Incidence and risk factors for venous thromboembolism in critically ill children after trauma.

BACKGROUND: Venous thromboembolism (VTE) causes major morbidity in adults after trauma, occurring in up to 50% of patients without prophylaxis. The incidence of VTE after trauma is lower in children. No study has measured the incidence of and risk factors for VTE in critically ill children after trauma.
METHODS: Nested case-control study of children, younger than 18 years, admitted to the pediatric intensive care unit at a level I trauma center. Three controls were selected for each identified VTE case.
RESULTS: Nine of 144 children admitted to the pediatric intensive care unit after trauma developed VTE (incidence 6.2%, 95% confidence interval [CI] 2.3-10.2), with a median age of 8.6 years (range, 2.3-17.9). VTE was diagnosed at a median of 9 days after admission, with 67% of VTE located at the site of previous or existing central venous line (CVL). Significant risk factors for thrombosis included parenteral nutrition (odds ratio [OR] 20, 95% CI 1.9-227), CVL (OR 19, 95% CI 2-178), deep sedation (OR 13, 95% CI 1.6-48), neuromuscular blockade (OR 10, 95% CI 1.4-70), inotropic support (OR 10, 95% CI 1.7-59), and recombinant factor VIIa administration (p = 0.012, OR not calculable). Logistic analysis found a 7.9-fold increase in the odds of developing VTE for each additional CVL (p = 0.005), a threefold increase with each additional risk factor present (p = 0.009), and a 1.3-fold increase for an increase in injury severity (p = 0.03). VTE was not associated with sepsis, spinal cord injury, fracture, or elevated D-dimer level.
CONCLUSIONS: VTE is not a rare event in critically ill children after trauma. Most patients developing thrombosis have multiple risk factors, including poor perfusion, immobility, and presence of a CVL.