Canadian Anaesthetists' Society journal
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Randomized Controlled Trial Clinical Trial
Cardiovascular effects of non-depolarizing neuromuscular blockers in patients with coronary artery disease.
To compare haemodynamic responses associated with equipotent doses of muscle relaxants and high dose fentanyl (50 micrograms X kg-1), 40 non-hypertensive patients who were receiving beta adrenergic and calcium channel blocker therapy and undergoing coronary bypass surgery were randomized to four study groups receiving the following: (1) atracurium: 0.4 mg X kg-1, (2) pancuronium: 0.12 mg X kg-1, (3) vecuronium: 0.12 mg X kg-1, or (4) pancuronium-metocurine mixture: (0.4 mg + 1.6 mg X ml-1):1 ml/10 kg. Neuromuscular blockers were injected with fetanyl at induction. Haemodynamics were recorded with the patients awake (baseline), at two minutes post-induction, and at two and five minutes after intubation. ⋯ The pancuronium-metocurine mixture caused tachycardia which was less than, though not significantly different than with pancuronium; however, HR returned to baseline by five minutes with the mixture, but remained elevated with pancuronium (3 vs. 18 per cent, p less than 0.05). SVR fell more on induction with atracurium when compared to vecuronium (-18 vs. 1 per cent, p less than 0.05). These changes in HR or SVR were not accompanied by ECG signs of ischaemia.(ABSTRACT TRUNCATED AT 250 WORDS)
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An overall management plan for malignant hyperthermia susceptible (MHS) parturients is presented based on the experience of managing 14 of these patients. A summary of the pertinent features of their deliveries and care plus a case report of one of these parturients is described. Discussion centres around the problems of diagnosis of malignant hyperthermia susceptibility in pregnancy, the differential diagnosis and management of fever and tachycardia in a MHS parturient during labour and the use of dantrolene prophylaxis. ⋯ The importance of being prepared for a potential crisis is stressed with particular emphasis on early diagnosis by monitoring of temperature at two sites, of heart rate and rhythm with a continuous ECG and of end-tidal carbon dioxide, should a general anaesthetic be required. Recommendations are made for appropriate anaesthetic agents for both regional and general anaesthesia. Treatment of a MH crisis is outlined, with emphasis on availability of appropriate resuscitative drugs.
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We present three patients with Treacher Collins or Pierre Robin syndromes who had historical and physical evidence of airway obstruction, difficulty feeding, and sleep disturbances. These preoperative findings correlated with difficult airway management intraoperatively. Based on this experience, we recommend that children with obstructive symptoms have laryngoscopy prior to anaesthetic induction. ⋯ After intubation, anaesthesia is best maintained with oxygen and a potent inhalational agent. Extubation should only be done with the patient fully awake and with emergency airway equipment immediately available. Postoperatively, these patients should be transferred to an intermediate care area or intensive care unit where they can be observed closely since delayed complications of airway obstruction are common in this group of patients.
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Expired carbon dioxide measurements (PeCO2) were used (1) to assess the adequacy of initial alveolar ventilation, and (2) to document intraoperative airway events and metabolic trends. Three hundred and thirty-one children were studied. Thirty-five intraoperative events were diagnosed by continuous PeCO2 monitoring; 20 were potentially life-threatening problems (malignant hyperthermia, circuit disconnection or leak, equipment failure, accidental extubation, endobronchial intubation, or kinked tube); only two of these were also diagnosed clinically. ⋯ Hypocarbia (peak expired PeCO2 less than or equal to 30) was more frequent in intubated cases (11 per cent) than in unintubated cases (three per cent) (p = 0.03). There was a high incidence of hypocarbia in infants less than one year of age (p = 0.02). We conclude: (1) life-threatening airway problems are common during anaesthesia in paediatric patients; (2) quantitative measurement of PeCO2 provides an early warning of potentially catastrophic anaesthetic mishaps; (3) the incidence of events increases with duration of anaesthesia.