Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada, Ontario Ministry of Health and Long-Term Care, Ontario Ministry of Research, Innovation and Science, UK National Institute of Academic Anaesthesia, UK Clinical Research Collaboration, Australian and New Zealand College of Anaesthetists, and Monash University.

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Background: The Duke Activity Status Index (DASI) questionnaire might help incorporate self-reported functional capacity into preoperative risk assessment. Nonetheless, prognostically important thresholds in DASI scores remain unclear. We conducted a nested cohort analysis of the Measurement of Exercise Tolerance before Surgery (METS) study to characterise the association of preoperative DASI scores with postoperative death or complications. Methods: The analysis included 1546 participants (!40 yr of age) at an elevated cardiac risk who had inpatient noncardiac surgery. The primary outcome was 30-day death or myocardial injury. The secondary outcomes were 30-day death or myocardial infarction, in-hospital moderate-to-severe complications, and 1 yr death or new disability. Multivariable logistic regression modelling was used to characterise the adjusted association of preoperative DASI scores with outcomes. Results: The DASI score had non-linear associations with outcomes. Self-reported functional capacity better than a DASI score of 34 was associated with reduced odds of 30-day death or myocardial injury (odds ratio: 0.97 per 1 point increase above 34; 95% confidence interval [CI]: 0.96e0.99) and 1 yr death or new disability (odds ratio: 0.96 per 1 point increase above 34; 95% CI: 0.92e0.99). Self-reported functional capacity worse than a DASI score of 34 was associated with increased odds of 30-day death or myocardial infarction (odds ratio: 1.05 per 1 point decrease below 34; 95% CI: 1.00e1.09), and moderate-to-severe complications (odds ratio: 1.03 per 1 point decrease below 34; 95% CI: 1.01e1.05). Conclusions: A DASI score of 34 represents a threshold for identifying patients at risk for myocardial injury, myocardial infarction, moderate-to-severe complications, and new disability.

Background: The 6-min walk test (6MWT) is a common means of functional assessment. Its relationship to disability-free survival (DFS) is uncertain. Methods: This sub-study of the Measurement of Exercise Tolerance for Surgery study had co-primary outcome measures: correlation of the preoperative 6MWT distance with 30 day quality of recovery (15-item quality of recovery) and 12 month WHO Disability Assessment Schedule scores. The prognostic utility of the 6MWT and other risk assessment tools for 12 month DFS was assessed with logistic regression and receiver-operating-characteristic-curve analysis. Results: Of 574 patients recruited, 567 (99%) completed the 6MWT. Twelve months after surgery, 16 (2.9%) patients had died and 444 (77%) had DFS. The 6MWT correlated weakly with 30 day 15-item quality of recovery (r¼0.14; P¼0.001) and 12 month WHO Disability Assessment Schedule (r¼e0.23; P<0.0005) scores. When the cohort was split into 6MWT distance tertiles, the adjusted odds ratio of low vs high tertiles for DFS was 3.13 [95% confidence interval (CI): 1.54e6.35]. The only independent variable predictive of DFS was the Duke Activity Status Index (DASI) score (adjusted odds ratio: 1.06; P<0.0005). The area under the receiver-operating-characteristic curve for DFS was 0.63 (95% CI: 0.57e0.70) for the 6MWT, 0.60 (95% CI: 0.53e0.67) for cardiopulmonary-exercise-testing-derived peak oxygen consumption, and 0.70 (95% CI: 0.64e0.76) for the DASI score. Conclusions: Of the risk assessment tools analysed, the DASI was the most predictive of DFS. The 6MWT was safe and comparable with cardiopulmonary exercise testing for all predictive assessments. Future research should aim to determine the optimal 6MWT distance thresholds for risk prediction.

done from the top downwards. Although obvious air bubbles were eliminated, small bubbles in the interior of the dialyser could not be seen. Thus it seems probable that more gas (and hence conceivably residual ethylene oxide) remained within the dialyser with this technique.We immediately rectified our technique, and no new patients developed the syndrome subsequently. None the less, three patients continued to have symptoms whenever they used a new disposable dialyser. ConclusionAlthough we have no absolute proof, we suggest that the following sequence of events may have occurred. Incorrect priming of the dialysers resulted in small amounts of ethylene oxide or some other easily removed substance remaining in small gas bubbles in the dialyser. This gradually sensitised some patients, who subsequently reacted to trace amounts in blood returning from incorrectly primed dialysers but were not affected by dialysers sterilised with formalin. Three patients became so sensitive that they continued to react to the even smaller amounts of ethylene oxide inevitably diffusing out of a dialyser despite proper preparation. An allergic reaction to ethylene oxide bound to albumin has been described previously.7This explanation is not, however, entirely satisfactory. We do not understand why these attacks appeared in an epidemic fashion in 1981, when there had been no obvious change in the technique of priming dialysers over the previous five years. The reactions were not attributable to faults in the manufacture or sterilisation of the dialysers since the products of four different firms were involved simultaneously.We are grateful to Extracorporeal Ltd for the time, trouble, and expense expended by them in attempts to solve our problem. We continue to use their flat plate dialysers with confidence.ADDENDUM-Since we submitted this paper a further patient who had not previously reacted to dialysis developed sneezing, wheezing, watery eyes, and urticaria within a minute of connection to a disposable flat plate dialyser. The dialyser had been properly primed in hospital. This further case strengthens our belief that incorrect priming of dialysers was not the sole cause of this syndrome. Haemophilia and the kidney: assessment after 11-year follow-up M SMALL, P E ROSE, N McMILLAN, J J F BELCH, E B ROLFE, C D FORBES, J STUART Abstract Radiological and biochemical investigations of renal function were performed in 57 patients with haemophilia, 27 of whom had been previously investigated in 1969. Although one-third of patients had a renal radiographic abnormality, only two had abnormalities persisting since 1969 and attributable to renal bleeding. Isotope renography was a sensitive indicator of renal abnormality whereas a history of haematuria was a poor discriminator for patients with abnormal intravenous urograms or impaired creatinine clearance. Haematuria was not associated with progressive loss of renal function and its natural history in haemophilia is probably benign. References