Anaesthesia and intensive care
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Anaesth Intensive Care · Nov 2011
Case ReportsAcute dapsone overdose: the effects of continuous veno-venous haemofiltration on the elimination of dapsone.
A 15-year-old girl presented after intentional ingestion of dapsone (7.2 g) and small quantities of azathioprine, methotrexate and prednisolone. The resulting methaemoglobinaemia and lactic acidosis persisted despite treatment with methylene blue, multiple-dose activated charcoal and ascorbic acid. ⋯ The rate of elimination of dapsone was over three times higher during, compared to after, continuous veno-venous haemofiltration. Continuous renal replacement therapy successfully reduced toxic dapsone concentrations in this patient with a good outcome.
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Anaesth Intensive Care · Nov 2011
Optimal dose of vancomycin for treating methicillin-resistant Staphylococcus aureus pneumonia in critically ill patients.
A prospective cohort study was performed to determine the optimal dose of vancomycin to maintain a serum trough concentration of at least 15 to 20 mg/l and to assess the efficacy of this target vancomycin concentration in the treatment of methicillin-resistant Staphylococcus aureus pneumonia. Vancomycin pharmacokinetic parameters were estimated using a CAPSIL software program from serum concentrations of 141 patients with pneumonia treated with vancomycin, regardless of methicillin-resistant Staphylococcus aureus status, at a 28-bed medical intensive care unit. ⋯ More than 70% of patients failed to reach the recommended therapeutic serum trough concentrations: a higher dose of vancomycin is necessary to maintain serum trough concentration at 15 to 20 mg/l, particularly in critically ill patients with creatinine clearance above 60 ml/minute and in those on intermittent haemodialysis. Among patients with methicillin-resistant Staphylococcus aureus pneumonia, no significant differences were observed in the treatment success rate, length of intensive care unit stay, and intensive care unit mortality rate between patients with vancomycin trough concentrations of >20 mg/l, 15 to 20 mg/l and <15 mg/l.
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We have previously postulated that it is possible to accidentally insert an epidural needle or catheter into the substance of the dura during attempted epidural block, creating an intradural space. It appears that injection of local anaesthetic into an intradural space leads to an initially inadequate neuraxial block but further doses may produce an extensive life-threatening block. In the laboratory, 54 samples of human thoraco-lumbar dura were obtained from six cadavers and prepared for scanning electron microscopy. ⋯ Electron microscopy revealed the concentric laminae that compose the dura and the presence of artefactual spaces between some of these. It was possible to insert an epidural catheter into the substance of the dura in eight specimens, creating intradural spaces which remained following catheter removal. If this represents the clinical situation, it may help to explain previously reported cases of atypical neuraxial block and their associated radiological findings.
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Anaesth Intensive Care · Nov 2011
Evaluation of a humidified nasal high-flow oxygen system, using oxygraphy, capnography and measurement of upper airway pressures.
In this study, we evaluated the performance of a humidified nasal high-flow system (Optiflow, Fisher and Paykel Healthcare) by measuring delivered FiO, and airway pressures. Oxygraphy, capnography and measurement of airway pressures were performed through a hypopharyngeal catheter in healthy volunteers receiving Optiflow humidified nasal high flow therapy at rest and with exercise. The study was conducted in a non-clinical experimental setting. ⋯ At 50 l/minute the system delivered a mean airway pressure of up to 7.1 cm H20. We believe that the high gas flow rates delivered by this system enable an accurate inspired oxygen fraction to be delivered. The positive mean airway pressure created by the high flow increases the efficacy of this system and may serve as a bridge to formal positive pressure systems.
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Anaesth Intensive Care · Nov 2011
Evaluating sleep characteristics in intensive care unit and non-intensive care unit physicians.
Healthcare workers' cognitive performances and alertness are highly vulnerable to sleep loss and circadian rhythms. The purpose of this study was to investigate the changes in sleep characteristics of intensive care unit (ICU) and non-ICU physicians. Actigraphic sleep parameters, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale and Hamilton Depression Rating Scale were evaluated for ICU and non-ICU physicians on the day before shift-work and on three consecutive days after shift-work. ⋯ Total sleep time, total activity score and sleep efficiency scores prior to shift-work were significantly different from shift-work and the three consecutive-days after shift-work, in both groups. Working in the ICU does not have an impact on objective sleep characteristics of physicians in this study. Large cohort studies are required to determine long-term health concerns of shift-working physicians.