Aerosol clearance by the bronchial circulation.

The importance of the tracheobronchial circulation in supporting mucociliary clearance is unclear. In anesthetized, ventilated sheep (n = 8), mucociliary transport of 99mTc-labeled sulfur colloid particles (2.1 microns) was measured during control perfusion of the cannulated bronchial branch of the bronchoesophageal artery or when perfusion through this artery was stopped. Particle retention 60 min after aerosol delivery of particles averaged 55% during control bronchial blood flow conditions. When perfusion was stopped, average retention was significantly increased to 76% (p < 0.05). These results indicate that the bronchial vasculature exerts an important modulating influence on mucociliary transport.