Tachypnea (high respiratory rate), which is defined as more than 20 breaths per minute, or when testing blood gas, a PaCO 2 less than 32 mmHg, which signifies hyperventilation. White blood cell count either significantly low, (< 4000 cells/mm3) or elevated (> 12000 cells/mm3). Tachycardia (rapid heart rate), which in sepsis is defined as a rate greater than 90 beats per minute.