Table 1 (abstract P169) Results

	Supine (N = 40)	Prone (N = 40)	p
PaO2/ FiO2 ratio, mmHg	166 [136, 224]	314 [232, 398]	< 0.001
Respiratory rate, breaths/min	20 [17, 24]	17 [15, 19]	< 0.001
Esophageal pressure, cmH2O	-7 [-9, -5]	-6 [-9, -5]	0.306
Pes * respiratory rate, cmH2O/min	152 [104, 197]	118 [90, 150]	< 0.001
Pes*tidal volume*respiratory rate, cmH2O * l/min	65 [46, 88]	51 [34, 67]	< 0.001
Tidal volume, ml/kg	6.9 [6.0, 7.9]	6.9 [5.7, 7.9]	0.517
Stress, cmH2O	17 [14, 19]	16 [14, 18]	0.34