26: Pulmonary Artery Catheterization

Published on 06/02/2015 by admin

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Last modified 06/02/2015

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CHAPTER 26 Pulmonary Artery Catheterization

James Duke, MD, MBA

1 What pressures are measured by pulmonary artery catheters?

Pulmonary artery (PA) catheters are balloon-tipped catheters with multiple orifices. After the catheter is attached to a transducer system and the balloon is inflated, the flow-directed catheter tip passes through the right-sided chambers of the heart into the pulmonary artery. The PA catheter continuously measures right atrial pressure (or central venous pressure [CVP]) and pulmonary artery pressures. Although in the pulmonary artery, this balloon can be intermittently inflated and wedged into a segment of the pulmonary artery; and the pulmonary artery occlusion pressure (PAOP), commonly referred to as the wedge pressure, is measured.

2 What are normal values for central venous, pulmonary artery, and pulmonary artery occlusion pressures?

Normal values are listed below. Slight discrepancies are found among different references.

image CVP
image PA systolic
image PA diastolic
image PAOP

2 to 6 mm Hg
20 to 30 mm Hg
5 to 15 mm Hg
8 to 12 mm Hg

3 What other hemodynamic variables can be measured or calculated from the pulmonary artery catheter? What are their normal values?

Most PA catheters can also measure cardiac output and mixed venous oxygen saturation (SvO2). Other variables such as heart rate, systemic blood pressure, and body mass index may be needed to derive additional hemodynamic indices such as those in the following list:

image SvO2
image Cardiac output
image Cardiac index
image Stroke volume
image Stroke index
image Systemic vascular resistance
image Pulmonary vascular resistance

60% to 75%
4 to 8 L/min
2.5 to 4 L/min/m2
50 to 100 ml
25 to 45 ml/m2
900 to 1300 dyn/sec cm−5
100 to 300 dyn/sec cm˜−5

4 In what surgical procedures are pulmonary artery catheters most likely to be placed? What medical problems might influence a clinician’s likelihood to insert a pulmonary artery catheter before surgery?

PA catheters are useful in patients undergoing cardiac surgery (valves, coronary arteries, heart and lung transplantation), liver transplantation, and vascular surgery and in high-risk patients having extensive operative procedures with high likelihood of substantial blood loss and fluid shifts. High-risk patients include those with valvular or ischemic heart disease, compromised ventricular function or pulmonary hypertension, or significant deterioration in other organ function (e.g., liver and kidney). In addition, patients who are hemodynamically unstable (e.g., shock or sepsis) or who have extreme ventilatory requirements (e.g., acute lung injury) are often catheterized to guide therapy.

5 Do pulmonary artery catheters improve patient outcomes?

PA catheters entered regular clinical use in the 1970s and still enjoy widespread use (estimated at more than 1.2 million insertions per year). However, only in the past decade have clinicians investigated in a rigorous fashion their clinical efficacy. The strength of evidence demonstrating a benefit has not been substantial overall, and there was some evidence demonstrating that PA catheters were in fact detrimental. At this time well-designed studies do not demonstrate a benefit in all groups. Certainly the issue continues to be examined and debated. Trials are ongoing in many patient subsets such as sepsis, acute lung injury, and congestive heart failure; such well-designed studies will continue to refine our knowledge of the risks and benefits of PA catheters. Finally it isimporant to note that the data obtained from PA catheterization must guide therapies of proven benefit.

6 What complications are associated with pulmonary artery catheterization?

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