What significant threat to ventilation occurs during fiberoptic bronchoscopy?

The primary concern during fiberoptic bronchoscopy is the potential for airway obstruction. This procedure involves introducing a flexible bronchoscope through the trachea and into the bronchial tree, which can inadvertently lead to several complications, including the blockage of airflow. While the bronchoscope itself occupies space within the airway, it can obstruct or compress surrounding tissues, particularly if there is pre-existing swelling or if secretions build up during the procedure.

Additionally, local anesthesia and sedation used during the procedure can impact the patient's airway reflexes, further increasing the risk of obstruction. The procedure also involves the collection of secretions, which can temporarily occlude airways when not adequately managed. Therefore, monitoring for signs of airway patency and potential obstructions is crucial during and after the bronchoscopy.

The other options, while may have relevance, do not represent the most significant threat to ventilation during fiberoptic bronchoscopy. Excessive airway resistance generally refers to conditions long before the procedure, loss of PEEP through suctioning primarily pertains to ventilatory management rather than direct complications from bronchoscopy, and though vagal stimulation can occur, its impact compared to potential airway obstruction is usually lesser in this scenario.