Postoperative analgesia using epidural infusions of sufentanil-levobupivacine 0.125% versus sufentanil-ropivacaine 0.165% after lower limb operations

Levobupivacaine 0.125% provides satisfactory analgesia with lumbar and thoracic epidural catheter placement. Two studies performed in 1999 suggest that ropivacaine may be 40% less potent than bupivacaine whereas this difference is only 2% for levobupivacaine. Ninety-two patients undergoing total hip or knee replacement were selected to participate in double-blind randomized, study comparing ropivacaine 0.165% with levobupivacaine 0.125% to which was added sufentanil 1ug/ml for postoperative analgesia by the epidural route. The total dose of ropivacaine was 60% greater than that of levobupivacaine. The larger consumption of ropivacaine does not necessarily suggest that the potency difference between both newer local anesthestics is even more than the 25% assumed in the present study design. A shorter duration of action of ropivacaine may have caused a requirement for additional demand, although it would be unwise to believe that a 50% larger dose can be entirely explained by a difference in duration of action. Both local anaesthestics levobupivacaine and ropivacaine provided effective postoperative analgesia but, even in a 25% weaker concentration a small volume of levobupivacaine and opiate substance was consumed. These differences may be explained by a potency difference or by the duration of action of levobupivacaine

comparison of cervical and lumbar epidural anesthesia on Heart rate variability and spontaneous baroreflex sensitivity

We designed this study to test the hypothesis that cervical epidural anesthesia would increase the high-frequency [HF] component of heart rate variability [HRV] as a result of cardiac sympathectomy, whereas lumbar epidural anesthesia would cause sympathetic predominance. HRV and spontaneous baroreflex [SBR] sensitivity were assessed before and after cervical and lumbar epidural anesthesia by using plain 1.5% lidocaine in healthy patients. Electrocrdiogram and noninvasive beat-to-beat arterial blood pressure were monitored. HRV was analyzed. Our results indicate that cervical, but not lumbar, epidural anesthesia depresses phasic and tonic dynamic modulation of the cardiac cycle by vagal nerve in conscious humans, we hypothesized that cervical epidural anesthesia would produce an imbalance of cardiac autonomic status i.e an increase vagaly mediated HR component of HRV as result of cardiac sympathectomy, whereas lumbar epidural anesthesia would cause sympathetic predominance