Canadian journal of anaesthesia = Journal canadien d'anesthésie
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Comparative Study
Neuromuscular and cardiovascular effects of pipecuronium.
Pipecuronium bromide (Arduan) is a bisquaternary, steroid-type neuromuscular blocking agent in clinical use in Eastern Europe. Before its introduction into clinical practice in the USA, in the first phase of this study the neuromuscular potency of pipecuronium was determined under "balanced" and enflurance anaesthesia by the cumulative log dose-response method in 30 patients each. In the second phase the intubation and onset times, clinical duration of the first and repeated doses, spontaneous recovery index, reversibility of its residual neuromuscular effect by an anticholinesterase and its effect on heart rate and blood pressure was compared with the same variables observed in patients, anaesthetized with identical techniques but who had received vecuronium or pancuronium. ⋯ Following the administration of 2 x ED95 doses there were no clinically significant differences in the intubation or onset times of pipecuronium, vecuronium and pancuronium. Under balanced anaesthesia the clinical duration of 2 x ED95 dose of pipecuronium (110.5 +/- 0.3 min) or pancuronium (115.8 +/- 8.1 min) were similar and about three times longer than that of vecuronium (36.3 +/- 2.1 min). The recovery indices of pipecuronium (44.5 +/- 8.2 min) and pancuronium (41.3 +/- 4.2 min) were also similar and about three times longer than that of vecuronium (14.3 +/- 1.4 min).(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
Clear fluids three hours before surgery do not affect the gastric fluid contents of children.
This prospective, randomized, single-blind study of 121 healthy children aged 2 to 12 yr investigated the effect of clear fluids on gastric contents. Gastric fluid volume and pH were measured immediately following the induction of general anaesthesia and were not significantly affected by the ingestion of unlimited clear fluids up to three hours preoperatively. ⋯ Gastric fluid volume (ml.kg-1) increased in both the control and study groups as age increased, P less than 0.005. It is concluded that drinking clear fluid up to three hours before scheduled surgery does not have a measurable effect on gastric volume and pH of healthy children of ages 2 to 12 yr.
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In a retrospective one-year study, we documented respiratory failure or prolonged neuromuscular blockade in eight of 65 patients with chronic renal failure who had received either vecuronium (four of 29 patients) or atracurium (four of 36 patients) during anaesthesia for kidney transplantation. We reviewed the charts of the patients and recorded all aspects of medication and anaesthesia to try to determine whether there might be a single factor associated with this high incidence (12 per cent) of respiratory failure. Anaesthesia for all patients was induced with thiopentone, isoflurane, and N2O/O2. ⋯ Neuromuscular blockade was reversed with edrophonium (0.75-1 mg.kg-1) or neostigmine (0.06-0.08 mg.kg-1). The eight patients with prolonged neuromuscular blockade received ventilatory support for one to three hours after operation. Respiratory failure was significantly more frequent in patients who received cyclosporine (P less than 0.05).
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Comparative Study
Occurrence of gastroesophageal reflux on induction of anaesthesia does not correlate with the volume of gastric contents.
In an attempt to explain the discrepancy between the high number of patients said to be at risk of aspiration pneumonitis and the low reported incidence of this anaesthetic complication, 100 ASA physical status I-II elective surgical patients were studied. The volume of fluid present in the stomach at the time of induction of anaesthesia was correlated with gastroesophageal reflux (GER) detected by visual inspection of the pharynx and by continuous measurement of upper oesophageal pH. Mean gastric volume was 30 +/- 28 ml (range 0-210 ml). ⋯ No GER was detected during induction of anaesthesia in our sample of 100 patients. Furthermore, patient age, duration of preoperative fasting, body mass index, cigarette smoking, alcohol consumption, preoperative anxiety, and a history of preoperative GER were not correlated with significant modifications of gastric volume or pH. We conclude that the low incidence of aspiration pneumonitis in elective surgical patients may be explained in part by the very low risk of GER, despite gastric fluid volumes of more than 0.4 ml.kg-1 in a high proportion of this patient population.
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The changes in the arterial to end-tidal carbon dioxide gradient. P(a-ET)CO2, were studied in postoperative cardiac surgery patients from the time of admission to the intensive care unit, during changing cardiorespiratory support, up to the time of tracheal extubation. Individual factors evaluated for their effects on P(a-ET)CO2 included rate of mechanical ventilation, infusion of vasoactive agents (nitroglycerin, nitroprusside, dopamine, dobutamine, and metariminol), and associated changes in haemodynamic pathophysiology (cardiac index, pulmonary artery pressure, pulmonary vascular resistance index, systemic vascular resistance index, and pulmonary capillary wedge pressure). ⋯ For many of the individual patients, however, the relationship between PaCO2 and ETCO2 did not maintain a significant correlation throughout the study period. In the postoperative cardiac surgery patient population P(a-ET)CO2 follows a normal distribution and PaCO2 and ETCO2 maintain a statistically significant correlation. However, when evaluating individual patients, this relationship has wide variability.