Hemodynamic Instability in Trauma Patients Assessed by Shock Index: A Prospective Cohort Study on Injury Patterns and Early Outcomes in Tanzania

Background Hemodynamic compromise remains a major contributor to trauma-related mortality, particularly in resource-limited settings. While validated in high-income countries, the prognostic utility of Shock Index (SI) as a marker of hemodynamic instability remains underexplored in the Eastern and Central African region. This study evaluated the proportion, injury patterns, and short-term outcomes of trauma patients presenting with elevated SI at a tertiary trauma center in Tanzania. Methods This prospective observational cohort study was conducted between June and September 2024. Adult trauma patients presenting with SI >0.7 were consecutively enrolled. Demographic characteristics, clinical parameters and trauma severity scores (New Injury Severity Score [NISS] and Revised Trauma Score [RTS]) were recorded on arrival. The primary outcomes were mortality within 7 days and prolonged hospital admission (>7 days). Multivariate logistic regression was used to identify independent predictors of the outcomes. Results Among 1235 trauma patients, 160 (13%) presented with SI >0.7, including 38% with SI ≥1. Markedly elevated SI (≥1) was associated with severe injury (P < 0.0001), anemia (P < 0.0001), and multisystem trauma (P = 0.044). Young males represented the majority of the population. Motor traffic crashes accounted for the majority of injuries (80.6%). The overall 7-day mortality rate of 5% was exclusive to patients with SI ≥1. Most patients (58.75%) experienced prolonged hospitalization. On multivariate analysis, SI ≥1, low RTS (P = 0.037), and low Glasgow Coma Scale (GCS) (P = 0.022) were significantly associated with mortality, while higher NISS (P < 0.0001) and head injury (P = 0.0029) were significantly associated with prolonged hospital stay. Conclusions Elevated SI was a useful early marker of hemodynamic instability and mortality risk among trauma patients in this setting. An SI ≥1, low RTS, and low GCS were associated with mortality. Higher NISS and head injury were associated with prolonged hospitalization. Incorporating these factors into triage may support improved risk stratification and resource use.