Shock index is better than conventional vital signs for assessing higher level of care and mortality in severe sepsis or shock.

BACKGROUND

Conventional vital signs alone have limitations in determining the physiological status. Age-adjusted shock-index (SIPA), a comprehensive physiological variable, defined as the ratio of heart rate (HR) and systolic blood pressure (SBP) may be better at predicting hemodynamic stability and outcome than vital signs.

OBJECTIVES

To compare discriminatory power of SIPA against vital signs in assessing higher level of care (vasopressor use and mechanical ventilation) and early mortality in severe sepsis/septic shock.

METHODS

Prospective cohort study of 116children <14 years with severe sepsis/septic shock admitted at emergency department of a tertiary care hospital. Association between abnormal signs (raised heart-rate; HR, lower systolic blood-pressure; SBP, high SIPA) and higher level of care and early mortality at 0 and completed 6 hours (t0, t6) were assessed using univariate/multivariate analysis. Area-under-receiver-operating-characteristic curves (AUROC) of SIPA and conventional vital signs for outcome variables and their correlation with arterial lactate using Pearson's-coefficient were noted.

RESULTS

High SIPA was independently associated with higher level of care i.e. vasopressor use, mechanical ventilation (AUROC t0: 0.698, 0.730; AUROC t6; 0.733, 0.735) as well as early mortality (AUROC t0: 0.638; AUROC t6:0.721) at t0 and t6. At t0, only high SIPA (r2 = 0.313) fairly correlated with arterial lactate (4.5 mmol/L). At t6, HR and SBP showed weak and SIPA (r2 = 0.434) demonstrated moderate correlation with arterial lactate.

CONCLUSIONS

SIPA performs better than conventional vital-signs in recognising higher-level-of-care and early mortality.