ISSN:
1432-055X
Keywords:
Schlüsselwörter„3-in-1“/Ischiadicus-Blockade
;
Mepivacain
;
Prilocain
;
Serumspiegel
;
Methämoglobinämie
;
Key words Combined 3-in-1/sciatic nerve block
;
Mepivacaine
;
Prilocaine
;
Serum level
;
Methaemoglobin
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Description / Table of Contents:
Abstract A high dose of local anaesthetic is necessary for the combined “3-in-1”/sciatic nerve block. Prilocaine is recommended for its low toxicity. However, in some patients prilocaine results in pronounced methaemoglobin formation due to toludine. Little has been known hitherto about the use of high-dose mepivacaine for the combined 3-1/sciatic nerve block. This study was undertaken to compare the use of 700 mg mepivacaine 1% and of 700 mg prilocaine 1%. Methods. The study was approved by the ethics committee of our hospital. Once their informed consent had been obtained in writing 3×20 patients (ASA 1–2) undergoing planned surgery on the foot or ankle joint were enrolled in the study. The patients were randomized to the following three groups on a double-blind basis: group 1,700 mg mepivacaine without epinephrine; group 2,700 mg mepivacaine with 0.2 mg epinephrine (1:350000); group 3,700 mg prilocaine 1%. Arterial blood samples for determination of local anaesthetic serum levels were collected over a 120-min period. We determined methaemoglobin and oxygen saturation before and 120 min after the blockade and continued these measurements for 6 h in group 3. At 15-min intervals, all patients were questioned about early signs of toxicity. The perioperative monitoring including blood pressure, ECG and pulse oximetry. Data were analysed using ANOVA and Student's t-test, P〈0.05 considered statistically significant. Results. The blocking efficacy did not differ among the groups (groups 1, 2, 3: 90%, 95%, 90%). The maximum mepivacaine serum level in group 1 was 3.91 μg/ml ±0.95 and 2.94 μg/,ml ±0.58 in group 2 (Fig. 2). Over the entire observation period the addition of epinephrine resulted in a significant reduction of the serum level (between 60.3% at t=15 min and 19.7% at t=120 min). In the prilocaine group the maximum serum level was 2.07 μg/ml ±0.56, significantly less than in either mepivacaine group. No patient showed signs or symptoms of local anaesthetic toxicity. In the prilocaine group there was wide variation in methaemoglobin formation among the patient, with a median of 10.1% (Fig. 3, Table 3). Three patients showed a maximum methaemoglobinemia between 16% and 17%. Five patients were still cyanotic after 6 h when they were transferred to the ward. The fractional SaO2 values amounted to 88% (median) with a minimum of 80.3%. Conclusion. Both mepivacaine 1% and prilocaine 1% are appropriate local anaesthetics for the combined 3-in-1/sciatic nerve block at a dose of 700 mg. There was no difference in the blocking efficacy. No patient showed clinical signs or symptoms of a local anaesthetic toxicity. Following prilocaine we are sometimes faced with high methaemoglobinemia, which may necessitate prolonged monitoring.
Notes:
Zusammenfassung In einer prospektiven, randomisierten Doppelblindstudie wurde bei 3mal 20 Patienten eine kombinierte „3-in-1“/Ischiadicus-Blockade durchgeführt. Wir verglichen den Blockadeerfolg, die arteriellen Serumspiegel und die Nebenwirkungen beim Einsatz von 700 mg Mepivacain 1% ohne (Gruppe I) und mit Adrenalin 1:350000 (Gruppe II) sowie 700 mg Prilocain 1% (Gruppe III). Der primäre Blockadeerfolg ohne supplementierende Analgetika war in allen drei Gruppen vergleichbar und lag zwischen 90 und 95%. Die maximalen Serumspiegel betrugen in Gruppe I 3,91±0,95 μg/ml nach 60 min und in Gruppe II 2,94±0,58 μg/ml nach 120 min. Zu allen Zeitpunkten führte Adrenalin zu einer signifikanten Reduktion der Mepivacain-Serumspiegel (p〈0,01). In der Prilocaingruppe waren die maximalen Serumspiegel mit 2,07±0,56 μg/ml signifikant niedriger als in beiden Mepivacaingruppen (p〈0,001) und traten nach 15 min auch signifikant früher auf. Bei keinem Patienten fanden sich Symptome oder klinische Zeichen einer Intoxikation durch zu hohe intravasale Lokalanästhetikumspiegel. Als einzige Nebenwirkung kam es in der Prilocaingruppe zu einer Methämoglobinbildung von im Median 10,1% 3 bis 4 h nach Injektionsende, wobei drei Patienten Werte zwischen 16 und 17% aufwiesen. Bei fünf Patienten dieser Gruppe war auch nach 6 h noch eine ausgeprägte periphere Zyanose nachweisbar. Sowohl Mepivacain 1% ohne und mit Adrenalin als auch Prilocain 1% eignen sich in einer Dosierung von 700 mg für die Durchführung der kombinierten „3-in-1“/Ischiadicus-Blockade, wobei Prilocain allerdings den Nachteil einer im Einzelfall klinisch relevanten Methämoglobinbildung aufweist.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s001010050240
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