European journal of anaesthesiology
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As atelectasis occurs in most patients during general anaesthesia and may be one of the major causes for the development of hypoxaemia and nosocomial pneumonia, its prevention may be considered as an important objective in perioperative management. The major causative mechanisms are the loss of respiratory muscle tone, compression and gas absorption. ⋯ In this review we describe the pathogenesis of atelectasis in the perioperative period and discuss in the light of recent published investigations the suitability of the vital capacity manoeuvre as a tool during general anaesthesia. Reviewing the current literature, a vital capacity manoeuvre during general anaesthesia may only be useful under specific circumstances when mechanical ventilation with a high inspiratory fraction of oxygen is required or during cardiac surgery at the end of cardiopulmonary bypass to reduce the amount of atelectasis and to maintain adequate gas exchange.
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To investigate the clinical application of a mathematical model of pulmonary gas exchange, which ascribes hypoxaemia to shunt and ventilation/perfusion mismatch. Ventilation/perfusion mismatch is quantified by deltaPO2, which is the drop in oxygen pressure from alveoli to lung capillaries. Shunt and deltaPO2 were used to describe changes in oxygenation after coronary artery bypass grafting. ⋯ Ventilation/perfusion mismatch (deltaPO2), rather than shunt, explains the changes in postoperative oxygenation. The model of pulmonary gas exchange may serve as a useful and potentially non-invasive clinical tool for monitoring patients at risk of postoperative hypoxaemia.
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Comparative Study
Postoperative changes in the full-field electroretinogram following sevoflurane anaesthesia.
We tested the hypothesis that disturbances of the visual pathway persist following general anaesthesia, even after normal clinical discharge criteria have been met. ⋯ Postoperative electroretinogram abnormalities are consistently present in patients who have undergone N2O/sevoflurane anaesthesia. These abnormalities persist beyond the time at which standard clinical discharge criteria have been met.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of patient-controlled and operator-controlled conscious sedation for restorative dentistry.
The use of midazolam for conscious sedation is an accepted method of anxiety control in restorative dentistry. A lack of predictability in its effects requires the dose of midazolam to be adjusted to individual patient's requirements. We determined whether patient-controlled sedation was a suitable alternative to operator-controlled sedation in restorative dentistry. ⋯ This study shows that patient-controlled sedation is a suitable alternative to operator-controlled sedation in the management of anxious dental patients.