Shock Index As a Predictor of Earlier Risk of Vaso-Occlusive Crisis in Trauma Patients with Sickle Cell Disease

Objectives: Clinical implications and management of traumatic injury in individuals with sickle cell disease (SCD) are poorly understood. Trauma exposure may increase post-injury vaso-occlusion, potentially causing secondary complications. The shock index (SI), calculated as the heart rate divided by systolic blood pressure at emergency department (ED) admission, represents the degree of shock after injury. Values of the SI >0.9 are associated with the need for massive transfusion, emergency surgery, and increased mortality in the setting of trauma. We evaluate the shock index (SI) as a predictive tool for prognosis, examining its association with vaso-occlusive events (VOE) in trauma patients with SCD.

Methods: In this retrospective cohort study, medical records of adult patients with SCD with an emergency department (ED) visit for traumatic injury from 2000-2022 were reviewed. The primary exposure was the SI. Our primary outcome was time-to-VOE. Cox regression determined the association between time-to-VOE and SI, adjusting for demographic data (age, gender), mechanism of injury, trauma team activation (TTA), hemoglobin and hematocrit at time of admission.

Results: Records of 356 adult SCD patients were reviewed; 54 patients had an ED visit for traumatic injury with measures for SI, hemoglobin, and hematocrit at time of admission. The cohort had a mean age of 31.83 years with male predominance (66.1%). Mean hemoglobin, hematocrit, and SI at admission were 10.80, 31.79, and 0.71 respectively. Mean time-to-VOE was 3.52 days. Cox proportional hazards model revealed that SI (HR = 14.63 (95% CI: 1.40-152.70), P = 0.025) particularly at a critical threshold of 0.79, and TTA (HR = 0.37, P = 0.03), were significantly associated with increased hazard of earlier time-to-VOE. Injury hematocrit and hemoglobin, SCD genotype, age, and gender did not exhibit statistically significant associations with time-to-VOE.

Conclusion: Patients with SCD with a higher SI value are expected to have a significantly earlier time-to-VOE than patients with lower SI, especially at a critical threshold above 0.79. Our results are consistent with prior data supporting the need for trauma team activation to provide critical interventions in patients with SCD following trauma. Future research may refine risk assessment models to anticipate disease-specific complications and allow tailored interventions in sickle cell patients following trauma.

Lapping-Carr:Agios: Other: attend meeting.