Table 1

Thresholds used for different physiological parameters

ParametersLower thresholdsUpper thresholds
MAP (mm Hg)<50, <60, <70>100, >110, >120
HR (bpm)<40, <50, <60>90, >100, >110
SpO2 (%)<90, <95None
EtCO2 (mm Hg)<25, <30>40, >45
FiO2 <0.35, <0.45>0.75, >0.85
Temp (°C)<35, <35.5, <36>37, >37.5, >38
iVt (mL/kg)<5, <6>8, >9, >10
aVt (mL/kg)<5, <6>8, >9, >10
Ppeak (cmH2O)<10, <15>25, >30, >35
PEEP (cmH2O)<3>7, >10
PI<0.5, <1>6, >10
SctO2 (%)<50, <55, <60>75, >80, >85, >90
SstO2 (%)<50, <55, <60>75, >80, >85, >90
  • aVt, tidal volume based on actual body weight; bpm, beat per minute; EtCO2,  end-tidal carbon dioxide; FiO2,  inspired oxygen fraction; HR, heart rate; iVt, tidal volume based on ideal body weight; MAP, mean arterial pressure; PEEP, positive end-expiratory pressure; PI, perfusion index; Ppeak, peak airway pressure; SctO2,  cerebral tissue oxygen saturation; SpO2, pulse oxygen saturation; SstO2, somatic tissue oxygen saturation; Temp, temperature.