In order to find out whether repeated doses of plain mepivacaine are appropriate for long-lasting microvascular surgery, a catheter-induced axillary plexus block was performed in 17 patients by using 400 mg of mepivacaine-HC1 every two hours. All patients underwent replantation surgery of one or more amputated fingers. Duration of operation varied from 8 to 24 hours. In all cases, there was adequate analgesia and muscle relaxation for the surgical procedure. Serum levels of mepivacaine were determined before, and 15 and 60 minute after the initial injection. With each following injection of mepivacaine, blood samples were taken at the same time schedule. Within the first eight hours, after four 400 mg doses of mepivacaine were given, all serum levels remained below the level of 5 to 6 micrograms/ml, which is said to be the lower level for mild cerebral toxic reactions in venous blood (blood/plasma distribution 0.92 +/- 0.04). After this time, when more than 1600 mg of mepivacaine had been administered, two patients exceeded the level of 6 micrograms/ml. The highest serum concentration observed in any of the patients was 7.0 micrograms/ml. This was 15 minutes after the 12th injection of 400 mg of mepivacaine and an overall dosage of 4800 mg. None of the patients showed evident signs of central nervous system or cardiovascular toxicity.

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Postdural puncture headache: comparison of 25-gauge Whitacre and Quincke needles.

BACKGROUND AND OBJECTIVES: To evaluate the influence of the shape of the needle tip on postdural puncture headache (PDPH) independent of the needle diameter, a 25-gauge Whitacre and a 25-gauge Quincke needle were compared. METHODS: In a prospective, randomized, double-blind fashion, the study was carried out on 400 patients who received spinal anesthesia for operations of the lower extremities. The 25-gauge Whitacre needle (group 1) and the 25-gauge Quincke needle (group 2) were randomly assigned to the patients, 200 in each group. Patients were interviewed postoperatively on days 1, 3, 5, and 7 using a standardized questionnaire. Only postural headache was defined as PDPH. The intensity of both postural and nonpostural headache were quantified using a 4-point rating scale and a visual analog pain scale (VAS). Statistical analysis was performed with parametric and nonparametric tests when appropriate, p < or = 0.05 was considered as significant. RESULTS: There were no differences in age and sex distribution between the two groups. Significantly more patients in group 2 (8.5%) complained of PDPH than in group 1 (3%, p < or = 0.02). Duration of PDPH ranged from 1-3 days (median: 1) in group 1, and from 1-9 days (median: 3) in group 2. This difference closely approached significance (p = 0.058). The mean maximal intensity of PDPH was comparable in both groups. Severe PDPH occurred only in two patients of group 2. One of them required a blood patch. With respect to the nonpostural headache, no significant differences were seen. CONCLUSIONS: The use of a conical tipped Whitacre needle results in significantly less PDPH compared to a standard Quincke spinal needle of the same size.

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