The efficacy and safety of 0.75% levobupivacaine vs 0.75% bupivacaine for peribulbar anaesthesia.

BACKGROUND: Levobupivacaine, the S(-)-enantiomer of racemic bupivacaine, is associated with a similar efficacy but a reduced potential for cardiovascular and central nervous system toxicity than racemic bupivacaine. Thus, this prospective, randomised, double-masked study was undertaken to assess the efficacy and safety of 0.75% levobupivacaine vs 0.75% bupivacaine, each with hyaluronidase, for peribulbar anaesthesia. METHODS: A total of 60 patients undergoing elective anterior segment surgery were randomly allocated to receive either agent by a single, inferotemporal peribulbar injection technique, supplemented with a medial canthus injection if necessary. Ocular akinesia and orbicularis oculi function were assessed by scoring systems at 2 min intervals until satisfactory akinesia was achieved, and movements were reassessed on the day after surgery to confirm regression of the block. RESULTS: The time taken to reach a state of satisfactory anaesthesia and akinesia was deemed to be the primary measure of efficacy. Both agents achieved this in a similar median time of 2 min after receiving 5 ml of the injectate, and the treatment difference was not statistically significant (P=0.24). Blood samples from the first 20 patients were taken at intervals up to 4 h. These were analysed for plasma levels and confirmed similar plasma concentration vs time profiles for the two agents. Seven patients in each group (23%) complained of pain on injection but the technique was generally well tolerated. Two patients in the levobupivacaine group experienced serious adverse events, but neither was considered related to the study medication. The most common minor post-operative adverse event was prolongation of the local anaesthetic block, which was reported by nine patients (four in the levobupivacaine group and five in the bupivacaine group). CONCLUSIONS: Levobupivacaine and bupivacaine are equally successful in achieving clinically satisfactory peribulbar anaesthesia with few adverse effects.

Outpatient paediatric dental anaesthesia. A comparison of halothane, enflurane and isoflurane.

One hundred and fifty unpremedicated children who presented for dental extractions were anaesthetised with nitrous oxide and halothane, enflurane or isoflurane. Ventricular arrhythmias occurred only in the halothane group (14%). Respiratory problems and desaturation were significantly more common in the isoflurane group. Induction times differed significantly between the groups halothane less than enflurane less than isoflurane, while recovery time and induction to recovery time were significantly shorter in the enflurane group. We suggest that enflurane is the most suitable agent for anaesthetising these patients.

Dose requirements of ICI 35,868 (propofol, 'Diprivan') in a new formulation for induction of anaesthesia.

In order to avoid Cremophor-related reactions and reduce the incidence of pain on injection, diisopropylphenol (ICI 35,868; propofol) has been reformulated as an emulsion. One hundred and fifteen patients received an induction dose of propofol in the new formulation. The dose required to induce anaesthesia in 95% of healthy, unpremedicated patients was 2.5 mg/kg. Induction was associated with a degree of cardiovascular and respiratory depression. There were no adverse reactions although there were a number of minor side-effects. The incidence of pain on injection was low (3%) and the overall quality of induction was assessed as good or adequate in 92% of patients.

Subarachnoid blockade with bupivacaine. A comparison with cinchocaine.

Subarachnoid anaesthesia was induced in 40 patients with 0.5% bupivacaine 3 ml with no glucose, 5% glucose or 8% glucose, or with hyperbaric cinchocaine . The injections were made in the lateral position and the patients turned supine immediately. The onset, extent and duration of sensory and motor blockade, the quality of anaesthesia, cardiovascular effects, and the frequency of side-effects were studied. The hyperbaric solutions produced a greater cephalad spread (T6-T7) than the glucose-free solution (T10-T11). Cinchocaine produced a longer duration of action at T10 and T12 than the hyperbaric bupivacaine solutions. No advantage was seen when 8% rather than 5% glucose was used. The glucose-free bupivacaine produced intense blockade of long duration and was suitable when a lower level of blockade was adequate for the proposed surgery.