Anaesthesia
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Observational Study
The effect of coughing at extubation on oxygenation in the post-anaesthesia care unit.
We prospectively studied 84 patients to investigate whether there is a relationship between coughing during emergence and tracheal extubation, and impaired oxygenation in the post-anaesthesia care unit. Our primary outcome measure was a change in the alveolar-arterial oxygen partial pressure gradient ((A-a)DO2 ) between time A (during general anaesthesia) and time B (1 h after extubation). ⋯ An overall linear regression model was not predictive for the observed change (adjusted R(2) = 0.01, p = 0.31) and nor were any of the individual predictors studied, including subjective cough score (p = 0.33), number of coughs (p = 0.95) and duration of coughing (p = 0.39). Despite the abnormal cough that occurs while tracheally intubated, we have been unable to demonstrate that coughing at extubation is associated with impaired oxygenation in the immediate postoperative period.
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Randomized Controlled Trial
The effects of Patent Blue dye on peripheral and cerebral oxyhaemoglobin saturations.
We measured the effect of Patent Blue dye on oxyhaemoglobin saturations after injection into breast tissue: 40 women had anaesthesia for breast surgery maintained with sevoflurane or propofol (20 randomly allocated to each). Saturations were recorded with a digital pulse oximeter, in arterial blood samples and with a cerebral tissue oximeter before dye injection and 10, 20, 30, 40, 50, 60, 75, 90, 105 and 120 min afterwards. ⋯ The falsely reduced oximeter readings persisted for at least 2 h. The mean (SD) intra-operative digital pulse oxyhaemoglobin readings were lower with sevoflurane than propofol, 97.8 (1.2) % and 98.8 (1.0) %, respectively, p < 0.0001.
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Multicenter Study
Sedation practice in six acute hospitals - a snapshot survey.
The number of UK hospital patients receiving procedural sedation remains unknown. Our trainee research network recorded all procedural sedation given over a 48-h period at six acute hospitals in the South West of England. Three hundred and sixty patients aged between 1 and 96 years old were sedated. ⋯ The most frequent sedative combination was midazolam and fentanyl, with median (IQR [range]) doses of 2 (2-3 [1-10]) mg and 50 (50-100 [10-300]) μg used, respectively. We tested a methodology that could be used in a UK-wide denominator survey to describe sedation practice across the NHS. A national audit collecting serious adverse outcomes of sedation (severe harm or death) could then identify hotspots of sedation risk (clinical areas, patient groups, procedures and sedation techniques) where consistent application of current and improved standards might reduce harm.
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Preconditioning has been shown to reduce myocardial damage caused by ischaemia-reperfusion injury peri-operatively. Volatile anaesthetic agents have the potential to provide myocardial protection by anaesthetic preconditioning and, in addition, they also mediate renal and cerebral protection. A number of proof-of-concept trials have confirmed that the experimental evidence can be translated into clinical practice with regard to postoperative markers of myocardial injury; however, this effect has not been ubiquitous. ⋯ Data from recent meta-analyses in cardiac anaesthesia are also not conclusive regarding intra-operative volatile anaesthesia. These inconclusive clinical results have led to great variability currently in the type of anaesthetic agent used during cardiac surgery. This review summarises experimentally proposed mechanisms of anaesthetic preconditioning, and assesses randomised controlled clinical trials in cardiac anaesthesia that have been aimed at translating experimental results into the clinical setting.
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Three quarters of all critical incidents and a third of all peri-operative cardiac arrests in paediatric anaesthesia are caused by adverse respiratory events. We screened for risk factors from children's and their families' histories, and assessed the usefulness of common markers of allergic sensitisation of the airway as surrogates for airway inflammation and increased risk for adverse respiratory events. One hundred children aged up to 16 years with two or more risk factors undergoing elective surgery were included in the study. ⋯ There was a significant difference (p = 0.001) between the presence of adverse respiratory events in patients with more than four (p = 0.006), compared with less than four (p = 0.001), risk factors. We conclude that while risk factors taken from the child's (or family) history proved good predictors of adverse respiratory events, immunological markers of allergic sensitisation demonstrated low predictive values. Pre-operative identification of children at high risk for an adverse respiratory event should rely on clinical, rather than immunological, assessment.