Background Retrospective studies suggest that plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiac troponin T are often elevated in patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) and are associated with increased mortality. These cardiac biomarkers were investigated in an unselected cohort of patients admitted to hospital with exacerbations of COPD. Methods Consecutive patients with physician-diagnosed COPD exacerbation but without clinical evidence of acute cardiac disease admitted to a public hospital over a 1 year period were studied prospectively. NT-proBNP and troponin T were measured on admission. The primary end point was all-cause mortality at 30 days. Results Elevated NT-proBNP (>220 pmol/l) was present in 65/244 patients (27.5%) and significantly predicted 30-day mortality (OR 9.0, 95% CI 3.1 to 26.2, p<0.001). Elevated troponin T (>0.03 mg/l) was found in 40/241 patients (16.6%) and also predicted 30-day mortality (OR 6.3, 95% CI 2.4 to 16.5, p<0.001). These associations persisted after adjusting for other clinical and laboratory predictors of mortality (arterial CO 2 pressure (PaCO 2 ), body mass index and CURB65 score). NT-proBNP and troponin T levels appeared to have additive associations with mortality: 30-day mortality among patients with abnormalities of both NT-proBNP and troponin T was 15-fold higher than among patients with normal values. Conclusion Elevated levels of NT-proBNP and troponin T are strong predictors of early mortality among patients admitted to hospital with acute exacerbations of COPD independently of other known prognostic indicators. The pathophysiological basis for this is unknown, but indicates that cardiac involvement in exacerbations of COPD may be an important determinant of prognosis.

TEG6s® is a new device introduced by the Haemonetics Corporation and designed to provide the same information as TEG® 5000 (Haemonetics Corporation, Braintree, MA, USA) but with much greater ease of use. We tested whether using citrated TEG6s gave reaction time, maximum amplitude and percentage of clot that had lysed at 30 minutes values similar to a non-citrated TEG5000, to allow clinical interchangeability using our current thrombelastography management algorithm for cardiac surgery. We also examined the agreement between the alpha-angle and functional fibrinogen maximum amplitude in our cardiac surgical patients.  In total, 243 paired arterial blood samples in 99 patients were tested, using TEG5000 (non-citrated) and TEG6s (citrated) after induction of anaesthesia (prior to heparin administration), following protamine administration at the end of the cardiac bypass and whenever a TEG5000 was requested after this by the attending anaesthetist. Bland–Altman plots and Lin’s concordance coefficient were used to compare agreement whereas modified Bland–Altman plots and McNemar’s test were used to illustrate the differences in management recommendations between the two thrombelastography devices.  All 243 samples were compared for reaction time and alpha-angle; 239 samples were compared for maximum amplitude; 136 samples were compared for the percentage of clot that had lysed at 30 minutes; 16 samples were compared for functional fibrinogen maximum amplitude. Lin’s concordance coefficient for these parameters was: reaction time 0.63, alpha-angle 0.39, maximum amplitude 0.5, percentage of clot that had lysed at 30 minutes 0.09 and functional fibrinogen maximum amplitude 0.31. Differences between the two devices became more marked at more abnormal values. Significant differences in median values, suggesting a fixed bias, were found for maximum amplitude and functional fibrinogen maximum amplitude. Differences in treatment recommendation could only be calculated for reaction time and maximum amplitude. Maximum amplitude was found to have a significant difference in treatment recommendation between the two devices using our current thrombelastography management algorithm for cardiac surgery with TEG6s recommending treatment in 11.5% more patients than TEG5000.  Using the TEG6s with our current TEG5000–based thrombelastography management algorithm for cardiac surgery would result in a change in treatment recommendation in at least 10% of our cardiac surgical patients. Agreement between the two thrombelastography devices appears to decrease with increasing patient coagulopathy. New algorithms will need to be developed and tested to validate TEG6s for cardiac surgical patients in our institution.