Extended femoral nerve sheath block after total hip arthroplasty: continuous versus patient-controlled techniques.

We assessed the efficacy of patient-controlled analgesia (PCA) techniques for extended femoral nerve sheath block after total hip arthroplasty. Forty-five patients were divided into three groups of 15. Over 48 h, all patients received 0.125% bupivacaine with clonidine 1 microg/mL and sufentanil 0.1 microg/mL via a femoral nerve sheath catheter as a continuous infusion at 10 mL/h in Group 1, as PCA boluses only of 10 mL/h in Group 2, or as PCA boluses of 5 mL per 30 min in Group 3. Pain scores, sensory block, supplemental analgesia, bupivacaine consumption, side effects, and satisfaction scores were recorded. Pain scores at rest and supplemental analgesia were comparable in the three groups. At 48 h, pain relief on movement was significantly better in Group 3 than in Group 1 (P = 0.01). Bupivacaine consumption was significantly less in Groups 2 and 3 than in Group 1 (P < 0.001). Side effects were comparable in the three groups. Satisfaction scores were significantly higher in Group 3 than in the other groups (P < 0.01). We conclude that, to maintain extended femoral nerve sheath block after total hip arthroplasty, PCA techniques reduce the local anesthetic consumption without compromise in patient satisfaction or visual analog scale scores. Of the two PCA techniques tested, PCA boluses (5 mL per 30 min) of 0.125% bupivacaine with clonidine 1 microg/mL and sufentanil 0.1 microg/mL are associated with the smallest local anesthetic consumption and the most patient satisfaction.

The effects of intraoperative intravenous clonidine on gastric intramucosal PCO2.

UNLABELLED: To investigate the effects of clonidine given as an anesthetic adjunct on splanchnic perfusion, we determined intramucosal gastric PCO2 using gastric tonometry in 60 patients scheduled for large intestine surgery. After induction of anesthesia, patients were randomly assigned to four groups. Patients in Group 1 received an IV infusion of sufentanil (0.2 microg x kg(-1) x h(-1)); patients in Group 2 received an IV infusion of clonidine (4 microg/kg in 20 min followed by 2 microg x kg(-1) x h(-1)); patients in Group 3 received an IV infusion of ketamine (0.5 mg/kg followed by 0.25 mg x kg(-1) x h(-1)); patients in Group 4 received an epidural infusion of bupivacaine (7 mL of 0.5% followed by 5 mL/h of 0.25%). Gastric intramucosal PCO2 was assessed immediately before skin incision and every hour during surgery using a nasogastric tube. A last measurement was taken after skin closure. An arterial sample was collected simultaneously to measure arterial PCO2. Oxygen consumption (VO2/min) was continuously recorded. Gastric intramucosal PCO2 significantly increased during surgery in all groups independent of the anesthetic technique considered (P < 0.01) and was not related to metabolic changes or blood pressure variations. This increase, however, remains in the physiologic range. In conclusion, our results demonstrate that clonidine given as an anesthetic adjutant at the dose used has no deleterious effect on splanchnic perfusion during colonic surgery. IMPLICATIONS: IV clonidine given as an anesthetic adjunct at a dose of 4 microg/kg in 20 min, followed by 2 microg x kg(-1) x h(-1), has no deleterious effect on splanchnic perfusion during colonic surgery.