Flow-directed pulmonary artery catheters are used as an invasive method to monitor hemodynamic status in critically ill patients and in diagnostic and therapeutic procedures in cardiology. Pulmonary artery (PA) catheters are also called Swan-Ganz catheters.
PA catheters can directly measure:
-Central venous pressure (CVP)
-Right-sided intracardiac pressures
-Pulmonary arterial pressure (PAP)
-Pulmonary artery wedge pressure, also called pulmonary capillary wedge pressure (PCWP)
In addition, automated thermodilution can be used to estimate cardiac output in a patient with a pulmonary artery Swan-Ganz catheter. Once vascular pressures and cardiac output are determined, this data can then be used to calculate systemic vascular pressures and pulmonary vascular pressures.
One additional useful aspect of Swan Ganz catheterization of critically ill patients is that samples of mixed venous blood can easily be drawn from Swan Ganz (PA) catheters. The mixed venous blood allows the clinician to quantify actual oxygen utilization by the patient.
PA catheters are an invasive means to measure the hemodynamic status of ill patients and are associated with fairly significant risks. PA catheters should only be placed when there is a specific question regarding a patient’s hemodynamic status that cannot be answered by clinical or noninvasive means.
Indications for the placement of a PA catheter includes diagnostic uses such as:
-Assessment of intravascular volume status
-Differentiation among causes of shock
-Differentiation among causes of respiratory failure and/or cardiac failure
-Evaluation of pulmonary hypotension
-Diagnosis of cardiac constriction, restrictive cardiomyopathy and tamponade
-Evaluation of tricuspid and mitral valve regurgitation
-Evaluation of intracardiac shunts such as atrial or ventricular septal defects.
Swan Ganz catheters can also be used therapeutically. For example:
-Management of perioperative patients with unstable cardiac status
-Management of patients with complicated myocardial infarction (MI)
-Management of patients following cardiac surgery
-Management of patients with severe pre-eclampsia
-Guide to pharmacologic therapy with pressors (drugs that increase blood pressure), inotropes (drugs that increase cardiac contractility) and vasodilators (especially in patients with pulmonary hypotension)
-Guide to non-pharmacologic therapy such as fluid management during GI bleeds or traumatic bleeding, renal failure, sepsis, heart failure, and decompensated cirrhosis
-Ventilator management, particularly useful in determining the best positive end expiratory pressure (PEEP) for oxygen delivery.
Catheterization of the right heart with a PA catheter is associated with risk. However, there are benefits of Swan Ganz catheterization in the ability to diagnose and therapeutically manage a patient. Physicians should carefully consider the risks and benefits of PA catheters in the ICU on an individual basis for each patient.