Table 5.

The Impact of Spontaneous Effort on Local Lung Stretch (Delta Z) at High versus Low PEEP: Pig

	High PEEP						Low PEEP
	Nondependent		Middle		Dependent		Nondependent		Middle		Dependent
	−SB	+SB	−SB	+SB	−SB	+SB	−SB	+SB	−SB	+SB	−SB	+SB
Delta Z (lung stretch)	4 ± 1.8*†	3.7 ± 1.7*†	9.9 ± 3.1	8.7 ± 2.9	6.6 ± 2.1	10.3 ± 5.3†	8.9 ± 3.8	7.1 ± 2.5	14.1 ± 5.1‡	9.8 ± 3.8	2.9 ± 2.1	8.6 ± 6.0†
Fold vs. −SB		×0.9 ± 0.1		×0.9 ± 0.2		×1.6 ± 0.4		×0.8 ± 0.2		×0.8 ± 0.5		×4.5 ± 4.5

For definition of abbreviations, see Table 1.

Data presented are mean ± SD.

^*P < 0.05 compared with low PEEP + SB.

^†P < 0.05 compared with low PEEP − SB.

^‡P < 0.05 compared with other groups.