We describe the case of a pregnant woman, 35 weeks' gestation, with primary pulmonary hypertension and coarctation of the aorta requiring emergency Caesarean section under general anaesthesia. The patient had a pulmonary artery catheter inserted before operation which revealed pulmonary artery pressures in excess of 80/40 mm Hg. These were lowered using an infusion of glyceryl trinitrate. After delivery of the baby and administration of oxytocin, pulmonary artery pressures were more difficult to control. An infusion of prostacyclin was substituted which stabilized pulmonary pressures. After operation, she was transferred to the intensive care unit where prostacyclin was administered by an "aerosolized" route. Her trachea was extubated after 48 h and she made an uneventful recovery.

SummaryThe incidence of muscle pains and changes in serum concentrations of potassium, calcium and creatine kinase following suxamethonium were investigated after no pretreatment or pretreatment with intravenous tubocurarine 0.05 mg.kg-'. intravenous chlorpromazine 0.1 mg.kg-'. alphatocopherol (vitamin E ) 600 mg in three divided doses orally, aspirin 600 mg orally or intravenous calcium chloride 5 mg.kg-' in groups of 20 patients each. The incidence of myalgia was reduced significantly by tubocurarine. chlorpromazine and alphatocopherol. However, the increase in creatine kinase was attenuated only in the groups of patients who received tubocurarine and chlorpromazine. The changes in serum potassium and calcium concentrations were within acceptable limits. The intubating conditions were not as good in the patients who received tubocurarine as in the other groups. Effectiveness of chlorpromazine in preventing both the myalgia and the biochemical changes suggests the involvement of phospholipases in the pathogenesis of suxamethonium-induced muscle damage.

SummaryEighty:four j t , unpremedicated patients who presented .for routine surgery and received a standard anaesthetic technique were alloccited randomly to three equal groups. Group I received tubocurarine 0.05 rnglkg before induction of anaesthesia. Group 2 received soluble aspirin 600 mg orally one hour before surgery, while Group 3 received no pretreatment. Aspirin prophylaxis prothrced a signijkant reduction in the incidence of subsequent suxamethonium-induced myalgia and the improvement was similar to that achieved with tubocurarine pretreatment. Pre-operative oral administration of aspirin effectively reduces muscle pain., and avoids many of the complications associated with pretreatment with non-depolarising agents.

We have examined postoperative muscle pain and early increases in serum concentrations of myoglobin after administration of suxamethonium to see if these changes were dependent on the dose of drug. Thirty ASA I and II adult patients undergoing day-case surgery received a standard anaesthetic technique, including one of three doses of suxamethonium: 0.5, 1.5 or 3.0 mg kg-1. The incidence of postoperative myalgia and the severity of fasciculations were greater after suxamethonium 1.5 mg kg-1 than after a dose of 0.5 or 3.0 mg kg-1. Serum concentrations of myoglobin increased in a dose-dependent manner. Intubating conditions were significantly better with suxamethonium 1.5 or 3.0 mg kg-1 than with 0.5 mg kg-1. Changes in serum concentrations of calcium and potassium were small and similar in the three groups. We conclude that a dose of 3.0 mg kg-1 of suxamethonium provided a better combination of intubating conditions and minimal postoperative myalgia than the two lower doses.

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