British journal of anaesthesia
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Thirty healthy women in active labour received an intrathecal injection of morphine 0.5 mg (n = 12) or 1 mg (n = 18) in 7.5% dextrose. Both doses provided excellent analgesia for labour, 93% of patients obtaining at least 50% pain relief. Analgesia began 15-60 min after injection and did not decrease until 6-8 h after injection. ⋯ These side effects were decreased by naloxone, which did not affect the degree of analgesia. There was no significant depression of ventilation in any patient. These results suggest that morphine 0.5 mg or 1 mg, administered intrathecally, effectively decreases the pain of labour, and that i.v. administration of naloxone can alleviate the common side effects.
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A control system was used to bring the tension of anaesthetic in the brain to any value specified (in MAC units) by the anaesthetist and then maintain it constant until a new value was specified. The control was applied to a volatile agent but allowance was automatically made for the anaesthetic effect of any nitrous oxide concomitantly administered by the anaesthetist. The inspired concentration required to achieve the desired brain tension was calculated from a model of the patient and set automatically on the vaporizer. ⋯ In order to adapt the model to the patient an arterial blood sample was taken every 30 min to obtain the arterial tension of halothane for use as feedback. The system has been tested on eight Alsatian dogs. After omitting results affected by avoidable errors, the SD of the measured-to-computed arterial tension ratio was less than 10%.
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Probable malignant hyperpyrexia (MH) developed and was successfully treated in a 20-yr-old man during anaesthesia for reduction of a fractured mandible. The sister of this patient had died after an anaesthetic at the age of 14 yr, but malignant hyperpyrexia was not suspected. Subsequent enquiries revealed that the patient and his sister both had osteogenesis imperfecta. This case illustrates the infrequently reported association of malignant hyperpyrexia with osteogenesis imperfecta, and the difficulties in obtaining an adequate personal and family history of previous anaesthetics.
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Eighty female patients were allocated randomly to groups, divided in three ways, to investigate the effects of using cuffed p.v.c. v. red rubber tracheal tubes, intermittent adjustment of the cuff volume, and humidification of inspired gases on the incidence and severity of sore throat after tracheal intubation. In addition, the influence of the anaesthetist's participation in the trial was studied by assessing sore throat in a further 60 female patients where the anaesthetists were unaware of the trial. ⋯ If there are any real differences produced by these changes, and if any of them were as large as 15% then, to show with 95% confidence that any difference is at least 10%, would require a trial involving about 1400 patients. Retrospective analysis of the results showed no difference between patients who received suxamethonium and those who did not.
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Subarachnoid blockade using 0.5% bupivacine after a "preload" of Ringer's lactate solution 1500-2000 ml i.v. was studied in nine patients undergoing elective Caesarean section. Ephedrine infusion 50 mg in 500 ml was instituted at the first signs of maternal hypotension in seven patients. ⋯ The babies were unaffected at delivery. Preventive measures, especially the "preload" infusion, are important in the maintenance of adequate placental perfusion in patients undergoing Caesarean section under subarachnoid blockade.