Table 1

Calculations for derived measures

Pulmonary vascular resistance(PAP−LAP)/PBF
Dynamic lung complianceVT / (PIP−PEEP)
Arterial oxygen content (CaO2)35 1.39×Hb×SaO2/100+0.003×PaO2
Cerebral oxygen delivery35 Carotid arterial blood flow×CaO2
  • Hb, arterial haemoglobin concentration (g/L); LAP, left atrial pressure, assumed to equal 9 mm Hg based on previous studies36; PAP, pulmonary arterial pressure (mm Hg); PaO2, partial pressure of arterial oxygen (mm Hg); PBF, pulmonary blood flow (mL/min); PEEP, positive end expiratory pressure (cmH2O); PIP, peak inspiratory pressure (cmH2O); SaO2, arterial oxygen saturation; VT, tidal volume (mL).