[Three subanaesthetic dose ketamines mixed with butorphanol in the postoperative continuous intravenous analgesia].
OBJECTIVE
To determine an optimal clinical dose of ketamine after comparing the efficacy and security of 3 low dose ketamines mixed with butorphanol in the postoperative continuous intravenous analgesia.


METHODS
Eighty ASA (American Society of Anesthesiologists) I-II patients scheduled for elective gynecological surgery under general anesthesia were divided randomly into 4 groups (n=20): Group B received butorphanol 3 microg/(kg x h);Group BK1 received butorphanol 2 microg/(kg x h) mixed with ketamine 60 microg/(kg x h); Group BK2 received butorphanol 2 microg/(kg x h) mixed with ketamine 90 microg/(kg.h); and Group BK3 received butorphanol 2 microg/(kg x h) mixed with ketamine 120 microg/(kg x h). Continuous intravenous infusion pump was used when the patients had obvious pain (visual analgesia scale of five), and the bolus infusion (4 mL) was given before the operation, and continuous infusion at 2 mL/h. In the postoperative period, pain was assessed using visual analogue scale (VAS) at 2,6,12,24, and 48 h.At the same time, Ramsay scores and adverse effects were recorded.


RESULTS
There was no significant difference in the adverse effects and the postoperative mean arterial pressure, heart rate, respiratory rate values, and pulse oxygen among the 4 groups. Postoperative VAS values in Group BK3 was the lowest, followed by Group BK2. There was no significant difference between Group BK1 and Group B. The incidence of somnolence in Group B was higher than that in Group BK1, BK2 and BK3(P<0.05).


CONCLUSIONS
Ketamine in subanaesthetic dose added to butorphanol for postoperative continuous intravenous infusion has a better postoperative analgesic effect and sedation. It can effectively spare butorphanol consumption without increasing adverse effects. The optimal combined dose is 90-120 microg/(kg x h).
Zhao
Yuan
Y
Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha 410008, China.
Guo
Qu-lian
QL
Zhang
Zhong
Z
Wang
E
E
Xiong
Yun-chuan
YC
Zou
Wang-yuan
WY
D000328:Adult; D000698:Analgesia / Q000379:methods*; D000700:Analgesics / Q000008:administration & dosage*; D002077:Butorphanol / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D013509:Gynecologic Surgical Procedures; D006801:Humans; D007262:Infusions, Intravenous; D007649:Ketamine / Q000008:administration & dosage*; D010149:Postoperative Pain / Q000188:drug therapy*
D000700:Analgesics; D007649:Ketamine; D002077:Butorphanol