Table 1

Effects of histamine/methacholine challenges

HistamineMethacholine
BeforeAfterBeforeAfter
FEV1 L3.2±0.12.0±0.1c3.1±0.12.0±0.1c
FEV1 % pred88±556±3c90±555±3c
Rrs cmH2O·L−1·s−14.1±0.57.5±1.2d4.1±0.67.3±1.2d
V'E L·min−15.2±0.36.0±0.4a5.3±0.46.1±0.3b
RR min−111±113±112±112±1
Pa,O2 mmHg98±173±4c95±168±3c
Pa,CO2 mmHg36±135±137±135±1
PA-a,O2 mmHg6±131±4c8±236±3c
V'O2 mL·min−1216±7223±9207±6229±11a
Log SDQ0.40±0.030.71±0.08d0.47±0.040.89±0.06c
Log SDV0.50±0.070.84±0.04d0.56±0.080.87±0.04d
DISP R-E*2.6±0.57.9±1.0c3.6±0.710.4±1.1c
HR min−175±478±373±377±2
Ps mmHg85±384±279±282±3
Q' L·min−15.8±0.36.2±0.25.6±0.35.7±0.3
  • Data presented as mean±sem. FEV1: forced expiratory volume in one second; Rrs: resistance of respiratory system; V'E: minute ventilation; RR: respiratory rate; Pa,O2: arterial oxygen tension; Pa,CO2: arterial carbon dioxide tension; PA-a,O2: alveolar-arterial oxygen tension; V'O2: oxygen uptake; Log SDQ: dispersion of pulmonary blood flow; Log SDV: dispersion of alveolar ventilation; DISP R-E*: dispersion of retention minus excretion of inert gases corrected for dead space; HR: heart rate; Ps: systemic arterial pressure; Q': cardiac output. a: p<0.05; b: p<0.01; c: p<0.001; d: p<0.005.