Right Heart Catheterization
Jun-Yang Lou
Venu Menon
I. INTRODUCTION.
In 1947, Dexter et al. (1) observed that the pressure recorded by a catheter wedged in the pulmonary artery (PA) was similar to the filling pressure in the left ventricle. In 1970, Swan and colleagues (2) reported that PA catheterization could be performed at the bedside by using a specially designed balloon-tipped catheter. This landmark observation brought right heart catheterization (RHC) to the bedside and it remains an integral part of the diagnostic armamentarium of the cardiologist. Although the routine use of RHC data to guide treatment in critically ill patients in the intensive care unit has been associated with harm, it remains the gold standard in hemodynamic monitoring, and its use can be crucial in diagnosing and treating critically ill patients with cardiovascular disease.
The utility of hemodynamic variables obtained from RHC as a diagnostic and prognostic marker in patients with acute myocardial infarction (MI), cardiogenic shock, and heart failure (HF) is well established. Proving that a clinical benefit exists for continuous RHC hemodynamic monitoring has, however, been challenging. Retrospective observational analyses on the utility have been limited by patient selection as well as survival biases. In the National Heart Lung Blood Institute—supported ESCAPE (Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness) trial, the utilization of PA catheters was not associated with worse outcomes. In this trial of 433 patients randomized to therapy for class IV HF guided by either clinical assessment or clinical assessment plus PA catheterization, there was no difference in the primary end point of days alive out of the hospital during the first 6 months after hospitalization. There was an increase in inhospital adverse events in the PA catheter group; however, there were no deaths related to PA catheter use and no difference in in-hospital or 30-day mortality between the two groups.
II. INDICATIONS AND COMMON USES.
See Table 60.1 for ACC recommendations for using PA catheterization.
(A) Acute MI complicated by hypotension, congestive heart failure, sinus tachycardia, right ventricular (RV) infarction, or mechanical complications (such as ventricular septal defect [VSD], pericardial tamponade, or acute mitral regurgitation [MR]).
(B) Assessment of volume status in patients in whom physical signs may be unreliable (e.g., morbidly obese or ventilated patients).
(C) Severe left ventricular (LV) failure to guide inotropic, diuretic, and afterload reduction management.
(D) Differentiation between various shock states (e.g., cardiogenic, distributive, or hypovolemic) and guidance of therapies.
(E) Risk stratification for patients during heart transplant evaluation.
(F) Cardiac tamponade. Although echocardiography is the diagnostic test of choice, PA catheterization may be used when echocardiography is not readily available or nondiagnostic and the risk or difficulty of pericardiocentesis is high.
(G) Assessment of the level and magnitude of an intracardiac shunt, especially if transthoracic echocardiography is nondiagnostic.
TABLE 60.1 Common Indications for the Use of Right Heart Catheterization | |||||||||||||||||||||||||
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(H) Differentiation between constrictive and restrictive cardiac physiology.
(I) Severe pulmonary hypertension (PH).
(J) High-risk cardiac patients during preoperative, intraoperative, and postoperative periods to monitor volume status and cardiac output (CO).
(K) Severe adult respiratory distress syndrome (Noncardiogenic Pulmonary Edema) during positive end-expiratory pressure trials to assess CO.
III. CONTRAINDICATIONS.
The absolute contraindications to PA catheter placement are right-sided endocarditis, a mechanical tricuspid or pulmonic valve prosthesis, thrombus or tumor in a right heart chamber, uncooperative patient, and terminal illness for which aggressive management is considered futile. Relative contraindications are profound coagulopathy (international normalized ratio > 2 or platelet count < 20,000 to 50,000), bioprosthetic tricuspid or pulmonic valve prosthesis, newly implanted pacemaker or defibrillator (unless fluoroscopic guidance is used), and left bundle branch block (LBBB). The latter is a relative contraindication because local trauma to the functioning right bundle while introducing the PA catheter may result in complete heart block and hemodynamic instability. Consequently, temporary pacing should be immediately available when inserting a PA catheter in patients with preexisting LBBB. Finally, it would be advisable to treat any pneumothorax/hemothorax on the contralateral lung before proceeding, in the event of an ipsilateral pulmonary injury caused by the procedure.
IV. TECHNIQUE
A. Venous introducer/sheath insertion. It is important to obtain informed consent in plain language from the patient before the procedure, addressing the utility and major complications of PA catheterization (Table 60.2). Once the procedure is ready to commence, a checklist system should be utilized to ensure safety and success, including a time-out process that confirms “right patient, right procedure, and right site of access.” Using a central line kit is a convenient way to streamline the procedure. The patient should be prepped and draped in a sterile fashion from head to toe during the catheter insertion, regardless of the insertion site chosen. Multiple sites can be used for introducer placement; however, a site that can be readily compressed, such as the internal jugular (IJ) vein, is preferred. Localization and entry into the vein is best performed under ultrasound guidance as an imaging-guided approach decreases procedural complications. Cannulation of the vein utilizing anatomical landmarks should only be used when ultrasound guidance is unavailable.
TABLE 60.2 Complications of Right Heart Catheterization | ||||||||||||||||||||||
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1. The IJ vein (see Fig. 60.1) has multiple advantages, such as compressibility and minimal risk of pneumothorax. The disadvantages are the potential for accidental carotid artery puncture and limited neck mobility for patients. The IJ vein can be entered via an anterior or posterior approach. The right side is generally preferred because the vein runs a direct path to the right atrium. Often, it is easier to access the IJ vein if the patient is in the Trendelenberg position. The anterior approach uses the triangle created by the two heads of the sternocleidomastoid muscle and the clavicle. A finger should always be placed on the carotid artery to identify its position and to retract it medially. The needle should be inserted at the apex of this triangle and advanced in the direction of the ipsilateral nipple at a 45° angle. The vein can usually be entered 3 to 5 cm from the skin surface. In order to minimize complications, the vein should be found with a finder needle (20G) before using the large-bore catheter (16G) needle. Once the IJ vein is cannulated, the catheterover-guidewire approach should be used to place the introducer. The guidewire minimizes damage to the vessel and should pass smoothly. Never force the guidewire. If difficulty in threading the wire is encountered, reattach the syringe and attempt to aspirate venous blood to ensure that the needle tip is still located in the vessel. An instructional video available from the New England Journal of Medicine web site (see reference) is a helpful tool for clinicians and students alike.
An alternative IJ vein access is the posterior approach. The advantage of this approach is that it minimizes the risk of carotid artery puncture. First, the external jugular vein is located, and the IJ vein is cannulated 1 cm superior to the point where the external jugular vein crosses the lateral edge of the sternocleidomastoid muscle. Another posterior approach is to puncture along the posterior edge of the sternocleidomastoid muscle, two fingerwidths above the clavicle. The needle should be pointing toward the posterior aspect of the upper portion of the manubrium sterni.
2. Cannulation of the subclavian vein (see Fig. 60.1) is associated with greater patient comfort. However, there is an increased risk of pneumothorax and inadvertent subclavian artery cannulation, especially in patients on mechanical ventilation or with chronic obstructive pulmonary disease. The vein lies just under the clavicle at the insertion site for the clavicular head of the sternocleidomastoid muscle. This is where the vein should be cannulated. The subclavian artery lies just beneath the anterior scalene muscle, which is just below the subclavian vein, with the lung just underneath the artery. For better landmark definition and separation of the vein from the pleura, a rolled-up towel can be placed between the scapulae. There are two approaches to cannulating the subclavian vein: infraclavicular and supraclavicular. The infraclavicular approach is used more frequently.
The needle is inserted under the clavicle at about 1 cm lateral to the sternocleidomastoid muscle insertion point. The needle is then advanced horizontally, nearly parallel to the clavicle, toward the suprasternal notch.
The needle is inserted under the clavicle at about 1 cm lateral to the sternocleidomastoid muscle insertion point. The needle is then advanced horizontally, nearly parallel to the clavicle, toward the suprasternal notch.
 FIGURE 60.1 Neck anatomy. |
With the supraclavicular approach, the vein is entered from above. The sternocleidomastoid muscle and the clavicle form an angle, and the needle is inserted at this point at a 45° angle. The vein should be cannulated no deeper than 2 cm below the skin surface. If there is uncertainty whether artery or vein has been cannulated, transduce pressure through the needle or obtain a blood gas sample to differentiate vein from artery before dilatation. An instructional video is available from the New England Journal of Medicine web site (see reference).
3. The femoral vein may also be used for PA catheterization, with the advantages being ease of cannulation, easy compressibility, and absence of pneumothorax risk. Palpate the femoral artery pulse at the level of the inguinal ligament. The femoral vein is usually located 2 cm medial to and 2 cm below the femoral artery. In some patients, the vein may lie closer to the artery. Sometimes, the Valsalva maneuver may make it easier to access the vein.
Unfortunately, there is a high risk of bloodstream infection, associated with central venous access from femoral veins. It is recommended in the Center for Disease Control guidelines for the prevention of intravascular catheter-related infection that it not be used routinely for central venous access.
4. Venous cutdown is rarely necessary, in which case right basilic and right median cubital veins are used. However, due to venospasm and difficulty with catheter insertion and advancement, the antecubital route is reserved for those who have failed other routes.
B. PA catheter insertion
1. After the introducer/sheath is placed and secured, the PA catheter can be inserted. Always test balloon inflation, flush the ports, and make sure the catheter is properly calibrated before beginning the procedure. After the PA catheter is tested, insert it through the protective sterile covering and then through the introducer. Keep the balloon deflated at this stage. Ideally, fluoroscopy and pressure waveforms should be used during PA catheter insertion for guidance. The catheter should advance easily; if not, do not force the catheter, but make sure the introducer is properly positioned and flushed.
Once the catheter has been inserted 15 to 20 cm or after the right atrial (RA) tracing is seen, inflate the balloon and advance across the tricuspid valve. The RV tracing should be visualized next, followed by the PA tracing, and finally the pulmonary capillary wedge pressure (PCWP) tracing (see Fig. 60.2). Not infrequently, the RV tracing is accompanied by a few premature ventricular ectopic beats. In general, the PA tracing should be reached within 50 to 55 cm if the catheter is inserted from the IJ vein or subclavian vein or 65 to 70 cm if via a femoral or an arm approach. If the PA tracing has not been visualized by this point, the catheter is likely coiled in the right ventricle. The balloon should be deflated and the catheter withdrawn. The process is repeated until proper placement is achieved. Once the PCWP tracing is obtained, deflate the balloon and reobtain the wedge pressure by inflating the balloon with 1.5 cm3 of air. If the PCWP tracing is obtained even when the balloon is deflated or with < 1.5 cm3 of air, the catheter has been advanced too far and needs to be pulled back. The pressure waveform should always be closely monitored when inflating balloon-tipped catheters to immediately identify this “overwedging.” The likelihood of PA rupture and infarction increases when catheters are overwedged. In the nonventilated patient, the PCWP should be obtained at end-expiration. In general, wedging the catheter should be avoided in patients with severe PH.
2. It is much easier to float the catheter from the right IJ vein or either subclavian vein. From the femoral veins, it is slightly more difficult, especially in patients with significant tricuspid regurgitation. Often, the femoral PA catheter needs
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