呼气末正压对血管外肺水及氧合的影响

Effect of positive end - expiratory pressure on extravascular lung water and oxygenation in the patients with septic shock

目的 探讨不同水平的呼气末正压（PEEP）对接受机械通气的感染性休克患者血管外肺水指数（EVLWI）及氧合指数（PaO2/FiO2）的影响.方法 采用前瞻性、干预性的研究方法对北京协和医院MICU 15例行机械通气的感染性休克患者应用跨肺热稀释法及持续脉搏轮廓的方法进行血流动力学监测（PiCCO plus）.所有患者采用容量控制通气,血流动力学稳定后,每隔1 h递增PEEP水平,PEEP从0增加到20 cm H2O（如果能耐受）,根据不同的PEEP水平分为五组（0、5、10、15、20 cm H2O）.应用one-way ANOVA和Pearson＇s进行统计分析及相关分析,观察不同水平的PEEP对EVLWI、PaO2/FiO2的影响及其相关性.结果 15例感染性休克患者,男10例（67%）,女5例（33%）,平均年龄（67.6 ± 19.5）岁,APACHEⅡ评分（22.1 ± 7.5）分,基础PEEP（ 8.5 ± 3.6 ）cm H2O, 基础PaO2/FiO2（225.6 ± 89.2）mm Hg,ICU病死率67.6%.随着PEEP的升高,PaO2/FiO2升高,各组间比较差异有统计学意义（P＜0.05）,PEEP 对EVLWI及肺毛细血管通透性（PVPI）无明显影响.PaO2/FiO2与EVLWI、PVPI呈负相关（PaO2/FiO2 vs. EVLWI： r=-0.258,P=0.034 PaO2/FiO2 vs. PVPI： r=-0.324,P=0.007）.结论 短时间应用PEEP 能改善氧合,但不降低 EVLWI.

Objective To evaluate the effect of positive e,2 - expiratory pressure （PEEP） on extravascular lung water index （EVLWI）and oxygenation in the patients with septic shock undergoing mechanical ventilation. Methods In a prospective clinical trial, 15 patients with septic shock admitted to Medical Intensive Care Unit （MICU） , Peking Union Medical College Hospital （PUMCH） from Sep 2007 to Mar 2008 were enrolled. All the patients were mechanically ventilated with volume control mode. Hemodynamics was monitored hy the transpulmonary thermodilution technique and pulse contour analysis （PiCCO plus）. PEEP was increased from 0 to 20 cm H20 （ if tolerated）, by 5 cm H20. The effect of PEEP on EVLWI and oxygenation was analyzed by one - way ANOVA and Pearson＇s correlation analysis. Results Fifteen patients with septic shock, 5 females and 10 males. Mean age was （67.6 ± 19.5 ） years, APACHE 1I score was （ 22.1 ± 7.5 ） , baseline PaO2/FiO2 was （225.6± 89.2） mm Hg, PEEP was （8.5 ± 3. 6） cm H20. The ICU mortality was 67.6%. With increasing level of PEEP, PaOJFiO2 improved siguificantly （ P 〈 0.05 ） , while EVLWI and PVP1 did not show any significant change. In addition, tb relations between PaO2/FiO2 and EVLWI or PVPI were negative （PaO2/ FiO2 vs EVLWI ： r = - 0. 258,P = 0. 034 ; PaO2/FiO2 vs PVP1 ： r = - 0. 324, P = 0. 007 ）. Conclusion PEEP could improve oxygenation in short time, but not decrease EVLWI.