血管外肺水在急性呼吸窘迫综合征最佳呼气末正压选择中的应用

Application of extravascular lung water in choosing optimal positive end - expiratory pressure for acute respiratory distress syndrome

目的探讨血管外肺水（extravascular lung water，EvLW）在急性呼吸窘迫综合征机械通气最佳呼气末正压（positive end expiratory pressure，PEEP）选择中的临床应用。方法采用内毒素（endotoxin，LPS）诱导实验犬ARDS模型，气管插管，呼吸机辅助呼吸，并测定P-V曲线，计算出P-V曲线低拐点对应的压力值（P-Vcurve，Plip），随机分为两组，对照组以Plip＋2cmH2O作为最佳PEEP进行机械通气，试验组进行PICCO监测，计算EVLW，以Plip＋2cmH2O作为初始PEEP值，根据EVLW以2cmH2O为间隔递增调整PEEP，并保证PEEP〈20cmH2O，监测O h（治疗开始时）、2、6、12及24h的PaO2、PaCO2、SPO2、EVLW及Cst。结果①在2、6、12、24h试验组氧合指数（PaO2/FiO2）高于对照组，P〈0．05；②在6及12h，试验组Cst高于对照组，P〈0．05，③在2、6、12及24h试验组SPO2高于对照组，P〈0．05。④在2、6、12及24h试验组PaO2高于对照组，P〈0．05。结论根据EVLW确定PEEP值组氧合指数、肺顺应性、PaO2及SPO2均较P-V曲线组有明显改善，且差异有统计学意义。

Objective To explore clinical application of extravascular lung water （EVLW） in choosing optimal positive end expiratory pressure （PEEP） in patients with acute respiratory distress syndrome （ARDS）. Methods Induced experimental ARDS model by the endotoxin （LPS）.Endotraeheal intubation, mechanical ventilation, and trace P-V curves. Calculate the lower inflection Point corresponding to the pressure value of P-Vcurve （Plip）, and divided into two groups randomly. In the control group, the optimal PEEP value was low inflection point（PLip） of the P-V curve with the addition of 2 cm H2O （PLip＋2 cm H2O）. In the experimental group, the optimal PEEP value was determined by the procedure as follows： PLip＋2 cm H2O was preset as initial PEEP value and then PEEP was increasing regulated at an interval of 2 cm H2O value according to the value of EVLW monitored,yet the maximal PEEP was not more than 20c m H2O. PaO2, PaCO2, EVLW, SPO2 and Cst were monitored at 0, 2, 6, 12 and 24 hours. Results （1） The oxygenation index（PaO2/FiO2） of the experimental group at 2, 6, 12, and 24 hour was higher than that of the control group, P 〈 0.05; （2） Cst in the experimental group at 6 and 12 hour was higher than that in the control group, P 〈 0.05. （3） The value of SPO2 at 2,6,12 and 24 hourof the experimental group was higher than those in the control group, P 〈 0.05. （4）PaO2 in the experimental group at 2,6,12 and 24 hour was higher than that in the control group, P 〈 0.05. Conclusion Determining optimal PEEP by combination of PLip ＋ 2 cm H2O with EVLW monitored might improve oxygenation index,SPO2, PaO2 and Cst.