SIRS, in the appropriate clinical setting, is defined as the presence of two or more of the following: Temperature > 38.3° C or < 36.0° C Heart rate > 90 / minute Respiratory rate > 20 / minute or PACO2 < 32 mmHg White blood cell count > 12, 000 / mcL (12 × 10 9 / L), < 4, 000 / mcL (4 × 10 9 / L) or with > 10% bands Organ failure is defined using the modified Marshall scoring system (see table Modified Marshall Organ Failure Score; 1), which is based on laboratory and vital sign indicators of respiratory, renal, and cardiovascular impairment.