TABLE 4.

Variability in recruitment–derecruitment (R/D) in relation to decremental or incremental positive end-expiratory pressure (PEEP) level.

	x	y	h	p
PEEP 0	Up	Down	1	0.0087
PEEP 3	Up	Down	0	0.0947
PEEP 6	Up	Down	0	0.6580
PEEP 9	Up	Down	0	0.7788
PEEP 12	Up	Down	0	0.5672

The table shows the significance of difference in variability between PEEP levels of incremental or decremental part of the ventilatory protocol according to Ansari–Bradley test. The results show non-significance except for PEEP level 0. The variability of R/D was significantly less in PEEP 0 during decremental stage of the protocol compared to the initial part of the protocol. This might indicate a stabilization of lung regions in response to a recruitment maneuver. h = 1 represents significant differences. h = 0 represents non-significant differences.