Table 1 The pre-injury effect of 10 cmH ₂ O PEEP on variables reflecting cardiopulmonary function and breath sound spectral power in six anesthetized, mechanically ventilated uninjured pigs

Heart rate (bpm)

86 ± 16

84 ± 12

81 ± 13

NS

Mean blood pressure (mmHg)

88 ± 13

74 ± 11

93 ± 11

<0.01

Cardiac output (L/min)

4.0 ± 0.4

2.6 ± 0.7

3.9 ± 0.6

<0.01

P_aO₂ (mmHg)

92 ± 18

102 ± 20

97 ± 16

NS

P_aCO₂ (mmHg)

37 ± 2

37 ± 3

39 ± 2

NS

pHa

7.44 ± 0.01

7.45 ± 0.03

7.42 ± 0.02

NS

SaO₂ (%)

94 ± 3

95 ± 3

94 ± 4

NS

Venous admixture (%)

19 ± 13

10 ± 12

13 ± 14

<0.05

C_st (ml/cmH₂O)

30 ± 6

26 ± 4

33 ± 4

NS

Average spectral power (dB)

−65.2 ± 7.8

−68.3 ± 4.8

−67.6 ± 3.9

NS

Spectral power 150 to 1,200 Hz (dB)

−60.1 ± 7.1

−64.2 ± 4.7

−62.6 ± 3.2

<0.05

Spectral power 1,200 to 3,000 Hz (dB)

−67.8 ± 8.2

−70.4 ± 4.9

−70.3 ± 4.4

NS