Diurnal variation in airflow obstruction in chronic bronchitis.
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.
D000368:Aged; D001991:Bronchitis / Q000188:drug therapy / Q000503:physiopathology*; D002908:Chronic Disease; D002940:Circadian Rhythm; D005260:Female; D005540:Forced Expiratory Flow Rates; D006801:Humans; D009241:Ipratropium / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate
D009241:Ipratropium