R. Latifi1, E. Tilley1, D. Samson1, A. A. El-Menyar1 1Westchester Medical Center,Surgery,Valhalla, NY, USA
Introduction: Post-traumatic significant bleeding represents a major challenge and needs immediate detection and treatment. Predicting which patients will require massive blood transfusion protocol (MTP) is still an art, more then a science. Shock index (SI) is a simple quick mathematic equation (heart rate/systolic blood pressure) that has shown a prognostic implication in trauma patients at certain cutoffs that differ from one study to another. In these studies, higher SI was associated with unfavorable outcomes. We aimed to evaluate the value of SI in predicting the need for MTP in trauma patient a Level 1 Trauma center
Methods: We conducted a retrospective analysis for trauma patients who received blood transfusion in the trauma room between 2012 and 2016. Data included patient demographics, heart rate, systolic and diastolic blood pressures , pulse pressure (PP) , mechanism of injury, Injury Severity Score (ISS), New Injury Severity Score (NISS) , Trauma and Injury Severity Score (TRISS), need for blood transfusion, MTP, hospital length of stay (HLOS) and mortality. Patients < 14 years old or with incomplete clinical data were excluded. Patients were classified into group I (SI<0.8) and group II
( SI ≥0.8). Comparisons were performed by Chi Square, and Student T test, whenever applicable. Correlation coefficient r measured the strength and direction of a linear relationship between the variables.
Results:There were 2808 patients eligible for the study, of them 531 (19%) had SI ≥ 0.8 and 273 (9.5%) who received blood transfusion. Of those who were transfused, 14.6% received MTP. In comparison to lower SI, patients with SI≥0.8 were 11 year younger (42±20 vs 53±23), sustained more penetrating injury (9.4% vs 6.7%), had greater ISS (15±12 vs 10.5±8), higher NISS (19±15 vs 14±11), lower TRISS (0.90±0.20 vs 0.96±0.10) and received more blood transfusion (21.2% vs 7.1%) and MTP (10.2% vs 1%),p=0.001 for all. Patients with high SI also had longer HLOS (10.6 vs 6.7 days, p=0.001) and higher mortality (6.2% vs 3.4%, p=0.004). There were correlations between SI and PP(r=-0.53), HLOS(r=0.15), ISS(r=0.21), NISS(r=0.20), and TRISS(r=-0.20), p=0.001 for all.
Conclusion:Shock index can be used early to predict the need of blood transfusion and correlates with PP, HLOS, ISS, NISS, and TRISS. However, its cutoff values for risk stratification and prognostication needs further evaluation in trauma patients.