Vascular thrombosis after pediatric liver transplantation: Is prevention achievable?

Background: Vascular thromboses (VT) are life-threatening events after pediatric liver transplantation (LT). Single-center studies have identified risk factors for intra-abdominal VT, but large-scale pediatric studies are lacking. Methods: This multicenter retrospective cohort study of isolated pediatric LT recipients assessed pre- and perioperative variables to determine VT risk factors and anticoagulation-associated bleeding complications. Results: Within seven postoperative days, 31/331 (9.37%) patients developed intra-abdominal VT. Open fascia occurred more commonly in patients with VT (51.61 vs 23.33%) and remained the only independent risk factor in multivariable analysis (OR = 2.84, p = 0.012). Patients with VT received more blood products (83.87 vs 50.00%), had significantly higher rates of graft loss (22.58 vs 1.33%), infection (50.00 vs 20.60%), and unplanned return to the operating room (70.97 vs 16.44%) compared to those without VT. The risk of bleeding was similar (p = 0.2) between patients on and off anticoagulation. Conclusions: Prophylactic anticoagulation did not increase bleeding complications in this cohort. The only independent factor associated with VT was open fascia, likely a graft/recipient size mismatch surrogate, supporting the need to improve surgical techniques to prevent VT that may not be modifiable with anticoagulation.

Critical Care and Mechanical Ventilation Practices Surrounding Liver Transplantation in Children: A Multicenter Collaborative.

OBJECTIVES: We aimed to determine which characteristics and management approaches were associated with postoperative invasive mechanical ventilation (IMV) and with a prolonged course of IMV in children post liver transplant as well as describing the utilization of critical care resources. DESIGN: Retrospective, multicenter, cohort study of children who underwent an isolated liver transplantation between January 2017 and December 2018. SETTING: Twelve U.S., pediatric, liver transplant centers. PATIENTS: Three hundred thirty children post liver transplant admitted to the ICU. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Six patients died in our cohort. The median length of PICU stay was 4.5 days (interquartile range [IQR], 2.9-8.2 d). Most patients were initially monitored with arterial catheters (96%), central venous pressures (95%), and liver ultrasound (93%). Anticoagulation (80%), blood product administration (52.4%), and vasoactive agents (23.0%) were commonly used therapies in the first 7 days. In multivariable logistic regression analysis, age (adjusted odds ratio [aOR] 0.9 [0.86-0.95]), open fascia (aOR 7.0 [95% CI, 2.6-18.9]), large center size (aOR 4.3 [95% CI 2.2-8.3]), and higher Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease scores (aOR 1.04 [95% CI, 1.01-1.06]) were associated with postoperative IMV. In multivariable logistic regression analysis, postoperative day 0 peak inspiratory pressure (PIP) (aOR 1.2 [95% CI, 1.1-1.3]), large center size (aOR 2.9 [95% CI, 1.6-5.4]), and age (aOR 0.89 [95% CI, 0.85-0.95]) were associated with length of IMV greater than 24 hours. Length of IMV greater than 24 hours was associated with bleeding complications ( p = 0.03), infections ( p = 0.03), graft loss ( p = 0.02), and reoperation ( p = 0.03). CONCLUSIONS: Younger age, preoperative hospitalization, large center size, and open fascia are associated with use of IMV, and younger age, large center size, and postoperative day 0 PIP are associated with prolonged IMV on multivariable analysis. Longer IMV is associated with negative outcomes, making it an important clinical marker.

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.