Background and objectives: Ambulatory surgery requires anesthesia methods that allow rapid recovery and safe discharge of the patient. Spinal anesthesia is easy and quick to perform, and the use of noncutting small gauge needles reduces the occurrence of postdural puncture headache. For minimal hemodynamic consequences and faster recovery and discharge it would be optimal to limit the spread of spinal anesthesia only to the area which is necessary for surgery. In this study, the possibility in achieving unilateral spinal anesthesia with 0.18% hypobaric bupivacaine was studied.
Methods: Spinal anesthesia with 3.4 mL of hypobaric 0.18% bupivacaine (6.12 mg), without any intravenous infusion or prophylactic vasopressors, was administered with 27-gauge Whitacre unidirectional needle to 70 ASA I and II patients undergoing knee arthroscopies. The patients were allocated randomly to be kept either 20 (group I) or 30 (group II) minutes in the lateral position operation side uppermost. Sensory and motor block (pinprick/modified Bromage scale) were compared between the operation and the contralateral side.
Results: The motor and sensory block between operation and contralateral sides were significantly different at all testing times in both groups (P < .001, Mann-Whitney U test). The motor block was completely unilateral in 14 patients (39%) in group I and in 22 patients (65%) in group II. The hemodynamics were stable in all 70 patients.
Conclusions: Approximately three and a half milliliters hypobaric 0.18% bupivacaine (6.12 mg) provides a predominantly unilateral spinal block. Thirty minutes spent in the lateral position does not provide benefits over 20 minutes. The main advantages of our method are the hemodynamic stability and the patient satisfaction.
Background and objectives: Unintentional extrasheath injection causes failed axillary brachial plexus block. We wanted to find out if extrasheath injections produce higher plasma concentrations of local anesthetics compared to intrasheath injections. We also studied the incidence of extrasheath injection with radiographs.
Methods: Axillary brachial plexus blocks were established using a catheter technique. Fifty milliliters of 1.5% mepivacaine without epinephrine mixed with contrast medium was injected through the catheter. An anteroposterior radiograph was used to determine the distribution of contrast medium. Mepivacaine concentrations in arterial plasma were compared when local anesthetic solution was injected unintentionally outside of the axillary neurovascular sheath (n = 6) and when it was injected correctly into the sheath (n = 6). The incidence of extrasheath injection was studied in a different series of 109 patients.
Results: Arterial plasma mepivacaine concentrations were higher after extrasheath injection [8.0 (6.3-9.7) vs 5.8 (4.5-7.0), microg/mL, means (95% confidence intervals), P < .05]. Pharmacokinetic parameters such as mean residence time and total clearance did not differ between intra- and extrasheath injections. Extrasheath injection was observed in 3.7% (4/109) of cases.
Conclusion: Failed extrasheath injection of 50 mL 1.5% plain mepivacaine produces higher arterial plasma concentration in axillary brachial plexus block.
There is substantial evidence that there is an increased incidence of cesarean delivery among patients who receive epidural analgesia during labor. The controversy as to whether there is a causal relationship between epidural analgesia and cesarean delivery. Two prospective, randomized studies suggest that epidural analgesia may increase the incidence of operative delivery in laboring women. However, retrospective population-based studies suggest that the introduction of an epidural analgesia service, or the increased use of epidural analgesia, does not increase the cesarean delivery rate. It is possible that epidural analgesia during labor may increase the risk of cesarean delivery in selected patients. Such an effect--if it exists at all--appears to be small in contemporary practice. Furthermore, the availability and use of epidural analgesia may encourage other patients to undergo an adequate trial of labor or attempt vaginal birth after cesarean delivery. It is important to consider the impact of epidural analgesia on the total population of obstetric patients. Maternal-fetal factors and obstetric management, not epidural analgesia, are the most important determinants of the cesarean delivery rate. Finally, physicians should remember that pain relief is itself a worthy goal.