356 g were randomly divided into 6 groups(n=7 each):group CVT6,group SVT6,group CVT10,group SVT10,group CVT14 and group SVT14.The tidal volume(VT)was set at 6,10 and 14 ml/kg respectively and the respiratory rate(RR) was 75,45 and 32 bpm respectively.The animals were anesthetized with intraperitoneal 3% Pentobarbital 50 mg/kg,then tracheostomized and intubated.VILI model was induced by high-pressure ventilation (HPV) with peak inspimtory pressure (PIP) 40 cm H2O and without positive end-expiratory pressure (PEEP).The air was injected into the trachea via the airway at the end ofexpiration before HPV (T0,baseline value) and 15-25 min of HPV,the airway pressure monitored and the lung compliance(C) calculated.When C was decreased to half of the baseline value,PEEP was increased to 7.5 cm H20.After the tracheal edema fluid was removed,the PS 100 mg/kg was immediately injected into the trachea in group SVT6,SVT10 and SVT14.The equal volume of air was injected into the trachea in group CVT6,CVT10 and CVr14 instead of PS.Then the rats in different groups were ventilated with the corresponding ventilation modes.MAP was monitored and blood samples were token from femoral artery for blood gas analysis at T0, 5 min after HPV (T1 ), and 15, 30, 60, 90, 120 min (T2-6) after administration of PS. The tracheal edema fluid was collected at T1 and T6.The rats were killed at T6 and the lung tissues taken for microscopic examination. Results With the same ventilation mode, the VILI was significantly alleviated after administration of PS. With different ventilation modes,the lung injury was significantly reduced in group SVT 10 compared with the other groups. Conclusion The efficacy of PS for the treatment of rats with VILI is good using the ventilation strategy with VT of 10 ml/kg and RR of 45 bpm.