British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Assessment of intubating conditions in children after induction with propofol and varying doses of alfentanil.
We have assessed tracheal intubating conditions in 60 ASA I or II children, aged 3-12 yr, after induction of anaesthesia with alfentanil 5, 10 or 15 micrograms kg-1, followed by an induction dose of propofol. Neuromuscular blocking agents were not given. ⋯ Intubation was successful in 70%, 95% and 95% of patients after alfentanil 5, 10 or 15 micrograms kg-1, respectively, and conditions were considered to be excellent in 20%, 70% and 80% of patients, respectively. Side effects included pain on injection of propofol (27%), excitatory movements (5%) and bradycardia (1.7%).
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Comparative Study
Neuromuscular and haemodynamic effects of mivacurium in elderly and young adult patients.
We have studied the neuromuscular effects of mivacurium and changes in heart rate and arterial pressure in 40 elderly (aged 70 yr) and 20 young adult (aged 18-40 yr) patients anaesthetized with thiopentone, fentanyl, nitrous oxide in oxygen and halothane. Neuromuscular block was monitored by train-of-four (TOF) stimulation of the ulnar nerve and recording of the force of contraction of the adductor pollicis muscle using a force displacement transducer and a neuromuscular function analyser (Myograph 2000, Biometer Ltd). Twenty elderly and 10 young adults received single doses of mivacurium 0.15 mg kg-1 and spontaneous recovery was recorded. ⋯ Onset of maximum block occurred at a mean time of 122 (SD 32) and 125 (49) s in elderly and young adults, respectively. Recovery of T1 to 25% occurred in 22.0 (5.7) and 17.2 (4.4) min, and T1 to 90% in 32.8 (6.9) and 24.4 (5.8) min in elderly and adult subjects, respectively. Recovery of the TOF ratio to 0.7 occurred in 32.8 (7.1) and 26.0 (15.0) min in the elderly and young subjects, respectively (all P < 0.05 between young and elderly).(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Effects of oral nizatidine on preoperative gastric fluid pH and volume in children.
We have studied the effect of oral nizatidine 6 mg kg-1 in total on preoperative gastric fluid pH and volume in children. One hundred and four healthy children, aged 4-11 yr, were allocated randomly to four groups (n = 26): placebo administered at 21:00 and 06:30 the night before and on the day of surgery, respectively (placebo-placebo: control); nizatidine 6 mg kg-1 at 21:00 and placebo at 06:30 (nizatidine-placebo); placebo at 21:00 and nizatidine 6 mg kg-1 at 06:30 (placebo-nizatidine); and nizatidine 3 mg kg-1 at 21:00 and 06:30 (nizatidine-nizatidine). Each child ingested a large volume of apple juice 3 h before estimated induction of anaesthesia. ⋯ Mean pH in the placebo-nizatidine and nizatidine-nizatidine groups was significantly higher than that in the placebo-placebo group (5.7 (SEM 0.3), 6.0 (0.3) vs 1.8 (0.2), respectively) (P < 0.05). Mean pH in the nizatidine-placebo group was similar to that in the control group (2.3 (0.3) vs 1.8 (0.2)). The number of children with pH < 2.5 and volume > 0.4 ml kg-1 in the nizatidine-nizatidine (0%) and placebo-nizatidine (4%) groups was reduced compared with the control (46%) or nizatidine-placebo (38%) group.(ABSTRACT TRUNCATED AT 250 WORDS)
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We have studied the effects of nitrous oxide on cerebral blood flow (CBF), cerebral blood flow velocity (CBFV) and intracranial pressure (ICP) during isoflurane-induced hypotension in 10 pigs. CBF was measured using laser Doppler flowmetry, CBFV in the right middle cerebral artery was calculated using Doppler ultrasound and ICP was measured using an extradural ICP monitor. Each animal was studied under four conditions, examined sequentially: (i) mean intra-arterial pressure (MAP) 85 mm Hg, maintained with isoflurane, (ii) MAP 50-55 mm Hg, induced by isoflurane only, (iii) MAP 85 mm Hg, maintained with isoflurane and 50% nitrous oxide, and (iv) MAP 50-55 mm Hg, induced by isoflurane and 50% nitrous oxide. ⋯ Comparing isoflurane-induced hypotension ((ii) vs (iv)), there was no statistical difference in either CBF or CBFV on addition of 50% nitrous oxide. The correlation between changes in CBF and CBFV was not significant. We conclude that the use of nitrous oxide during isoflurane-induced hypotension has no significant effect on CBF, CBFV or ICP compared with the use of isoflurane alone.