右美托咪定对气管插管全身麻醉诱导期中心静脉血氧饱和度的影响

Effect of dexmedetomidine on central venous oxygen saturation during induction of general anesthesia with endotracheal intubation

目的探讨右美托咪定(Dex)对气管插管全身麻醉诱导期中心静脉血氧饱和度的影响。方法将2018年11月至2019年12月60例美国麻醉医师协会(ASA)分级Ⅰ~Ⅱ级、年龄49~75岁的下腹部和四肢手术患者按数字表法随机分配进入对照组(D组,气管插管全身麻醉,30例)和试验组(S组,Dex预处理,30例)。S组在麻醉诱导开始前持续泵注0.8μg/kg的Dex 12 min,然后以1.6μg·kg^(-1)·h^(-1)的速率持续泵注Dex至气管插管后20 min,D组泵注等量0.9%氯化钠注射液。分别在中心静脉穿刺后(T0)、气管插管后5 min(T_(1))、15 min(T_(2))、20 min(T_(3))、术中(T4)采集动脉血气分析与中心静脉血气分析,比较各时间点2组患者中心静脉血氧分压(PcvO_(2))、氧饱和度(ScvO_(2))、中心静脉血与动脉血二氧化碳分压差(Pcv-aCO_(2))以及中心静脉血pH值(pHcv)、乳酸(Hlacv)、血糖(Gluv)的差异和循环改变。结果与T0比较,S组T_(1)~T_(4)、D组T_(3)~T_(4)MAP下降差异有统计学意义(P<0.05),S组与D组组间比较差异无统计学意义(P>0.05);与T0比较,S组T_(1)~T_(4),D组T_(3)~T_(4)心率(HR)减慢有统计学意义(P<0.01),与D组比较,S组T_(1)~T_(4)HR减慢差异有统计学意义(P<0.05)。气管插管后,2组患者PcvO_(2)、ScvO_(2)均表现为快速上升然后缓慢下降、术中再次上升的趋势;与T0比较,2组患者T_(1)~T_(4)PcvO_(2)、ScvO_(2)升高均有统计学意义(P<0.01);S组T_(1)~T_(3)时PcvO_(2)和T_(1)~T_(4)时ScvO_(2)低于D组,差异有统计学意义(P<0.05)。与T0比较、与D组比较,S组T1~T4 Gluv升高有统计学意义(P<0.05、P<0.01)。Pcv-aCO_(2)、pHcv、Hlacv组间比较差异无统计学意义(P>0.05)。结论伴随全身麻醉气管插管后的循环波动,存在全身血流再分布改变,增加老年患者重要脏器异常灌注的风险。Dex能够有效缓解气管插管后全身血流再分布改变,维护围术期PcvO_(2)、ScvO_(2)的稳定,从而起到心脏和脑神经保护。

Objective To investigate the effect of dexmedetomidine(DEX)on central venous oxygen saturation during induction of general anesthesia with endotracheal intubation.Methods Included in this study were 60 patients(ASAⅠtoⅡ,aged 49 to 75 years old)who underwent surgeries of the lower abdomen or limbs between November 2018 and December 2019.According to number table,the subjects were randomly assigned to the control group(group D,undergoing general anesthesia with endotracheal intubation,n=30)and the study group(group S,pretreatment with Dex,n=30).In group S,0.8μg/kg Dex was infused continuously within 12 minutes via a minipump before anesthesia induction,followed by subsequent sustained infusion of Dex at a pumping rate of 1.6μg·kg^(-1)·h^(-1)until 20 minutes after endotracheal intubation.Group D received the same amount of normal saline pumping.Arterial and central venous blood gas analyses were performed after central venous puncture(T_(0)),at 5 min(T_(1)),15 min(T_(2))and 20 min(T_(3))after endotracheal intubation,and during surgery(T_(4)).The central venous partial oxygen pressure(PcvO_(2)),oxygen saturation(ScvO_(2)),central venous blood-arterial carbon dioxide partial pressures difference(Pcv-aCO_(2)),changes in central venous pH value(pHcv),lactic acid(Hlacv),blood glucose(Gluv)and hemodynamics at each time point were compared between the two groups.Results Compared with T0,statistically significant decreases in MAP were noted in group S from T_(1)to T_(4)and in group D from T_(3)to T_(4)(P<0.05).There was no statistical difference in MAP between groups S and D(P>0.05).Compared with T0,statistically significant decreases in HR were noted in group S from T_(1)to T_(4),and in group D from T_(3)to T_(4)(P<0.01).Compared with group D,HR was significantly lower in group S from T_(1)to T_(4)(P<0.05).After endotracheal intubation,the PcvO_(2)and ScvO_(2)in patients of the two groups showed a trend of rapid rise,slow decline and then rise again during the operation.Compared with T0,significant increases in PcvO_(2)and ScvO_(2)were noted in the two groups from T_(1)to T_(4)(P<0.01).Compared with group D,the group S showed statistically lower PcvO_(2)from T_(1)to T_(3)and lower ScvO_(2)from T_(1)to T_(4)(P<0.05).Compared with T0 and compared with group D,the group S had significantly higer Gluv from T_(1)to T_(4)(P<0.05,P<0.01).There was no statistical difference in Pcv-aCO_(2),PHcv and Hlacv between the two groups(P>0.05).Conclusion Systemic redistribution of blood flow as part of hemodynamic fluctuation following endotracheal intubation for general anesthesia may add to risk of perfusion abnormalityof important organs in elderly patients.Dex can effectively alleviate the systemic redistribution of blood flow after endotracheal intubation,maintain the stability of PcvO_(2)and ScvO_(2)during the perioperative period,and thereby protect the heart and cranial nerves.