Epidemiology and clinical predictors of biphasic reactions in children with anaphylaxis.

BACKGROUND: Epidemiologic data regarding biphasic reactions in children with anaphylaxis are sparse. OBJECTIVE: To investigate the incidence and clinical predictors of biphasic reactions in children presenting to the emergency department (ED) with anaphylaxis. METHODS: A health records review of ED visits at 2 large Canadian academic pediatric EDs was conducted. All visits that satisfied anaphylaxis diagnostic criteria of the National Institute of Allergy and Infectious Diseases and the Food Allergy and Anaphylaxis Network were included. Predictors of biphasic reaction were analyzed using univariate and multiple logistic regression analyses. RESULTS: Of 1,749 ED records reviewed, 484 visits met the study inclusion criteria. Seventy-one patients (14.7%) developed biphasic reactions. The median age was 6 years (interquartile range 2.7-10.1) and 51 (71.8%) were boys. Forty-nine of the 71 (69%) delayed reactions involved respiratory and/or cardiovascular manifestations and 35 (49%) were treated with epinephrine. Five independent predictors for biphasic reactions were found: age 6 to 9 years (odds ratio [OR] 3.60, 95% confidence interval [CI] 1.5-8.58), delay in presentation to the ED longer than 90 minutes after the onset of the initial reaction (OR 2.58, 95% CI 1.47-4.53), wide pulse pressure at triage (OR 2.92, 95% CI 1.69-5.04), treatment of the initial reaction with more than 1 dose of epinephrine (OR 2.7, 95% CI 1.12-6.55), and administration of inhaled ß-agonists in the ED (OR 2.39, 95% CI 1.24-4.62). CONCLUSION: Biphasic reactions seem to be associated with the severity of the initial anaphylactic reactions. We identified clinical predictors that could ultimately be used to identify patients who would benefit from prolonged ED monitoring and enable better utilization of ED resources.

A Multicentre Prospective Cohort Study to Identify High-Risk Transient Ischemic Attack/Minor Stroke Patients Benefiting from Echocardiography.

BACKGROUND: We aimed to derive a clinical decision rule to identify transient ischemic attack (TIA)/minor stroke patients most likely to benefit from echocardiography. METHODS: This multicentre prospective cohort study enrolled adults diagnosed with TIA/minor stroke in the emergency department who underwent a echocardiogram within 90 days, from 13 Canadian academic emergency departments from October 2006 to May 2017. Our outcome was clinically significant echocardiogram findings. RESULTS: In 7,149 eligible patients, a clinically significant finding was found in 556 (7.8%). There were a further 2,421 (33.9%) with a potentially significant finding. History of heart failure (adjusted odds ratio [OR] 3.9) or coronary artery disease (OR 2.7) were the factors most strongly associated with clinically significant echocardiogram findings, while young age, male sex, valvular heart disease and infarct (any age) on neuroimaging were modestly associated (OR between 1.3 and 1.9). The model combining these predictors into a score (range 0 to 15), had a C-statistic of 0.67 (95%CI 0.65-0.70). A cut point of 6 points or more classified 6.6% of cases as high likelihood, defined as >15% for clinically significant echocardiogram findings. CONCLUSION: Echocardiography is a very useful test in the investigations of TIA/minor stroke patients. We identified high risk clinical features, combined to create a clinical decision rule, to identify which TIA/minor stroke patients are likely to have clinically significant echocardiogram findings requiring an immediate change in management. These patients should have echocardiography prioritized while others may continue to have echocardiography conducted in a less urgent fashion.

Ambulatory vital signs in the workup of pulmonary embolism using a standardized 3-minute walk test.

OBJECTIVE: Diagnosing pulmonary embolism can be difficult given its highly variable clinical presentation. Our objective was to determine whether a decrease in oxygen saturation or an increase in heart rate while ambulating could be used as an objective tool in the diagnosis of pulmonary embolism. METHODS: This was a two-site tertiary-care-centre prospective cohort study that enrolled adult emergency department or thrombosis clinic patients with suspected or newly confirmed pulmonary embolism. Patients were asked to participate in a standardized 3-minute walk test, which assessed ambulatory heart rate and ambulatory oxygen saturation. The primary outcome was pulmonary embolism. RESULTS: We enrolled 114 patients, including 30 with pulmonary embolism (26.3%). A ≥2% absolute decrease in ambulatory oxygen saturation and an ambulatory change in heart rate >10 beats per minute (BPM) were significantly associated with pulmonary embolism. An ambulatory heart rate change of >10 BPM had a sensitivity of 96.6% (95% confidence interval [CI] 83.3 to 99.4) and a specificity of 31.0% (95% CI 22.1 to 45.0) for pulmonary embolism. A ≥2% absolute decrease ambulatory oxygen saturation had a sensitivity of 80.2% (95% CI 62.7 to 90.5) and a specificity of 39.3% (95% CI 29.5 to 50.0) for pulmonary embolism. The combination of both variables yielded a sensitivity of 100.0% (95% CI 87.0 to 100.0) and a specificity of 11.0% (95% CI 6.6 to 21.0). CONCLUSION: In summary, our study found that an ambulatory heart rate change of >10 BPM or a ≥2% absolute decrease in ambulatory oxygen saturation from baseline during a standardized 3-minute walk test are highly correlated with pulmonary embolism. Although the findings appear promising, neither of these variables can currently be recommended as a screening tool for pulmonary embolism until larger prospective studies examine their performance either alone or with pre-existing rules.