2.5 Clinical Data Collection

The baseline characteristics of the patients were collected at the time of enrollment. The collected data included age, sex, ratio of septic shock to sepsis, ratio of ventilated to nonventilated patients, source of infection, vital signs, laboratory data, arterial blood gas (ABG), fraction inspired oxygen to partial pressure of oxygen, APACHE II score (Knaus et al., 1985), Glasgow Coma Scale score (Teasdale and Jennett, 1974), and SOFA scores (Vincent et al., 1996). The level of procalcitonin (PCT) was also measured at this time (Dandona et al., 1994).

The primary outcome was change in SOFA score (ΔSOFA), which was calculated by subtracting the final SOFA score at 120 h (5 days) from the corresponding initial value at enrollment. If the patient died within 120 h after enrollment, the worst score collected before death was used in the analysis.

Secondary outcomes included 7-days mortality, 28-days mortality, ICU length of stay, and percentage of shock reversal. Reversal of shock was defined as maintaining a stable systolic arterial pressure (>90 mm Hg) for ≥24 h without catecholamine or resuscitation fluid infusion (Bollaert et al., 1998). Shock reversal was assessed for 28 days follow up period or until patient was discharged or died. Besides, at 120 h after enrollment the following secondary outcomes were measured; percentage of progression to septic shock from sepsis, mean increase in vasopressor dose, percentage of patients who required combined vasopressors, percentage of patients with increased vasopressor dose, percentage reduction of PCT, percentage of patients with reduced PCT level, percentage of patients who achieved ≥50% reduction in PCT, and change in lactate. For lactate, if the patient died within 120 h after enrollment, the last follow-up values were used.

Safety outcomes included the percentage of patients who required atropine, percentage of patients who were reventilated, percentage of patients with hyperglycemia (blood glucose >300 mg/dl or new insulin infusion during 120 h after enrollment), hypernatremia (serum sodium >150 mmol/L during 120 h after enrollment), serious allergic reaction such as anaphylaxis, and any other unexpected adverse event.

The PCT level was measured at baseline and at 120 h after enrollment using a standard phlebotomy procedure. The serum sample was separated by centrifugation and measured by Suresign Finecare^™ FIA Procalcitonin Rapid Test (Suresign Professional, United Kingdom). This method is based on the fluorescence immunoassay principle and is used professionally in hospitals and laboratories. The measuring range was 0.1–100 ng/ml. Intralot precision was determined by using 10 test cartridges of the same batch to test the PCT and coefficient of variability (CV; ≤15%). In addition, interlot precision was determined by using three random and continuous batches to test PCT and CV (≤15%).