Ventilation-perfusion alterations induced by fiberoptic bronchoscopy.

Pulmonary perfusion (Q) and ventilation (V) scintiphotography was performed in 16 patients undergoing diagnostic fiberoptic bronchoscopic examinations. Regional V/Q did not change in the majority of the patients who developed hypoxemia after bronchoscopic studies. An improvement in V/Q was detectable in the patients with a rise in arterial oxygen pressure (PaO2) after bronchoscopic examination, and this rise was associated in most with the removal of mucous plugs or extensive secretions. The data indicate that the behavior of PaO2 after bronchoscopic study is dependent upon both the extent of lavage and the yield of the procedure in terms of secretions and plugs. The results also indicate that the removal of secretions or plugs can be associated with rapid return of regional V and Q.