Table 2.

CT-scan slice mass during PEEP titration procedure

Parameter	Descending PEEP titration steps
PEEPappl (cmH2O)	27.1 (25.3–27.7)	21.0 (19.8–22.1)	16.3 (15.6–17.2)	12.3 (12–13.1)	8.4 (7.7–9.2)	6.2 (5.9–6.9)	0.8 (0.5–1.7)
Slice mass (g)
Exp	4.8 (3.0–5.1)	4.9 (3.2–5.1)	5.3 (3.5–5.8)	6.0 (4.0–6.3)	6.7 (4.5–7.9)	7.4 (4.9–9.2)	8.6 (6.4–10.2)
Ins	4.4 (2.9–4.8)	4.6 (3.1–5.2)	4.9 (3.2–5.4)	5.5 (3.4–7.0)	6.2 (3.9–7.0)	6.6 (4.3–8.3)	7.5 (5.1–9.1)
Hyperinflated (g)
Exp	0.06 (0.02–0.12)	0.06 (0.01–0.1)	0.04 (0.01–0.08)	0.03 (0.00–0.05)	0.02 (0.00–0.06)	0.01 (0.00–0.03)	0.00 (0.00–0.00)
Ins	0.087 (0.03–0.15)	0.07 (0.03–0.12)	0.05 (0.02–0.10)	0.03 (0.01–0.07)	0.03 (0.01–0.06)	0.03 (0.01–0.06)	0.01 (0.00–0.04)
Normally (g)
Exp	2.7 (1.9–3.2)	2.8 (2.1–3.4)	2.61 (2.2–3.1)	2.16 (1.8–2.5)	1.79 (1.4–2.1)	1.59 (1.2–1.9)	0.83 (0.5–1.4)
Ins	2.67 (1.9–3.14)	2.69 (2.0–3.3)	2.73 (2.1–3.2)	2.30 (1.9–2.5)	1.89 (1.6–2.3)	1.70 (1.4–2.0)	1.15 (0.9–1.3)
Poorly (g)
Exp	1.4 (0.8–1.7)	1.3 (0.9–1.9)	2.0 (1.0–2.4)	2.7 (1.5–3.1)	2.5 (1.5–3.0)	2.3 (1.8–2.8)	2.3 (2.0–2.9)
Ins	1.0 (0.8–1.5)	1.3 (0.8–1.6)	1.5 (0.9–1.8)	2.1 (1.1–2.4)	2.0 (1.3–2.5)	1.9 (1.2–2.4)	2.0 (1.6–3.0)
Non-aerated (g)
Exp	0.3 (0.2–0.4)	0.3 (0.2–0.7)	0.4 (0.2–0.9)	0.9 (0.3–1.5)	2.3 (0.8–3.5)	3.5 (1.1–5.3)	5.6 (3.2–7.3)
Ins	0.3 (0.1–0.6)	0.3 (0.2–0.8)	0.5 (0.2–0.8)	0.8 (0.3–2.8)	2.3 (0.6–2.8)	3.0 (1.0–4.5)	3.8 (2.2–6.2)

Shown are the slice mass (absolute slice tissue mass, in grams), and the mass in hyperinflated compartments (Hyperinflated), in normally aerated compartments (Normally), in poorly aerated compartments (Poorly) and in the non-aerated compartments (Non-aerated). Data are presented as median (range). CT, computed tomography; Exp, end-expiratory slice; Ins, end-inspiratory slice; PEEP, positive end-expiratory pressure; PEEP_appl, applied positive end-expiratory pressure.