Effects of S(+) ketamine added to bupivacaine for spinal anaesthesia for prostate surgery in elderly patients.
OBJECTIVE
Intrathecal ketamine as the sole anaesthetic agent has demonstrated a lack of cardiovascular depression that should be of advantage in an elderly population. S(+) ketamine has three-times the analgesic potency of R(-) ketamine and its antinociceptive effects after intrathecal administration in rats are known. We decided to evaluate the effects of intrathecal S(+) ketamine added to a small dose of spinal bupivacaine in elderly patients undergoing transurethral prostate surgery.


METHODS
Forty males over 60 yr old, scheduled for transurethral prostate resection under spinal anaesthesia, were studied in a prospective, double-blinded, randomized way. Patients were allocated to receive either bupivacaine 10 mg or bupivacaine 7.5 mg combined with S(+) ketamine 0.1 mg kg(-1). Spinal block onset time, maximum sensory level, duration of blockade, haemodynamic variables, postoperative analgesic requirements and adverse events were recorded.


RESULTS
Onset times of motor and sensory block were shorter in the bupivacaine plus S(+) ketamine group. Incomplete motor block of the lower extremities was seen in 80% of the patients in bupivacaine plus S(+) ketamine group. Duration of complete motor block and spinal analgesia was shorter in the bupivacaine plus S(+) ketamine group. There was no significant difference in arterial pressure. Heart rate decreased after spinal anaesthesia in the bupivacaine plus S(+) ketamine group and was significantly lower until the end of anaesthesia. The incidence of adverse effects was not different between groups.


CONCLUSIONS
Intrathecal S(+) ketamine administered with a low dose of bupivacaine provides shorter motor and sensory block onset time, shorter duration of action and less motor blockade in elderly males.
Togal
T
T
Inonu University School of Medicine, Department of Anaesthesia, Malatya, Turkey. ttogal@inonu.edu.tr
Demirbilek
S
S
Koroglu
A
A
Yapici
E
E
Ersoy
O
O
D000368:Aged; D000701:Analgesics, Opioid / Q000627:therapeutic use; D000775:Anesthesia, Spinal; D000779:Anesthetics, Local / Q000008:administration & dosage*; D001794:Blood Pressure / Q000187:drug effects; D002045:Bupivacaine / Q000008:administration & dosage*; D004311:Double-Blind Method; D004338:Drug Combinations; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007649:Ketamine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000187:drug effects; D011446:Prospective Studies; D012677:Sensation / Q000187:drug effects; D013237:Stereoisomerism; D013997:Time Factors; D014147:Tramadol / Q000627:therapeutic use; D020728:Transurethral Resection of Prostate
D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D004338:Drug Combinations; D018691:Excitatory Amino Acid Antagonists; D014147:Tramadol; D007649:Ketamine; D002045:Bupivacaine