Anaesthesia
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The models used to predict outcome after adult general critical care may not be applicable to cardiothoracic critical care. Therefore, we analysed data from the Case Mix Programme to identify variables associated with hospital mortality after admission to cardiothoracic critical care units and to develop a risk-prediction model. We derived predictive models for hospital mortality from variables measured in 17,002 patients within 24 h of admission to five cardiothoracic critical care units. ⋯ We included additional interaction terms between creatinine, lactate, platelet count and cardiac surgery as the admitting diagnosis. We validated this model against 10,238 other admissions, for which the c index (95% CI) was 0.904 (0.89-0.92) and the Brier score was 0.055, while the slope and intercept of the calibration plot were 0.961 and -0.183, respectively. The discrimination and calibration of our model suggest that it might be used to predict hospital mortality after admission to cardiothoracic critical care units.
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The objective was to develop a sodium percarbonate/water/catalyst chemical oxygen generator that did not require compressed gas. Existing devices utilising this reaction have a very short duration of action. ⋯ Having undertaken full-scale experiments using a stainless steel vessel, an optimum combination of reagents was found to be 1 litre water, 0.75 g manganese dioxide catalyst, 60 g sodium percarbonate granules and 800 g of custom pressed 7.21 (0.28) g sodium percarbonate tablets. This combination of granules and slower dissolution tablets produced a rapid initial oxygen flow to 'purge' an attached low-flow breathing system allowing immediate use, followed by a constant flow meeting metabolic requirements for a minimum of 1 h duration.