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Table 2 Phase II protocol: physiologic parameters

From: Effect of positive end-expiratory pressure and tidal volume on lung injury induced by alveolar instability

  

Tween

 

Baseline

Instillation

30 min

60 min

90 min

120 min

150 min

180 min

High Vt plus low PEEP

   Ppeak

23 ± 0.6

31 ± 1.3*

37 ± 1.9*†

38 ± 2.0*†

37 ± 2.0*†

37 ± 2.0*†

37 ± 2.0*†

36 ± 1.9*†

   Pmean

9 ± 0.4

11 ± 0.1*

12 ± 0.3*

12 ± 1.0*

12 ± 1.0*

12 ± 1.0*

12 ± 1.0*

11 ± 0.3*

   Cstat

30 ± 4

18 ± 3*

17 ± 2*

15 ± 3*

18 ± 2*

18 ± 2*

19 ± 2*

19 ± 2*

   CO

8.5 ± 1

6.6 ± 1.2

4.9 ± 0.6*

3.7 ± 0.8*†

3.3 ± 0.4*†

3.4 ± 0.5*†

3.4 ± 0.5*†

2.7 ± 0.3*†

   SAT

100 ± 1

80 ± 2.3*

84 ± 1.0*

90 ± 4.2*

91 ± 1.2

92 ± 1.5*

92 ± 0.6*

90 ± 1.0*

   PO2

295 ± 22

54 ± 5*

53 ± 3*

64 ± 8*

65 ± 5*

70 ± 5*

71 ± 6*

71 ± 4*

   PCO2

38 ± 0.6

51 ± 2.7*

41 ± 2.0†

36 ± 3.2†

36 ± 1.9†

35 ± 4.1†

33 ± 2.5†

32 ± 0.6†

   pH

7.52 ± 0.1

7.42 ± 0.1

7.49 ± 0.1

7.51 ± 0.1

7.53 ± 0.1

7.53 ± 0.1

7.54 ± 0.1

7.54 ± 0.1

   Aa

28 ± 13

596 ± 5*

566 ± 40*

578 ± 27*

572 ± 17*

543 ± 25*

520 ± 34*

523 ± 34*

Low Vt/high PEEP

   Peak

23 ± 1.0

33 ± 0.9*

49 ± 0.9*†

40 ± 1.8*†

42 ± 2.0*†

42 ± 2.5*†

42 ± 3.1*†

43 ± 3.8*†

   Pmean

10 ± 0.9

12 ± 0.6*

25 ± 0.3‡*†

24 ± 0.3*†‡

25 ± 0.3*†‡

25 ± 0.7*†‡

25 ± 0.7*†‡

26 ± 0.9*†‡

   Cstat

33 ± 4

19 ± 2*

12 ± 1*†

12 ± 1*†

12 ± 1*†

13 ± 2*†

15 ± 2*†

15 ± 2*†

   CO

7.4 ± 1.8

8.9 ± 0.8

8.1 ± 0.8‡

6.6 ± 0.8

5.8 ± 1.3

5.0 ± 1.4*

5.9 ± 1.9

5.0 ± 2.0*

   SAT

99 ± 0.3

64 ± 3.2‡ *

98 ± 0.3†‡

96 ± 1.0†

95 ± 0.3†‡

88 ± 6.5†

98 ± 0.8†‡

98 ± 1.0†‡

   PO2

361 ± 115

59 ± 14*

216 ± 62‡

178 ± 37‡

139 ± 14‡

127 ± 10‡

138 ± 15‡

142 ± 15*‡

   PCO2

49 ± 1.9‡

62 ± 0.7‡

108 ± 8.9*†‡

122 ± 15*†‡

119 ± 15*†‡

114 ± 13*†‡

112 ± 17*†‡

103 ± 14*†‡

   pH

7.41 ± 0.1‡

7.30 ± 0.1*‡

7.12 ± 0.1*†‡

7.07 ± 0.1*†‡

7.07 ± 0.1*†‡

7.06 ± 0.1*†‡

7.05 ± 0.1*†‡

7.09 ± 0.1*†‡

   Aa

53 ± 15

576 ± 14*

362 ± 64*†

382 ± 46*†‡

425 ± 30*†‡

444 ± 27*†

463 ± 36*†

473 ± 31*†

  1. The physiologic parameters recorded were peak airway pressure (Ppeak; cmH2O), mean airway pressure (Pmean; cmH2O), airway plateau pressure (Pplat; cmH2O), static pulmonary compliance (Cstat; ml/cmH2O), cardiac output (CO; l/min), hemoglobin oxygen saturation (SAT; %), partial arterial oxygen tension (PO2; mmHg), partial arterial carbon dioxide tension (PCO2; mmHg), and alveolar arterial oxygen gradient (Aa; mmHg). Data are expressed as mean ± standard error. *P < 0.05 versus baseline;†P < 0.05 versus post-Tween; ‡P < 0.05 versus the high Vt/low PEEP group. Vt, tidal volume; PEEP, positive end-expiratory pressure.