Table 3

Effect of PEEP on gas exchange and respiratory mechanics

PEEP 20

PEEP 15

PEEP 10

PEEP 5

P < 0.05 PEEP-level between groups:

PaO₂/FiO₂

Normal IAP

238.67 ± 87.84^c

232.65 ± 85.17

191.33 ± 40.59

169.85 ± 44.09

NS

IAH

218.72 ± 70.13^c

208.67 ± 67.54^e

181.25 ± 55.45

161.13 ± 47.59

PaCO₂, mmHg

Normal IAP

46.44 ± 8.20

46.40 ± 8.18

46.85 ± 8.12

46.88 ± 8.17

NS

IAH

45.64 ± 8.44

47.00 ± 8.22

44.55 ± 7.43

45.27 ± 8.31

pH

Normal IAP

7.34 ± 0.1

7.34 ± 0.11

7.34 ± 0.10

7.34 ± 0.11

NS

IAH

7.37 ± 0.06

7.38 ± 0.06

7.39 ± 0.04

7.39 ± 0.06

VT (ml/kg IBW)

Normal IAP

5.35 ± 0.43

5.36 ± 0.39

5.30 ± 0.43

5.31 ± 0.40

NS

IAH

5.53 ± 0.30

5.58 ± 0.28

5.59 ± 0.32

5.59 ± 0.30

RR, breaths/min

Normal IAP

18.30 ± 3.20

18.30 ± 3.20

18.30 ± 3.20

18.30 ± 3.20

NS

IAH

16.70 ± 3.20

16.70 ± 3.20

16.90 ± 3.21

16.90 ± 3.21

PEEP, cmH₂O

Normal IAP

20.00 ± 0.00

15.00 ± 0.00

10.00 ± 0.00

5.00 ± 0.00

20,15,10,5

IAH

20.00 ± 0.00

15.00 ± 0.00

10.00 ± 0.00

5.00 ± 0.00

Pplat, cmH₂O

Normal IAP

36.30 ± 6.40^{a, b, c}

28.90 ± 3.21^{d, e}

23.50 ± 2.92^f

19.60 ± 3.66

NS

IAH

35.80 ± 3,77^{a, b, c}

29.20 ± 3.16^{d, e}

24.50 ± 3.50^f

22.10 ± 4.70

Pes insp, cmH₂O

Normal IAP

22.70 ± 5.83^{a, b, c}

20.00 ± 3.94^{d, e}

17.80 ± 3.71^f

16.90 ± 4.36

NS

IAH

24.69 ± 2.92^{a, b, c}

21.15 ± 3.42^e

19.25 ± 4.44^f

18.85 ± 6.48

Pes exp, cmH₂O

Normal IAP

16.40 ± 4.50^{a, b, c}

14.50 ± 3.63^{d, e}

12.50 ± 3.31^f

11.20 ± 3.52

NS

IAH

16.91 ± 3.57^{a, b, c}

14.35 ± 2.58^{d, e}

12.55 ± 3.25^f

11.65 ± 3.53

Ptranspul insp, cmH₂O

Normal IAP

16.60 ± 9.65^{a, b, c}

11.90 ± 5.11^{d, e}

8.70 ± 3.33^f

5.70 ± 3.74

NS

IAH

13.64 ± 3.75^{a, b, c}

11.05 ± 3.88^{d, e}

8.25 ± 4.97

6.25 ± 5.47

Ptranspul exp, cmH₂O

Normal IAP

6.60 ± 4.50^{a, b, c}

3.50 ± 3.63^{d, e}

0.50 ± 3.31^f

-3.20 ± 3.52

NS

IAH

6.09 ± 3.57^{a, b, c}

3.65 ± 2.58^{d, e}

0.45 ± 3.25^f

-3.65 ± 3.53

FiO₂ = fraction of inspired oxygen; IAH = intra-abdominal hypertension; IAP = intra-abdominal pressure; IBW = ideal body weight; NS = not significant; PaCO₂ = partial pressure of arterial carbon dioxide; PEEP = positive end-expiratory pressure; Pes exp = expiratory esophageal pressure; PaO₂ = partial pressure of arterial oxygen; Pes insp = inspiratory esophageal pressure; Pplat = inspiratory plateau pressure; Ptranspulexp = expiratory transpulmonary pressure; Ptranspul insp = inspiratory transpulmonary pressure; RR = re spiratory rate; V_T = tidal volume.

^aP < 0.05 PEEP 20 vs. PEEP 15; ^bP < 0.05 PEEP 20 vs. PEEP 10; ^cP < 0.05 PEEP 20 vs. PEEP 5; ^dP < 0.05 PEEP 15 vs. PEEP 10; ^eP < 0.05 PEEP 15 vs. PEEP 5: ^fP < 0.05 PEEP 10 vs. PEEP 5.

Data are presented as mean ± standard deviation

Krebs et al. Critical Care 2009 13:R160   doi:10.1186/cc8118