血管外肺水联合P（cv-a）CO2/C（a-cv）O2在脓毒性休克 早期治疗中的应用研究

Clinical value of extravascular lung water combined with central venous-to-arterial carbon dioxide difference/arterial-to-venous oxygen difference ratio in early treatment of patients with septic shock

摘要:

目的：探讨血管外肺水（extravascular lung water，EVLW）联合中心静脉-动脉二氧化碳分压差/动脉-中心静脉氧含量差比值[central venous-to-arterial carbon dioxide difference/arterial-to-venous oxygen difference ratio，P（cv-a）CO2/C（a-cv）O2]在指导脓毒性休克早期治疗中的临床价值。方法：选择在2015至2017年重庆医科大学附二院和重庆市中医院中心ICU入住的脓毒性休克患者50例，采用随机分组的原则将患者分为早期目标导向性治疗组（EGDT组，n＝28）和EVLW联合P（cv-a）CO2/C（a-cv）O2组（P/C组，n＝22）。监测指标：①所有患者持续监测平均动脉压（MAP）、心率（HR）及中心静脉压（CVP），并抽取动脉血和中心静脉血行血气分析，通过血气分析测定患者PaCO2、PcvCO2、PcvO2、ScvO2、Hbcv、PaO2、SaO2、Hba以及入ICU时和复苏6 h后血乳酸值。计算 P（cv-a）CO2/C（a-cv）O2。其中CaO2=1.34×Hba×SaO2+0.003×PaO2；CcvO2=1.34×Hbcv×ScvO2+0.003×PcvO2；C（a-cv）O2=CaO2－CcvO2；②P/C组通过脉搏指示连续心排血量技术（PiCCO），采用经肺热稀释法测血管外肺水（EVLW），每3 h 1次，连续测量3次取平均值；③乳酸清除率（乳酸清除率=（入ICU时血乳酸值-6 h后血乳酸值）/入ICU时血乳酸值×100%；④6 h内血管活性药物去甲肾上腺素用量比较；（5）统计患者28 d病死率。比较2组患者液体复苏后各指标的差异。结果：复苏6 h后MAP、ScvO2、复苏6 h达标率2组间无统计学差异（P>0.05）；P/C组复苏6 h后的乳酸清除率和每小时尿量均明显高于EGDT组（P＜0.05）；复苏液体量、CVP、P（cv-a）CO2/C（a-cv）O2、血管活性药物用量均明显低于EGDT组（P＜0.05）；2组患者28 d病死率无统计学差异（P>0.05）。结论：血管外肺水联合P（cv-a）CO2/C（a-cv）O2联合指导下脓毒性休克早期目标导向治疗，能尽早且更准确地判断脓毒性休克患者的组织灌注状态和容量负荷状态，指导临床合理的液体治疗和血管活性药物的使用。

Abstract:

Objective：To investigate the clinical value of extravascular lung water（EVLW） combined with central venous-arterial par－tial pressure of carbon dioxide/arterial-central venous oxygen content difference ratio[P（cv-a）CO2/C（a-cv）O2 ] in the early treatment of septic shock. Methods：A total of 50 patients with septic shock who were admitted to the intensive care unit（ICU） of The Second Affiliated Hospital of Chongqing Medical University and Chongqing Hospital of Traditional Chinese Medicine from 2015 to 2017 were enrolled and randomly divided into early goal-directed therapy（EGDT） group with 28 patients and EVLW+P（cv-a）CO2/C（a-cv）O2 group with 22 patients（P/C group）. Mean arterial pressure（MAP），heart rate（HR），and central venous pressure（CVP） were con－tinuously monitored for all patients，and arterial blood samples and central venous blood samples were collected for blood gas analysis to measure PaCO2，PcvCO2，PcvO2，ScvO2，Hbcv，PaO2，SaO2，Hba，and blood lactate at the time of ICU admission and at 6 hours after resuscitation. P（cv-a）CO2/C（a-cv）O2 was calculated；CaO2=1.34×Hba×SaO2+0.003×PaO2，CcvO2=1.34×Hbcv× ScvO2+0.003×PcvO2，and C（a-cv）O2=CaO2-CcvO2. For patients in the P/C group，extravascular lung water（EVLW） was measured by pulse-induced contour cardiac output（PiCCO），once every 3 hours，and the mean value of three consecutive measurements was recorded. Lactate clearance rate was calculated according to the following equation：lactate clearance rate=（blood lactate value at the time of ICU admission-blood lactate value at 6 hours after resuscitation）/blood lactate value at the time of ICU admission×100%. The dose of the vasoactive agent norepinephrine within 6 hours after resuscitation was compared between the two groups. The 28-day mortality rate was calculated. Related indices after fluid resuscitation were compared between the two groups. Results：There were no significant differences between the two groups in MAP，ScvO2，and the proportion of patients achieving EGDT target at 6 hours after fluid resus－citation（P>0.05）. Compared with the EGDT group，the P/C group had significantly higher lactate clearance rate at 6 hours after fluid resuscitation and urine volume per hour（P<0.05），as well as significantly lower resuscitation fluid volume，CVP，P（cv-a）CO2/C（a-cv）O2，and dose of vasoactive agent（P<0.05）. There was no significant difference in 28-day mortality rate between the two groups（P>0.05）. Conclusion：EVLW combined with P（cv-a）CO2/C（a-cv）O2 can be used to guide EGDT for septic shock. It can accurately evaluate tissue perfusion and volume load in patients with septic shock as early as possible and guide the rational use of liquid therapy and vasoactive drugs in clinical practice.