Serum mast cell tryptase measurements: Sensitivity and specificity for a diagnosis of anaphylaxis in emergency department patients with shock or hypoxaemia.

OBJECTIVE: Clinical diagnosis of anaphylaxis is principally based on symptoms and signs. However, particularly for patients with atypical symptoms, laboratory confirmation of anaphylaxis would be useful. This study investigated the utility of mast cell tryptase, an available clinical biomarker, for differentiating anaphylaxis from other causes of critical illness, which can also involve mast cell activation. METHODS: Tryptase was measured (ImmunoCAP) in serum from patients with anaphylaxis and non-anaphylactic critical illness (controls) at ED arrival, and after 1-2, 3-4 and 12-24 h. Differences in both peak and delta (difference between highest and lowest) tryptase concentrations between groups were investigated using linear regression models, and diagnostic ability was analysed using Receiver Operating Characteristic curve analysis. RESULTS: Peak tryptase was fourfold (95% CI: 2.9, 5.5) higher in anaphylaxis patients (n = 67) than controls (n = 120) (P < 0.001). Delta-tryptase was 5.1-fold (95% CI: 2.9, 8.9) higher in anaphylaxis than controls (P < 0.001). Optimal test characteristics (sensitivity: 72% [95% CI: 59, 82] and specificity: 72% [95%CI: 63, 80]) were observed when peak tryptase concentrations were >11.4 ng/mL and/or delta-tryptase ≥2.0 ng/mL. For hypotensive patients, peak tryptase >11.4 ng/mL had improved test characteristics (sensitivity: 85% [95% CI: 65, 96] and specificity: 92% [95% CI: 85, 97]); the use of delta-tryptase reduced test specificity. CONCLUSION: While peak and delta tryptase concentrations were higher in anaphylaxis than other forms of critical illness, the test lacks sufficient sensitivity and specificity. Therefore, mast cell tryptase values alone cannot be used to establish the diagnosis of anaphylaxis in the ED. In particular, tryptase has limited utility for differentiating anaphylactic from non-anaphylactic shock.

The TARGET pain study: Lessons from a painful marathon.

This perspective article summarises the experience of conducting a multicentre research project. We describe expected and unexpected hurdles we experienced as well as suggesting possible solutions for researchers embarking on multicentre studies.

Best-practice pain management in the emergency department: A cluster-randomised, controlled, intervention trial.

OBJECTIVES: We aimed to provide 'adequate analgesia' (which decreases the pain score by ≥2 and to <4 [0-10 scale]) and determine the effect on patient satisfaction. METHODS: We undertook a multicentre, cluster-randomised, controlled, intervention trial in nine EDs. Patients with moderate pain (pain score of ≥4) were eligible for inclusion. The intervention was a range of educational activities to encourage staff to provide 'adequate analgesia'. It was introduced into five early intervention EDs between the 0 and 6 months time points and at four late intervention EDs between 3 and 6 months. At 0, 3 and 6 months, data were collected on demographics, pain scores, analgesia provided and pain management satisfaction 48 h post-discharge (6 point scale). RESULTS: Overall, 1317 patients were enrolled. Logistic regression (controlling for site and other confounders) indicated that, between 0 and 3 months, satisfaction increased significantly at the early intervention EDs (OR 2.2, 95% CI 1.5 to 3.4 [P < 0.01]) but was stable at the control EDs (OR 0.8, 95% CI 0.5 to 1.3 [P = 0.35]). Pooling of data from all sites indicated that the proportion of patients very satisfied with their pain management increased from 42.9% immediately pre-intervention to 53.9% after 3 months of intervention (difference in proportions 11.0%, 95% CI 4.2 to 17.8 [P = 0.001]). Logistic regression of all data indicated that 'adequate analgesia' was significantly associated with patient satisfaction (OR 1.4, 95% CI 1.1 to 1.8 [P < 0.01]). CONCLUSIONS: The 'adequate analgesia' intervention significantly improved patient satisfaction. It provides a simple and efficient target in the pursuit of best-practice ED pain management.