Table 1

Calculations for derived measures

Measure	Calculation
Pulmonary vascular resistance	(PAP−LAP)/PBF
Dynamic lung compliance	V_T / (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; V_T, tidal volume (mL).