Anaesthesia and intensive care
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Anaesth Intensive Care · Sep 2008
Clinical TrialNon-invasive cardiac output measurement using a fast mixing box to measure carbon dioxide elimination.
This study investigated the accuracy of a new technique for measuring cardiac output using the derivative Fick principle based on the ratio of change in the partial pressures of end-tidal and mixed expired carbon dioxide produced by short periods of partial rebreathing. A prospective clinical study involving 24 patients following cardiopulmonary bypass for coronary artery bypass grafting or valvular surgery was undertaken in the intensive care unit of a university-affiliated hospital. Haemodynamic measurements were performed after admission to the intensive care unit. ⋯ Cardiac output measurement using the new technique demonstrated a significant but consistent underestimate, with a bias of -0.60 +/- 0.87 l/min. This new adaptation of the partial rebreathing technique is reliable in measuring cardiac output in postoperative patients. Reasons for the consistent discrepancy between thermodilution and partial rebreathing techniques are discussed.
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Dreaming is reported by one in five patients who are interviewed on emergence from general anaesthesia, but the incidence, predictors and consequences of dreaming during procedural sedation are not known. In this prospective observational study, 200 patients presenting for elective colonoscopy under intravenous sedation were interviewed on emergence to determine the incidences of dreaming and recall. Sedation technique was left to the discretion of the anaesthetist. ⋯ Frank recall of the procedure was reported by 4% of the patients, which was consistent with propofol doses commensurate with light general anaesthesia. The only significant predictor of recall was lower propofol dose. Satisfaction with care was generally high, however dreamers were more satisfied with their care than non-dreamers.
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Anaesth Intensive Care · Sep 2008
Randomized Controlled TrialView of the larynx obtained using the Miller blade and paraglossal approach, compared to that with the Macintosh blade.
The purpose of this study was to determine if laryngoscopy using a Miller blade with a paraglossal approach would yield an improved view of the larynx compared to that obtained with a Macintosh blade using the standard approach. One-hundred and sixty-one patients, scheduled for elective surgery requiring tracheal intubation, voluntarily participated in this study. Patients were randomly assigned to one of the two groups (Miller vs. ⋯ A grade 1 Cormack and Lehane view of the larynx was obtained in 96.5% of cases in the Miller group compared with 85% in the Macintosh group (P = 0.02). Direct laryngoscopy using the Miller blade and paraglossal approach, afforded a much-improved view of the larynx in the majority of cases. For this reason trainees should learn laryngoscopy using both blades.
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Anaesth Intensive Care · Sep 2008
Case ReportsAbdominal compartment syndrome complicating paediatric extracorporeal life support: diagnostic and therapeutic challenges.
We report three paediatric cases, and summarise the reported experience in two others, with cardiorespiratory failure requiring extracorporeal life support for which supportive pump flows could not be maintained due to abdominal compartment syndrome. In two of our patients, the mechanism of abdominal compartment syndrome was massive intra-abdominal fluid extravasation secondary to sepsis, while in the third, the mechanism was post-traumatic intra-abdominal haemorrhage. ⋯ Once correctable causes of inadequate venous cannula drainage have been excluded, abdominal compartment syndrome should be considered in any patient on extracorporeal life support with a taut abdomen and reduced venous return. If abdominal compartment syndrome can be proven or is strongly suspected, there may be a role for selective decompressive laparotomy.
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Anaesth Intensive Care · Sep 2008
Evaluation of an Oxford Miniature Vaporizer placed in-circuit during the maintenance phase of low-flow anaesthesia.
The aim of the study was to assess Oxford Miniature Vaporizer output when mounted in-circuit during the maintenance phase of anaesthesia, using isoflurane, controlled ventilation and a fresh gas flow rate less than 1 l/min. Twenty patients of ASA Physical Status I and II were recruited from routine general surgical lists. All patients were paralysed and ventilated. ⋯ At a dial setting of 0.5, the Oxford Miniature Vaporizer produced a steady end-tidal isoflurane of 0.63% (95% confidence interval 0.60 to 0.66). However, when the dial was turned to 1.0 the output was almost always excessive and had to be reduced. These findings indicate that a stable, predictable and clinically useful output can be achieved when the Oxford Miniature Vaporizer is positioned in-circuit using low-flow and controlled ventilation.