Air trapping and cardiopulmonary exercise testing in patients with mild to moderate bronchial obstruction: clinical role of trapped gas measurements.
In 14 patients with obstructive airways disease (7 atopic asthmatics, 7 COPD pts with stable disease, FEV1 < 65% pred., 11 m, 3 f, age 50.9 +/- 17.2 y) the effect of a beta mimetic agent on physical performance was studied.


METHODS
Inhalation of 2.5 ml normal saline (P) or salbutamol 0.1% (S) in double-blind random order on 2 successive days. Spirometry, body-plethysmography, single-breath helium dilution at rest. Spiroergometry with incremental workload to tolerance. The volume of trapped gas (D) was derived from: TLC Body-TLC Helium Single Breath.


RESULTS
Base line values revealed mild to moderate airways obstruction (FEV1 2.04 +/- 0.81 L, FEV1/VC 60.2 +/- 8.5%). Subsequent to inhaling S FEV1 increased significant by 20% to 2.38 +/- 0.87 L. There was a concomitant substantial improvement of VC (3.37 +/- 1.09 L to 3.60 +/- 0.93 L). Rs declined sign. (2.37 +/- 1.43 to 1.69 +/- 0.8 kPa*s), and so did D (1.15 +/- 0.73 L to 0.55 +/- 0.89 L = -20% from base line). Despite clear-cut bronchodilation exercise performance did not improve in response to S (114.6 +/- 49.3 vs 112.5 +/- 50.0 Watt max, ns). Base line max. VO2 (19.78 +/- 6.36 ml/min/kg) and VO2 at anaerobic threshold (13.29 +/- 3.21 ml/min/kg) suggested only minimal impairment of physical performance. S induced a small but significant decrease in max. VO2 (19.78 +/- 6.36 to 18.43 +/- 6.27 ml/min/kg, p < 0.025). Gas exchange (derived from AaDO2) was impaired at rest (30.18 +/- 10.4 mmHg) and during exercise (28.07 +/- 13.03 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)
Wassermann
K
K
IIIrd Medical Department, University of Cologne.
Pothoff
G
G
Subbe
C
C
Bahra
J
J
Hilger
H H
HH
D000328:Adult; D000368:Aged; D000420:Albuterol / Q000008:administration & dosage; D004311:Double-Blind Method; D005080:Exercise Test / Q000187:drug effects; D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000188:drug therapy / Q000503:physiopathology*; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D010993:Plethysmography, Whole Body; D011659:Pulmonary Gas Exchange / Q000187:drug effects / Q000502:physiology*; D012126:Respiratory Dead Space / Q000187:drug effects / Q000502:physiology; D013147:Spirometry
D000420:Albuterol