Monday, February 18, 2008

Physiology Basics

A central venous line is put into an 80 year old to monitor fluid status. You notice on the central venous pressure waveform that there are no "a" waves. Your attending tells you that he should be put on warfarin.

Challenge: What would you see on an EKG?

Related Questions:
1. What is the cause of "a" waves on a central venous pressure waveform?
2. Why the warfarin?


Alex said...

a waves = atrial contraction. no a waves could mean a-fib, so warfarin to prevent dangerous clots.

Craig said...

Physiology Basics

"A" waves represent right atrial contraction, leading to increased atrial pressure; it would correlate with the P wave on an EKG. The loss of "a" waves is characteristic of atrial fibrillation. The warfarin is important to prevent clot formation leading to a stroke.

Source: Wikipedia, University of Virginia Health System website.