Pulmonary artery catheter nursing: Swan-Ganz monitoring and hemodynamic parameters

The pulmonary artery catheter (PAC) — commonly called a Swan-Ganz catheter — is a flow-directed, balloon-tipped catheter that sits in the pulmonary artery and provides a level of hemodynamic detail no noninvasive monitor can match. For ICU nurses, understanding the PAC is non-negotiable: you are responsible for interpreting waveforms at the bedside, measuring cardiac output, recognizing dangerous complications before they escalate, and translating raw numbers into clinical meaning that guides treatment.

This guide covers everything from catheter anatomy and insertion mechanics to normal parameter ranges, waveform recognition, wedge pressure technique, shock hemodynamic profiles, and complication management. A comprehensive NCLEX section with 20 high-yield tips and 20 scenario questions closes the article.

What is a pulmonary artery catheter?

A pulmonary artery catheter is a long, flexible, 7–8 French catheter with a small latex balloon at its distal tip. The balloon inflates to 1.5 mL of air, catches the venous bloodstream like a sail, and carries the catheter from a central vein through the right atrium (RA), right ventricle (RV), and out into the pulmonary artery (PA). This property — flotation with blood flow — is what makes insertion possible without fluoroscopy (though fluoroscopy is still preferred when available).

Jeremy Swan and William Ganz introduced the catheter at Cedars-Sinai in 1970, and their names remain attached to it decades later. Before the Swan-Ganz, direct measurement of left heart filling pressures required open thoracotomy. The PAC made bedside hemodynamic monitoring of the left heart a clinical reality.

Catheter design

A standard PAC has four functional lumens:

• Proximal lumen (RA port): Opens in the right atrium. Used to measure CVP/RAP, infuse fluids or medications, and inject the cold saline bolus for thermodilution cardiac output.
• Distal lumen (PA port): Opens at the catheter tip in the pulmonary artery. Measures PA pressures and provides access for mixed venous oxygen saturation (SvO₂) samples from PA blood.
• Balloon inflation port: Connected to the balloon at the catheter tip. Inflated to wedge the catheter distally, occluding blood flow ahead of the tip — this creates the PCWP reading.
• Thermistor port: A temperature sensor 4 cm from the tip. Detects the temperature change after cold saline injection to calculate cardiac output by thermodilution.

Some catheters include a fifth lumen for continuous SvO₂ monitoring via fiberoptic oximetry (oximetric PAC).

Why a PAC when arterial lines and CVP lines exist?

An arterial line measures systemic blood pressure continuously and enables ABG sampling — but it tells you nothing about cardiac output, left heart filling pressures, or pulmonary vascular resistance. A central venous catheter measures CVP (right heart preload) — but in patients with left ventricular dysfunction, CVP can be near-normal while left filling pressures are critically elevated. The PAC bridges that gap by directly assessing the pulmonary circulation and, indirectly, the left heart.

Hemodynamic parameters measured by the PAC

Table 1 summarizes all parameters, normal ranges, clinical meaning, and what abnormal values suggest.

Thermodilution cardiac output technique

Cardiac output by thermodilution uses the Stewart-Hamilton principle: inject a known volume (10 mL) of cold normal saline (iced or room temperature) through the proximal (RA) port. The thermistor at the catheter tip detects the temperature change in blood as the cold injectate mixes and travels through the right heart into the PA. The computer integrates the temperature-time curve to calculate CO.

Technique tips:

• Inject smoothly within 4 seconds — jerky or slow injection increases error
• Take three measurements and average them; discard outliers differing by more than 10%
• Inject at end-expiration to minimize respiratory variation (or use random injection with averaging)
• Verify injectate temperature and volume match the computer’s settings

Continuous cardiac output

Many modern PACs use thermal filaments to measure CO continuously (CCO), displaying a running 3–6 minute average. CCO eliminates bolus injection technique variability and provides trend data without nurse intervention.

Indications and contraindications

The decision to place a PAC requires weighing the information gained against the procedural risk. The PAC is powerful but invasive — it should be used when hemodynamic data would meaningfully change management and the information is not obtainable by other means.

Indications:

• Cardiogenic shock — particularly when diagnosis is unclear or response to therapy is inadequate
• ARDS — distinguishing ARDS (normal/low PCWP) from cardiogenic pulmonary edema (elevated PCWP)
• High-risk cardiac surgery (CABG, valve replacement, cardiac transplant)
• Pulmonary hypertension — hemodynamic classification (pre-capillary vs post-capillary) and vasoreactivity testing
• Hemodynamic instability unresponsive to empirical fluid and vasopressor therapy
• Perioperative monitoring in patients with severe LV dysfunction or significant valvular disease

Contraindications:

• Left bundle branch block (LBBB): The catheter passing through the RV can trigger right bundle branch block; combined with pre-existing LBBB, this causes complete heart block. Transcutaneous pacing must be immediately available; insertion should be by experienced operators with fluoroscopy.
• Prosthetic tricuspid or pulmonic valve: Catheter passage is difficult and risks valve damage or entanglement.
• Coagulopathy (relative) — increased hemorrhage risk at insertion site
• Active right-sided endocarditis (relative) — risk of seeding or embolizing vegetation

Insertion procedure and the nursing role

PAC insertion is typically performed in the ICU, cardiac catheterization lab, or operating room by a physician or APRN with the nurse at the bedside monitoring waveforms and vital signs throughout.

Access site

A large-bore central venous introducer sheath (8–9 French) is placed first — most commonly the right internal jugular vein (shortest, most direct path to the RA) or subclavian vein. The femoral vein is an alternative but the greater distance and tortuosity make catheter flotation harder. The PAC is inserted through this sheath.

Balloon flotation

Once the catheter tip enters the vascular space, the balloon is inflated to 1.5 mL air and the catheter is advanced while the nurse calls out waveform transitions. Blood flow carries the balloon-tipped catheter:

1. Through the superior vena cava (SVC) into the right atrium
2. Through the tricuspid valve into the right ventricle
3. Through the pulmonic valve into the pulmonary artery
4. Forward until the balloon occludes a PA branch — the wedge position

Critical nursing rule: Never advance the catheter with the balloon deflated. A deflated catheter tip can lacerate endocardium or valve leaflets.

Post-insertion confirmation

A chest X-ray confirms catheter tip position. Correct position places the tip approximately 2 cm from the pulmonary hilum, in the right or left PA (Zone III of the lung — below the level of the left atrium — ensures reliable PCWP readings). Fluoroscopy during insertion provides real-time guidance, particularly in patients with dilated right ventricles where the catheter may loop.

Nursing preparation checklist

• Obtain informed consent (confirm with provider)
• Position patient supine; Trendelenburg for IJ/subclavian access
• Set up pressure transducer system, zero-reference at the phlebostatic axis
• Have emergency resuscitation cart, transcutaneous pacing, and defibrillator immediately available
• Attach continuous cardiac monitor — watch for dysrhythmias during catheter passage through the RV
• Document baseline vital signs and SpO₂
• Label all lumens before use; confirm balloon volume is noted (never exceed 1.5 mL)

Waveform recognition

Waveform interpretation is the most NCLEX-tested aspect of PAC nursing. As the catheter advances, the bedside monitor displays characteristic pressure waveforms that confirm position and guide the inserting clinician.

Table 2 shows the waveform progression from RA to wedge position.

RA waveform components in detail

The RA waveform has three waves and two descents:

• a-wave: Produced by atrial contraction at end-diastole. Absent in atrial fibrillation.
• c-wave: Small wave caused by tricuspid valve closure; often merged with the a-wave and may not be visible.
• v-wave: Passive venous filling of the atrium while the tricuspid valve is closed (during ventricular systole). Elevated v-waves in the RA suggest tricuspid regurgitation.
• x-descent: Downward deflection as the atrium relaxes and the tricuspid valve annulus descends during ventricular systole.
• y-descent: Downward deflection as the tricuspid valve opens and blood flows into the RV.

An exaggerated x-descent with prominent y-descent is characteristic of cardiac tamponade and constrictive pericarditis. Equalization of all diastolic pressures (RAP = RVDP = PADP = PCWP) strongly suggests tamponade.

The dicrotic notch — PA vs RV

The most important waveform distinction for NCLEX is the dicrotic notch in the PA waveform. The notch represents pulmonic valve closure at end-systole. When the RV is ejecting blood, the pulmonic valve is open and no notch appears. As the catheter advances from RV to PA, the diastolic pressure rises (from ~2–5 mmHg to 4–12 mmHg) and the dicrotic notch becomes visible. These two changes together confirm PA placement.

Wedge pressure measurement technique

The pulmonary capillary wedge pressure (PCWP) is measured by briefly inflating the balloon until it occludes a pulmonary artery branch, creating a static column of blood between the catheter tip and the pulmonary veins. This static column transmits left atrial pressure back to the transducer, giving an indirect measure of LVEDP and left heart preload.

Step-by-step technique

1. Confirm PA waveform is present before inflating — never inflate in an unknown position.
2. Inflate slowly using a 1.5-mL syringe. Watch the waveform — stop inflating the moment the PA waveform transitions to the lower-amplitude, blunted wedge waveform. Use the minimum volume needed; do not routinely inject all 1.5 mL if the waveform changes sooner.
3. Read at end-expiration. Respiratory variation can cause significant error; end-expiration is when intrathoracic pressure is nearest to zero, minimizing its effect on PCWP.
4. Hold for ≤15–30 seconds maximum. Prolonged balloon inflation occludes blood flow to the lung segment distal to the catheter, causing pulmonary infarction.
5. Deflate passively. Remove your thumb from the syringe plunger and allow the balloon to deflate on its own. Never actively aspirate air back into the syringe — aspiration risks rupturing the balloon, which can release air emboli or latex fragments into the pulmonary circulation.
6. Confirm PA waveform returns before documenting. If the PA waveform does not return, the catheter may have migrated distally — notify the physician immediately.
7. Document the PCWP with the patient position, respiratory status, and ventilator settings (if applicable).

PCWP vs PADP as a surrogate

In patients with normal pulmonary vascular resistance, PA diastolic pressure (PADP) tracks closely with PCWP (within 1–4 mmHg), and PADP can be used as a continuous non-balloon surrogate for PCWP. This tracking relationship breaks down when PVR is elevated (PE, ARDS, pulmonary hypertension) — in those cases, PADP overestimates PCWP and direct wedge measurements are needed.

Nursing monitoring and ongoing care

Phlebostatic axis and zero-referencing

The pressure transducer must be leveled to the phlebostatic axis — the intersection of the fourth intercostal space and the mid-axillary line, which approximates the level of the right atrium. If the transducer is too high, readings are falsely low; too low, falsely high. Every 1 cm of height difference from the phlebostatic axis introduces approximately 0.74 mmHg of error.

Zero the transducer:

• Before initial use
• After any patient position change
• When readings seem inconsistent with clinical picture
• Every 8–12 hours per unit protocol

Continuous PA waveform monitoring

The PA distal port must display a continuous PA pressure waveform. Loss of waveform, waveform dampening, or spontaneous transition to a wedge pattern without balloon inflation signals catheter migration — the balloon-free tip has floated distally and is now wedged. This is a medical emergency:

• Do not flush a wedged catheter — high-pressure flushing can rupture the PA.
• Allow passive deflation and check if the PA waveform returns.
• If it does not return, notify the physician immediately.
• Document time of recognition and all actions taken.

Infection prevention

Central line care principles apply to the PAC introducer sheath and all PAC lumens:

• Daily chlorhexidine dressing changes per protocol
• Cap all lumens not in use with sterile injection caps
• Maintain sterile technique whenever accessing a port
• Assess insertion site daily for erythema, drainage, or tenderness
• Remove the catheter as soon as it is no longer clinically indicated — the longer it remains, the higher the infection risk

Complications and nursing response

The PAC provides invaluable data but carries real procedural and device-related risks. Table 4 summarizes complications, mechanisms, early warning signs, and nursing actions.

Pulmonary artery rupture — the most catastrophic complication

PA rupture is uncommon but has mortality exceeding 50% in severe cases. Risk factors include distal catheter migration, pulmonary hypertension (thin, fragile PA walls), anticoagulation, and advanced age. The cardinal sign is sudden massive hemoptysis — bright red blood welling from the ETT or mouth. Nursing response is simultaneous and immediate: call the physician, apply 100% FiO₂, position the patient with the affected lung dependent (to protect the unaffected lung), deflate the balloon, and do not flush the catheter. The patient will likely need emergent bronchoscopy to tamponade bleeding or surgery.

Interpreting PAC data in clinical scenarios

Hemodynamic values in isolation mean little — pattern recognition across multiple parameters guides clinical decisions. Table 3 shows hemodynamic profiles for common shock states.

ARDS versus cardiogenic pulmonary edema

One of the most clinically important applications of the PAC is distinguishing ARDS from cardiogenic pulmonary edema — two conditions that can look identical on chest X-ray (bilateral infiltrates, hypoxemia) but require completely different treatment. A PCWP ≤18 mmHg in a patient with bilateral infiltrates and hypoxemia supports ARDS; a PCWP >18 mmHg points toward cardiogenic pulmonary edema (left heart failure). The Berlin Definition of ARDS now excludes patients whose pulmonary edema is fully explained by cardiac failure or fluid overload, making PCWP data central to diagnosis.

For detailed ARDS management nursing protocols including lung-protective ventilation strategies, see the ARDS guide.

SvO₂ interpretation

Mixed venous oxygen saturation is measured from blood drawn from the distal (PA) port. Because this is truly mixed venous blood (SVC + IVC mixing in the RA and RV), SvO₂ reflects global tissue oxygen delivery and extraction.

• SvO₂ 60–75% (normal): Supply and demand in balance.
• SvO₂ <60%: Tissues are extracting more oxygen than normal — signals low CO, anemia, fever, or high metabolic demand. If SvO₂ is trending down over hours, CO is likely falling before the patient becomes overtly hypotensive.
• SvO₂ >80%: Tissues are not extracting oxygen efficiently — characteristic of early sepsis (distributive shock), left-to-right shunts, or cyanide toxicity. A falsely high SvO₂ can also indicate catheter wedging (sampling oxygenated PA capillary blood).

Central venous oxygen saturation (ScvO₂), measured from an upper-body central line, correlates with SvO₂ and is used as a surrogate in sepsis management when a PAC is not in place.

PAC in specific clinical contexts

Post-cardiac surgery

Patients after CABG or valve surgery routinely have PACs placed intraoperatively. The data guides postoperative volume management, vasoactive drug titration, and detection of post-bypass complications including RV failure (common after cardiac surgery) and cardiac tamponade. IABP nursing frequently overlaps with PAC care in this population — both devices are often managed simultaneously in the post-cardiac surgery ICU.

LVAD patients

Patients with left ventricular assist devices require PAC monitoring to optimize right ventricular function, which cannot be supported by the LVAD. In LVAD recipients, PCWP is kept low (6–12 mmHg) to prevent pulmonary hypertension from overloading the RV. See LVAD nursing for detailed management.

Pulmonary hypertension vasoreactivity testing

In the cardiac catheterization lab, the PAC enables acute vasoreactivity testing for idiopathic pulmonary arterial hypertension — a short-acting vasodilator (inhaled nitric oxide, epoprostenol, or adenosine) is administered and the hemodynamic response is measured. Positive responders (PAMP fall ≥10 mmHg to absolute value ≤40 mmHg) are candidates for long-term calcium channel blocker therapy. Cardiac catheterization nursing covers the peri-procedural aspects of this testing.

Vasoactive drug titration using PAC data

Vasopressors and inotropes are titrated using PAC parameters as the primary endpoints:

• Dobutamine: Increases CO and CI; reduces SVR; used when PCWP is elevated and CO is low (cardiogenic shock). Monitor for tachycardia and hypotension.
• Norepinephrine: Increases SVR and MAP; used in distributive shock with low SVR. Monitor for rising PVR and RV strain.
• Milrinone (PDE-3 inhibitor): Increases CO, reduces SVR and PVR; preferred for RV failure and post-cardiac surgery low CO with pulmonary hypertension. Monitor for hypotension.
• Nitroprusside: Vasodilator that reduces SVR and afterload; used in cardiogenic shock with high SVR and elevated PCWP. Requires concurrent CO/CI monitoring to ensure CO rises appropriately.

The PAC is the tool that makes precise, data-driven titration possible — rather than guessing, the nurse and provider can watch the hemodynamic response to each intervention in real time.

Cardiac arrhythmias during PAC management

Ventricular dysrhythmias during PAC insertion are common as the catheter traverses the RV. Sustaining cardiac arrhythmias in this setting may require catheter withdrawal and ACLS intervention. Even after successful placement, arrhythmias can recur if the catheter migrates back into the RV — a reason to maintain continuous PA waveform monitoring and recognize when the PA waveform is replaced by the high-systolic, low-diastolic RV pattern.

Patient education and consent

Patients and families need clear, honest explanation about why the PAC is being placed and what to expect. Keep language accessible:

• Why it’s needed: “This specialized catheter goes into the blood vessels near your heart and lungs. It measures how hard your heart is working and how your blood pressure and fluid levels are affecting your heart — information we can’t get from the monitors on your finger or arm. It helps us dial in your medications much more precisely.”
• What to expect during insertion: Sedation or local anesthesia will be used. The patient will be draped with sterile covers. There may be brief discomfort at the insertion site. The procedure typically takes 20–40 minutes.
• Activity restrictions: Limit movement of the shoulder and neck on the insertion side. Report any chest pain, shortness of breath, or coughing of blood immediately.
• Length of use: The catheter stays in place only as long as the information it provides is guiding treatment decisions. When it’s no longer needed, it will be removed.

PAC removal

Removal is typically performed by the physician or APRN, with nursing preparation and post-removal monitoring:

Before removal:

• Confirm balloon is fully deflated — verify via balloon port that syringe is empty
• Turn off anticoagulation infusions if applicable per protocol (discuss with physician)
• Position patient flat or slight Trendelenburg for IJ/subclavian sites

During removal:

• Maintain sterile technique
• Apply firm pressure at the insertion site immediately upon removal
• Monitor cardiac rhythm continuously throughout removal — catheter passing back through the RV can trigger dysrhythmias

After removal:

• Inspect the catheter tip for integrity — a frayed or missing tip suggests embolization; notify physician and prepare for imaging
• Apply occlusive dressing to the site; maintain pressure until hemostasis is confirmed
• Monitor for bleeding, hematoma, pneumothorax signs (from central site), and arrhythmias
• Document catheter tip appearance, estimated blood loss at site, and post-removal vital signs

NCLEX high-yield tips

NCLEX scenario questions

Clinical sources

The hemodynamic values and clinical content in this article are consistent with the following authoritative references:

• AACN Advanced Critical Care (formerly AACN Clinical Issues) — standard reference for hemodynamic monitoring in critical care nursing practice
• Darovic GO. Hemodynamic Monitoring: Invasive and Noninvasive Clinical Application, 3rd ed. — the definitive nursing reference for PAC parameter ranges and waveform interpretation
• Urden LD, Stacy KM, Lough ME. Critical Care Nursing: Diagnosis and Management, 9th ed. — PCWP normal ranges, shock hemodynamic profiles, complication management
• UpToDate: Pulmonary artery catheterization: clinical features, interpretation, and complications — evidence base for indications, LBBB risk, balloon inflation time limits, PA rupture management
• Swan HJC, Ganz W, et al. Catheterization of the heart in man with use of a flow-directed balloon-tipped catheter. N Engl J Med. 1970;283(9):447–451 — original description of the PAC technique
• AACN Practice Alerts: Pulmonary Artery Pressure Monitoring — phlebostatic axis leveling, end-expiration reading, waveform monitoring standards

Written by Lindsay Smith, AGPCNP. For questions about site content, contact [email protected].