RT Journal Article
SR Electronic
T1 Diurnal variation in airflow obstruction in chronic bronchitis.
JF Thorax
JO Thorax
FD BMJ Publishing Group Ltd and British Thoracic Society
SP 618
OP 621
DO 10.1136/thx.36.8.618
VO 36
IS 8
A1 K D Dawkins
A1 M F Muers
YR 1981
UL http://thorax.bmj.com/content/36/8/618.abstract
AB Twelve patients fulfilling strict criteria for chronic obstructive bronchitis recorded serial peak expiratory flow rates (PEFR) five times daily for a two-week period. Despite a 9.2% improvement in forced expiratory volume in one second (FEV1) with ipratropium bromide, and an 11.3% improvement with ipratropium bromide plus salbutamol, the inherent diurnal variation in PEFR while on no medication was greater than the improvement caused by either bronchodilator. In the group as a whole, the difference between the highest and the lowest daily PEFR over the two weeks was 24% of the mean daily value. Using cosinor analysis, 10 of the 12 patients showed a significant rhythm in PEFR with a computed mean amplitude between highest and lowest readings of 8.6% of the mean daily value. This is no greater than that found in normal subjects, but is considerably less than the variation in PEFR in patients with bronchial asthma.