Pharmacodynamics of different local anestheties administered intrathecally for elderly patients undergoing transurethral resection of the prostate / 中华麻醉学杂志

ABSTRACT

Objective To investigate the pharmacodynamics of different local anesthetics administered intrathecally for elderly patients undergoing transurethral resection of the prostate (TURP). Methods Ninety ASA Ⅰ - Ⅲ elderly patients, aged 69-82 yr, with body mass index less than 30 kg/m2 , undergoing TURP under combined spinal-epidural anesthesia, were randomly divided into 3 groups ( n = 30 each) levobupivacaine group (group L), ropivacaine group (group R) and bupivacaine group (group B). Group L, R and B received intrathecai (IT) 0.5 % levobupivacaine, 0.5 % ropivacaine and 0.5 % bupivacaine respectively. The initial dose was 7,10 and 6 mg in group L, R and B respectively. The ratio of two successive doses was 0.9. If the upper sensory block reached T10 within the 20 min after IT injection, the IT analgesia was considered to be effective. The median effective dose (EDs0) and 95 % confidence interval (95 % CI) were calculated by Dixon. Results The ED50 and 95% CI of levobupivacaine, ropivacaine and bupivacaine were 6.781 (95% CI 6.561-7.024) mg, 9.135 (95%CI8.670-9.616) mg and 5.170 (95% CI 5.012-5.333) ng respectively. The relative potency ratio between levobupivacaine, ropivacaine and bupivacaine is 0.76∶0.57∶1.00. ConclusionThe relative potency ratio be tween levobupivacaine, ropivacaine and bupivacaine is 0.76∶0.57∶1.00.