Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Pre-operative intramuscular ranitidine and cimetidine. Double blind comparative trial, effect on gastric pH and volume.
A controlled trial was carried out on 120 healthy patients presenting for elective surgery. The patients were divided randomly into three groups, which received respectively, 50 mg ranitidine, 100 mg ranitidine, or 300 mg cimetidine intramuscularly at least 45 minutes before operation. Following induction of anaesthesia, a nasogastric tube was passed, the stomach contents aspirated and analysed for volume and pH. ⋯ No side effects attributable to the administration of either drug were observed. It is concluded that intramuscular administration of ranitidine or cimetidine is an effective method of reducing the number of patients at risk of acid aspiration during anaesthesia. However, neither drug eliminates the risk of acid aspiration in all patients, and thus careful anaesthetic technique to protect the airway remains essential.
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Randomized Controlled Trial Comparative Study Clinical Trial
The effect of magnesium trisilicate mixture, metoclopramide and ranitidine on gastric pH, volume and serum gastrin.
Eighty women (40 for elective Caesarean section and 40 for elective gynaecological surgery) were randomly assigned to one of five treatment groups and received pre-operatively either no medication; magnesium trisilicate mixture (BP) 30 ml; metoclopramide 10 mg intramuscularly; ranitidine 150 mg orally on the night prior to, and the morning of, surgery; or metoclopramide 10 mg intramuscularly in combination with oral ranitidine 150 mg (the latter again given on the night prior, and the morning, of surgery). The effect of these medications on intragastric pH, volume and serum gastrin-17 was measured. No patient receiving ranitidine had a pH of less than 4. ⋯ The largest intragastric volumes were seen in the patients who had received magnesium trisilicate mixture, whilst the patients who had received metoclopramide in combination with ranitidine had the smallest intragastric volumes. Magnesium trisilicate mixture and metoclopramide resulted in no change in serum gastrin levels. However, in the subjects who had received ranitidine on the night prior to surgery, the fasting serum gastrin was significantly higher (p less than 0.01) than the values in the remaining subjects, the mean (SEM) values being 60.3 (6.3) pg/ml in those not receiving ranitidine and 111.3 (19.5) pg/ml in those who had been given ranitidine.
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Glycopyrronium 10 micrograms/kg has been compared with atropine 20 micrograms/kg in a mixture with neostigmine 50 micrograms/kg administered for antagonism of residual nondepolarising neuromuscular block in patients over 65 years of age. The initial peak increase in heart rate was less after glycopyrronium, but there were no differences beyond the first two minutes. ⋯ The control of secretions was superior with glycopyrronium. It is suggested that the dosage of anticholinergic agents given with neostigmine could be reduced in elderly patients in comparison to that in younger patients.
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A new, simple, versatile co-axial breathing system combining the features of Mapleson A, D and E type systems is described. The change from an A system to a D/E system is effected by a single switch and without reversal of the gas flow. Fresh gas flows in the order of 70 ml/kg/min are required for both spontaneous ventilation in the Mapleson A mode and controlled ventilation in the Mapleson D mode. The co-axial configuration offers the advantages of a single, lightweight breathing system with easy scavenging of anaesthetic gases, while the ability to switch between the A and D or E configurations offers the economic advantages of low fresh gas flows and the need for a single anaesthetic breathing system for all situations.