肺复张对急性呼吸窘迫综合征患者血管外肺水的影响

目的 探讨肺复张(RM)策略对急性呼吸窘迫综合征(ARDS)患者血管外肺水(EVLW)的影响.方法 采用随机对照病例研究方法,将20例ARDS患者随机分为RM组和对照组.按肺保护性通气策略的原则给患者进行机械通气;用双水平气道正压(BIPAP)通气模式进行RM,每8 h重复1次,连续7 d或至脱机前;除RM外,其余治疗两组相同.记录患者的基线资料和每日RM结束后的EVLW、血管外肺水指数(EVLWI)、呼吸力学参数、氧合指数(PaO2/FiO2)、中心静脉压(CVP)、血浆胶体渗透压(COP)以及糖皮质激素、肾上腺素能药物用量和24 h液体出入量平衡等影响EVLW各因素的数值.结果 RM组和对照组EVLW、EVLWI随时间延长呈逐渐降低趋势,但两组间比较差异无统计学意义(P均>0.05).两组间CVP、COP和去甲肾上腺素、氢化可的松用量比较差异均无统计学意义(P均>0.05);RM组多巴胺用量在4 d时明显少于对照组(P<0.05);液体出入量平衡RM组7 d时为负平衡,对照组则为正平衡(P<0.05).RM组平均气道压(Pmean)的均值[(18.8±3.2)cm H2O(1 cm H2O=0.098 kPa)]和肺准静态顺应性(Cstat)的均值[(36.5±14.5)ml/cm H2O]均明显高于对照组[(16.6±3.9)cm H2O和(29.3±12.0)ml/cm H2O,P均<0.05];其中RM组5 d时Cstat大于2 d和3 d时(P均<0.05).两组间PaO2/FiO2比较则未见明显差异(P均>0.05).结论 针对ARDS患者实施的RM治疗并没有明显影响EVLW,而仅起到了改善肺呼吸力学特征的作用.本研究中所涉及的影响肺水的因素并未影响肺水的形成和清除.

A study on the effect of recruitment maneuver imposed on extravascular lung water in patients with acute respiratory distress syndrome

Objective To investigate the possible effects of recruitment maneuver(RM)imposing on extravascular lung water(EVLW)in patients with acute respiratory distress syndrome CARDS).Methods Twenty patients with ARDS who were eligible for the study were randomized to two groups,one group of which received regular therapy+ RM(RM group),and to the other group only regular therapy was given (control group).Mechanical ventilation of all the patients was performed on the principles of lung protective ventilation.RM was carried out in bi-level positive airway passage(BIPAP)mode,and repeated every 8 hours per day until on the 7th day or before weaning of mechanical ventilation.The treatment was same between the two groups except RM.Baseline data and the influencing factors of EVLW were all recorded,which included everyday EVLW,extravascular lung water index(EVLWI)after RM,respiratory mechanics,oxygenation parameters,central venous pressure(CVP),plasma colloid osmotic pressure (COP),dosage of corticosteroid and adrenergic drugs,24-hour net fluid balance.Results EVLW and EVLWI in RM and control group showed a tendency of decrease with passage of time,but the difference between both groups had no statistical significance(all P>0.05).The comparisons between the influencing factors of the groups,consisting of CVP,COP,noradrenalin and hydrocortisone,had no significant difference either(all P>0.05).Dopamine dosage in RM group on the 4th day was smaller than that of control group(P<0.05).Net fluid balance in RM group on the 7th day was negative,whereas it was positive in control group(P<0.05).Mean airway pressure[Pmean,RM group(18.8 ±3.2)cm H2O (1 cm H2O=0.098 kPa)vs.control group(16.6±3.9)cm H2O]and lung quasi-static compliance[Cstat,RM group(36.5±14.5)ml/cm H2O vs.control group(29.3±12.0)ml/cm H2O]in RM group were higher than those in control group(both P<0.05).Cstat on the 5th day was higher than that on the 2nd and 3rd day in RM group(both P<0.05).But oxygenation index(PaO2/FiO2)showed no distinct difference between the groups(all P>0.05).Conclusion RM for the patients with ARDS can merely improve lung mechanics without obvious effect on EVLW.Neither of the influencing factors involved in the study has impact on emergence and clearance of EVLW.