Articles: anesthetics.
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Halothane-nitrous oxide-oxygen (GOF), nitrous oxide-oxygen with diallyl-nor-toxiferine (Jackson-Rees method), or nitrous oxide-oxygen with droperidol-pentazocine (modified NLA) were administered in 190 instances of repair of cleft lips and cleft palates. Epinephrine, 1:30,000, 1:100,000, or 1:300,000, was injected as the vasoconstrictor around the operative field. Epinephrine concentration of 1:100,000 provided sufficient hemostasis, whereas 1:300,000 was insufficient. ⋯ Propranolol was given in only one instance. All others returned to normal rhythm with hyperventilation with pure oxygen. The use of 1:100,000 solution of epinephrine as an adjunct with modified NLA is the most satisfactory and safe method for cleft palate operations, and 1:30,000 with the Jackson-Rees is the better method for cleft lip repairs.
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The interactions of four anaesthetic drugs (ketamine, propanidid, Althesin and methohexitone) with two neuromuscular blocking agents (suxamethonium and pancuronium) have been investigated. On the isolated rat phrenic nerve-diaphragm preparation, all the anaesthetic drugs examined potentiated suxamethonium more than they potentiated pancuronium. ⋯ With the exception of Althesin, all the anaesthetics decreased the sensitivity of the frog rectus preparation to acetylcholine. The possible sites and mechanisms of these interactions are discussed.
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The effects of sodium thiopentone 19-757 mumol/litre, sodium pentobarbitone 25-806 mumol/litre, propanidid 74-1186 mumol/litre, Althesin 55-220 mumol/litre, diazepam 17.6-140 mumol/litre and ketamine 1.8-116.8 mumol/litre on the time-course of miniature end-plate currents of the excised mouse diaphragm were investigated. The currents were detected by means of extracellular electrodes and recorded with a transient recorder. ⋯ This reduction in the duration of end-plate currents reduced the amplitude of postsynaptic potentials. A similar effect at central synapses may account for a failure of synaptic transmission caused by anaesthetic drugs and it is suggested that a reduction in the lifetime of open postsynaptic ionic channels is a common action of anaesthetic drugs.
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Operating-room personnel exposed over a long period to trace concentrations of anesthetic gases may acquire both organic disturbances and impairment of cerebral function, though this has not been proven. However, the dangers of miscalculations due to disturbances of cerebral function and the fact that all working personnel should be breathing unpolluted air are sufficient indications to make scavenging of anesthetic gases mandatory. Scavenging has been carried out in many hospitals. At Vancouver General Hospital venting of the gases has decreased the nitrous oxide pollution to what is considered an acceptable level.