Chapter 34: Pericardiocentesis

Cardiac tamponade is a relatively rare condition. If a pericardial effusion compromises hemodynamics, pericardiocentesis can be lifesaving. The cause of cardiac tamponade may be determined by fluid analysis after pericardiocentesis (Table 34-1).^1,2,3,4

In a small study of medical cardiac tamponade, the mean volume drained was 593 ± 313 mL. When the primary cause was malignancy, the 1-year mortality was almost 80%.⁵ In Africa, up to 70% of pericardial effusions in patients with human immunodeficiency virus are caused by tuberculosis.⁶

Maintain a high degree of suspicion of cardiac tamponade for oncology patients who fit the clinical signs and symptoms of tamponade.

Blunt cardiac rupture is rare, occurring approximately in 1 in 2400 blunt trauma patients. Of this subgroup, 89% arrive alive to the ED.⁷ Those who arrive alive may benefit from a bedside US examination to detect a traumatic effusion. Tamponade, as a result of trauma, may require a temporizing pericardiocentesis while the patient is prepared for definitive surgical repair.

In a South African study, the mortality rates from gunshot wounds and stab wounds were 81% and 15.6%, respectively.⁸ This comparison underlines the probability that patients with stab wounds to the heart are more likely to survive to the ED and may benefit from pericardiocentesis.

The pericardium is a fibrocollagenous sac covering the heart that contains a small amount of physiologic serous fluid. The fibrocollagenous pericardium has elastic properties and will stretch in response to increases in intrapericardial fluid. Accumulation of fluid that exceeds the stretch capacity of the pericardium precipitates hemodynamic compromise and results in pericardial tamponade.

The initial portion of the pericardial volume–pressure curve is flat, so early on, relatively large increases in volume result in comparatively small changes in intrapericardial pressure. The pericardium becomes less elastic as the slope of the curve marches upward. As fluid continues to accumulate, intrapericardial pressure rises to a level greater than that of the filling pressures of the right atrium and ventricle. When this occurs, ventricular filling is restricted and results in cardiac tamponade.⁹

Pulsus paradoxus is commonly seen with cardiac tamponade and is defined as an abnormal decrease in systolic blood pressure and pulse wave amplitude. During normal respirations, systolic blood pressure drops less than 10 mm Hg. In pulsus paradoxus, systolic blood pressure drops >10 mm Hg, resulting in a cardiac contraction that does not result in a normal radial pulse. This causes a paradoxical pulse.¹⁰

In blunt trauma, forces within the thorax can compress the right atrium, resulting in rupture of the atrium or the right atrial appendage. This occurs when blood continues to fill the relatively inelastic pericardial sac. Deceleration injuries can lead to a cardiac or pericardial rupture, herniation, or a myocardial contusion with intrapericardial hemorrhage. Blast injuries can cause acute cardiac tamponade.¹¹ During an acute rapidly expanding pericardial effusion, stroke volume will increase with removal of even a small amount of fluid (as little as 50 mL) from the pericardial sac (Figure 34-1).

HISTORY

Trauma as a cause of pericardial tamponade is generally evident from history and clinical presentation. Oncology patients comprise the largest group with pericardial effusions leading to hemodynamic compromise. Other conditions that may predispose a patient to pericardial effusion and tamponade include acute infection (viral, bacterial, mycoplasma, fungal, parasitic, or endocarditis) or radiation exposure. Other chronic conditions in which this diagnosis may be considered include tuberculosis, renal failure, autoimmune diseases, drugs that induce a lupus-like syndrome, hypothyroidism, or ovarian hyperstimulation syndrome.¹² Many cases are idiopathic.

The key symptoms of tamponade are dyspnea and chest pain. Trauma patients may or may not exhibit pleuritic pain, tachypnea, and dyspnea before becoming confused, losing consciousness, or developing shock.¹³ Other symptoms include chest fullness, nausea, esophageal pain, or abdominal pain from hepatic and visceral congestion. Other nonspecific symptoms include lethargy, fever, weakness, fatigue, anorexia, palpitations, and shock. Be aware of these symptoms and accordingly focus the examination to exclude life-threatening conditions, such as cardiac tamponade.

PHYSICAL EXAMINATION

Common clinical signs of cardiac tamponade may resemble other severe cardiopulmonary disease processes, such as tension pneumothorax or decompensated congestive heart failure. The sensitivities of examination findings are pulsus paradoxus >10 mm Hg (82%), tachycardia (77%), jugular venous distention (76%), diminished heart sounds (28%), and hypotension (26%). These findings are not surprising because the Beck triad includes low blood pressure, elevated jugular venous distention, and decreased heart sounds.¹⁰ Detection of jugular distention may be difficult to appreciate in patients with a short, thick neck or if working under levels of low lighting. The combination of pulsus paradoxus and elements of the Beck triad should prompt imaging with bedside US to search for a pericardial effusion. Any disorder that increases intrathoracic pressure may result in pulsus paradoxus, including chronic obstructive pulmonary disease, obesity, tense ascites, severe asthma, congestive heart failure, mitral stenosis, and massive pulmonary embolism.

The diagnosis in an undifferentiated patient relies on clinical suspicion using the signs and symptoms of cardiac tamponade, with confirmation by bedside US (see discussion in "Echocardiography" section, below).

The ECG can be normal. The classic ECG finding is electrical alternans. Electrical alternans is alternating high- and low-voltage QRS complexes as the heart swings toward and then away from the ECG leads on the chest wall with each contraction (Figure 34-2). Other findings can include nonspecific ST-T wave changes or bradycardia, which can be seen in the late stages of cardiac tamponade progressing to pulseless electrical activity (PEA). In the absence of hypotension and tension pneumothorax in a patient with PEA, consider the diagnosis of cardiac tamponade.

IMAGING

Chest radiographs may show a normal or enlarged cardiac silhouette with clear lungs, as demonstrated in Figure 34-3. On lateral chest radiographs, a double lucency sign demonstrates the epicardial fat pad.

Echocardiography

Cardiac tamponade can be imaged at the bedside with two-dimensional echocardiography and Doppler echocardiography. This allows for visualization of a pericardial effusion and the compression of the ventricles. The most characteristic sign on echocardiogram is right-sided heart collapse. During diastole, the right ventricle presses inward (Figure 34-4), and during systole, the right atrium presses inward. Right-sided collapse portends rapid development of cardiac tamponade. Right atrial collapse during at least 30% of the cardiac cycle is more sensitive than the finding of right ventricular collapse for cardiac tamponade. In 25% of patients with tamponade, a late finding is left atrium collapse. Doppler US can be used to monitor the respiratory changes in flow between ventricle and atrium.⁹

When hemodynamic compromise is present, infusion of a normal saline fluid bolus can be temporizing by improving right ventricular volume while preparations are made for emergency pericardiocentesis.¹

PURPOSE AND INDICATIONS

The purpose of emergency pericardiocentesis is treatment of hemodynamic compromise from cardiac tamponade. Emergency pericardiocentesis is also indicated during resuscitation from PEA after other causes of PEA have been excluded.

Postoperative or penetrating trauma patients may develop tamponade 2 weeks or more after surgery.⁷ In one study of traumatic tamponade, the most common indications for pericardiocentesis were clinical tamponade (83%), with echocardiographic findings of ventricular diastolic collapse (69%) and right atrial collapse (33%).¹⁴ Pericardiocentesis for a traumatic effusion from penetrating cardiac trauma may be performed during resuscitation to stabilize a patient until surgery for definitive repair is available, but surgical drainage is preferred in traumatic effusions and purulent pericarditis.¹⁵ If the patient is hemodynamically compromised and on the verge of cardiac arrest, perform emergency pericardiocentesis in the ED, rather than delay treatment by transporting to the OR.

BEDSIDE US

If bedside US is available, two-dimensional echocardiographic imaging is preferred to guide pericardiocentesis^16,17,18,19 and can also evaluate the size of the effusion and its effect on cardiac output. The 2010 Focused Cardiac Ultrasound in the Emergent Setting guidelines state: "When emergency pericardiocentesis is indicated ultrasound can provide guidance by first imaging the fluid collection from the subxiphoid/subcostal or other transthoracic windows to define the best trajectory for needle insertion."²⁰ The guidelines further emphasize that bedside US results in fewer complications and greater success in performance of pericardiocentesis.²⁰ The European Society of Cardiology's 2004 Guidelines on the Diagnosis and Management of Pericardial Disease has evidence-based guidelines on pericardiocentesis. Pericardiocentesis is lifesaving in cardiac tamponade (level of evidence B, Class I indication) and indicated in effusions >20 mm in echocardiography but also in smaller effusions for diagnostic purposes (pericardial fluid and tissue analyses, pericardioscopy, and epicardial/pericardial biopsy; level of evidence B, Class IIa indication). American College of Cardiology/American Heart Association 2005 guidelines for the use of echocardiography gives Class I recommendations to using this methodology for visualizing effusions and detecting hemodynamic compromise secondary to tamponade. The European Society of Cardiology 2004 guidelines recommend that practitioners use US guidance rather than blind approaches and the ECG-alone guided approach for pericardiocentesis.²¹ Using echocardiographic-guided pericardiocentesis reduces radiation associated with fluoroscopy and allows the procedure to be performed safely at the bedside.²²

CONTRAINDICATIONS TO PERICARDIOCENTESIS

Some authors list aortic dissection as an absolute contraindication. Relative contraindications include uncorrected coagulopathy, anticoagulant therapy, thrombocytopenia, and small posterior loculated effusions.

RISKS AND PRECAUTIONS

Traditional blind subxiphoid approaches increase risk of damage to adjacent structures, such as the liver, lung, diaphragm, and GI tract. The cardiovascular system may also sustain injuries during the procedure, including chamber puncture, myocardial damage, and laceration of coronary arteries/veins. Resultant arrhythmias may develop as well, secondary to myocardial damage. Although risks must be considered, use of specific techniques and imaging can significantly reduce injury from the procedure itself. If bedside US is not available and the patient has cardiac or hemodynamic compromise, the blind subxiphoid approach for cardiac tamponade for acute hemopericardium can be used.²³ See Table 34-2 for a list of equipment needed.

PATIENT PREPARATION AND POSITIONING

If time and conditions permit, obtain and review a stat portable chest x-ray to identify mediastinal shift or pneumothorax. Traditional positioning for pericardiocentesis is with the head of the bed elevated to approximately 30 to 45 degrees, but in cardiac arrest or near-arrest, this position may not be feasible. Therefore, the procedure is often performed with the patient supine. Before choosing the needle insertion site, it must be noted if the patient has mediastinal shift, as this can displace structures and alter normal anatomic locations. In some instances, very small effusion volumes (50 to 100 mL) precipitate cardiac tamponade, and therefore, fluid may collect in dependent portions of the pericardial space. If the size of the effusion is small, rolling a patient to the left lateral decubitus position allows fluid to collect around the apex and provides easier access. This positioning also allows the left lung to move laterally, thereby increasing cardiac exposure.

ANESTHESIA AND MONITORING

Patients undergoing emergency pericardiocentesis in the ED are often in significant distress and are being resuscitated. They may therefore already be sedated or paralyzed, or both. If local anesthesia is needed, immediately before the procedure, administer 1% to 2% lidocaine SC and along the plane of expected needle insertion. Aspirate during infiltration to avoid injection of lidocaine directly into vascular structures.

Institute cardiac monitoring and pulse oximetry, and provide supplemental oxygen. Assistants can monitor the pulse amplitude.

1. Use universal precautions.

2. Organize needed materials.

3. Position patient as needed.

4. Identify point of maximal effusion with US (i.e., closest to transducer/skin and where accumulation is maximal). Pericardial effusions are dark, or anechoic, areas surrounding the heart. Usually the pericardium can be seen overlying the effusion. In addition, paradoxical motion of the right ventricular wall with collapse during diastole is noted in states of tamponade. Distance from the skin surface to the effusion border can be measured with most US models to better assess expected needle depth.

5. Choose needle trajectory. Trajectory should be chosen to coincide with the plane of the US beam. Identify any anatomic structure between the skin and pericardial space that lies within the expected needle path. Although many approaches can be used, the best approach should aim for the point of maximal effusion with the fewest intervening structures. For most patients, the optimal approach is the left chest wall. Most common is the left parasternal approach or the apical approach, both at the fifth intercostal space (Figure 34-5), or the subxiphoid approach. If using the left parasternal approach, select a site approximately 3 to 5 cm from the sternal edge to avoid the left internal mammary artery. Direct the needle over the superior margin of the rib to avoid injuring the neurovascular bundle on the inferior margin of each rib. The site may be marked with a surgical pen for easier location after sterile preparation.

6. Sterile preparation. Prepare area with povidone-iodine or equivalent antiseptic. Drape the surrounding area with sterile towels or a premade drape (clear drapes available commercially).

7. Inject local anesthetic. Inject 1% to 2% lidocaine with a 25-gauge, ⁵/₈ inch needle at the selected site before the procedure. Produce a subcutaneous wheal, and then inject into deeper tissues while avoiding entry into the chest cavity. Aspirate before injection to avoid injection of anesthetic into vascular structures.

8. Preparation of US. Using the cardiac probe, place a sterile cover over the probe (may use sterile glove) after placing US gel on the probe tip. Place sterile US gel over the planned site of entry. Using the nondominant hand, hold the US probe in the plane of planned needle insertion. A second operator technique may be used.

9. Pericardial needle insertion. Under direct US guidance, insert needle at the predetermined site at an approximately 45-degree angle to the skin at the transducer. Visualize the needle "tenting" the pericardium. Upon entry into the pericardial sac, a return of blood, serous fluid, pus, and so on, should be obtained. Clotted blood may prevent aspiration. Blood can clot within the needle or may have clotted within the pericardial space. Often, clotted blood within the pericardial space can be identified on US examination as echogenic material. If you suspect needle obstruction, attempt flushing the needle with 1 to 2 mL of normal saline to cleanse the needle. If aspiration is too easy, suspect ventricular puncture. To decrease complications of needle insertion, do not redirect the needle within the pericardium while aspirating. This may reduce the number of occurrences of inadvertent coronary artery lacerations or penetrating the pericardium.

10. Fluid collection. Fluid may be collected for diagnostic testing to assess for protein or albumin, cell counts, Gram stain, and cultures, among others.

11. Catheter removal. Once adequate fluid has been withdrawn from the pericardial space and hemodynamic equilibrium has returned, the catheter may be removed. The site should be dressed as with any needle insertion site. Alternatively, an optional indwelling flexible J-tip catheter may be placed as in step 2 under "Optional Steps." Although recurrence rates have been shown to decrease significantly with indwelling or extended catheter drainage, this is not routinely performed in the ED secondary to patient acuity and ongoing resuscitative measures. Once hemodynamics have been returned to normal and the patient stabilized, evaluation and possible indwelling catheter placement can be performed by the cardiologist.

OPTIONAL STEPS

1. Saline echo-contrast technique. When confirmation of the needle tip is necessary, agitated saline solution can be used. Using a three-way stopcock, attach one end to the catheter. Attach one syringe with 3 mL of normal saline and one syringe with an equivalent amount of air to the remaining two ports. Quickly mix the saline and air together and then inject into the pericardial sac under US visualization. Alternatively, the saline may be agitated by simply shaking a 10-mL syringe filled with 3 to 5 mL of normal saline and then injecting this into the pericardial space. An echo-contrasted medium should appear in the pericardial space. If the contrast disappears quickly after injection, suspect tip placement in ventricle. Rather than attempting to reinsert needle into the catheter, it is best to start again with a new needle should this complication arise.

2. Catheter placement. Using the standard Seldinger technique, a flexible J-tip guidewire is introduced through the catheter. The catheter is then removed. Next, a small "stab" incision is made at the needle entry site. A 6- to 8-French dilator is introduced over the guidewire and then removed. A 6- to 8-French pigtail catheter is then introduced over the guidewire. The guidewire is then removed. Confirmation of placement can be done by saline echo-contrast as in step 1 above. Catheter is then placed to suction.

3. Dressing. Secure catheter to chest wall with suture, dressing, or both.

4. Catheter drainage and maintenance. Pericardial fluid should be aspirated intermittently approximately every 4 to 6 hours. To prevent catheter blockage, continuous drainage is avoided. Flushing of the catheter with saline after drainage will ensure patency. Strict inputs and outputs should be measured by staff.

5. Catheter removal. Although not routinely done by ED staff, the catheter may be removed once drainage has decreased to <30 mL in 24 hours. In addition, follow-up two-dimensional echocardiography should confirm resolution of the effusion.

The blind subxiphoid approach starts with similar preparation and anesthetic. The point of needle insertion starts either directly below or adjacent to the xiphoid process. An 18-gauge needle is inserted at a 45-degree angle to the patient's skin, and the needle tip is directed to either the left or right shoulder (Figure 34-6). Some authors advocate using the right shoulder as the direction of choice because this direction is parallel to the ventricular wall (in contrast to perpendicular for left shoulder direction), thereby theoretically reducing the chance of myocardial injury. In either approach, the needle is aimed toward the heart with continuous aspiration of the syringe until return of pericardial fluid.

ECG MONITORING TECHNIQUE

The ECG monitoring technique uses ECG monitoring to detect myocardial injury patterns and localize needle location. However, ECG injury monitoring alone is not an adequate safeguard.¹⁷ The approach is similar to the blind approach in orientation. Attach the V₁ monitor lead to the needle. Watch the monitor while introducing the needle. ST elevation on the monitor indicates that the needle tip has contacted the myocardium. Withdraw the needle slightly and aspirate. This technique is rarely used currently due to complexity in the emergent setting and advances in US allowing for safer alternatives.

A favorable outcome is the restoration of hemodynamic stability with return of normal blood pressure and heart rate. Two-dimensional echocardiography should also show decreased effusion, increased cardiac contractility, and increased cardiac output.

Complications may vary widely, dependent on approach and the underlying cause of tamponade. Traditional blind techniques have been associated with morbidity of 20%, with mortality as high as 6%. The overall complication rate of US-guided approaches is <5%.¹⁶

Major complications include chamber lacerations requiring surgery, intercostal vessel injury requiring surgery, pneumothorax requiring chest tube placement, ventricular tachycardia, and bacteremia. Minor complications include transient chamber entries, small pneumothorax not requiring intervention, hypotension secondary to vasovagal response, sinus tachycardia, pericardial catheter occlusion, and possible pleuropericardial fistulas.¹⁶ Cardiac arrhythmias, such as atrial fibrillation, ventricular tachycardia, or asystole, may occur when the needle penetrates the pericardium. Monitor the patient closely for reaccumulation of pericardial fluid after pericardiocentesis.

All patients undergoing pericardiocentesis in the ED require admission to the intensive care unit. Consult the trauma surgeon, cardiologist, or cardiothoracic surgeon, as appropriate, early in patient evaluation.