Abstract:

Abstract:Objective To observe the reasonable dosage of single spinal anesthesia with isobaric ropivacaine on block in elder patients undergoing daytime anorectal operation and its safety evoluation,and to provide the basis on clinical anesthesia for the elderly daytime anorectal surgery.Methods 120 elder patients underwent selective anorectal operation were randomly divided into ropivacaine 0.8,1.0,1.3 and 1.5 mL groups,and there were 30 cases in each group. 0.8,1.0,1.3,and 1.5 mL  1% ropivacaine mixed with cerebrospinal fluid were injected into  the patients in each group through subarachnoid cavity.The effect of anesthesia,the  vital signs,the time of anesthesia level fixation,the time of postoperative anesthesia complete recovery,and the adverse reaction were recorded.
Results With the increasing of the doses of ropivacaine，the vital signs changes and the sense level fixation time had no statistical differences between various groups(P>0.05).The incidence of maximum block level ≤T5-8 in ropivacaine 1.3 and 1.5 mL groups were higher than that in 0.8 and 1.0 mL groups (P<0.05).The sense block maintenance time in ropivacaine  1.5 mL group  was  longer than  that in the  other groups
 (P<0.05).The intraoperative muscle relaxation degrees in  ropivacaine 1.0,1.3,and 1.5 mL groups
were all satisfied compared with ropivacaine 0.8 mL group(P<0.05).The incidence of intraoperative force abdominal pain  in ropivacaine 0.8 mL group was the highest (P<0.05).The  complete recovery time of motor nerve block in  ropivacaine 1.3 and 1.5 mL groups was the longest,there was significant difference compared with ropivacaine 0.8 mL group(P<0.05).But the patients in ropivacaine 1.5 mL group needed mostly urethral catheterization after operation(P<0.05).Conclusion 1.0-1.3 mL  1% ropivacaine  are suitable for single spinal anesthesia in elder patients underwent daytime anorectal operation，and the patients have stable vital signs and little adverse reaction under these conditions.

Key words: ropivacaine；spinal anesthesia,single；reasonable dosages；anorectal operation