平均动脉压对脓毒性休克液体反应性的预测价值

Mean arterial pressure as an indicator of fluid responsiveness in patients with septic shock

目的探讨平均动脉压（MAP）对脓毒性休克患者液体反应性的预测价值。方法采用回顾性分析方法，选择2011年6月至2012年2月南京大学医学院附属鼓楼医院重症监护病房（ICU）收治的68例脓毒性休克患者，所有患者均实施容量负荷试验，监测容量复苏前后心率（HR）、MAP、收缩压（SBP）、舒张压（DBP）、脉压（PP）、中心静脉压（CVP）等，并通过脉搏指示连续心排血量（PiCCO）技术监测心排血指数（CI）、胸腔内血容量指数（ITBVI）、全身血管阻力指数（SVRI）、血管外肺水指数（EVLWI）等血流动力学指标。根据容量复苏后CI的变化（ACI％）分为液体有反应组（ACI％≥10％）和无反应组（△CI％〈10％），观察两组容量复苏前后血流动力学指标的变化；根据基础MAP水平将患者分为低MAP组（LMAP，MAP≤65mmHg，1mmHg=0．133kPa）和高MAP组（HMAP，MAP〉65mmHg），比较容量复苏前后两亚组各血流动力学指标的变化及MAP变化（△MAP％）与ACI％的相关性。结果68例患者中液体有反应者44例，占64．7％。有反应组患者容量负荷试验后SBP、DBP、MAP、PP、CI、CVP和ITBVI较试验前明显升高[SBP（mmHg）：126．5±23．8比110．7±20．2，DBP（mmHg）：58．1±14．8比52．8±13．5，MAP（mmHg）：80．3±19．2比70．1±15．8，PP（mmHg）：68．2±18．7比58．0±15．8，CI（ml·s-1·m-2）：70．0±21．7比53．3±20．0，CVP（mmHg）：13．0±4．5比10．2±4．4，ITBVI（ml／m2）：909．1±248．7比773．5±220．7，均P〈0．01]，SVRI（kPa·s·L-1·m-2）明显降低（130．9±47．7比157．1±59．1，P〈0．01），HR和EVLWI元明显变化。68例患者容量复苏后AMAP％与ACI％无显著相关性（r=0．266，P=0．054），而LMAP亚组（39例）AMAP％与ACI％呈正相关（r=0．473，P=0．03），AMAP％受试者工作特征曲线（ROC曲线）下面积（AUC）为0．763，95％可信区间（95％CI）0．554～0．973，P=0．231；HMAP亚组（29例）AMAP％与ACI％无显著相关性（r=-0．088，P=0．633）。结论脓毒性休克患者血压处于低水平时（MAP≤65mmHg），MAP可作为评估容量复苏时液体反应性的指标之一。

Objective To assess the value of mean arterial pressure （MAP） as an indicator for fluid responsiveness in patients with septic shock. Methods A retrospective analysis of clinical data of 68 patients with septic shock receiving volume resuscitation in intensive care unit （ICU） of Drum-tower Hospital Affiliated to Medical School of Nanjing University from June 2011 to February 2012 was conducted. The changes in heart rate （HR）, MAP, systolic arterial pressure （SBP）, diastolic arterial pressure （DBP）, pluse pressure （PP）, central venous pressure （CVP） were recorded before and after volume resuscitations. Cardiac index （CI）, intrathoracic blood volume index （ITBVI）, systemic vessel resistance index （SVRI） and extravascular lung water index （EVLWI） were evaluated by using the thermodilution technique of pulse induced continuous cardiac output （PiCCO）. All the patients were divided into two groups, responded group （△CI% ≥10% ） and the unresponded group （△CI% 〈 10% ）, according to the change in CI （△CI%）. Then the patients were divided into two subgroups, namely low MAP group（LMAP, MAP≤65 mm Hg, 1 mm Hg=0.133 kPa） and high MAP group （HMAP, MAP〉65 mm Hg）, according to the initial value of MAP. Then compared the changes in hemodynamic variables before and after volume resuscitation in each subgroup and assess the correlation between the changes in MAP （△MAP%） and △CI%. Results Forty-four （ 64.7% ） patients responded to the fluid challenge according to the predetermined criteria, SBP, DBP, MAP, PP, CI, CVP, ITBVI were increased significantly [SBP （mmHg）： 126.5±23.8 vs. 110.7±20.2, DBP （mmHg）： 58.1±14.8 vs. 52.8 ±13.5 , MAP （mm Hg） ： 80.3 ± 19.2 vs. 70.1 ± 15.8, PP （mm Hg） ： 68.2 ± 18.7 vs. 58.0 ± 15.8, CI （ml.s-1.m-2）： 70.0 ± 21.7 vs. 53.3±20.0, CVP （mmHg）： 13.0±4.5 vs. 10.2±4.4, ITBVI （ml/m2）： 909.1±248.7 vs. 773.5±220.7, all P〈0.01], and SVRI （kPa.s.L-1.m-2） was decreased significantly （130.9 ±47.7 vs. 157.1 ±59.1, P〈0.01）. HR and EVLWI did not change significantly. There was no significant correlation between AMAP% and △CI% in all the patients （r=0.266,P=0.054）. In the sub-group of LMAP （n=39）, △MAP% was positively correlated with △CI% （r=0.473, P=0.03）, the under the receiver operating characteristic curve （ROC curve, AUC） was 0.763, 95% confidence interval （95% CI） 0.554 - 0.973, P=0.231. However, there was no significant correlation between the AMAP% and △CI% （r=0.088, P=0.633） in the sub-group of HMAP （n=29）. Conclusion MAP can be used as an indicator of fluid responsiveness when the initial value of MAP was at a relative low level （MAP ≤65 mm Hg） inpatients with septic shock.