During aortic valve replacement, the invasive radial arterial trace appears rounded and blunted, with a slow upstroke and absent dicrotic notch. The fast flush test shows a sluggish return to baseline without oscillations. Which displayed value remains most reliable despite this overdamping?

• A Mean arterial pressure ✓
• B Diastolic blood pressure
• C Systolic blood pressure
• D Arterial pulse pressure

Explanation

Overdamping flattens the waveform, causing underestimation of systolic pressure, overestimation of diastolic pressure, and narrowing of the displayed pulse pressure. Because these errors act in opposite directions on either side of the mean, the electronically integrated mean arterial pressure is minimally affected and remains the most reliable displayed value. The fast flush test confirms overdamping by showing a slow, undamped return to baseline instead of one or two crisp oscillations. Causes include clots, bubbles, kinking and long compliant tubing.

Reference: Miller's Anesthesia, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.