Abstract

Background: Currently for physicians, there are limited parameters to stratify patients at risk for short term cardiovascular collapse (i.e. vasopressor dependence). The shock index (SI, heart rate divided by systolic blood pressure) is a simple formula useful for detecting changes in cardiovascular performance before the onset of systemic hypotension. It is an easily accessible, non-invasive, and non-costly risk stratification tool that may enhance current methods for differentiating severe sepsis patients at risk for imminent cardiovascular collapse.
Materials: In this study, we have taken patients who are above 18 years diagnosed to have sepsis were followed up and shock index was calculated every 6th hour. In 50 such patients who required vasopressor use within 72 hours of admission, percentage of SI elevation for each patient was determined by taking the total number of SI values greater than 0.8 and dividing this number by the total number of vital signs taken. The patients were divided into Sustained SI elevation (i.e. >or=80%) group and non-sustained SI elevation group (i.e. < 80%) and comparison was done.
Results: 80 patients were followed up, out of which 50 patient’s required vasopressor use with in 72 hours of admission. Among them 41 patients had sustained shock index elevation and 9 patients had non sustained SI elevation. It is found that sustained shock index was statistically significant in predicting vasopressor use in sepsis patients. Sustained SI had sensitivity of 82%, specificity of 83.3%, PPV of 89.13%, NPV of 73.55% and Diagnostic accuracy of 82.5% in predicting vasopressor use.
Conclusion: Patients with sepsis and a sustained SI elevation appear to have higher rates of vasopressor use short term after admission contrasted to patients without a sustained SI Elevation. A sustained SI elevation may be a promising simple, cost-efficient, and non-invasive measurement to help risk stratify patients who present with sepsis, and may complement other predictors of disease progression. A sustained SI elevation may be a useful modality to identify patients with severe sepsis at risk for disease progression.