Table 1.

Data are presented as mean (sd) unless otherwise specified. Predicted body weight (PBW), Cardiopulmonary bypass (CPB), Coronary artery by-pass graft (CABG), Arterial partial pressure of O₂ $(P{\text{a}}_{{\mathrm{O}}_2})$, Fraction of inspired oxygen $(F{\mathrm{I}}_{{\mathrm{O}}_2})$, Arterial partial pressure of CO₂ $(P{\text{a}}_{\mathrm{C}{\mathrm{O}}_2})$

Patient characteristics
No. of patients	15
Age (yr)	70 (8)
Male/Female	13/2
Height (cm)	176 (13)
Weight (kg)	86 (18)
Predicted body weight (kg)	70 (13)
BMI	28 (4)
CPB time (min)	112 (35)
Type of surgery	CABG	Valve replacement	CABG+Valve replacement
	10	3	2
Haemodynamic data at ICU admission
Mean arterial pressure (mm Hg)	70 (9)
Heart rate (BPM)	77 (15)
Ventilator settings and respiratory measurements at ICU admission
Positive end-expiratory pressure (cm H2O)	8 (1)
Peak inspiratory pressure (cm H2O)	22 (2)
Expiratory tidal volume (ml)	494 (74)
Expiratory tidal volume/Predicted body weight (ml kg PBW−1)	7.1 (0.6)
Respiratory rate(Bpm)	17 (2)
$P{\text{a}}_{{\mathrm{O}}_2}/F{\mathrm{I}}_{{\mathrm{O}}_2}$ (mm Hg)	350 (101)
$P{\text{a}}_{\mathrm{C}{\mathrm{O}}_2}$ (mm Hg)	42.2 (4.5)