The analgesic effect of lornoxicam when added to lidocaine for intravenous regional anaesthesia.

BACKGROUND: The aim of the study was to evaluate the effect of lornoxicam (L) on sensory and motor block onset time, tourniquet pain, and postoperative analgesia, when added to lidocaine in intravenous regional anaesthesia (IVRA). METHODS: Forty-five patients undergoing hand surgery were randomly and blindly divided into three groups as to receive either i.v. saline and IVRA with lidocaine 0.5% (Control group, n=15), i.v. saline and IVRA lidocaine 0.5% with lornoxicam (L-IVRA group, n=15), or intravenous lornoxicam and IVRA lidocaine 0.5% (L-IV group, n=15). Sensory and motor blocks onset time, and tourniquet pain was measured after tourniquet application at 5, 10, 20, and 30 min, and analgesic use were recorded during operation. After the tourniquet deflation, at 1, 30 min, and 2, 4 h, visual analogue scales score, the time to first analgesic requirement, total analgesic consumption in first 24 h, and side effects were noted. RESULTS: Sensory and motor block onset times were shorter and the recovery time prolonged in the Group L-IVRA compared with the other group (P=0.001). A decreased tourniquet pain, a prolonged time first analgesic requirement [229 (85) min vs 28 (20) and 95 (24) min, P=0.0038) and less postoperative analgesic requirements during 24 h were found in Group L-IVRA compared with the other groups (P<0.05). CONCLUSIONS: The addition of lornoxicam to lidocaine for intravenous regional anaesthesia shortens the onset of sensory and motor block, decreases tourniquet pain and improves postoperative analgesia without causing any side effect.

Neurotoxicity with single dose intrathecal midazolam administration.

BACKGROUND AND OBJECTIVE: The aim of study was to investigate the electron microscopic changes in the medulla of the spinal cord that occur with intrathecal midazolam administration. METHODS: Twenty-eight albino rabbits of New Zealand type were randomized into two groups. Following anaesthesia, 16 rabbits were given 300 microg of midazolam (Group M) and 12 rabbits were given 0.3 mL of normal saline solution (Group C) intrathecally. Eight rabbits from Group M (Group M1) and 6 rabbits from Group C (Group C1) were sacrificed 24 h after the anaesthesia and 8 rabbits from Group M (Group M2) and 6 rabbits from Group C (Group C2) were sacrificed 6 days after the anaesthesia. The lumbosacral portion was removed by laminectomy and thin sections were examined microscopically. RESULTS: Severe separation in myelin lamella of the large axons, honeycomb appearance, slight separation in myelin lamella of small to moderately large axons, degenerate vacuoles in the cytoplasm and nuclear membrane irregularity were observed in neurons of Groups M1 and M2. Myelin lamella and nuclear membranes were found to be regular, vacuoles and oedema were observed in the neurons in the Groups C1 and C2. CONCLUSION: Midazolam administered at single dose by the intrathecal route may have neurotoxic effects on the neurons and myelinated axons at 24 h and 6 days following administration.

The persisting analgesic effect of low-dose intravenous ketamine after spinal anaesthesia for caesarean section.

BACKGROUND AND OBJECTIVES: To compare the analgesic effects of intrathecal fentanyl and low-dose intravenous ketamine as adjuvants to intrathecal bupivacaine for Caesarean section. METHODS: Ninety elective Caesarean section patients were randomized into three groups. Spinal anaesthesia was performed with 15 mg hyperbaric bupivacaine in all groups. Ketamine (0.15 mg kg(-1)) or an equal volume of normal saline was given intravenously immediately after initiating spinal anaesthesia in the ketamine and control group, respectively. In the fentanyl group, 10 microg fentanyl was added to the intrathecal bupivacaine. Arterial pressures, heart rate values, adverse effects, the time of first request for postoperative analgesia, visual analogue pain scores, total analgesic consumptions at 24 and 48 h were recorded in all patients. RESULTS: The time to first request for analgesia was significantly longer in the ketamine (197 min) and fentanyl (165 min) groups compared to the control group (144 min). Postoperative pain scores were significantly lower in the ketamine group than in both other groups. Although the analgesic requirements during first 24 h were significantly lower in the ketamine group, there was no significant difference between the groups during the following 24 h. CONCLUSION: Intravenous low-dose ketamine combined with intrathecal bupivacaine for Caesarean section provides longer postoperative analgesia and lower postoperative analgesic consumption than bupivacaine alone suggesting a pre-emptive effect.

Antimicrobial activity of ropivacaine and other local anaesthetics.

BACKGROUND AND OBJECTIVE: It is claimed that local anaesthetics have antimicrobial properties. Our aim was to investigate the antimicrobial effects of different concentrations of ropivacaine, bupivacaine, lidocaine and prilocaine on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. METHODS: All local anaesthetic dilutions were exposed to microorganisms for 0, 30, 60, 120, 240 min at room temperature. The inoculums taken from diluted suspensions were reinoculated on blood agar and incubated for 18-24 h at 35 degrees C and then the colonies were counted. RESULTS: Ropivacaine did not inhibit any of the microorganisms tested. Bupivacaine reduced the viable cells of P. aeruginosa at 0.5% and 0.25% solutions. Lidocaine 5% and 2% and prilocaine 2.0% dilutions reduced the viable cells of all microorganisms tested. Prilocaine 1.0% reduced the viable cells of E. coli, S. aureus and P. aeruginosa. Lidocaine 1% reduced only the viable cells of P. aeruginosa and prilocaine 0.5% reduced only E. coli. CONCLUSION: Ropivacaine had no antimicrobial effect on microorganisms tested. Bupivacaine showed poor antimicrobial effectiveness. Lidocaine and prilocaine had more powerful antimicrobial effects than the other two local anaesthetics.