Postoperative sore throat and hoarseness following tracheal intubation using air or saline to inflate the cuff--a randomized controlled trial.

Sore throat and hoarseness following tracheal intubation is common. The aetiology may include high tracheal cuff pressures. We performed a double-blind, randomized controlled trial in 126 intubated patients to compare the incidence and severity of sore throat and hoarseness following inflation of the cuff using air or saline. Intra-cuff pressures were compared to assess any change due to inward diffusion of nitrous oxide. The incidence of significant sore throat and/or hoarseness overall was 15.0%. There was no statistically significant difference between the groups (air 15.9%, saline 14.5%). In the air group mean intra-cuff pressure increased significantly (start 14.0 mmHg, end 40.9 mmHg), while in the saline group there was no significant increase (start 12.7 mmHg, end 14.6 mmHg). The substitution of saline reliably results in sustained low intra-cuff pressures but high tracheal cuff pressure is not an important factor in the development of sore throat or hoarseness postoperatively within the pressure range and duration of operation studied.

Anaesthetic considerations for children undergoing stereotactic radiosurgery.

An anaesthetic case report of children undergoing stereotactic radiosurgery is presented, with a review of the inherent unique anaesthetic challenges. Twelve stereotactic radiosurgery procedures performed at The Prince of Wales Hospital, Sydney, were retrospectively reviewed. Despite differences in approach by individual anaesthetists to managing these children, an overall safe sequence may be evolved. The use of stereotactic radiosurgery for paediatric neuropathology is reviewed. The potential anaesthetic problems related to the paediatric patient and the peculiarities of the procedure are discussed and related to our series.

The effect of the addition of lignocaine on propofol emulsion stability.

The stability of propofol emulsion following the addition of various amounts of lignocaine solution was investigated. The investigations used were macroscopic and microscopic observations and electroacoustic determination of both droplet size and zeta potential. Evidence of emulsion instability was present following the addition of even small amounts of lignocaine. Resultant changes are unlikely to be clinically important following the addition of less than 20 mg of lignocaine to 200 mg of propofol (20 ml of propofol emulsion). It is recommended, however, that anaesthetists consider the possibility of destabilisation of propofol emulsion when adding larger doses of lignocaine, or when there is a delay between formulation and administration of the propofol-lignocaine mixtures.

Compatibility of propofol, fentanyl, and vecuronium mixtures designed for potential use in anesthesia and patient transport.

STUDY OBJECTIVE: To determine whether propofol emulsion, fentanyl, and vecuronium remain compatible and stable when mixed in clinically appropriate concentrations. DESIGN: Seven separate in vitro experiments. Two different propofol-fentanyl-vecuronium mixtures were formulated. Regular assays of propofol, fentanyl, and vecuronium were performed during a 90-minute infusion period and also during storage of one of the mixtures for 30 days at 4 degrees C, 22 degrees C, and 30 degrees C. Initial and storage pH were determined, and assays of the three drugs were performed when pH of the mixtures was varied between 1.4 and 12.7. Emulsion stability was assessed by measuring immediate and delayed alterations in droplet charge (zeta potential) and size. Finally, samples of the stored mixtures were incubated in culture medium for one week. SETTING: Teaching hospital and university laboratories. MEASUREMENTS AND MAIN RESULTS: Concentrations of the three drugs remained unchanged during infusion. During storage, concentrations of all three drugs were stable for two weeks at 4 degrees C or 22 degrees C, and for several days at 30 degrees C. Initial pH of the two mixtures was 5.1 and 5.3, and pH of the stored mixture increased slowly after 8 days. When the pH of mixtures was greater than or equal to 5.6, concentrations of fentanyl and vecuronium were unstable, but the concentration of propofol remained unchanged. Despite a reduction in zeta potential, immediate droplet size was essentially unchanged. No microbial growth was detected in stored mixtures. CONCLUSION: The propofol, fentanyl, and vecuronium mixtures studied were compatible and stable immediately after mixing. Appropriate in vitro compatibility testing is recommended before clinical evaluation of propofol-opioid or propofol-opioid-muscle relaxant mixtures.