Table 2.

Quantitative CT analysis parameters

Parameter	All (N = 42)			Non-recruiters (N=32)			Recruiters (N=10)
	PEEP 8 cmH2O	PEEP 16 cmH2O	p	PEEP 8 cmH2O	PEEP 16 cmH2O	p	PEEP 8 cmH2O	PEEP 16 cmH2O	p
Total lung volume (ml)	3076 [2610–3810]	3461 [2982–4190]	<0.001*	3120 [2687–3727]	3575 [3107–4150]	<0.001*	2619 [2331–3907]	2953 [2454–4645]	0.005*
Total lung weight (g)	1515 [1295–1811]	1539 [1336–1852]	0.866	1504 [1274–2091]	1520 [1322–2126]	0.080	1532 [1302–1773]	1455 [1244–1728]	0.116
Excess lung weight (%)	56.6 [24.0–74.8]			56.7 [23.2–90.5]			55.0 [26.3–59.59]
Gas volume (ml)	1360 [1064–2118]	1858 [1301–2599]	<0.001*	1448 [1105–2159]	1931 [1459–2583]	<0.001*	1216 [701–2115]	1540 [1085–2957]	0.005*
Mean attenuation (HU)	-526 [-591–-329]	-565 [-637–-404]	<0.001*	-549 [-616–-333]	-581 [-644–-405]	<0.001*	-434 [-541–-301]	-539 [-634–-379]	0.005*
Hyper-aerated mass (g)	14 [7–28]	23 [12–39]	<0.001*	17 [8–29]	26 [13–39]	<0.001*	12 [5–17]	17 [8–43]	0.005*
Normally aerated mass (g)	367 [259–465]	424 [347–528]	<0.001*	375 [307–462]	440 [366–532]	<0.001*	331 [190.9–504.4]	383 [267.4–520.3]	0.005*
Poorly aerated mass (g)	504 [391–671]	487 [346–673]	<0.001*	504 [388–687]	496 [349–683]	0.001*	477 [393.9–587.5]	433 [328.1–580.8]	0.093
Non aerated mass (g)	625 [377–810]	576 [354–775]	<0.001*	564 [375–785]	581 [350–854]	0.014*	737 [515.7–819.1]	573 [435.2–710.4]	0.005*
Dynamic lung strain	0.33 [0.23–0.46]	0.26 [0.19–0.35]	<0.001*	0.33 [0.24–0.43]	0.25 [0.19–0.3]	<0.001*	0.41 [0.22–0.63]	0.33 [0.16–0.45]	<0.005*

Data are presented as median [interquartile range]

PEEP positive end-expiratory pressure, HU Hounsfield Units, IQR interquartile range, CI confidence interval

*Signigicant difference between PEEP levels, p < 0.05