Canadian Anaesthetists' Society journal
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A new method for the detection and recording of the oculocardiac reflex (OCR) is described and applied to 49 healthy infants and children (six months to nine years old) undergoing strabismus surgery under halothane anaesthesia with spontaneous ventilation. Eighty-one extraocular muscles were studied. Square wave stimuli (abrupt and sustained tractions) were definitely more reflexogenic than slow slope stimuli (very gradual, progressive and gentle tractions). ⋯ Controlled ventilation is recommended. The routine use of intravenous anticholinergic drugs is briefly discussed. Prevention of the OCR, and prophylaxis of cardiac arrhythmias during strabismus surgery, now seem to be placed on a more rational basis.
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Clinical Trial Controlled Clinical Trial
Neuromuscular blockade in infants following intramuscular succinylcholine in two or five per cent concentration.
This study determined the characteristics of the neuromuscular block which followed intramuscular succinylcholine 4 mg . kg-1 in 20 infants during halothane anaesthesia. The infants were divided into two groups of ten; the first received succinylcholine in two percent solution and the second in five per cent solution. The mean maximum depression of the first twitch of the train-of-four (T1) was 89.7 +/- 5.0 per cent in 4.0 +/- 0.6 min, and the mean full recovery of T1 occurred in 15.6 +/- 0.9 min after injection. ⋯ Depolarizing block, with equal depression of all twitches of the train-of-four was observed during the onset of neuromuscular blockade. During recovery, phase II block, as determined by a train-of-four ratio (T4/T1) of 0.5 or less, occurred frequently at T1 recovery of 25-50 per cent, but was not associated with prolonged paralysis. It is concluded that the onset time of 4 min for intramuscular succinylcholine 4 mg . kg-1 may be too long for emergency use in infants, and no improvement is obtained by increasing the concentration of injected succinylcholine from two to five per cent.
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Comparative Study
Catecholamine and cortisol responses to sufentanil-O2 and alfentanil-O2 anaesthesia during coronary artery surgery.
The effects of alfentanil-O2 and sufentanil-O2 anaesthesia on plasma catecholamines and cortisol were investigated in 32 patients undergoing coronary artery bypass grafting operations. After lorazepam-atropine premedication and pancuronium pretreatment, alfentanil was given to 16 patients at a rate of 3 mg.min-1 and sufentanil was given to 16 patients at 300 micrograms.min-1 until the patients were unconscious; at this time they were given succinylcholine and were intubated. After intubation an amount of alfentanil or sufentanil equal to the dose producing unconsciousness was infused over the next 30 min, at which time the operation began. ⋯ During bypass both hormones became increased and remained increased at the end of operation. Plasma cortisol decreased after incision and remained decreased until the end of operation. These data indicate that alfentanil-O2 and sufentanil-O2 anaesthesia produce similar changes in plasma catecholamines and cortisol as does fentanyl-O2 anaesthesia and hormonal effects are, therefore, not an explanation for any advantages the newer narcotics may have over fentanyl.
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A case is presented of a female with respiratory distress who was initially treated as having asthma. Her chest x-ray was normal but tracheal tomograms revealed a tracheal tumour almost completely occluding the tracheal lumen. The impending tracheal occlusion was managed with femoral-femoral cardiopulmonary bypass instituted under local anaesthesia prior to induction of anaesthesia and diagnostic bronchoscopy and airway establishment with tracheal intubation. Other indications for the use of cardiopulmonary bypass prior to the induction of anaesthesia are reviewed.