The nurse is suctioning the PT to obtain a sputum specimen. During the 10 seconds of suctioning, the cardiac monitor shows bradycardia and the PT becomes very diaphoretic. What is the best explanation for this occurrence?
1) PT demonstrated anxiety due to the procedure
2) The nurse caused hypoxia by suctioning for a prolonged time
3) Cardiac changes are unrelated to the procedure
4) The catheter caused direct stimulation of vagal nerve fibers