The effect of bronchofiberscopic examination on oxygenation status.

Arterial blood gases were measured in 62 patients, none of whom was critically ill, to determine the effect of transnasal fiberoptic bronchoscopy on oxygenation status. Blood samples were obtained at regular intervals during the procedure. Thirty-four patients who were bronchoscoped while breathing room air had a significant drop in the arterial P02 following saline solution lavage. Twenty-eight patients who were given 28 percent oxygen via a Ventimask during the procedure were protected from this hypoxemia. Simultaneously measured arterial pH and Pco2 were unchanged during the procedure. Premedication alone resulted in a minimal but insignificant drop in PaO2 in 7 patients. These observations suggest that if the initial PaO2 is less than 70 mm Hg on room air, bronchoscopy by the transnasal approach is best performed with the administration of oxygen through an appropriate mask. If the patient is at risk of developing hypercapnia with supplemental oxygen, a 28 percent Ventimask should be utilized to prevent significant hypoxemia without causing hypercapnia.