We have shown previously that a plasma fentanyl concentration of 1.67 ng ml-1 reduced the MAC of isoflurane by 50%. By comparing equal degrees of MAC reduction by sufentanil, we may determine the potency ratio of these opioids. Seventy-six patients were allocated randomly to receive predetermined infusions of sufentanil, and end-tidal concentrations of isoflurane in oxygen. Blood samples were obtained 10 min after the start of the infusion, and just before and after skin incision. Any purposeful movement by the patient was recorded. The MAC reduction of isoflurane produced by sufentanil was obtained using a logistic regression model. A sufentanil plasma concentration of 0.145 ng ml-1 (95% confidence limits 0.04, 0.26 ng ml-1) resulted in a 50% reduction in the MAC of isoflurane. At a plasma concentration greater than 0.5 ng ml-1, sufentanil exhibited a ceiling effect.

SummaryThe aim of this double-blind, randomised study was to assess the effects of the addition of 0.5 mg of vecuronium bromide to a standard local anaesthetic mixture used for peribulbar anaesthesia. We studied 60 patients undergoing regional anaesthesia for intra-ocular surgery and were primarily interested in the quality of globe and lid akinesia. All received a mixture of 5 ml 2% lignocaine with 1:200 000 adrenaline, 5 ml 0.75% bupivacaine and 150 IU hyaluronidase with either 0.9% saline 0.25 ml (group A, n ¼ 30) or vecuronium bromide 0.25 ml (0.5 mg) (group B, n ¼ 30). Eye movements assessed at both 5 and 10 min were significantly reduced in the vecuronium group (group B) (p < 0.05). We conclude that the addition of vecuronium at a dose of 0.5 mg to the standard local anaesthetic mixture improves the quality of globe and lid akinesia.

Thirty patients awaiting prostatectomy with no history of cardiovascular disease were selected for a trial of alpha-adrenergic blocking agents. Twenty-seven patients completed the trial, 19 of them with unpleasant side effects. Eighteen of them found their symptoms were improved and 10 showed urodynamic improvement.

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