Airways Function During Mild Viral Respiratory Illnesses

Abstract

The effect of viral respiratory illnesses on pulmonary function was studied prospectively. Base-line studies on 52 normal subjects included a serum specimen, spirometry, lung volumes, "closing volumes," and maximal expiratory flow volume curves with air and with 80% helium and 20% oxygen (He-O2). Twenty-two subjects, 9 cigarette smokers and 13 nonsmokers, returned for serial studies at the onset of acute illness and at weekly intervals thereafter until after symptoms completely subsided. The illnesses were mild and similar except for greater duration of symptoms in smokers. Rhinovirus was the causative agent in 7 of 9 smokers and 9 of 13 nonsmokers. During illness pulmonary function changes occurred only in smokers and consisted of an increase in "closing volume" and a decrease in maximal expiratory flow rates with He-O2 at lung volumes near residual volume. The functional changes were reversible and are thought to indicate development or worsening of peripheral airways obstruction.