摘要目的 探讨连续性动态监测分流率(Qs/Qt)对急性呼吸窘迫综合征(ARDS)患者预后的预测价值.方法 采用前瞻性观察性研究方法,选择2014年6月至2015年12月天津市第三中心医院重症加强治疗病房(ICU)收治的进行有创机械通气的成人ARDS患者.记录患者的基线特征、人口学资料及生理学参数,并按照28 d生存状况分为存活组和死亡组.患者入院后立即抽取动脉血和混合静脉血进行血气分析,连续监测ARDS患者7d内Qs/Qt的变化;采用受试者工作特征曲线(ROC)评价Qs/Qt判断患者预后的准确性.结果 共入选46例ARDS患者,死亡20例,存活26例.ARDS发病1周内,存活组Qs/Qt在早期呈上升趋势[1～3d分别为(23±6)％、(27±6)％、(28±9)％],4d起呈逐渐下降趋势[4～7d分别为(27±5)％、(25±4)％、(19±4)％、(16±2)％],而死亡组Qs/Qt呈逐渐升高趋势[1～7d分别为(28±7)％、(30±3)％、(33±6)％、(33±11)％、(34±5)％、(33±6)％、(35±6)％];5 d起死亡组Qs/Qt明显高于存活组(均P＜0.05).两组氧合指数(PaO2/FiO2)于ARDS发病1周内波动均较小,存活组1～7 d PaO2/FiO2 (mmHg,1 mmHg=0.133 kPa)分别为167.37±43.98、180.55±39.90、174.27±35.47、188.64±39.74、252.54±49.22、239.35±25.63、248.93±45.64,死亡组分别为168.65±35.54、182.31±32.36、159.80±34.39、176.97±31.75、200.69±45.33、185.98±36.47、175.43±30.98;死亡组5d起PaO2/FiO2明显低于存活组(均P＜0.05).ROC曲线分析显示,5 d Qs/Qt判断患者预后的ROC曲线下面积(AUC)为0.958,95％可信区间(95％CI)为0.777～0.999 (P＜ 0.000 1,Z=13.13);当Qs/Qt临界值为28％时,敏感度和特异度分别为83.3％、90.0％.5 d PaO2/FiO2判断患者预后的AUC为0.790,95％CI为0.577～ 0.928(P=0.002 1,Z=3.08);当PaO2/FiO2临界值为223 mmHg时,敏感度和特异度分别为69.2％、81.8％.结论 连续性动态监测Qs/Qt可以帮助临床医生综合判断ARDS患者病情变化,其预测价值优于PaO2/FiO2,可作为判断ARDS患者预后的重要评价指标.

abstractsObjective To investigate the predictive value of continuous dynamic monitoring of intrapulmonary shunt (Qs/Qt) in patients with acute respiratory distress syndrome (ARDS).Methods A prospective observational study was conducted.The adult patients with ARDS undergoing mechanical ventilation admitted to intensive care unit (ICU) of Tianjin Third Central Hospital from June 2014 to December 2015 were enrolled.Baseline characteristics,demographic data and relevant physiologic data were recorded.All patients were divided into survivors and non-survivors according to the outcome of patients within 28 days.Artery and mixed venous blood was collected immediately after admission for blood gas analysis,and daily Qs/Qt within 7 days was continuously monitored in ARDS patients.The receiver operating characteristic curve (ROC) was used to evaluate the prognosis accuracy of Qs/Qt.Results In 46 enrolled ARDS patients,20 died,and 26 survived.During the first 7 days of ARDS,the mean Qs/Qt in survivors showed an increasing tendency [(23 ± 6)％,(27 ± 6)％,(28 ± 9)％,respectively,at 1-3 days] and a downtrend tendency from 4 days [(27 ± 5)％,(25 ± 4)％,(19 ± 4)％,(16 ± 2)％,respectively,at 4-7 days].However,a rising tendency of Qs/Qt in non-survivors was found at 1-7 days [(28 ± 7)％,(30 ± 3)％,(33 ± 6)％,(33 ± 11)％,(34 ± 5)％,(33 ± 6)％,(35 ± 6)％,respectively],and Qs/Qt from the 5th day in non-survivors was significantly higher than that in survivors (all P ＜ 0.05).The fluctuation of oxygenation index (PaO2/FiO2) within 1 week in both groups was small,and PaO2/FiO2 (mmHg,1 mmHg =0.133 kPa) at 1-7 days in survivors was 167.37±43.98,180.55±39.90,174.27±35.47,188.64±39.74,252.54±49.22,239.35±25.63,248.93±45.64,respectively,and it was 168.65±35.54,182.31 ± 32.36,159.80 ± 34.39,176.97 ± 31.75,200.69 ± 45.33,185.98 ± 36.47,and 175.43 ± 30.98 in non-survivors respectively.PaO2/FiO2 was significantly lower in non-survivors than survivors from 5 days (all P ＜ 0.05).It was shown by ROC curve that area under ROC curve (AUC) for Qs/Qt evaluating the prognosis on the 5th day was 0.958,and 95％ confidence interval (95％CI) was 0.777-0.999 (P ＜ 0.000 1,Z =13.13).When the cut-off value of Qs/Qt was 28％,sensitivity and specificity were 83.3％ and 90.0％,respectively.AUC for PaO2/FiO2 evaluating the prognosis on the 5th day was 0.790,and 95％CI was 0.577-0.928 (P =0.002 1,Z =3.08).When the cut-off value of PaO2/FiO2 was 223 mmHg,sensitivity and specificity were 69.2％ and 81.8％,respectively.Conclusion Dynamic Qs/Qt surveillance can help physician to analyze the changes of the patient's condition,and it was better than PaO2/FiO2,and can be an important evaluation indicator of prognosis for ARDS patients.