Canadian Anaesthetists' Society journal
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Clinical Trial Controlled Clinical Trial
The effects of cimetidine and ranitidine with and without metoclopramide on gastric volume and pH in morbidly obese patients.
The efficacy of preanaesthetic intravenous cimetidine versus ranitidine with and without metoclopramide for acid aspiration prophylaxis was assessed in 60 morbidly obese patients in a double-blind manner. Group 1 patients received cimetidine 300 mg + saline. Group 2 patients received cimetidine 300 mg + metoclopramide 10 mg. ⋯ Gastric fluid was aspirated for analysis of volume and pH following induction of anaesthesia. All four premedication regimens were equally effective in reducing the gastric volume and acidity and the inclusion of metoclopramide had no additive effect. Although statistically not significant, two patients in the cimetidine groups remained at risk (volume greater than 25 ml and pH less than 2.5) while no patients in the ranitidine groups remained so.
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Patients who present for abdominal aortic surgery often have significant atherosclerotic disease which may involve the coronary arteries. Haemodynamic responses occurring during fentanyl (100 micrograms X kg-1) oxygen anaesthesia for abdominal aortic surgery were studied in 16 patients. Anaesthesia was induced with fentanyl 100 micrograms X kg-1 with no supplemental doses and metocurine-pancuronium mixture (4:1). ⋯ Eleven of the 16 patients required treatment for postoperative hypertension. Five of the 16 patients developed myocardial ischaemia, defined as ST segment depression greater than 0.1 mV, at some time during the operative procedure. Unsupplemented fentanyl anaesthesia (100 micrograms X kg-1) was unable to maintain a hypodynamic circulation in patients having abdominal aortic operations.
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Randomized Controlled Trial Comparative Study Clinical Trial
Left ventricular ejection fraction during anaesthetic induction: comparison of rapid-sequence and elective induction.
A randomized clinical trial was conducted in 14 women, aged 24-60 years, to compare the effects of rapid-sequence induction of anaesthesia and elective induction on heart rate, blood pressure and left ventricular ejection fraction (LVEF). None of the patients suffered from heart or lung diseases, and all were scheduled for hysterectomy. Cuff blood pressure was measured repeatedly by an automatic recording device, and heart rate and LVEF were monitored by a portable nonimaging nuclear probe. ⋯ Similar decreases in LVEF was observed in both groups, from 0.60 to 0.42 in the elective induction group, and from 0.60 to 0.41 in the rapid-sequence induction group. The equal depression of LVEF indicates that laryngoscopy and intubation produce, with both induction regimens, sudden impairment of cardiac function. The more pronounced hypertension and tachycardia observed during rapid-sequence induction suggests a higher myocardial oxygen consumption which may represent a serious additional burden for the poorly perfused heart.
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Comparative Study
Neuromuscular blockade for rapid tracheal intubation in children: comparison of succinylcholine and pancuronium.
To compare the effectiveness of succinylcholine and pancuronium for rapid intubation in children, 49 healthy children ages two to eight years were studied. After induction of anaesthesia with thiopentone and atropine, and administration of droperidol, fentanyl, nitrous oxide, and oxygen, each child received one of the following muscle relaxants: succinylcholine 1.5 mg X kg-1 (n = 12), succinylcholine 1.0 mg X kg-1 (n = 13), pancuronium 0.15 mg X kg-1 (n = 11), or pancuronium 0.10 mg X kg-1 (n = 13). The force of thumb adduction was measured by stimulating the ulnar nerve with repetitive supramaximal single twitches (0.15 Hz). ⋯ The intubating conditions were excellent in 100% of the children who received succinylcholine 1.5 and 1.0 mg X kg-1, and pancuronium 0.15 mg X kg-1, but were excellent in only 69 per cent of those who received pancuronium 0.10 mg X kg-1. We conclude that succinylcholine 1.5 mg X kg-1 produces the most rapid onset of excellent intubating conditions in children. In children in whom succinylcholine is contra-indicated, pancuronium 0.15 mg X kg-1 provides excellent intubating conditions within 80 seconds.