Introduction: The usage of clinical scoring systems could help in the risk stratification of patients with hemodynamically unstable pulmonary embolism (PE), and could be of prognostic significance.

The goal: We aimed to identify if Shock Index (SI) had a significant positive predictive value to recognize patients at higher mortality risk and to compare it against other clinical scoring systems, such as Early Warning Score (EWS), Modified Early Warning score (MEWS), Pulmonary Embolism Severity Index (PESI), and its simplified form known as sPESI.

Materials and methods: Retrospective study included 137 hemodynamically unstable patients with PE treated at the Institute for Pulmonary Diseases of Vojvodina. The prognostic significance of the sex, age, SI, EWS, MEWS, PESI, and sPESI score was analyzed. The Student's t-test was used to compare values of numerical features between the two groups. In order to investigate the connection between two or more features, univariate and multivariate regression analyses were used. Values of significance level p<0.05 are considered statistically significant.

Results: Shock index and EWS had no positive prognostic value amongst patients with hemodynamically unstable PE. MEWS score had a prognostic value in differentiating patients with a higher risk of poor outcomes, having an AVPU score and diuresis as the statistically most important variables.

Conclusion: According to the results of our study the SI has no prognostic significance in ruling out patients with a higher mortality risk. However, MEWS score values were significantly higher in deceased patients.