Canadian journal of anaesthesia = Journal canadien d'anesthésie
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Case Reports
Anaesthesia for a patient with central alveolar hypoventilation syndrome (Ondine's Curse).
The perioperative anaesthetic management of an adult patient with central alveolar hypoventilation syndrome (CAHS), Ondine's Curse, is described for anterior resection of a carcinoma of the bowel. This rare syndrome results in alveolar hypoventilation, hypercarbia, hypoxaemia with secondary polycythaemia, pulmonary artery hypertension, and cor pulmonale. ⋯ However, postoperative mechanical ventilation was required until recovery of the respiratory drive, which was ablated by anaesthetic drugs, epidural morphine and high inspired oxygen concentrations. The pathophysiology and treatment of this syndrome are reviewed.
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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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Randomized Controlled Trial Clinical Trial
Esmolol bolus and infusion attenuates increases in blood pressure and heart rate during electro-convulsive therapy.
To determine whether a standardized dose of esmolol can effectively attenuate the cardiovascular response to electroconvulsive therapy (ECT), 17 ASA physical status I-II patients were studied in a randomized within-patient, crossover design. Each patient received "no esmolol" during one ECT and three to five days later crossed over to the alternative treatment receiving an esmolol 80 mg bolus followed by 24 mg · min-1 infusion two minutes prior to induction of anaesthesia and continued for five minutes after induction. Esmolol blunted the maximum increases in heart rate (HR) by 26 per cent, mean arterial pressure (MAP) by 14 per cent, and rate pressure product by 37 per cent with significant differences (P < 0.05) noted at one, two, three and four minutes after ECT (minutes five, six, seven, and eight of the esmolol infusion). There was no significant difference in seizure duration between the two groups and no adverse reactions occurred.
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Comparative Study
A clinical comparison of indices of pulmonary gas exchange with changes in the inspired oxygen concentration.
Several indices have been introduced as convenient alternatives to calculation of the physiological shunt fraction (Qs/QT) for the assessment of pulmonary gas exchange. These include: the arterial-alveolar oxygen tension ratio (a/APO2), the arterial oxygen tension-inspired oxygen concentration ratio (PaO2/FIO2), the respiratory index (RI), [A-a)DO2/PaO2) and the alveolar-arterial oxygen tension difference [A-a)Do2). These indices are in use clinically despite the fact that they may not accurately predict gas exchange in situations where FIO2, Qs/QT or arterial-venous oxygen content is changing. ⋯ As FIO2 was increased incrementally from 0.30 to 1.00, 42 to 55 per cent of the measured changes in these indices were opposite in direction to the corresponding changes in the physiological shunt. The maximum magnitudes of the opposite changes were substantial; 24 and 22 per cent for the a/APO2 and PaO2/FIO2 ratio respectively, 67 per cent for the RI and 101 per cent for the (A-a)DO2. We conclude that the use of any of these indices for clinical assessment of a patient's gas exchange defect when FIO2 is varying can be substantially misleading.
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Anaesthetists are responsible for the management of the airway in patients with unstable cervical spines. Unfortunately, the anaesthetic literature does not contain a recent, critical analysis of the current medical literature to aid anaesthetists attending such patients. This review is intended to serve such a purpose. ⋯ Relevant findings included the high prevalence of cervical spinal instability in such disorders such as Trisomy 21 and rheumatoid arthritis and the relatively low incidence after trauma. There are deficiencies in the minimalist approaches to assessing the cervical spine, such as a simple cross table lateral radiograph after trauma, as they are neither sensitive nor specific. Finally, recognizing the potential for instability and intubating with care, while avoiding spinal movement, appears to be more important than any particular mode of intubation in preserving neurological function.