At last two of the following criteria, one being abnormal temperature or leukocyte
count.
Hyper or hypothermia, defined as core temperature of > 38. 3 °C or <
36 °C.
Tachycardia or bradycardia (for children <1 year old). Tachycardia is
defined as a mean heart rate >2 SD above mean for age or otherwise
unexplained persistent elevation over a 0.5-to 4-hr time period. Similarly,
bradycardia is defined as a mean heart rate <10th percentile for age in the
absence of external vagal stimulus, β-antagonists, or congenital heart
disease or otherwise unexplained persistent depression over a 0.5-hr time
period.
Tachypnea, defined as mean respiratory rate > 2 SD above normal for
age or need for mechanical ventilation, except if secondary to recent
general anesthesia administration and/or underlying neuromuscular
disease.
Leukocytosis or leukopenia, defined as elevated or depressed counts
for age (excluding chemotherapy-induced leukopenia) or presence of
>10% immature neutrophils.