低中心静脉压联合急性高容量血液稀释在胸科手术中的应用

The application of low central venous pressure combined with acute hypervolemic hemodilution in thoracic surgery

目的:探讨低中心静脉压(LCVP)联合急性高容量血液稀释(AHHD)在胸科手术单肺通气期间对肺内分流和动脉氧分压的影响。方法 选择ASA分级为I～Ⅱ级择期全麻下行肺癌根治切除术的胸科患者50例，随机分为2组：LCVP联合AHHD组（LA组）和对照组（C组），每组均为25例，其中LA组麻醉后先行LCVP技术，采取限制晶体输液量并硝酸甘油持续微泵注射的方法，控制术中CVP在2～5 cmH2O，随后再联合应用AHHD技术，快速输注6%羟乙基淀粉（130/0.4）15 ml/kg进行血液稀释，使Hct维持在25%~30%；C组术中始终维持CVP在正常水平6～12 cmH2O。分别在平卧位双肺通气10 min(T0)、平卧位单肺通气10 min(T1)、侧卧位单肺通气10 min(T2)、肺叶切除后10 min(T3)等时间点采集肘静脉血测定血糖(GLU)和血清皮质醇(COR)水平；采集桡动脉血和右心房混合静脉血行血气分析，并记录GLU、COR水平、SpO2、HR、MAP、CVP、BIS、PetCO2、动脉血氧含量（CaO2）、混合静脉血氧含量（CvO2）、动脉血和混合静脉血氧分压（PO2）、动脉血和混合静脉血血红蛋白氧饱和度（SO2）、动脉血和混合静脉血血红蛋白（Hb）等。根据肺血流分布标准三室模型计算各时间点肺内分流率（Qs/Qt），Qs/Qt＝（CcO2－CaO2）/（CcO2－CvO2）×100%。结果 两组患者各时点GLU、COR水平、SpO2、HR、MAP、BIS、PetCO2基本稳定，但在单肺通气后，LA组和C组肺内分流明显增加(P＜0.05)，其中平卧位分别增加13.7%和14.9%，侧卧位分别增加11.4%和14.3%；两组动脉氧分压明显下降(P＜0.05)，且平卧位较侧卧位下降更明显，但两组间差异无统计学意义(P＞0.05)。在肺叶切除后，LA组和C组肺内分流明显减少(P＜0.05)，分别减少7.2%和8.6%，两组动脉血氧分压明显升高（P＜0.05），但两组间差异无统计学意义（P＞0.05）。术中LA组输血比例明显低于C组（4%比28%）（χ2＝4.902 0，P＝0.039 5）。结论 低中心静脉压联合急性高容量血液稀释在胸科手术单肺通气期间对肺内分流、动脉氧分压无明显的抑制，且可明显减少术中输血比例。

Objective To investigate the effect of low central venous pressure(LCVP)combined with acute hypervolemic hemodilution(AHHD)on intrapulmonary shunt and arterial oxygen partial pressure during one lung ventilation in thoracic surgery.Methods 50 thoracic surgery patients with ASA grade I-II undergoing elective radical resection of lung cancer were randomly divided into 2 groups:LCVP combined with AHHD group(LA group)and control group(C group),25 cases in each group.LA group received LCVP technology immediately after anesthesia with the methods of limited amount of crystalloid infusion and continuous micro pump injection of nitroglycerin,with intraoperative CVP in 2~5 cmH2O,and then received AHHD technology with rapid infusion of 6%hydroxyethyl starch(130/0.4)15 ml/kg,with Hct at 25%~30%.Intraoperative CVP in C group was maintained at the normal level(6~12 cmH2O).The blood glucose(GLU)and cortisol(COR)levels were measured by collecting the elbow venous blood at 10 min after double lung ventilation in the horizontal position(T0),10 min after one lung ventilation in the horizontal position(T1),10 min after one lung ventilation in the lateral position(T2),10 min after pulmonary lobectomy(T3).The radial artery blood and right atrial mixed venous blood were collected for blood gas analysis;and recorded GLU,COR level,SpO2,HR,MAP,CVP,BIS,PetCO2,arterial oxygen content(CaO2),mixed venous oxygen content(CvO2),arterial and mixed venous blood oxygen partial pressure(PO2),arterial and mixed venous blood oxygen saturation of hemoglobin(SO2),arterial and mixed venous blood hemoglobin(Hb).The rate of intrapulmonary shunt(Qs/Qt)was calculated according to the standard three compartment model of pulmonary blood flow distribution[Qs/Qt=(CcO2-CaO2)/(CcO2-CvO2)×100%].Results The GLU,COR level,SpO2,HR,MAP,CVP,BIS,PetCO2 of the two groups at each time point were basically stable,but intrapulmonary shunt significantly increased in both LA group and C group after one lung ventilation(P<0.05),which increased by 13.7%and 14.9%respectively in the horizontal position,11.4%and 14.3%respectively in the lateral position.The arterial oxygen partial pressure significantly decreased in both LA group and C group(P<0.05),that in the horizontal position decreased more obviously compared with the lateral position,but without statistically significant difference between the two groups(P>0.05).After lobectomy,the intrapulmonary shunt in LA group and C group significantly reduced(P<0.05),which increased by 7.2%and 8.6%respectively;the arterial oxygen partial pressure increased significantly in both two groups(P<0.05),but without statistically significant difference between the two groups(P>0.05).The proportion of blood transfusion in group LA was significantly lower than that in group C(4%vs.28%,χ2=4.902 0,P=0.039 5).Conclusion Low central venous pressure combined with acute hypervolemic hemodilution has no significant inhibition on intrapulmonary shunt and arterial oxygen partial pressure during one lung ventilation during thoracic surgery,and can significantly reduce the proportion of intraoperative blood transfusion.