title: Symptomatic bronchoconstriction after short-term inhalation of sulfur dioxide.
abstract: We studied the relationship between duration and concentration of exposure in SO2-induced bronchoconstriction in 8 asthmatic subjects. On separate days, we administered SO2 in humidified air through a mouthpiece at 2 concentrations (0.5 and 1.0 ppm) for 3 time periods (1, 3, and 5 min) during eucapnic hyperpnea (60 L/min). Humidified air was administered for 5 min as a control. Bronchoconstriction was assessed by measurement of specific airway resistance (SRaw). The magnitude of the bronchoconstrictor response to both concentrations of SO2 increased progressively over the 3 time periods studied. The mean (+/- SE) increase in SRaw (in L x cm H2O/L/s) and percent increase above baseline (in parentheses) after each exposure to SO2 were as follows: 2.5 +/- 0.3 (34%) after 0.5 ppm for 1 min; 7.5 +/- 4.7 (93%) after 1.0 ppm for 1 min; 13 +/- 3.2 (173%) after 0.5 ppm for 3 min; 31.4 +/- 7.4 (395%) after 1.0 ppm for 3 min; 19.6 +/- 4.0 (234%) after 0.5 ppm for 5 min; 44.1 +/- 9.8 (580%) after 1.0 ppm for 5 min; 3.5 +/- 1.5 (46%) after humidified air for 5 min. For the group, the increases in SRaw caused by inhalation of both concentrations of SO2 for 1 min were small. However, 2 of 8 subjects did develop large increases in SRaw and chest tightness after inhalation of 1.0 ppm for 1 min. Seven of 8 subjects developed wheezing, chest tightness, or dyspnea and used an inhaled bronchodilator after inhalation of 0.5 ppm for 3 and 5 min and 1.0 ppm for 3 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)
authors: Lung Biology Center, Francisco General Hospital, University of California.
authors: J R
authors: JR
authors: Balmes
authors: J M
authors: JM
authors: Fine
authors: D
authors: D
authors: Sheppard
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000403:Airway Resistance / Q000187:drug effects*; D001249:Asthma / Q000503:physiopathology*; D001980:Bronchi / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D006985:Hyperventilation / Q000503:physiopathology; D008297:Male; D013458:Sulfur Dioxide / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D013458:Sulfur Dioxide