Utility of the Shock Index at ICU admission as a prognostic tool in patients with COVID-19-related ARDS: Implications for nursing practice

Abstract

Objective

To evaluate the prognostic value of the Shock Index (SI) at intensive care unit (ICU) admission in predicting hospital mortality among patients with Acute Respiratory Distress Syndrome (ARDS), and to explore its potential application in nursing-led risk assessment.

Methods

This retrospective cohort study was conducted in five public and private hospitals in Sergipe, Brazil, between April 2020 and January 2022. Adult patients diagnosed with ARDS and admitted to ICUs were included if data were available to calculate the SI (heart rate/systolic blood pressure), along with clinical and laboratory variables. All ARDS cases in this cohort were exclusively secondary to COVID-19 infection. Patients were categorized as survivors or non-survivors. Bivariate analyses, logistic regression, and Cox regression models were used to assess associations with hospital mortality.

Results

A total of 180 patients were included. The hospital mortality rate was 45%. Patients with SI ≥ 0.9 at ICU admission had a significantly higher risk of death (HR: 1.57; 95% CI: 1.01–2.45; p = 0.046). In the adjusted analysis, SI ≥ 0.9 remained independently associated with increased mortality risk (OR: 2.63; 95% CI: 1.21–6.09; p = 0.018), regardless of age, comorbidities, or severity scores. Additional predictors of mortality included advanced age, renal dysfunction, and elevated SAPS-3 and SOFA scores.

Conclusion

The Shock Index at ICU admission demonstrated independent prognostic value for hospital mortality in COVID-19–related ARDS patients. As a simple, cost-effective, and nurse-accessible tool, SI may support early risk stratification, guide care prioritization, and assist in clinical decision-making in intensive care settings.