Computed tomographic assessment of lung aeration at different positive end-expiratory pressures in a porcine model of intra-abdominal hypertension and lung injury

Intensive Care Medicine Experimental

Table 2 Optimum PEEP relative to titration targets

PEEP titration targets	Healthy lungs PEEP, cmH₂O	Injured lungs PEEP, cmH₂O	p
P/F ratio, highest	12 (12, 27)	22 (22, 22)	0.416
E_rs,, lowest	22 (22, 22)	22 (22, 22)	0.317
E_W, lowest	22 (17, 22)	22 (17, 22)	0.854
E_L, lowest	22 (22, 22)	22 (17, 22)	0.180
C.O., highest	5 (5, 5)	5 (5, 5)	0.317
Lung gas volume, highest	27 (27, 27)	27 (27, 27)	1.000
Overdistended lung, least	5 (5, 5)	5 (5, 5)	1.000
Normally aerated lung, most	27 (27, 27)	27 (27, 27)	1.000
Atelectatic lung, least	27 (27, 27)	27 (27, 27)	1.000
Lower inflection point
Lung gas volume	8.9 (8.6, 9.4)	9.5 (9.2, 10.4)	0.138
Overdistended lung	14.9 (14.1, 14.9)	13.3 (12.5,14.6)	0.345
Normally aerated lung	8.3 (7.9, 8.4)	9.2 (9.1, 9.4)	0.043
Atelectatic lung	7.5 (6.6, 7.5)	8.1 (7.9,8.3)	0.345
Upper inflection point
Lung gas volume	29.0 (28.4, 29.1)	28.6 (27.5, 29.8)	0.500
Overdistended lung	34.8 (34.5, 36.4)	29.7 (24, 31.8)	0.225
Normally aerated lung	27.1 (26.0, 28.4)	29.0 (28.2, 29.4)	0.043
Atelectatic lung	15.1 (15.0, 15.3)	22.3 (21.3, 22.4)	0.043

Bold indicates significant p-values or lower inflection points of atelectatic and overdistended lung with the difference defining an “optimal CT inflation PEEP range”
Median (IQR) are shown
PEEP positive end-expiratory pressure; P/F ratio arterial oxygen tension/fractional inspiratory concentration of oxygen; E elastance; _rs respiratory system; _W chest wall; _L lung; C.O. cardiac output