2.3. Definitions

Currently, sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection [1]. Septic shock is defined as a subset of sepsis in which profound circulatory, cellular, and metabolic abnormalities pose a greater risk of mortality than sepsis alone [1,2]. The latest Sepsis-3 definitions recommend the use of the quick SOFA (qSOFA) score to find patients with poor prognosis outside the intensive care unit (ICU) [1]. This score uses three criteria—low blood pressure (systolic blood pressure: ≤100 mmHg), high respiratory rate (≥22 breaths/min), and altered mental status (Glasgow coma score: <15)—assigning 1 point for each criterion, with the final score ranging from 0 to 3 points. A positive qSOFA score is defined as the presence of ≥2 qSOFA points near the onset of infection. We used this positive qSOFA score as the inclusion criterion for our study. According to the Sepsis-3 definition, the diagnostic criteria for sepsis include an increase in the SOFA score by ≥2 points due to current infection. Similarly, the criteria for septic shock include vasopressor requirement to maintain a MAP of 65 mmHg and serum lactate level >2 mmol/L despite adequate fluid resuscitation [1,2].

The VISmax was calculated as follows using the maximum dosing rates of vasopressors and inotropes during the first 6 h after ED admission, which were retrieved from the ED information system: