D i.e. >50% immature neutrophilsRef: Nelson, Textbook of Pediatrics, 20th edition, page 522Explanation:Systemic Inflammatory Response Syndrome (SIRS)It's an inflammatory cascade that is initiated by the host in response to infection, occurs when the host defense system does not adequately recognize or clear the infection.InfectionSuspected or proven infection or a clinical syndrome associated with high probability of infectionSystemic Inflamma-tory Response Syndrome (SIRS)2 out of 4 criteria, 1 of which must be abnormal temperature or abnormal leukocyte count1. Core temperature >38.5degC or <36degC (rectal, bladder, oral, or central catheter)2. Tachycardia: Mean heart rate >2 SD above normal for age in absence of external stimuli, chronic drugs or painful stimuli; OR unexplained persistent elevation over 0.5-4 hr; OR in children <1 year old persistent bradycardia over 0.5 hr (mean heart rate <10th percentile for age in absence of vagal stimuli, (3 blocker drugs, or congenital heart disease)3. Respiratory rate >2 SD above normal for age or acute need for mechanical ventilation not related to neuromuscular disease or general anesthesia4. Leukocyte count elevated or depressed for age (not secondary to chemotherapy) or >10% immature neutrophilsSepsisSIRS plus a suspected or proven infectionSevere SepsisSepsis plus 1 of the following:1 Cardiovascular organ dysfunction defined as:Despite >40 mL/kg of isotonic intravenous fluid in 1 hrHypotension <5th percentile for age, systolic blood pressure <2 SD below normal for age OR Need for vasoactive drug to maintain blood pressure OR2 of the following:Unexplained metabolic acidosis: Base deficit >5 mEq/LIncreased arterial lactate >2 times upper limit of normalOliguria: Urine output <0.5 mL/kg/hrProlonged capillary refill 5 secCore to peripheral temperature gap >3degC2.Acute respiratory distress syndrome (ARDS) as defined by the presence of a Pa02/Fi02 ratio <300 mm Hg, bilateral infiltrates on chest radiograph and no evidence of left heart failureORSepsis plus 2 or more organ dysfunctions (respiratory, renal, neurologic, hematologic or hepatic)Septic ShockSepsis plus cardiovascular organ dysfunction as defined aboveMultiple Organ Dysfunction Syndrome (MODS)Presence of altered organ function such that homeostasis cannot be maintained without medical intervention