Effects of different depth of total intravenous anesthesia on postoperative hyperalgesia in patients undergoing lower abdominal operation / 临床麻醉学杂志

ABSTRACT

Objective By observing the incidence of postoperative hyperalgesia in patients with total intravenous anesthesia,to study the effects of different anesthesia depth on postoperative hyperalgesia.Methods Forty gynecologic patients undergoing open lower abdominal operation were randomized into two groups (n=20) group B1 with BIS 40-49 and the group B2 with BIS 50-59.Anaesthesia was induced and maintained with intravenous anesthetics.The threshold of haphalgesia and the range of mechanical hyperalgesia were measured before operation.The consumption of the intravenous anesthetics,the emergence time and the extubation time were recorded.The vital signs were recorded at eight time points pre-aneasthesia (T0),abdominal exploration (T1),the end of operation (T2)and 1 h (T3),4 h (T4),12 h (T5),24 h (T6),48 h (T7) after extubation.The VAS scores at T3-T7 were recorded.The PCA dosage of analgesic and superaddition in postoperative 24 h and 48 h were recored.The Von Frey Hairs were used to assessed the threshold of haphalgesia and the range of mechanical hyperalgesia at T6 and T7.Results The MAP at T6 and T7 and the VAS scores at T6 of the group B1 were lower than those of the group B2 (P<0.05).The range of mechanical hyperalgesia at T7 of the group B1 was narrower than that of the group B2 (P<0.05).Conclusion Maintaining the anesthesia depth within BIS 40-49 can reduce the body′s stress reaction,decrease the incidence of postoperative hyperalgesia and accelerate the recovery time of mechanical hyperalgesia in postoperative 48 h.