Acute ozone exposure increases bronchial blood flow in conscious sheep.
This study was initiated to determine the effects of ozone (O3) on sheep airway blood flow. Twenty-three nasally intubated sheep were exposed to filtered air (n = 5), 1 ppm O3 (n = 4), 2 ppm O3 (n = 5), 3 ppm O3 (n = 5), and 4 ppm O3 (n = 4) for 3 h. Bronchial artery flow (Qbr) was measured using a chronically implanted 20 MHz pulsed Doppler flow probe. Qbr, mean aortic pressure, cardiac output, pulmonary artery pressure, arterial blood gases, and core temperature were monitored during the period of the exposures. Exposure to 3 and 4 ppm O3 resulted in a significant increase in Qbr (103 and 204% change, respectively) without affecting any of the other cardiopulmonary parameters measured. These results indicate that O3 induces a dose dependent increase in Qbr which is the result of a vasodilation of the bronchial vasculature which is not dependent upon changes in blood gases or upstream driving pressure.
Schelegle
E S
ES
Department of Medicine, School of Medicine, University of California, Davis.
Gunther
R A
RA
Parsons
G H
GH
Colbert
S R
SR
Yousef
M A
MA
Cross
C E
CE
D000281:Administration, Intranasal; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000502:physiology; D001831:Body Temperature; D001980:Bronchi / Q000098:blood supply* / Q000187:drug effects / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D003243:Consciousness / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D010126:Ozone / Q000008:administration & dosage / Q000494:pharmacology*; D011651:Pulmonary Artery / Q000187:drug effects / Q000502:physiology; D012039:Regional Blood Flow / Q000187:drug effects; D012756:Sheep / Q000502:physiology*; D013997:Time Factors; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
D010126:Ozone