British journal of anaesthesia
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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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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.
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Extradural pressure was measured in the lateral and the supine positions in three groups of patients using the extradural catheter as a manometer. The groups consisted of 20 pregnant patients at or near term, 10 patients in the period after childbirth and 10 male surgical patients. In every patient, the extradural pressure in the supine position was greater than that in the lateral position. ⋯ It is suggested that the difference between the extradural pressures in the lateral and the supine positions is physiological and occurs irrespective of vena caval compression. Extradural pressure changes are probably the result of postural changes in the cerebrospinal fluid (CSF) pressure. The influence of CSF pressure on extradural pressure was confirmed further by measuring the extradural pressure in the prone position in five pregnant patients.
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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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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%.