Regional anesthesia and pain medicine
-
Reg Anesth Pain Med · Mar 1999
Randomized Controlled Trial Comparative Study Clinical TrialContinuous spinal anesthesia: a comparative study of standard microcatheter and Spinocath.
This prospective, randomized study evaluated the advantages and disadvantages of a new subarachnoid catheter. ⋯ Spinocath insertion required 6.3 +/- 3.2 minutes in group 1 versus 3.9 +/- 1.2 minutes in group 2 (P < .01) with similar difficulties with catheter introduction. Perception of dural puncture was better in group 1 (P < .05). There were significant intergroup differences in time to free flow of CSF through the catheter. In group 2, correct catheter positioning had to be confirmed by aspiration in 80% of cases (P < .05). At the end of surgery, the catheters were removed, and there were no significant differences between groups. The anesthetic blocks were similar with both systems. Patient opinion of the technique did not differ between groups, and regression analysis did not show any differences between groups or correlation to any incident during performance of the technique. Globally, the anesthesiologists participating in the study considered both systems to be easy to use and adequate for continuous spinal anesthesia. With respect to the advantage afforded by a directional needle in orientating the catheter within the spinal canal, the Spinocath system-with a longer technique performance time than the standard approach-involves a success rate and incidence of technical problems similar to that of the conventional technique.
-
Reg Anesth Pain Med · Mar 1999
Randomized Controlled Trial Clinical TrialEvaluation of peripheral morphine analgesia for lumpectomy and axillary node dissection: a randomized, double-blind, placebo-controlled study.
Morphine may elicit potent antinociceptive effects by binding and activating peripheral opioid receptors. However, the results in clinical studies have varied. We examined the postoperative analgesic effects of incisional morphine in patients undergoing lumpectomies and axillary node dissections for breast cancer. For this purpose, a concentration of morphine within the range (0.25-0.6%) of those utilized in previous studies for postarthroscopy analgesia was chosen (0.6%). ⋯ These results suggest that under the conditions of the study protocol, there is no value in utilizing morphine in solution at the surgical site for postoperative lumpectomy and axillary node dissection analgesia.
-
Reg Anesth Pain Med · Mar 1999
Case ReportsAnxiety, vocalization, and agitation following peripheral nerve block with ropivacaine.
Central nervous system (CNS) and cardiovascular toxicity are potential side effects of local anesthetics. However, ropivacaine has been reported to be less CNS toxic than bupivacaine in human volunteers. ⋯ This case report shows that ropivacaine may cause CNS toxicity that differs from classical signs of local anesthetic-induced toxicity. This effect might be related to the unique structure of ropivacaine, which is formulated in an S-enantiomer preparation. It has been shown that S-enantiomers bind differently to receptors in both the CNS and cardiovascular systems. This property may account for the disinhibition of select neural pathways that are specifically involved in mediation of anxiety and aggression.
-
Reg Anesth Pain Med · Mar 1999
An investigation of the neurophysiologic mechanisms of tourniquet-related pain: changes in spontaneous activity and receptive field size in spinal dorsal horn neurons.
Several theories have been proposed for the pain resulting from the nerve compression and ischemia associated with maintaining the inflation of a pneumatic tourniquet on an extremity. This investigation observes changes in the spontaneous activity and receptive field (RF) size of spinal dorsal horn neurons during tourniquet-related nerve compression and ischemia. ⋯ The results of this study indicate that nerve compression and ischemia results in block of input to LTM neurons having RFs distal to the tourniquet cuff and an increase in spontaneous activity and expansion of the RFs of NRs, especially those with RFs located proximal to the tourniquet. Increases in spontaneous firing activity and expansion of the RFs of nociresponsive dorsal horn neurons receiving input from primary afferent nociceptors proximal to the tourniquet may explain, in part, the neurophysiologic mechanism of tourniquet-related pain.