Does a Pulmonary Artery Catheter Have Continuous Fluid Running Through It?
No, a pulmonary artery catheter does not require continuous fluid infusion through its lumens during routine monitoring. The catheter measures pressures and cardiac output through its internal channels, but these are typically maintained patent with intermittent flush systems rather than continuous fluid administration.
Technical Design and Fluid Management
The PAC contains multiple lumens that are kept patent using pressurized flush systems, similar to arterial lines, where small volumes of heparinized saline maintain catheter patency without continuous fluid administration 1, 2.
Modern PACs use thermal filament technology for continuous cardiac output measurement, which heats blood at random intervals rather than requiring fluid injection, eliminating the need for repeated cold saline boluses 3, 2.
The catheter's pressure monitoring lumens connect to transducers that must be zeroed at the mid-thoracic line, but this involves fluid-filled tubing systems external to the patient rather than continuous infusion through the catheter itself 4, 5.
Intermittent vs. Continuous Measurements
Traditional thermodilution cardiac output measurement requires intermittent bolus injections of cold saline (typically 10 mL) into the right atrium, with temperature change measured downstream in the pulmonary artery 6, 3.
Contemporary PACs provide semi-continuous cardiac output monitoring using a thermal filament that periodically warms the blood, eliminating the need for repeated manual fluid injections 6, 3.
The balloon inflation port requires only intermittent use when obtaining pulmonary capillary wedge pressure measurements, with the balloon deflated during routine monitoring to prevent pulmonary artery complications 1.
Infection Prevention Considerations
Administration sets connected to PACs should be changed no more frequently than every 72 hours, as more frequent changes do not reduce infection risk and may increase costs 1.
The protective plastic sleeve that covers the PAC during insertion significantly reduces catheter-related bloodstream infections compared to catheters placed without this barrier 1.
PAC-related infection risk increases significantly after 5-7 days of catheter residence, with catheter-related bloodstream infection rates of 2.6 per 1,000 catheter days for heparin-bonded catheters 1.
Common Pitfall to Avoid
Do not confuse the pressurized flush system with continuous fluid infusion—the flush system delivers only 1-3 mL/hour to maintain catheter patency, which is negligible compared to the patient's overall fluid balance and should not be considered a source of continuous fluid administration 1.