血管外肺水指数在脓毒症相关性ALI／ARDS患者液体管理中的意义

The effect of EVLW in fluid managemeent on sepsis ALI/ARDS

目的 通过观察严重脓毒症/脓毒性休克患者血管外肺水指数（extravascular lung water index,EVLWI）与氧合指数（PaO2/FiO2）和胸腔内血容量指数（intrathoracic blood volume index,ITBVI）的相关性,探讨血管外肺水在脓毒症相关性急性肺损伤/急性呼吸窘迫综合征（ALI/ARDS）患者液体管理中的指导意义,为脓毒症相关性ALI/ARDS患者的液体管理提供新的临床策略.方法 选择2006年4月至2008年4月浙江大学医学院附属第二医院重症医学科符合严重脓毒症/脓毒性休克伴ALI/ARDS患者24例,应用PiCCO技术监测患者胸腔内血容量指数（ITBVI）和血管外肺水指数（EVLWI）,用血气分析同时监测动脉血氧分压（PaO2）,以PaO2/吸入氧浓度（FiO2）计算氧合指数.比较EVLWI与PaO2/FiO2和ITBVI与EVLWI之间的相关性.采用简单相关分析法进行统计学分析.结果 EVLWI与PaO2/FiO2呈明显负相关（r=-0.45,P＜0.01）.进一步以EVLWI=14 mL/kg进行分层分析,当EVLWI≤14 mL/kg时,两者无明显相关性（r=0.12,P=0.243）;当EVLWI＞14 mL/kg时,两者呈明显负相关（r=-0.47,P＜0.01）.这可以提示对严重脓毒症/脓毒性休克伴ALI/ARDS患者,EVLW不是影响氧合的唯一因素,当EVLWI＞14 mL/kg时,可以通过降低EVLW来改善氧合,但更应综合考虑影响氧合指数的各种因素.ITBVI与EVLWI无明显相关性（r=0.02,P=0.84）.进一步以ITBVI=1000 mL/m2进行分层分析,当ITBVI≤1000 mL/m^2时,两者无明显相关性（r=0.13,P=0.17）;当ITBVI＞1000 mL/m^2时,两者呈明显正相关（r=0.40,P＜0.01）.这提示我们对于脓毒症相关性ALI/ARDS,当ITBVI＞1000mL/m^2时,可以通过降低ITBV来降低EVLW,但对于肺毛细血管通透性增高症引起的EVLW,不能通过降低ITBV来降低.结论 EVLW在脓毒症相关性ALI/ARDS的液体管理中具有重要指导意义.

Objective The management of fluid infusion is crucial in severe sepsis/septic shock patients.The correlation of extravascular lung water index（EVLWI） versus oxygenation index （ PaO2/FiO2 ） and EVLWI versus intrathoracic blood volume index（ITBVI） were analysed in this present study. Method Totally 24 patients,admitted to the Intensive Care Unit of Second Affiliated Hospital of Zhejiang University, College of Medicine and diagnosed as severe sepsis/septic shock with acute lung injury and/or acute respiratory distress syndrome,were enrolled. ITBVI and EVLWI were detected with PiCCO technique. Correlation of EVLWI and PaO2/FiO2, ITBVI and EVLWI were analysed,respectively. Simple correlation and simple linear regression were used for statistical analysis. Results Significant negative correlation was found of EVLWI and PaO2/FiO2 （ r = - 0. 45, P 〈 0.01）.EVLWT = 14 mL/kg was defined as the cutoff value for the subgroup analysis. No correlation was found between EVLWI and PaO2/FiO2 in the subgroup with EVLWI≤ 14 mL/kg （ r = 0. 12, P = 0.243）, but in the subgroup with EVLWI 〉 14 mL/kg, significant negative correlation was found （ r = - 0. 47, P 〈 0. 01 ）. When EVLWI was higher than 14 mL/kg,EVLW should be decreased to improve oxygenation and other aspects should be taken into account. No significant correlation was found between ITBVI and EVLWI. A ITBVI value 1000 mL/m^2 was also defined as the cutoff value for the subgroup analysis. No significant correlation was found in the subgroup with ITBVI≤ 1000 mL/m2（ r = 0.13, P = 0.17）, while significant positive correlation was found in the subgroup with ITBVI 〉 1000 mL/m^2. This result suggested that in patients of severe sepsis/septic shock with ALI/ARDS, when the blood volume is high, ITBV should be decreased to improve the oxygenation,however,it is not useful in the situation of high pulmonary vascular permeability. Conclusions Extravascular lung water has a important role in the fluid management in patients of severe sepsis/septic shock with ALI/ARDS.