Mechanical ventilation worsens abdominal edema and inflammation in porcine endotoxemia

Table 1 Ventilation pressures and arterial blood gases at Baseline and at 150 and 300 min (median and range).

	Study group	Baseline All healthy	150 minutes Healthy/LPS	Change to ventilation	300 minutes Healthy/LPS
P _aw max cm H ₂ O	PEEP 5 Healthy	18.5; 17-21	18.7; 17-22		21.2; 18-26
				CPAP 5 LPS	9.0; 8-10
	PEEP 5 LPS	20.1; 17-23	25.3; 18-35	PEEP 5 LPS	26.5; 25-32⁴
				PEEP 15 LPS	34.0; 32-37^4,5
P _aw mean	SB Healthy	2,0; 2.0-2.0	1.5; 1.0-3.0		1.0; 1.0-2.0
cm H ₂ O	PEEP 5 Healthy	9.0; 8.0-10.0¹	9.0; 8.0-10.0		9.0; 8.0-10.0¹
				CPAP 5 LPS	6.0; 5.0-6.0
	PEEP 5 LPS	8.3; 8.0-9.0	9.8; 9-11	PEEP 5 LPS	10; 9.0-11.0⁴
				PEEP 15 LPS	19.5; 19.0-20.0,^4,5
PaO ₂	SB Healthy	25.5; 22.2-27.2	25.3; 20.5-30.6		22.7; 15.1-25.9
mm Hg	PEEP 5 Healthy	37.7; 31.0-39.2¹	32.8; 29.8-36.8		32.5; 28.3-34.4¹
				CPAP 5 LPS	13.5; 8.2-39.5
	PEEP 5 LPS	33.1; 24.3-37.0	24.3; 6.9-36.5²	PEEP 5 LPS	25.4; 8.7-32.1
				PEEP 15 LPS	32.3; 26.4-34.4*
PaCO ₂	SB Healthy	5.5; 4.7-5.9	5.0; 4.7-5.3		5.0; 4.5-5.2
mm Hg	PEEP 5 Healthy	4.9; 4.1-5.3¹	4.8; 4.4-5.3		4.9; 4.4-5.3
				CPAP 5 LPS	6.7; 6.2-8.7³
	PEEP 5 LPS	4.7; 3.7-5.2	5.7; 4.4-6.6²	PEEP 5 LPS	5.5; 4.5-6.6⁴
				PEEP 15 LPS	5.1; 4.5-6.4⁴

(Peak airway pressure was not recorded in the healthy, spontaneously breathing pigs.) Note that the pigs given endotoxin (LPS) were all ventilated with PEEP 5 for the first 150 minutes (2.5 hours) and then either maintained on MV + PEEP 5 or switched to MV + PEEP 15 or SB + CPAP 5 for the next 2.5 hours (until 300 minutes); n = 6 in all groups. Significances (P < 0.05) after correction for multiple comparisons (Bonferroni):
Comparison with:
1: SB Healthy
2: Baseline
3: 150 minutes
4: CPAP 5 LPS
5: PEEP 5 LPS
*: indicates difference of borderline significance between MV+PEEP 15 and CPAP 5 (0.05 <P < 0.10; correction for multiple comparisons).

ISSN: 1364-8535