Comparison of diastolic shock index and vital signs in the follow-up of septic shock patients in the emergency department

Introduction: The shock index is effective in evaluating the severity of shock and treatment response in critically ill patients. In addition, the main pathology in septic shock is peripheral vasodilation, and influence of diastolic blood pressure is expected to be more effective than systolic blood pressure. In this study, we aimed to evaluate the effectiveness of the diastolic shock index [heart rate/diastolic blood pressure] in predicting mortality among patients with sepsis and septic shock, and in monitoring the response to treatments, and comparing it with vital signs and other shock indices. Materials & Methods: This study included patients diagnosed with sepsis and septic shock according to Sepsis-3 diagnostic criteria, who applied to our emergency department between 01.07.2019 and 01.07.2021 and received vasopressor therapy. Vital signs of the patients [at admission, after intravenous fluid therapy and before and after vasopressor therapy, simultaneous with lactate measurements, before vasopressor therapy (Q1), and after first (Q2)-second (Q3) and fourth hours (Q4)], comorbid diseases, source of sepsis, antibiotic and 2L or more of intravenous fluids administration times, blood gas analysis and biochemical results were recorded. Diastolic (DSI), systolic (SSI) and modified shock indices (MSI), SOFA score, and Charlson comorbidity indices were calculated by researchers. The primary endpoint was 28-day survival. Factors affecting mortality, changes in vital signs and shock indices during follow-up, and their performance in predicting mortality were examined. Results: During the study period, 343 patients in the ED who were given norepinephrine therapy with the diagnosis of sepsis and septic shock were analysed. The median age of the patients was 76 (min-max: 20-101) and 52,8% (n=181) of them were male. The 28-day mortality of the patients was determined as 73,5% (n=252). The mortality was higher among patients requiring mechanical ventilation (OR: 7,87 [95% CI: 4,56-13,56]) or renal replacement therapy (OR: 2,22 [95% CI: 0,90-5,48]); and patients with more than one hour delayed administration of 2 L or more of fluids (OR: 2,97 [95% CI: 1,80-4,89]) and antibiotics (OR: 1,28 [95% CI: 0,75-2,19]) had higher mortality. There was no significant correlation at admission between the patients' lactate levels and the correlations of vital signs, but a weak correlation was found between lactate levels obtained during follow-up and heart rate, DSI, SSI, and MSI (r=0,142; r=0,121; r=0,166; r=0,144 respectively). Although there was a difference between the initial and post-vasopressor vital signs of survivors and non-survivors, no significant difference was found between the two groups in the repeated measurements in four periods (repeated-measures ANOVA). In the evaluation of the areas under the curve for mortality with the ROC curve, while SBP, DBP, and MAP performed poorly, better performance was displayed by the SOFA score, HR, SSI, MSI, and DSI, which had similar performances. Conclusion: In our study, we found that heart rate, shock indices and SOFA score had better performances than the other vital signs in predicting mortality in sepsis and septic shock patients receiving vasopressor therapy. The heart rate, shock indices and SOFA score had similar performances among them. Evaluation of vasopressor response with blood pressure monitoring, regardless of heart rate, does not make a significant contribution to the prediction of prognosis. Changes in shock indices should be considered in the follow-up of patients in septic shock. However, the results of our study do not support the use of modified shock indices instead of the traditional shock index. Keywords: Sepsis, septic shock, mortality, norepinephrine, diastolic shock index, systolic shock index, modified shock index