Canadian Anaesthetists' Society journal
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In 150 Sprague-Dawley rats, morphine and fentanyl dose-effect curves were determined for the following three end points--prevention of purposeful movement response to a noxious stimulus (PM), loss of righting reflex (RR), and prevention of heart rate increase to a noxious stimulus (HR). Accordingly, for each agent, three series of experiments were performed with intravenous administration of the following doses: morphine--3-10 mg X kg-1 for PM, 3-10 mg X kg-1 for HR, 35-55 mg X kg-1 for RR; fentanyl - 5-15 micrograms X kg-1 for PM, 18-30 micrograms X kg-1 for RR, 200-400 micrograms X kg-1 for HR. ⋯ The ratios of RR ED50 to PM ED50 were 7.8 for morphine vs 2.4 for fentanyl (p less than 0.001), the ratios of HR ED50 to PM ED50 were 1 and 33, respectively (p less than 0.001). These results suggest that blockade of movement response to noxious stimulation (which is usually regarded as an index for analgesic action of opioids) and blockade of heart rate increase to noxious stimulation (which is one of the goals of anaesthesia) is not necessarily induced by intravenous narcotic anaesthetics through the same mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)
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Comparative Study
Comparison of oral pentazocine, oral diazepam and intramuscular pentazocine for paediatric premedication.
Oral pentazocine-atropine, oral diazepam-atropine and IM pentazocine-atropine were compared as preoperative medication in children. Observations in 300 children ages 1-14 years included the emotional state at time of induction of anaesthesia, smoothness of induction, dryness of oral mucosa and tongue, incidence of vomiting, and emotional state and length of stay in the recovery room. The incidence of a calm state at the time of induction and smoothness of induction of anaesthesia was the same following oral and IM premedication. ⋯ However, children in age groups 1-4 and 5-9 years who received diazepam-atropine were more restless in the recovery room than those who received oral or IM pentazocine-atropine. More children in groups 1-4 and 5-9 years who received IM pentazocine-atropine stayed longer in the recovery room. We conclude that oral diazepam-atropine and oral pentazocine-atropine are comparable as to preoperative medication IM pentazocine-atropine and that they can be given as an alternate to intramuscular injection.
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Biography Historical Article
Canadian Anaesthetists' Society Medal. Dr. Richard G.B. Gilbert.
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Anticholinesterases were administered in an attempt to antagonize prolonged neuromuscular blockade following the administration of succinylcholine in a patient later found to be homozygous for atypical plasma cholinesterase. Edrophonium 10 mg, given 74 min after succinylcholine, when train-of-four stimulation was characteristic of phase II block, produced partial antagonism which was not sustained. ⋯ Spontaneous respiration recommenced 200 min after succinylcholine administration. It is concluded that anticholinesterases are only partially effective in restoring neuromuscular function in succinylcholine apnoea despite muscle twitch activity typical of phase II block.