Left ventricular dysfunction in Duchenne muscular dystrophy.

BACKGROUND: Duchenne muscular dystrophy is associated with progressive cardiorespiratory failure, including left ventricular dysfunction. METHODS AND RESULTS: Males with probable or definite diagnosis of Duchenne muscular dystrophy, diagnosed between 1 January, 1982 and 31 December, 2011, were identified from the Muscular Dystrophy Surveillance Tracking and Research Network database. Two non-mutually exclusive groups were created: patients with ≥2 echocardiograms and non-invasive positive pressure ventilation-compliant patients with ≥1 recorded ejection fraction. Quantitative left ventricular dysfunction was defined as an ejection fraction <55%. Qualitative dysfunction was defined as mild, moderate, or severe. Progression of quantitative left ventricular dysfunction was modelled as a continuous time-varying outcome. Change in qualitative left ventricle function was assessed by the percentage of patients within each category at each age. Forty-one percent (n = 403) had ≥2 ejection fractions containing 998 qualitative assessments with a mean age at first echo of 10.8 ± 4.6 years, with an average first ejection fraction of 63.1 ± 12.6%. Mean age at first echo with an ejection fraction <55 was 15.2 ± 3.9 years. Thirty-five percent (140/403) were non-invasive positive pressure ventilation-compliant and had ejection fraction information. The estimated rate of decline in ejection fraction from first ejection fraction was 1.6% per year and initiation of non-invasive positive pressure ventilation did not change this rate. CONCLUSIONS: In our cohort, we observed that left ventricle function in patients with Duchenne muscular dystrophy declined over time, independent of non-invasive positive pressure ventilation use. Future studies are needed to examine the impact of respiratory support on cardiac function.

Low-Dose Epinephrine Boluses for Acute Hypotension in the PICU.

OBJECTIVES: To describe the use of low-dose bolus epinephrine in critically ill children during an acute hypotensive episode or prearrest condition. DESIGN: Institutional Review Board approved, single-center, retrospective medical chart review. SETTING: Large medical-surgical PICU within a freestanding, tertiary care children's hospital. PATIENTS: Patients admitted to the PICU between June 1, 2015, and June 1, 2016, who received low-dose (≤ 5 µg/kg) IV bolus epinephrine. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Twenty-four resuscitation episodes (63 doses; 19 patients) were analyzed. Median age and weight of patients were 9 years (interquartile range, 1-15 yr) and 38.5 kg (interquartile range, 12-54.8 kg). Median Pediatric Risk of Mortality III score was 17 (interquartile range, 10-27). Mean epinephrine dose was 1.3 ± 1.1 µg/kg. Median number of doses per patient was two. If more than one dose was provided, median dosing interval was 6.5 minutes. Heart rate and mean arterial blood pressure were compared at the time of epinephrine administration and 1-4 minutes (median = 1 min) following administration. Heart rate changed from 130 ± 41 to 150 ± 33 beats/min (p < 0.05), and mean arterial blood pressure changed from 51 ± 17 to 75 ± 27 mm Hg (p < 0.001). Variability in mean arterial blood pressure response was observed; nonresponders required extracorporeal membrane oxygenation; 66% of doses resulted in up to 100% mean arterial blood pressure increase, and 21% of doses resulted in greater than 100% mean arterial blood pressure increase. Doses below 1 µg/kg were associated with a lower mean arterial blood pressure increase than doses between 1 and 5 µg/kg (mean percent change in mean arterial blood pressure = 6.6% vs 60%, respectively). Children less than or equal to 2 years old had the greatest percentage increase in heart rate and mean arterial blood pressure. CONCLUSIONS: Provision of low-dose bolus epinephrine during periods of acute hypotension can result in a significant increase in mean arterial blood pressure and heart rate. This dosing strategy may provide temporary stabilization while other therapies are added or adjusted, but further research is needed.

Pulmonary capillaritis in monozygotic twin boys.

Pulmonary hemorrhage can be classified as either proximal or distal (alveolar). Causes of proximal hemorrhage include infection, foreign body aspiration, pulmonary embolus, trauma, vascular malformation, and pulmonary hypertension. Causes of distal or diffuse alveolar hemorrhage are divided by the histologic presence or absence of capillaritis, which is characterized by inflammation of the alveolar interstitium and pulmonary capillary structure. Pulmonary capillaritis is a rare event in children and is associated with higher morbidity and mortality than diffuse alveolar hemorrhage without capillaritis. This is a report of 17-month-old previously healthy monozygotic twins presenting simultaneously with diffuse alveolar hemorrhage, pulmonary capillaritis, and an otherwise negative serologic workup. This suggests a role of genetic predisposition in this rare disease.