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Pulmonary artery catheters: Insertion technique in adults

Pulmonary artery catheters: Insertion technique in adults
Literature review current through: Jan 2024.
This topic last updated: Sep 26, 2023.

INTRODUCTION — Pulmonary artery catheters (PACs; also called Swan-Ganz catheters) are inserted in the intensive care unit and in the operating room for the evaluation and management of critically ill patients. They are also placed in clinically stable patients (eg, in a coronary catheterization unit), most often for the diagnosis and management of some patients with suspected or known pulmonary hypertension or for unexplained dyspnea.

The insertion of PACs is reviewed here. The indications, contraindications, complications, and interpretation of PAC measurements are discussed separately. (See "Cardiac catheterization techniques: Normal hemodynamics" and "Pulmonary artery catheterization: Interpretation of hemodynamic values and waveforms in adults" and "Pulmonary artery catheterization: Indications, contraindications, and complications in adults".)

INDICATIONS AND CONTRAINDICATIONS — The major hemodynamic indices measured on pulmonary artery catheter (PAC) are pulmonary artery and pulmonary artery occlusion (ie, wedge) pressure, right atrial and right ventricular pressure, cardiac output and cardiac index, systemic and pulmonary vascular resistance, and mixed venous oxyhemoglobin saturation (SvO2). (See "Pulmonary artery catheterization: Indications, contraindications, and complications in adults", section on 'Physiologic measurements'.)

Although the routine use of PACs in critically ill patients has fallen out of favor, hemodynamic measurements obtained by PAC can be helpful in those with unexplained shock or those with unknown volume status despite active fluid resuscitation, as well as in patients with severe cardiogenic shock (eg, acute valvular disease) or those with suspected or known pulmonary artery hypertension (table 1). PACs can also be used to guide fluid resuscitation, titrate vasopressors, assess the hemodynamic effects of changes in mechanical ventilator settings, or assess response to medications (eg, pulmonary hypertension-specific medication). PACs are occasionally inserted preoperatively for high risk cardiopulmonary surgery and in rare cases are inserted for the investigation of unexplained dyspnea. (See "Approach to the patient with dyspnea", section on 'Cardiopulmonary exercise testing with pulmonary artery catheterization'.)

Absolute contraindications include infection at the insertion site, right ventricular assist device, and insertion during cardiopulmonary bypass, as well as lack of consent. Relative contraindications to the placement of a PAC include those with a coagulopathy (international normalized ratio >1.5), thrombocytopenia (platelet count <50,000/microL), electrolyte disturbances (hypo- or hyper-kalemia, -magnesemia, -natremia, -calcemia), and severe acid-base disturbances (eg, pH <7.2 or >7.5).

Detailed discussion of the indications, contraindications, and complications of PAC insertion are discussed separately. (See "Pulmonary artery catheterization: Indications, contraindications, and complications in adults".)

PREPARATION — Once a decision is made to insert a pulmonary artery catheter (PAC), a site should be selected, the appropriate personnel recruited, and all necessary equipment should be placed in the patient’s room. When feasible, we prefer that the PAC be placed in the right jugular vein under ultrasound guidance. Consent should be in place and laboratory studies should ensure that no severe coagulopathy, electrolyte, or acid-base disturbances exist to increase the risk of hemorrhage or arrhythmias.

Selecting the site — The site of insertion should be selected in advance so that the appropriate equipment can be in place (eg, fluoroscopy and a longer catheter is required for femoral or antecubital vein approaches).

Options include insertion into the internal jugular, subclavian, femoral, or antecubital (basilic or brachial) vein [1,2]. We prefer to use the right internal jugular vein or as an alternative, the left subclavian vein; these approaches facilitate passage of the catheter into the pulmonary artery. The femoral and antecubital veins are generally avoided but can be used when no other access is available (eg, hematoma or altered neck and chest anatomy from prior radiation).

For cardiac surgery, the right followed by left internal jugular vein is often the first-choice approaches because after sternotomy and sternal retraction, a PAC inserted by the subclavian route may be compressed and kinked under the clavicle, making it impossible to withdraw or advance the catheter, should this be required during the course of surgery. The advantages and disadvantages of each location are described in the table (table 2). (See "Placement of jugular venous catheters" and "Placement of subclavian venous catheters" and "Placement of femoral venous catheters".)

When feasible, we advise that the target vessel be visualized by using a hand-held ultrasound device to determine the optimal insertion site by allowing the clinician to see the size, configuration, and position of the blood vessels. (See "Basic principles of ultrasound-guided venous access".)

In some patients, a central venous catheter (CVC) that is already in place can be exchanged for PAC provided sufficient access is in place elsewhere during PAC insertion for the infusion of critical life-sustaining and life-saving medications. In such circumstances, ensuring that a sterile wire of sufficient length is used to exchange the CVC for the PAC introducer is important.

Should a pacemaker be in place (usually in the left subclavian vein), a site on the opposing side is preferred to minimize pacemaker dislodgement and infection during insertion.

Personnel — Once the decision has been made to insert a PAC, an adequate number of personnel need to be recruited. This includes a clinician experienced in the insertion of PACs to insert the catheter and nursing personnel to monitor and care for the patient. A fluoroscopist may be required for PACs that require fluoroscopy for insertion.

Additional clinicians may be necessary in the intensive care unit to care for unattended patients as PAC insertion can be time-consuming. As an example in a study of 120 insertions, the median duration from the decision to insert a PAC to the initiation of catheter-based treatment was approximately two hours [3].

Equipment — The following items should be gathered and placed in the patient's room prior to insertion:

The introducer and PAC with attendant equipment and cables (picture 1). All equipment needed for catheter insertion, pressure monitoring, sedation, and sterilization is listed in the table (table 3).

An ultrasound device, transducer gel, and sterile probe sheath, if ultrasound-guided insertion is planned. Ultrasonography is suggested for the safe insertion of the introducer needle when placing PACs. They can also be used to check for suspected pneumothorax during or postinsertion. (See "Central venous catheters: Overview of complications and prevention in adults", section on 'Arterial injury'.)

Resuscitation equipment. Arrhythmias and vascular complications can occur during insertion, which may require emergent resuscitation. As an example an external pacing device may be necessary should complete heart block develop, or paddles (or hands-free electrode patches) may be needed should persistent ventricular tachycardia develop. (See "Pulmonary artery catheterization: Indications, contraindications, and complications in adults" and "Advanced cardiac life support (ACLS) in adults".)

Telemetry equipment. Telemetry with the ability to monitor pressure tracings and concurrent electrocardiography tracings during placement is necessary for the safe insertion of PACs. (See 'Advancing the catheter' below.)

Fluoroscopic equipment, if fluoroscopic-guided insertion is planned. Fluoroscopy may be performed in patients who have marked right atrial enlargement, right ventricular dilatation, severe tricuspid regurgitation, or a left bundle branch block. It is also generally needed for patients who have PACs placed in the femoral vein or for those with unusual anatomy (eg, persistent left superior vena cava). Portable fluoroscopic equipment may not be available at some institutions, in which case insertion in either a cardiac catheterization laboratory or radiology department may be an alternative. (See 'Advancing the catheter' below.)

INSERTION OF THE INTRODUCER — Following site selection, the patient should be positioned in Trendelenburg (jugular or subclavian approach) or supine (femoral or antecubital approach). Local anesthesia with lidocaine and/or intravenous sedation (eg, midazolam and/or fentanyl) is administered and the introducer is placed under sterile conditions using the modified Seldinger technique. Confirmation of venous placement and a chest radiograph (jugular or subclavian approach) should be performed after introducer insertion and before the pulmonary artery catheter (PAC) is placed.

Patient positioning — The patient should be in Trendelenburg for the jugular and subclavian approaches and supine for the femoral and antecubital approaches. The clinician should be able to observe and palpate the relevant anatomical landmarks for the selected site. The bed should be placed at a height that is comfortable for the clinician throughout the procedure. Additional details regarding positioning for each approach are described separately. (See "Placement of subclavian venous catheters", section on 'Positioning' and "Placement of femoral venous catheters", section on 'Positioning' and "Placement of jugular venous catheters", section on 'Positioning'.)

Sterilizing the field — For internal jugular and subclavian venous access, a wide skin preparation that includes the neck and chest above the nipple line should be performed. If difficult access is anticipated, the neck and chest can be prepared bilaterally so that an alternative site can be chosen, should the initial plan fail. For femoral venous access, a wide skin preparation encompasses the anterior and medial surfaces of the proximal thigh and extends superior to the inguinal ligament.

For all selected sites, a wide procedural field should be prepared with strict adherence to aseptic technique. This includes hand washing with antiseptic-containing soap or alcohol-based gels or foams, full barrier precautions (sterile gloves, long-sleeved surgical gown, a surgical mask, a surgical cap, a large sterile sheet drape), skin disinfection with 2 percent chlorhexidine, and avoidance of the femoral insertion site, if feasible [4]. A more detailed discussion of site preparation is provided separately [4,5]. (See "Central venous access in adults: General principles", section on 'Aseptic technique'.)

Analgesia and sedation — The insertion site should be infiltrated with a local anesthetic (eg, 1 or 2 percent lidocaine), including the superficial and deep structures of the puncture site and the anticipated needle tract. For subclavian approaches, the periosteum of the clavicle should be anesthetized.

For patients who are awake and anxious, low dose of intravenous midazolam (0.2 mg/kg to a maximum of 2 mg) and/or fentanyl (0.5 mcg/kg to a maximum of 200 mcg) may facilitate the procedure (eg, outpatients with suspected pulmonary hypertension). For those on mechanical ventilation, increasing sedative infusions or administering a bolus of alternate sedative is appropriate. Selection of agents for procedural sedation should be individualized, the details of which are discussed separately. (See "Procedural sedation in adults in the emergency department: General considerations, preparation, monitoring, and mitigating complications".)

Insertion of the introducer — An introducer is a wide bore (8.5 F), short, central venous catheter through which the PAC is placed (eg, cordis) (picture 1). The proximal end contains a hemostatic valve (external to the skin), through which the PAC is eventually introduced to the target vein. It also has a side-arm extension that allows continuous central venous access for fluid and drug administration. Insertion of the introducer is similar to that of central venous catheters. It is generally accomplished using the modified Seldinger technique (figure 1) and once in place, the catheter is secured with sutures. Details regarding the insertion of central venous catheters/introducers are described separately. (See "Placement of jugular venous catheters", section on 'Internal jugular vein cannulation' and "Placement of subclavian venous catheters", section on 'Subclavian vein cannulation' and "Placement of femoral venous catheters", section on 'Femoral vein cannulation' and "Central venous access in adults: General principles", section on 'Central venous access' and "Central venous access: Device and site selection in adults", section on 'Types of central venous catheters'.)

Arterial puncture during introducer needle insertion is not unusual. The risk is reduced, but not eliminated, using ultrasound. Arterial puncture with the introducer needle is typically managed by withdrawing the needle and placing pressure on the artery for 10 to 15 minutes. However, arterial dilation and cannula placement (ie, arterial cannulation) with the introducer catheter itself is considered a more life-threatening complication, in which case, the catheter should be left in place and not removed; a vascular surgeon should be consulted for management. (See "Central venous catheters: Overview of complications and prevention in adults", section on 'Arterial injury' and "Vascular complications of central venous access and their management in adults", section on 'Arterial complications' and "Central venous access in adults: General principles".)

Confirmation of cordis or introducer placement inside the target vein should occur before the PAC is placed. Options include visualization of dark blood lacking a pulsatile flow, transduction of a pressure waveform from the catheter, and blood gas analysis, none of which is fool-proof. However, when in doubt we prefer pressure transduction as the more accurate method for confirmation of venous placement. For jugular and subclavian approaches, a chest radiograph to confirm that no pneumothorax has occurred during insertion is advisable. Details regarding confirmation of catheter placement are discussed separately. (See "Central venous access in adults: General principles", section on 'Confirming catheter tip position' and "Placement of jugular venous catheters", section on 'Confirmation of jugular catheter position' and "Placement of subclavian venous catheters", section on 'Confirmation of subclavian catheter position' and "Placement of femoral venous catheters", section on 'Confirmation of femoral catheter position'.)

INSERTION OF THE PULMONARY ARTERY CATHETER — Once the introducer has been inserted into the target blood vessel, the field should be resterilized. The pulmonary artery catheter (PAC) ports should be flushed; the integrity of the balloon and the ability of the PAC to transduce pressure should also be checked. With the patient in the supine position, the PAC is advanced through the introducer, and then through the superior vena cava (SVC), cardiac chambers, and pulmonary artery (PA) while the pressure at its tip is transduced (figure 2). As a general rule, during advancement the balloon may only be inflated once the pressure tracing indicates that the tip of the catheter is in the SVC or right atrium (RA). Additionally, the balloon should only be inflated whenever the catheter is advanced, and deflated whenever the catheter is withdrawn. Distinct changes in the pressure waveforms indicate transition through each cardiac chamber as well as a final pulmonary artery wedge position.

Resterilizing the field — Once the introducer placement is confirmed, a new sterile field should be prepared. A wide procedural field from the head of the bed to mid-thigh is appropriate using a similar aseptic technique to that described for the insertion of the introducer. (See 'Sterilizing the field' above.) In addition to the skin of the surrounding field, the introducer hub should also be disinfected with 2 percent chlorhexidine prior to PAC insertion. (See "Central venous access in adults: General principles", section on 'Aseptic technique'.)

Preparing the catheter

Flushing and connecting the ports — Under sterile conditions, the catheter should be removed from the package. There are four ports in most PACs (picture 2):

The pulmonary artery distal pressure monitoring port (PA distal port) connects to the distal tip of the PAC and is used to transduce pressure.

The proximal drug infusion port (proximal infusion or injectate port), usually 30 cm from the catheter tip is intended for central venous pressure (CVP) monitoring as well as for intravenous fluid and drug administration.

The balloon inflation port leads to the balloon at the catheter tip and allows the balloon to be inflated and deflated during catheter placement.

The thermistor port contains fine wires that lead to a temperature thermistor just proximal to the balloon. It is used to monitor pulmonary artery blood temperature as part of the thermodilution method for cardiac output monitoring.

The right ventricle (RV) infusion port is a fifth port that is available on some catheters. It can be used for infusions and occasionally for pacing the RV.

All ports should be capped and flushed with sterile saline (except the thermistor port which does not need a cap and cannot be flushed). The balloon should be inflated to test for leaks. It should inflate symmetrically without obstructing the opening of the distal lumen (figure 3). The syringe provided with the package is used to fill the balloon with air, which is limited to only 1.5 mL in order to prevent overinflation.

A protective sleeve (provided with the package) that connects to the introducer is typically placed if the PAC is to be left in place for a prolonged period of time. The PAC should be placed through the sleeve ensuring that the sleeve connector is facing the distal end of the catheter and that the balloon is not damaged in the process (picture 3).

The pressure lines and transducers should be connected to the distal and proximal pressure monitoring ports, calibrated, zero-balanced, and transducer function checked (see below).

Zeroing and referencing — The PAC must be appropriately zeroed and referenced to obtain accurate readings [6]. Zeroing and referencing are usually performed by nursing and should always occur with the patient lying in the recumbent position. They are done in one step, but they represent two separate processes:

Zeroing involves opening the system to the air to establish atmospheric pressure as zero.

Referencing (or leveling) is accomplished by placing the air-fluid interface of the catheter or transducer at a specific point to negate the effects of the weight of the catheter tubing and fluid column [1]. The system can be referenced by placing the air-fluid interface of either the in-line stopcock or the stopcock on top of the transducer at the "phlebostatic level" (ie, reference point zero) (figure 4). This point is usually the intersection of a frontal plane passing midway between the anterior and posterior surface of the chest and a transverse plane lying at the junction of the fourth intercostal space and the sternal margin. It is important to note that this "phlebostatic level" changes with differences in the position of the patient (figure 5) [7,8].

Checking transducer function — Pressure transducer function can be confirmed by waving the distal catheter tip gently, which should result in a sinusoidal waveform on the monitor. The operator must have an unobstructed view of the hemodynamic monitor during the entire procedure because the pressure tracing monitors the location of the catheter tip (figure 2). Although operator-dependent, we prefer to use a 0 to 60 mmHg calibration on the monitor screen to fully appreciate the change in pressure tracings during catheter advancement. (See "Pulmonary artery catheterization: Interpretation of hemodynamic values and waveforms in adults", section on 'Catheter waveforms and pressures'.)

A simple maneuver is performed by some experts to check for proper assembly and function of the PAC and monitoring system. When the tip of the PAC is held near heart level, the recorded pressure should be 0 mmHg, confirming that the transducer was correctly adjusted to the level of the heart at the beginning of the procedure. The catheter tip is then raised up straight to create a 30 cm tall vertical column, which should produce a recorded pressure of 22 mmHg (equivalent to 30 cm H2O) on the bedside monitor.

Patient positioning — The patient should be placed in the supine position regardless of the approach. Occasionally, when catheter advancement is difficult, the patient can be repositioned to encourage appropriate device floatation. (See 'Advancement through cardiac chambers' below.)

Advancing the catheter — PACs are positioned using either pressure waveform or fluoroscopic guidance:

Pressure waveform guidance is the more common approach. The balloon at the distal tip of the catheter is inflated and the catheter is advanced until the pulmonary artery wedge pressure waveform is identified. The balloon is then deflated.

Fluoroscopic guidance is less commonly performed. The catheter is visualized by fluoroscopy as it is advanced and balloon inflation is not necessary until the catheter reaches the pulmonary artery.

General rules — The following rules should be kept in mind during PAC advancement:

Catheter curve – The catheter has a natural curve. Thus, prior to insertion, it should be oriented so that its curve facilitates passage through the cardiac chambers (figure 6). The pulmonary artery (PA) is caudal and anteromedial to the right ventricle (RV). Thus, it is preferable that when the tip enters the RV, it is naturally pointing in this direction. As an example, when the operator is caudal, the natural curvature should be counterclockwise (picture 3).

Catheter distance – The catheter has graduations with distance in centimeters from the tip clearly indicated on it. We find it useful to verbally state the distance at the bedside during advancement. While advancing the catheter, it is useful to keep in mind the "rule of 10s," where anatomic and hemodynamic changes occur at approximately 10 cm intervals. As an example, when the insertion site is an internal jugular or subclavian vein, the RA is generally entered after inserting the catheter 20 cm, the RV after inserting 30 cm, the PA after inserting 40 cm, and the pulmonary capillary wedge pressure (PCWP) after inserting 50 cm. Estimated distances from the various insertion sites to the RA, RV, and PA are shown in the table (table 2). (See "Cardiac catheterization techniques: Normal hemodynamics".)

Balloon inflation and deflation – The balloon should only be inflated after the SVC or RA has been reached. (See 'Advancement through cardiac chambers' below.) The balloon should be fully inflated whenever the catheter is advanced to aid “floatation” and minimize myocardial or vessel rupture; in contrast, it should be completely deflated whenever the catheter is withdrawn to minimize valvular rupture (figure 3). The balloon should be fully inflated to a maximum volume per the manufacturers recommendation (typically 1 to 1.5 mL) during advancement. Inflation is normally met with a small amount of resistance. Excessive resistance usually indicates malposition of the catheter tip, which should prompt immediate deflation, withdrawing, and repositioning before another attempt is made to inflate the balloon. Little resistance suggests rupture of the balloon, in which case the balloon should be deflated, the catheter removed and the integrity of the balloon rechecked.

Clear instructions – Catheter advancement should always involve clear verbal bedside instructions such as "balloon up," "balloon down," or calling out the location of the catheter (eg, "catheter at 10 cm") to minimize the risk of complications. (See "Pulmonary artery catheterization: Indications, contraindications, and complications in adults", section on 'Complications'.)

Advancement through cardiac chambers — The appearance of expected hemodynamic waveforms during PAC insertion for a pressure waveform guidance approach is described in this section. Additionally, the clinician should bear in mind that expected waveforms and pressures may appear abnormal in patients with severe underlying cardiopulmonary disease. Additional details regarding normal and abnormal left- and right-sided cardiac hemodynamic parameters are provided separately (table 4). (See "Pulmonary artery catheterization: Interpretation of hemodynamic values and waveforms in adults" and "Cardiac catheterization techniques: Normal hemodynamics" and "Hemodynamics of valvular disorders as measured by cardiac catheterization" and "Clinical features and diagnosis of pulmonary hypertension of unclear etiology in adults", section on 'Right heart catheterization' and "Pericardial effusion: Approach to diagnosis", section on 'Cardiac catheterization'.)

Inserting the catheter into the SVC and RA — The tip of the catheter is inserted into the hub of the introducer with the balloon deflated. The balloon should not be inflated inside the introducer. The balloon may be inflated once the pressure tracing indicates that the tip of the catheter is in the SVC or RA (eg, when using the internal jugular approach, the operator should expect to see a central venous pressure/RA tracing at 20 cm, or approximately 5 cm beyond the tip of the introducer sheath) (figure 2 and waveform 1 and figure 7). The normal mean RA pressure is between 0 and 7 mmHg. Balloon inflation or deflation does not change the waveform or recorded pressure until the wedge position in the pulmonary artery is achieved.

Transitioning from the SVC or RA to the RV — Once the balloon is inflated in the SVC or RA, the catheter is advanced slowly. When the catheter tip is advanced across the tricuspid valve (from the RA to the RV), the pressure waveform changes and the systolic pressure increases (figure 2 and waveform 1 and figure 8). The normal right ventricular diastolic pressure is 3 to 12 mmHg and the peak systolic pressure is 15 to 25 mmHg.

If a RV waveform is not observed after inserting the catheter 40 cm (ie, from an internal jugular or subclavian vein approach), coiling in the RA is likely. In this situation, the balloon should be deflated, the catheter withdrawn to 20 cm, following which advancement should be repeated with the balloon inflated.

Occasionally, difficulties occur as a consequence of congenital or acquired anatomical anomalies (eg, persistence of the left SVC, absent right SVC, prior radiation).

Rarely, does the PAC enter the left atrium (LA) through a coronary sinus–left atrial communication. LA waveforms can be recognized by their higher amplitude when compared with RA waveforms as well as by their similar appearance to pulmonary capillary wedge waveforms (waveform 2); the level of oxyhemoglobin saturation will also be higher in the LA when compared with the RA.

In many cases, because the balloon tends to float to nondependent regions, positioning the patient head down may aid flotation past the tricuspid valve. Alternatively, fluoroscopy may be required for future attempts at PAC placement especially if tricuspid stenosis is suspected.

Transitioning from the RV to the PA — The risk of arrhythmia is greatest while the catheter tip is in the RV. Thus, the catheter should be advanced from the RV to the PA without delay. When the catheter tip passes across the pulmonic valve (from the RV to the PA), the diastolic pressure increases and a characteristic dicrotic notch appears in the waveform (figure 2). The normal pulmonary artery systolic pressure is 15 to 25 mmHg and the pulmonary artery diastolic pressure is 4 to 15 mmHg.

If more than 30 cm to 40 cm of the catheter has been inserted (assuming that the insertion site is an internal jugular or subclavian vein) and the pressure tracing still indicates that the tip is within the RV, then the catheter is probably coiling in the RV, or the RV is enlarged. In this situation, the balloon should be deflated and then the catheter should be withdrawn until the RA waveform appears usually at 20 cm. Then, the balloon can be reinflated and another attempt can be made to advance the catheter through the RV and into the PA.

If persistent coiling is suspected or difficulties in transitioning into the PA occurs (eg, severe tricuspid valve regurgitation), then the balloon should be deflated and the catheter should be withdrawn until the RA waveform reappears; the patient can be repositioned in the left lateral position with the head tilted slightly upward to encourage floatation into the PA. On occasion, a catheter may be floated to the proper position by injecting 10 to 20 mL of the iced solution prepared for cardiac output measurement or cold saline through the distal lumen "stiffens" the tip. In a patient with low cardiac output, deep inspiration during spontaneous ventilation will increase venous return and right ventricular output transiently which may also facilitate catheter flotation into the PA. Some clinicians fill the balloon with 1.5 mL of sterile saline. However, this maneuver is risky because saline, unlike air, is noncompressible, a feature that may increase the risk of pulmonary artery rupture.

Owing to gravitational and anatomic factors, most catheters float to the right PA. Thus, to catheterize the left PA selectively, the patient should be positioned with the right side down.

Identifying the pulmonary occlusion pressure — Once the catheter tip has reached the PA, it should be advanced until the pulmonary capillary occlusion pressure (PCOP) is identified by a decrease in the pressure combined with a change in the waveform (figure 2). The balloon should then be deflated and the PA tracing should reappear.

If the PCOP tracing persists or there is any uncertainty about whether the tracing is a PCOP or PA tracing, then the catheter should be withdrawn (with the balloon deflated) until a definitive PA tracing is identified. Occasionally, the uncertainty persists despite withdrawing the catheter. In this situation, simultaneous pressure and electrocardiographic tracings may be helpful. The peak systolic pressure in the PA occurs just prior to the electrocardiographic T wave, whereas the peak V wave of a PCOP tracing occurs after the electrocardiographic T wave. The normal mean PCOP (which is reflective of left atrial pressure) is between 4 and 12 mmHg. (See "Pulmonary artery catheterization: Interpretation of hemodynamic values and waveforms in adults", section on 'Pulmonary artery occlusion pressure (PAOP)'.)

Once the operator has confirmed that the catheter tip is in the PA and a PCOP can be obtained, an accurate final wedge position should be confirmed and recorded (see below).

Final wedge position — The final position of the catheter within the PA must be such that a PCOP tracing is obtained whenever 75 to 100 percent of the 1.5 mL maximum volume of the balloon is insufflated (figure 3).

If less than 1 mL is required to obtain a PCOP tracing, the tip of the catheter is probably in the distal PA (ie, "over wedged") and further inflation may lead to vessel rupture. In this situation, the catheter should be withdrawn 0.1 to 0.5 cm with the balloon deflated, and then the balloon is reinflated with 1 to 1.5 mL of air to check the position. If it remains over wedged, then this process should be repeated until the optimal position is found.

If maximal balloon inflation fails to result in a PCOP tracing, or does so only after a 2 to 3 second delay, the catheter is probably too proximal. This means that it could slip back into the RV, increasing the risk of arrhythmia and intracardiac damage. In this situation, the catheter should be advanced with balloon inflated in small increments (0.1 to 0.5 cm) until the optimal position is located. The length of the catheter that was passed (indicated by marks on the catheter at 10 cm intervals) should be documented in the patient's medical record.

Once the desired position is reached, if a protective sleeve is to be used it should be attached to the hub of the introducer, and a secure antiseptic dressing should be applied. If a protective sleeve is not in place, the catheter can be taped to the skin with a sterile dressing.

The PCOP is best measured with the patient in the supine position, at the end of expiration. In a spontaneously breathing patient, the PAC waveform has a positive deflection during expiration, while in a ventilated patient, the PAC waveform has a negative deflection during expiration. However, at end-expiration, all intrathoracic pressures are equal to atmospheric pressure which allows the PCOP to be accurately measured regardless of whether the patient is spontaneously breathing or mechanically ventilated. Accurate measurement of the PCOP and sources of error including the effects of respiration are discussed separately. (See "Pulmonary artery catheterization: Interpretation of hemodynamic values and waveforms in adults", section on 'Pulmonary artery occlusion pressure (PAOP)'.)

Checking catheter position — After the PAC has been secured, a chest radiograph should be obtained to confirm the position of the catheter. The catheter tip should ideally be located in zone 3 (figure 9) and should cross the midline by no more than 3 to 5 cm (image 1). However, the chest radiograph is not specific such that the tip may be located in zone 3 but facing anteriorly or posteriorly. Daily chest radiographs are often obtained to monitor for migration of the catheter tip and other complications associated with prolonged use. (See "Pulmonary artery catheterization: Indications, contraindications, and complications in adults" and "Pulmonary artery catheterization: Interpretation of hemodynamic values and waveforms in adults", section on 'Lung zone misplacement'.)

POSTINSERTION CARE — A sterile technique should be used when injecting drugs, connecting tubing (eg, cardiac output measurement) or repositioning the catheter if it migrates. Dressings should be changed routinely and the site should be checked daily for the signs of erythema or purulent exudate that might indicate infection.

The sheath or sleeve, if used, covers a length of the PAC residing outside the patient and thereby allows minor manipulations of PAC position during the monitoring period, while attempting to maintain catheter sterility.

COMPLICATIONS — Complications associated with insertion of a pulmonary artery catheter include trauma to the vessels and heart, valvular damage, and arrhythmias. These adverse consequences as well as those associated with maintenance and use of pulmonary artery catheters are discussed in detail elsewhere. (See "Pulmonary artery catheterization: Indications, contraindications, and complications in adults", section on 'Complications'.)

REMOVAL — It is preferred that pulmonary artery catheters (PACs) be left in place for as little time as possible. The PAC can be removed as a separate procedure to introducer removal. For subclavian or jugular catheter removal, the patient should be placed in slight Trendelenburg position. With the balloon deflated, the catheter should be removed during exhalation in a spontaneously breathing patient or during inspiration in a patient undergoing positive pressure ventilation to prevent air embolism. The catheter should not be withdrawn against resistance. Resistance during catheter withdrawal may indicate that the catheter is entangled in cardiac structures. Consultation with an invasive cardiologist or a vascular or cardiac surgeon should be sought if the catheter does not withdraw easily.

Following catheter removal, the introducer can be used as a central venous catheter (CVC) for the administration of fluids and medications, if necessary. Alternatively, it can be replaced with a fresh CVC or removed completely. For introducer removal, the patient should be placed in Trendelenburg. The sutures should be removed, light pressure applied to the site with gauze and the catheter removed during exhalation in a spontaneously breathing patient or during inspiration in a patient undergoing positive pressure ventilation. After removal, pressure is applied at the site for one to two minutes to ensure hemostasis, and a sterile dressing should be placed over the puncture site.

SUMMARY AND RECOMMENDATIONS

The routine use of pulmonary artery catheters (PACs) in critically ill patients has fallen out of favor. However, hemodynamic measurements obtained by PACs can be helpful in selected patients such as those with unexplained shock or those with unknown volume status despite adequate fluid resuscitation, as well as in patients with severe cardiogenic shock (eg, acute valvular disease) or in those with suspected or known pulmonary artery hypertension (table 1). PACs are occasionally inserted preoperatively for high risk cardiopulmonary surgery and in rare cases are inserted for the investigation of unexplained dyspnea. (See "Pulmonary artery catheterization: Indications, contraindications, and complications in adults" and 'Indications and contraindications' above.)

Once a decision is made to insert a PAC, a site should be selected, the appropriate personnel recruited, and all necessary equipment should be placed in the patient’s room. We prefer that the PAC be placed in the right jugular vein or as an alternative, the left subclavian vein under ultrasound guidance. Consent should be in place and laboratory studies should ensure that no severe bleeding disorder, electrolyte, or acid-base disturbances exist to increase the risk of hemorrhage or arrhythmias. (See 'Preparation' above.)

The patient should be positioned in Trendelenburg (jugular or subclavian approach) or supine (femoral or antecubital approach). Local anesthesia with 1 to 2 percent lidocaine and/or intravenous sedation (eg, 0.2 mg/kg of midazolam and/or 0.5 mcg/kg of fentanyl) is administered and the introducer is placed under sterile conditions using the modified Seldinger technique. Confirmation of venous placement and a chest radiograph (jugular or subclavian approach) should be performed before the PAC is placed. (See 'Insertion of the introducer' above and "Central venous access in adults: General principles", section on 'Central venous access' and "Central venous access: Device and site selection in adults", section on 'Types of central venous catheters'.)

Once the introducer has been inserted into the target blood vessel, the field should be resterilized. The PAC ports should be flushed, and the integrity of the balloon and the ability of the PAC to transduce pressure should also be checked. With the patient in the supine position, the PAC is advanced through the introducer into the superior vena cava (SVC), cardiac chambers, and pulmonary artery (PA) while the pressure at its tip is transduced. (See 'Resterilizing the field' above and 'Preparing the catheter' above and 'Patient positioning' above.)

As a general rule during advancement, the balloon may only be inflated once the pressure tracing indicates that the tip of the catheter is in the SVC or right atrium (RA) (figure 2). Additionally, the balloon should only be inflated whenever the catheter is advanced and deflated whenever the catheter is withdrawn. (See 'General rules' above.)

Once the catheter tip is in the SVC or RA and the balloon is inflated, the PAC is advanced slowly into the right ventricle (RV) where the pressure waveform changes and the systolic pressure increases (figure 2). Due to the increased risk of ventricular arrhythmias, the catheter tip should be advanced through the RV and into the PA without delay. Entry in to the PA is easily recognized because the diastolic pressure increases and a dicrotic notch appears. Once the catheter tip reaches the PA, it should be advanced until the pulmonary capillary occlusion pressure (PCOP) is identified by a decrease in the pressure combined with a change in the waveform. (See 'Advancement through cardiac chambers' above.)

The final position of the catheter must be such that a PCOP tracing is obtained whenever 75 to 100 percent of the 1.5 mL maximum volume of the balloon is insufflated. Once the desired position is reached, it is essential that the catheter be secured to prevent migration. A chest radiograph should then be obtained to confirm the position of the catheter. (See 'Final wedge position' above.)

A sterile technique should be used when injecting drugs, connecting tubing, or repositioning the catheter if it migrates. Dressings should be changed routinely and the site should be checked daily for the signs of erythema or purulent exudate that might indicate infection. Complications associated with insertion of a pulmonary artery catheter include trauma to the vessels and heart, valvular damage, and arrhythmias. (See "Pulmonary artery catheterization: Indications, contraindications, and complications in adults" and 'Postinsertion care' above.)

It is preferred that PACs be left in place for as little time as possible. The PAC should be removed separately with the patient in slight Trendelenburg and the balloon deflated. Resistance during catheter withdrawal should prompt consultation with a subspecialist (eg, invasive cardiologist, cardiac surgeon). The introducer can be removed as a separate procedure, also with the patient in Trendelenburg, following which, pressure should be applied for one to two minutes and a sterile dressing applied. (See 'Removal' above.)

Topic 1658 Version 25.0

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