A patient with increased ICP has an external ventricular dra…

A patient with increased ICP has an external ventricular drain (EVD) in place, leveled at the tragus, with the drip chamber set to 10 cmH2O above the reference point. The nurse notes the ICP monitor reading is 24 mmHg with no CSF drainage in the collection chamber over the last hour despite the patient’s head position being unchanged. What is the priority nursing action?