Table 1

Respiratory variables during methacholine and positive airway pressures

Methacholine (control)

Methacholine (study)

Before

During

IPAP

EPAP

CPAP

Vt (ml)

87 ± 17

139 ± 9*

194 ± 9^‡

175 ± 13^‡

200 ± 13^‡

Respiratory rate (breaths/min)

40 ± 5

71 ± 8^†

56 ± 6^‡

47 ± 6^‡

59 ± 9^‡

Ve (l/min)

7.2 ± 0.9

10.1 ± 1.0*

11.4 ± 1.1

9.3 ± 1.4

11.2 ± 1.6

Vinsp, peak (l/min)

22 ± 2

24 ± 3

32 ± 3^‡

32 ± 4^‡

28 ± 3

Vt/Ti (ml/s)

306 ± 29

368 ± 36

449 ± 40

446 ± 56

423 ± 54

Ti/Ttot

0.39 ± 0.02

0.46 ± 0.01*

0.41 ± 0.02

0.38 ± 0.04

0.43 ± 0.02

Vexp, peak (l/min)

33 ± 2

27 ± 3

29 ± 3

28 ± 3

32 ± 3

Vt/Te (ml/s)

313 ± 21

331 ± 30

359 ± 25

345 ± 33

368 ± 52

Te/Ttot

0.42 ± 0.04

0.52 ± 0.01

0.53 ± 0.02

0.49 ± 0.05

0.52 ± 0.03

C dyn, lung (ml/cmH₂O)

70 ± 7

40 ± 4*

28 ± 3^‡

20 ± 2^‡

43 ± 4

C dyn, cw (ml/cmH₂O)

124 ± 21

49 ± 7^†

61 ± 9

36 ± 6

79 ± 17

C dyn, rs (ml/cmH₂O)

232 ± 50

92 ± 10*

91 ± 8

60 ± 8^‡

105 ± 8

Ptp, exp (cmH₂O)

-0.4 ± 0.6

-0.8 ± 0.5

1.4 ± 0.9

5.0 ± 1.3^‡

5.6 ± 1.1^‡

Pabd, exp (cm H₂O)

4.5 ± 0.9

9.1 ± 1.8*

10.0 ± 1.9

11.3 ± 1.5

11.0 ± 2.0

Ppl, exp (cmH₂O)

-0.6 ± 0.1

2.2 ± 0.2

4.0 ± 0.2^‡

4.9 ± 0.2^‡

4.6 ± 0.3^‡

C dyn, cw; dynamic compliance of the chest wall; C dyn, lung, dynamic compliance of the lung; C dyn, rs, dynamic compliance of the respiratory system; Pabd, exp, end-expiratory abdominal pressure; Ppl, exp, end-expiratory pleural pressure; Ptp, exp, end-expiratory transpulmonary pressure; Te, expiratory time; Ti, inspiratory time; Ttot, duration of one breath; Ve, minute ventilation; Vexp, peak, peak expiratory volume; Vinsp, peak, peak inspiratory volume; Vt, tidal volume. *P < 0.05, versus pre-methacholine values; ^†P < 0.005, versus pre-methacholine values; ^‡P < 0.05, versus post-methacholine control values.

Miro et al. Critical Care 2004 8:R72