What would cause a high venous pressure alarm?

• A. Arterial needle against the wall of the vessel
• B. Venous needle is against the wall of the vessel
• C. Blood leak in the dialyzer
• D. Air in the line

Answer: (B)

High venous pressure means the return path from the dialyzer back to the patient is becoming obstructed on the venous side. When the venous needle or its tip sits against the wall of the vein, the flow path is narrowed, increasing resistance as blood tries to leave the dialyzer. That back pressure shows up as a rise in venous pressure, triggering the high venous pressure alarm to warn that blood isn’t flowing freely back to the patient.

The arterial-side issue would more likely affect arterial pressures or flow on the input side, not the venous return. A blood leak in the dialyzer causes a blood leak alarm, not a venous pressure alarm. Air in the line triggers an air/blood-jet or air detector alarm and can disrupt flow, but it’s a different alarm type than high venous pressure.