Canadian journal of anaesthesia = Journal canadien d'anesthésie
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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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Au cours de 18 cœlioscopies chez des jeunes femmes A. S. A. status physique 1, les conséquences hémodynamiques du pneumopéritoine et de la position de Trendelenburg ont été évaluées par la méthode non invasive de bioimpédance électrique thoracique. ⋯ Elevated intra-abdominal pressure was also associated with a significant increase in mean arterial pressure (from 68 to 88 mmHg) and systemic vascular resistance index (from 1620 to 2491 dyn · s · cm-5· m-2). However, values were not restored after peritoneal exsufflation: systemic vascular resistance index values remained 30 per cent higher than that before insufflation. Decreased venous return may account for the significant decrease in cardiac output but mechanical compression does not explain the persistent elevation of systemic vascular resistance.
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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.
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Since 1847 anaesthesia in Canada has evolved through six phases. In the first (1847-1898), it was a craft without an academic and professional base. The second (1899-1919) was marked by the first academic appointments and by Canadians' wartime experiences of anaesthesia. ⋯ The fifth phase (1944-1971) was one of resolution of problems affecting the status of anaesthesia: the first autonomous department of anaesthesia in a Canadian university was founded (at McGill in 1945), the Royal College Fellowship was approved for anaesthesia (in 1951), the Canadian Anaesthetists' Society Journal was launched (in 1954) and a single standard for certification of specialists was finally established (in 1971). In the sixth (1972-1989), the main elements were the assumption of responsibility for residency training by the universities and by the renaming of the journal as the Canadian Journal of Anaesthesia. Through these years of increasing professionalism, it has, however, been the accomplishments of individual Canadian physicians, facing many challenges, that have made the specialty in Canada recognizably Canadian.
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Letter Case Reports
A simple solution to blood clot obstruction of epidural catheter during labour.