血管外肺水肿对急性呼吸窘迫综合征肺损伤程度及预后的评估价值

Effects of extravascular lung water on severity of illness and survival of patients with acuterespiratory distress syndrome

目的评估血管外肺水（EVLW）与急性呼吸窘迫综合征肺损伤程度和预后的关系。方法2011年1月至12月入住ICU的早期急性呼吸窘迫综合征行机械通气者27例，连续观察3d，根据患者实际体重和理想体重，计算实际血管外肺水指数（EVLWa）和理想血管外肺水指数（EVLWp）；分别比较两者与患者动脉血氧分压（PaO2）／吸氧浓度（FiO2）、肺静态顺应性及肺损伤评分的相关性，分析这些指标对急性呼吸窘迫综合征患者预后的预测价值。结果死亡组急性生理和慢性健康Ⅱ评分、前3d液体平衡、机械通气时间以及ICU住院日均显著高于存活组（均P〈0．05）。第1天和第3天死亡组的氧合指数（0I）、肺损伤评分、EVLWa、EVLWp均较存活组明显升高（均P〈0．05）。EVLWa、EVLWp与肺损伤评分（r值分别为0．471、0．528，P〈0．05）、0I（r值分别为0．527、0．627，P〈0．05）呈明显正相关，与PaO2／FiO2（r值分别为-0．467、-0．646，P〈0．05）呈明显负相关，EVLWp与肺损伤评分、0I以及PaO2／FiO2的相关系数均高于EVLWa；EVLWa、EVLWp与肺静态顺应性负相关，但是无统计学意义（r值分别为-0．260、-0．226，P〉0．05）。应用受试者工作特征曲线分析进行预后分析，EVLWa、EVLWp的曲线下面积分别为0．675（P〉0．05）、0．739（P〈0．05）。以EVLWp12．5mmol/L为折点，EVLWp预测急性呼吸窘迫综合征患者存活的灵敏度为80．0％，特异度为62．5％。结论EVLW能反映急性呼吸窘迫综合征肺损伤严重程度，并能判断患者预后；与EVLWa相比，EVLWp与肺损伤相关指标相关性更好，对急性呼吸窘迫综合征预后的早期预测价值更高。

Objective To evaluate the relationship between the extravascular lung water （EVLW） and other markers of lung injury and determine whether or not EVLW predicts survival in patients with acute respiratory distress syndrome （ARDS） and examine if indexing EVLW with predicted body weight （EVLWp） strengthens its discriminative power. Methods EVLW and other markers of lung injury [including： PaO2/FiO2（ P/F）, oxygenation index （OI） = mean pressure （Pm）×FiO2×100/PaO2, static compliance （Cst） and lung injury score （LIS） ] were measured prospectively for 3 days in 27 patients with early ARDS between January 2011 and December 2011 at intensive care units （ICU） of Subei People＇s Hospital. The relationship between indexing EVLW with actual body weight （EVLWa）, EVLWp and other markers of lung injury, the 28-day mortality were evaluated. Results Acute physiology and chronic health evaluation Ⅱ （APACHE Ⅱ ）, fluid balance in first 3 days, days of mechanical ventilation and ICU stay were significantly higher on admission in nonsurvivors compared with survivors （ P 〈 0. 05 ）. Nonsurvivors had higher OI, LIS, EVLWa and EVLWp than survivors at Days 1 and 3 （ P 〈 0. 05 ）. EVLWa and EVLWp were correlated positively with LIS （ r = 0. 471, 0. 528 P 〈 0. 05 ） and OI （ r = 0. 527, 0. 627, P 〈 0. 05 ） and negatively with P/F （ r = - 0. 467, - 0. 646, P 〈 0. 05）. EVLWp had a stronger correlation to LIS, OI and P/F than did EVLWa. No obvious correlation existed between EVLWa, EVLWp and Cst （ r = - 0. 260, 0. 226, P 〉 0. 05 ）. ROC curve analysis indicated that EVLWp （ 0. 759, P 〈 0. 05 ） but not EVLWa （0. 661, P 〉0. 05 ） discriminated between survivors and nonsurvivors. Three-day average EVLWp ≥ 12. 5ml/kg predicted the 28-day mortality with 62. 5% specificity and 80% sensitivity. Conclusion Increased extravascular lung water is a feature of early ARDS and predicts survival. EVLWp, instead of EVLWa, improves the predictive value of extravascular lung water for survival and it is correlated with markers of disease severity.