Canadian journal of anaesthesia = Journal canadien d'anesthésie
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Surgical patients often are receiving antiarrhythmic therapy. Thus, because anaesthetic agents can affect cardiac function and may interact with concurrent antiarrhythmic medications, the anaesthetist should be aware of the electrophysiology associated with dysrhythmias and their management. ⋯ In addition, unexpected untoward reactions and toxicity can result from interactions of anaesthetic agents and these drugs. This review discusses normal cardiac electrophysiology, common dysrhythmias and the electrophysiological effects of the newer oral antiarrhythmic drugs.
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The sensitivity of the masseter to atracurium was measured in ten children aged 3-10 yr undergoing elective surgery, and compared with that of the adductor pollicis. During nitrous oxide-halothane anaesthesia and mechanical ventilation, supramaximal nerve stimulation was applied to the ulnar nerve at the elbow and to the nerve to the masseter, at a point inferior to the zygomatic arch, anterior to the mandibular condyle. Jaw closure was measured by a force displacement transducer system attached to an oral airway and connected to a metal frame fixed to the operating table 10 cm caudad to the chin. ⋯ However, this relationship was not constant in every patient, and in some patients the masseter was much more sensitive than the adductor pollicis. The time from injection of the first dose of atracurium to maximum blockade was 2.5 +/- 0.2 min at the masseter and 3.2 +/- 0.2 min at the adductor pollicis (P less than 0.05). It is concluded that when atracurium is administered to paediatric patients, neuromuscular blockade is usually of the same intensity at each muscle but occurs sooner at the masseter than at the adductor pollicis.(ABSTRACT TRUNCATED AT 250 WORDS)