Temporal Analysis of Diastolic Shock Index in Patients with Septic Shock and Its Correlation with Clinical Outcomes in an Indian Setting: A Prospective Observational Study

Background: Diastolic shock index (DSI), the ratio of heart rate to diastolic arterial pressure, reflects vascular tone and sympathetic drive in septic shock. While baseline DSI correlates with mortality, its temporal evolution remains exploratory. Patients and methods: In this single-center prospective observational study, adult patients with septic shock (as per sepsis-3) were enrolled. Diastolic shock index, shock index (SI), and modified shock index (MSI) were recorded at 0, 6, 12, and 24 hours. Delta diastolic shock index (DSI), lactate clearance, and vasoactive-inotropic score (VIS) were analyzed using repeated-measures ANOVA, receiver operating characteristic (ROC) analysis, Cox regression, and multivariable logistic regression (SPSS v23, MedCalc). Results: Of 157 patients screened, 90 were included. Median age was 40 years (male 64. 4%) with median SOFA and APACHE II scores of 9 and 18, respectively. Nonsurvivors had higher lactate (24 mg/dL, p < 0. 001) and lower platelet counts. Overall, 28-day mortality was 37. 8%. Declining DSI, MSI, and SI over 24 hours were seen in the survivor group. Delta diastolic shock index correlated inversely with lactate clearance (r = -0. 40, p < 0. 01) and vasopressor-free days (r = -0. 33, p = 0. 001). Receiver operating characteristic analysis showed that DSI (AUC = 0. 684) outperformed baseline DSI (AUC = 0. 402). A combined model (DSI + VIS₀ + Lactate₀) improved discrimination (AUC = 0. 781). In logistic regression, DSI (OR 4. 07, p = 0. 006), Lactate₀ (OR 1. 04, p = 0. 012), and APACHE II (OR 1. 14, p = 0. 002) independently predicted mortality. Conclusion: Temporal improvement in DSI (DSI) independently predicts ICU mortality and correlates with vascular recovery. Integrating DSI with VIS and lactate enhances risk stratification in septic shock.