A patient who has suffered a traumatic brain injury is admitted to the ICU with a ventriculostomy drain in place to monitor intracranial pressure. Which of the following nursing interventions is most important in preventing complications related to the ventriculostomy drain?

Clamp the drain for 10 minutes before moving the patient to reduce the risk of infection.

Flush the ventriculostomy drain with normal saline every shift to prevent obstruction.

Ensure that the drainage system is positioned at the correct level to maintain accurate ICP readings.

Position the patient flat in bed to ensure adequate drainage and prevent displacement of the drain.