A Study on Shock Index in Early Diagnosis of Sepsis in Emergency Department of Tertiary Care Centre of Nepal

Introduction: Sepsis and its consequences, severe sepsis and septic shock is at menace in country like ours where infectious disease are at toll. Early diagnosis and treatment is very important to decrease the morbidity and mortality. Shock index is one of such tool that is very handy in these situations as this is just a mathematical calculation using heart rate(HR) and systolic blood pressure(SBP). The main aim of this study was to find the effectiveness of using SI as an adjunct to blood lactate in diagnosing patients in sepsis. Methods: This was an observational hospital-based study conducted at Emergency Department of TUTH, Maharajgunj on 104 patients, obtained by purposive sampling method, who had presented to the “Red Area”, aged between 18 to 65 years. These patients were screened for severe sepsis using triage vital signs, basic laboratory tests and an initial serum lactate level. Test characteristics were calculated for hyperlactatemia. I considered the following covariates in our analysis: heart rate >90 beats/min; mean arterial pressure 20 breaths/min; ≥2 SIRS including white blood cell count; SI <0.6; SI 0.6 to 1; SI 1 to 1.4and SI ≥ 1.4.  Results: There was a positive correlation between shock index and blood lactate level, r=0.2, n=104, p=0.042. No relationship was found between SI>=1 and hyperlactemia, X2 (.285, N = 104) = 1, p =.594 and relationship was found between SI >=0.7 and hyperlactemia, X2 (4.1, N = 104) = 1, p =.04. sensitivity and specificity for detecting hyperlactemia of SI>=1, SI.=0.7, SIRS was 84% and 20%, 93% and 0%, 79% and 20% respectively. Conclusions: There was weak correlation between the lactate level and shock index with statistically significant correlation between the shock index grouped >=0.7 and hyperlactatemia with high sensitivity and very low specificity.