Table 3.

Intergroup analysis of mean partial pressure of oxygen/fraction of inspired oxygen ratio by Newman- Keuls test

Time periods	ZEEP versus PEEP	ZEEP versus IRM	PEEP versus IRM
Before intubation	0.994	0.960	0.677
After intubation	0.986	0.856	0.991
30 min after intubation	0.969	0.946	0.996
1:00 h after intubation	0.678	0.793	0.985
1:30 h after intubation	0.294	0.562	0.712
2:00 h after intubation	0.007	0.007	0.992
2:30 h after intubation	<0.001	<0.001	0.968
3:00 h after intubation	<0.001	<0.001	0.998
3:30 h after intubation	<0.001	<0.001	0.986
4:00 h after intubation	<0.001	<0.001	0.986
4:30 h after intubation	<0.001	<0.001	0.946
30 min postextubation	<0.001	<0.001	0.987
6:00 h after extubation	<0.001	<0.001	0.998
12:00 h after extubation	<0.001	<0.001	0.995
18:00 h after extubation	0.003	<0.001	0.971
24:00 h after extubation	0.024	0.006	0.929

ZEEP=Zero positive end-expiratory pressure, PEEP=Positive end-expiratory pressure, IRM=Intermittent lung recruitment maneuver