To what level should the extraventricular drain transducer be transported?

• A. Heart level
• B. At the level of the tragus of the ear
• C. Umbilicus level
• D. Xiphoid process

Answer: (B)

Positioning the transducer at the level of the tragus of the ear establishes the reference point that corresponds to the brain’s ventricular level when the patient is supine. This placement aligns with the foramen of Monro, providing an accurate ICP reading. If the transducer is placed lower, such as at the umbilicus or xiphoid, the hydrostatic column between the brain and transducer is longer, producing a falsely elevated ICP. If placed higher, toward the heart, the reading will be falsely low because the transducer sits above the ventricular level. Therefore, the appropriate level is the tragus.