麻醉诱导后低血压对机体组织氧饱和度的影响

Effect of hypotension on tissue oxygen saturation after anesthesia induction

目的通过观察全身麻醉诱导后血压变化对机体组织氧饱和度的影响,探讨循环变化与组织灌注之间的调节机制。方法选取2020年6—12月解放军总医院第四医学中心全身麻醉下行肝射频消融术患者91例,应用近红外组织血氧参数无创检测仪监测患者左前额脑氧饱和度(regional cerebral oxygen saturation,rScO_(2))及左前臂肱桡肌氧饱和度(regional muscle oxygen saturation,rSmO_(2))。常规全身麻醉诱导,记录患者入室(T_(0))、吸氧5 min(T_(1))及气管插管5 min(T_(2))后的平均动脉压(mean arterial pressure,MAP)、rSmO_(2)及rScO_(2),观察麻醉后循环变化对患者肌肉及脑组织氧供需平衡的影响。结果与T_(0)和T_(1)相比,T_(2)时MAP[(88.63±11.36)mmHg比(99.05±11.03)mmHg、(98.53±11.04)mmHg,1 mmHg=0.133 kPa]、HR[(59.78±8.76)次/min比(72.15±9.57)次/min、(71.85±7.29)次/min]和脑电双频指数(bispectral index,BIS)[(50.95±9.90)比(95.37±3.00)、(94.96±2.91)]均明显降低,差异有统计学意义(P<0.05)。与T_(0)相比,T_(1)时rSmO_(2)[(68.24±3.65)%比(66.71±3.67)%]及T_(1)和T_(2)时的rScO_(2)[(65.69±3.00)%、(66.98±3.77)%比(63.91±3.71)%]均明显升高,差异有统计学意义(P<0.05)。与T_(1)相比,T_(2)时rSmO_(2)降低[(66.35±4.80)%]而rScO_(2)升高,差异均有统计学意义(P<0.05)。与rSmO_(2)相比,T_(0)和T_(1)时rScO_(2)较低,差异有统计学意义(P<0.05)。麻醉诱导后14例发生诱导后低血压。非低血压与低血压患者相比,在性别、年龄、BMI、ASA分级方面差异均无统计学意义(P>0.05)。与非低血压患者相比,诱导后低血压患者的T_(2)时MAP和rSmO_(2)更低[(75.13±12.51)mmHg比(91.08±9.29)mmHg,(63.71±8.35)%比(66.83±3.72)%],ΔMAP和ΔrSmO_(2)更高[24.71(23.37,32.43)%比6.65(4.10,9.03)%,4.07(2.88,6.36)%比1.52(0.00,4.26)%],差异均有统计学意义(P<0.05)。结论通过对患者肌肉及脑组织氧饱和度的动态观察发现,全身麻醉诱导后低血压对rScO_(2)无明显影响,但对rSmO_(2)影响较大。

Objective To observe the effect of blood pressure changes on tissue oxygen saturation after induction of general anesthesia,and investigate the regulating mechanism between circulation changes and tissue perfusion.Methods A total of 91 patients undergoing hepatic radiofrequency ablation under general anesthesia in the Fourth Medical Center of PLA General Hospital from June to December 2020 were selected.The regional cerebral oxygen saturation(rScO_(2))and regional muscle oxygen saturation(rSmO_(2))of the left forearm were measured by near-infrared tissue oxygen parameter non-invasive detector.After induction of general anesthesia,mean arterial pressure(MAP),rSmO_(2) and rScO_(2) after entering the operation room(T_(0)),5 min after oxygen inhalation(T_(1))and 5 min after tracheal intubation(T_(2)) were recorded,to observe the effect of circulation changes on oxygen supply and demand in muscle and brain tissue after anesthesia.Results Compared with T_(0)and T_(1),MAP[(88.63±11.36)mmHg vs.(99.05±11.03)mmHg,(98.53±11.04)mmHg,1 mmHg=0.133 kPa],HR[(59.78±8.76)bpm vs.(72.15±9.57)bpm,(71.85±7.29)bpm]and bispectral index(BIS)[(50.95±9.90)vs.(95.37±3.00),(94.96±2.91)]at T_(2)were significantly lower(P<0.05).Compared with T_(0),rSmO_(2)[(68.24±3.65)%vs.(66.71±3.67)%]at T_(1)and rScO_(2)[(65.69±3.00)%,(66.98±3.77)%vs.(63.91±3.71)%]at T_(1)and T_(2)were significantly higher(P<0.05).Compared with T_(1),rSmO_(2)decreased[(66.35±4.80)%]and rScO_(2)increased at T_(2)(P<0.05).Compared with rSmO_(2),rScO_(2)was lower at T_(0)and T_(1)(P<0.05).Hypotension occurred in 14 cases after anesthesia induction.There was no significant differences in gender,age,BMI,ASA grade between non-hypotensive patients and hypotensive patients(P>0.05).Compared with non-hypotensive patients,patients with induced hypotension had lower MAP and rSmO_(2)[(75.13±12.51)mmHg vs.(91.08±9.29)mmHg,(63.71±8.35)%vs.(66.83±3.72)%]at T_(2),andΔMAP andΔrSmO_(2)were higher[24.71(23.37,32.43)%vs.6.65(4.10,9.03)%,4.07(2.88,6.36)%vs.1.52(0.00,4.26)%],the differences were statistically significant(P<0.05).Conclusions It is found that the decrease of blood pressure after general anesthesia has no significant effect on brain oxygen saturation,but has a great effect on muscle oxygen saturation.