I. N. Liras1, B. A. Cotton1, J. C. Cardenas1, M. T. Harting1 1University Of Texas Health Science Center At Houston,Houston, TX, USA
Introduction: Hyperfibrinolysis (HF) on admission is associated with increased mortality in adult trauma patients. Several studies have demonstrated that 9% of severely injured adults present to the emergency department (ED) with HF. The purpose of the current study was to (1) define HF in pediatric patients and a relevant cut-point for therapeutic intervention (if any), (2) identify the prevalence of HF in severely injured pediatric patients, and (3) determine if HF on admission is as lethal a phenomenon as it is in adults.
Methods: Following IRB approval, we identified all pediatric trauma admissions (≤17 years old) that met highest-level trauma activation criteria between 01/2010 and 12/2013. Fibrinolysis rates were determined using LY-30 by rapid thrombelastography (rTEG),which represents the percent reduction of the maximal clot amplitude (fibrinolysis) 30 minutes after such amplitude is achieved. HF was defined a priori as initial LY-30 inflection point that translated to a doubling of mortality. Two previous studies in adults demonstrated an inflection point of ≥3%; where mortality doubled from 9 to 20%. We began by identifying a relevant inflection point to define HF and its prevalence, followed by univariate analysis to compare HF and non-HF patients. Finally, a purposeful logistic regression model was developed to evaluate predcitors of mortality in severely injured pediatric patients.
Results: 819 patients met study criteria. LY-30 values were plotted against mortality. A distinct inflection point was noted at ≥3%, where mortality doubled from 6 to 14%. Of note, mortality continued to increase as the amount of lysis increased, with a 100% mortality demonstrated at an LY-30 ≥30% (compared to 77% in adults). Using LY-30 ≥3%, patients were stratified into HF (n=197) and non-HF (n=622), with prevalence on admission of 24%. With the exception of HF patients being younger (median 11 vs. 15 years; p<0.001), there were no differences in demographics, scene vitals or injury severity scores between the groups. On arrival to the ED, HF patients had a lower systolic blood pressure (median 118 vs. 124 mmHg) and lower hemoglobin (median 12.2 vs. 12.7 g/dL); both p<0.001). Controlling for age, arrival vital signs, admission hemoglobin and injury severity (ISS), logistic regression identified admission LY30 ≥3% (OR 6.2, 95% CI 2.47-16.27) as an independent predictor of mortality.
Conclusion: Similar to adults, admission HF appears to reach a critical threshold at LY30 ≥3% in pediatric patients. Admission HF in pediatric patients occurs more frequently than in adults (24 vs. 9%) but is similarly associated with a doubling in mortality (6 to 14%). Admission LY-30 ≥3% carries a 6-fold increased likelihood of mortality in severely injured pediatric patients. HF on admission may serve to rapidly identify those injured children and adolescents likely to benefit from hemostatic resuscitation efforts and to guide anti-fibrinolytic therapy.