by David Wald and Lindsay Davis
A 52-year-old female with a history of metastatic breast cancer presents to the emergency department with a complaint of progressive shortness of breath throughout the past week. She initially felt tired and out of breath with walking and climbing stairs. This has progressed to the point where she would feel short of breath just walking around her house. Over the last day, she noted that it has become difficult lying flat in bed. Today she is experiencing shortness of breath at rest. She reports no other active health conditions. Her initial vital signs are blood pressure 92/66 mmHg, heart rate of 108, respiratory rate of 20 per minute, temperature 37.1°C and a room air oxygen saturation of 96%. On evaluation, the patient appears uncomfortable and mildly dyspneic. She has JVD at 5cm. Her heart sounds are regular without a murmur but are barely audible. Lungs are clear in all fields. Her abdomen is soft and non-tender. She has no lower extremity edema. She is awake, alert and moves all of her extremities equally. A 12 lead electrocardiogram shows sinus tachycardia with low voltage in the limb leads. Her chest radiograph is shown in figure 1. An emergency medicine bedside cardiac ultrasound is performed, see figure 2.
Figure 1. Pericardial effusion on chest radiograph demonstrating an enlarged “water bottle” shaped heart. This finding can be seen in pericardial effusions that have developed slowly, allowing time for the pericardial sac to stretch.
Figure 2. Echocardiography of a pericardial effusion in the subcostal 4-chamber view. Note the inward bowing of the right ventricle indicating cardiac tamponade and hemodynamic compromise.
Pathophysiology and Indications
The heart is surrounded by a double layer fibrous sac known as the pericardial sac. The first layer, the visceral pericardium, is adherent to the cardiac epicardium. The second layer, the parietal pericardium, is separated by the visceral pericardium by 25-50 mL of physiologic serous fluid, allowing the heart to beat without friction.
A pericardial effusion develops when fluid accumulates in the potential space between the visceral and parietal pericardium. Pericardial effusion can be caused by a number of conditions including trauma, malignancy, uremia, cardiac rupture, and infectious causes such as tuberculosis and viral pathology. The clinical effect of pericardial effusion can vary based on etiology, volume, and particularly the speed at which the effusion accumulates. If fluid accumulates very gradually, the pericardium can remodel and stretch to accommodate the increased volume. In these cases, symptoms are often insidious and progressive over days to weeks. Alternatively, if fluid accumulates suddenly, as in the case of penetrating chest trauma, the pericardium is not able to stretch to accommodate the increased volume of fluid. The result can be the rapid development of pericardial tamponade and death.
Pericardial tamponade occurs when the pressure of a pericardial effusion becomes greater than the pressure in the right atrium, resulting in the collapse of the right atrium during diastole. Remember, the right side of the heart is a low flow system, and it does not take much pressure to impede flow. The increased pressure within the pericardial space can eventually cause compression of the entire right side of the heart, leading to the restricted ventricular filling. This, in turn, can lead to decreased stroke volume and decreased cardiac output. If not treated, this can result in hypotension, cardiogenic shock, and death. If an effusion develops rapidly, as little as 150 mL of fluid, can cause tamponade physiology. A pericardial effusion that restricts cardiac output resulting in tamponade is a true cardiovascular emergency and is the primary indication for emergency pericardiocentesis.
At times, making the diagnosis of pericardial tamponade can be difficult because the condition can present in an insidious fashion if the effusion accumulates slowly over many days to weeks. In these cases, the differential diagnosis will include many other causes of shortness of breath. Alternatively, pericardial tamponade should always be considered as a potentially reversible cause in the patient who develops cardiac arrest shortly after chest trauma.
Cardiothoracic surgeon Claude Schaeffer Beck originally described the physical exam findings of pericardial tamponade in 1935 as what is now commonly known as Beck’s triad: muffled heart sounds, jugular venous distension (JVD), and hypotension. Though these findings are described in every textbook discussion of pericardial tamponade, studies have shown that these exam findings have poor sensitivity and specificity and are present together with a minority of the time. The most common signs and symptoms exhibited by patients with tamponade include dyspnea, tachycardia, JVD, and a narrowed pulse pressure. Pulsus paradoxus (a decrease in systolic blood pressure of greater than 12 mmHg during inspiration) has been found to be one of the more sensitive and specific exam findings associated with cardiac tamponade. However, the tedious and time-consuming nature of this exam technique makes it difficult at best and often an impractical tool for diagnosing a life-threatening condition in an unstable patient in the emergency department.
Electrocardiographic findings can include low voltage QRS complexes, PR segment depression, ST elevation and electrical alternans (see figure 3), though these findings are also not specific or sensitive. Chest radiographs are equally nonspecific. In the case of a chronic pericardial effusion, a chest radiograph may demonstrate an enlarged “water bottle” shaped cardiac silhouette (see figure 1). However, if the effusion is from an acute traumatic etiology, the pericardial sac will not have had time to stretch to accommodate the increased volume, leaving the cardiac silhouette unchanged.
Figure 3. Electrocardiogram demonstrating electrical alternans in a patient with a large pericardial effusion. Note the alternating QRS amplitude due to the swinging motion of the heart within the pericardial sac.
Ultrasound is the best and most applicable diagnostic imagining modality used to identify a pericardial effusion or tamponade. It is noninvasive and safe, with no risk of radiation to the patient. The increased availability of bedside ultrasound in the emergency department has allowed for instant point of care diagnosis of this potentially life-threatening condition. In addition to offering direct visualization of the effusion itself, sonography allows the operator to assess for hemodynamic compromise secondary to increased pericardial pressure. The initial sign of this process is the collapse of the right atrium in diastole, followed by bowing of the right ventricle. A pericardial effusion on ultrasound appears as a dark (anechoic) stripe between the myocardium and the pericardium. Pericardial effusion can typically best be viewed by one of three commonly used cardiac windows: 1) subxiphoid, 2) parasternal long axis, and 3) apical 4-chamber. Ultrasound images of a pericardial effusion from these three views are seen in figures 4-6.
Figure 4. Echocardiography of a pericardial effusion (PE) in the subxiphoid view. Note that the effusion is seen as a large anechoic stripe surrounding the heart.
Figure 5. Echocardiography of a pericardial effusion (PE) with tamponade physiology as demonstrated by the collapse of the right ventricle (RV) seen in parasternal long-axis view.
Figure 6. Echocardiography of a pericardial effusion (PE) in the apical 4-champer view. The arrow indicates collapse of the right ventricle (RV) seen in cardiac tamponade.
- Aortic dissection.
- Uncorrected coagulopathy or anticoagulant therapy
- Thrombocytopenia (platelets <50)
- Traumatic hemopericardium (managed surgically)
Equipment and Patient Preparation
- If the time permits and the patient is awake, the procedure should be explained to the patient, and the physician performing the procedure should obtain written informed consent.
- Cardiopulmonary resuscitation equipment should be readily available in the event of a life-threatening arrhythmia or further hemodynamic decompensation.
- Intravenous sedation should be considered but must be reconciled with the urgency of the procedure and the patient’s hemodynamic stability.
- If possible, elevate the chest wall 30-45%; this brings the heart itself closer to the chest wall.
- All providers involved in the procedure should wear sterile protective clothing including gown, gloves, and mask.
- Sterile gowns, gloves, masks, and caps for all providers in the room
- Sterile drapes
- Sterile ultrasound transducer cover
- Sterile ultrasound gel
- Chlorhexidine sponge
- 1% lidocaine with epinephrine
- 25 gauge needle (1.5 inches) and 10mL syringe for lidocaine injection
- 16 or 18 gauge spinal needle (5-10cm)
- 1 empty 5mL syringe
- 5 mL syringe filled with 8cc of saline
- 3-way stopcock
- 60 mL syringe
Central venous access kit/Pericardiocentesis kit
Before bedside ultrasound was readily available, practitioners would perform emergent pericardiocentesis in a “blind” fashion, relying on anatomic landmarks to guide the placement and direction of the needle. This approach can put surrounding structures at greater risk of injury. Bedside ultrasound allows direct visualization of the heart, not only leading to faster, more accurate diagnosis of tamponade, but it also allows practitioners to choose the approach that offers them the best access to the pericardial effusion while avoiding surrounding structures. The three most commonly used ultrasound approaches are the Subxiphoid, parasternal and apical approach (see figures 7-9). Details regarding probe positions and the pros and cons of each approach can be found in Table 1.
Figure 7. To achieve a subxiphoid view of the heart, place the probe inferior to the xiphoid process and angle it cephalad and towards the patient’s left.
Figure 8. For a parasternal long approach, position the probe to the left of the sternum, in the 4th or 5th intercostal space.
Figure 9. To use an apical approach, place the probe slightly lateral to the midclavicular line, in the 5th or 6th intercostal space.
Table 1. Probe positions for ultrasound-guided pericardiocentesis
Probe positions for ultrasound guided-pericardiocentesis
|Subxiphoid||Inferior to the xiphoid process, angling the probe cephalad and left towards the heart||Good acoustic window created by liver, no overlying bony structures||Risk of hepatic puncture|
|Parasternal||To the left of the sternum, in the 4th or 5th intercostal space||No overlying organs||Risk of damage to internal mammary artery, which lies 3-5 cm lateral to sternal border|
|Apical||Slightly lateral to midclavicular line, in 5th or 6th intercostal space. Insert needle above the rib to avoid neurovascular bundle and aim toward right shoulder||The part of the heart closest to the needle is the left ventricle, which is thick walled and will suffer less significant injury if inadvertently penetrated. The coronary arteries are also smallest at the apex.||Often most challenging view due to body habitus, increased risk of pneumothorax|
- Clean and drape the patient in a sterile fashion.
- Prepare the ultrasound transducer with a sterile sheath.
- The ideal probe for this procedure is the 5 to 1 MHz transducer due to its small footprint.
- If that is not available, the 5 to 2 MHz curvilinear probe should provide adequate views.
- Visualize the area of maximal pericardial effusion with the ultrasound probe.
- If time allows and the patient is awake, infiltrate the area of planned needle insertion with 5 mL of 1% lidocaine.
- Using an in-plane approach, insert the needle at a 45-degree angle (for subxiphoid approach 30-45 degrees to prevent liver puncture), maintaining negative pressure on the syringe while keeping the needle tip in view on the screen at all times.
- Observe the needle entering the pericardial sac.
- Once the pericardial sac has been penetrated, inject agitated saline and look for the bubbles visible on ultrasound in the pericardial sac to confirm correct placement.
- Once placement is confirmed, proceed with Seldinger technique
- remove the syringe from the needle,
- insert the guidewire into the needle tip and thread the wire.
- Once the guidewire is in place, remove the needle, keep the wire in place.
- Thread a dilator over the guidewire.
- Remove the dilator, keep the wire in place.
- Slide a catheter over the wire. When the catheter is in place, the guidewire can be removed.
- Aspirate/drain the pericardial effusion/blood.
- Check the vitals and check with ultrasound.
Hints and Pitfalls
- Do not confuse the epicardial fat pad with a pericardial effusion. Keep in mind that significant effusions are circumferential, and the fat pad is only an anterior structure. Also, fat pads will move with each contraction, whereas a pericardial effusion does not and thus will appear to change size as the ventricular wall constricts inward away from the pericardium with each contraction.
- Use the ultrasound to measure the depth of the pericardial effusion, and make sure you use a needle that is long enough.
- Keep your needle tip in view at all times! This may require tilting or adjusting the probe to maintain visualization around surrounding structures as you progress.
- Rapid drainage of pericardial effusion can lead to rapid increases in preload, which can rarely cause flash pulmonary edema, bradycardia and rebound hypertension.
- If there is a question about the source of bloody aspirate, look for clotting ability. If the blood is from a traumatic effusion or intracardiac, it will clot easily. If the blood has migrated into the pericardial space and results from a non-traumatic effusion, it will be defibrinated and thus will not clot or will take much longer to clot.
- Agitated saline can be prepared by connecting two 5mL syringes to the needle catheter via a 3-way stopcock valve. One syringe contains saline, the other air. Agitate the saline by rapidly pushing the saline from one syringe to the other with the stopcock closed to the needle catheter. The saline is sufficiently agitated when it appears cloudy.
Post Procedure Care and Recommendations
- Immediately after the procedure, a chest x-ray should be obtained to ensure there is no pneumothorax or air under the diaphragm.
- If a pigtail catheter was inserted for continuous drainage, it should be sutured in place. Avoid tying the sutures so tightly that it occludes the catheter.
- Cover the catheter insertion site with sterile gauze and tape.
- The patient should remain on a cardiac monitor.
- Vital signs and cardiac rhythm should frequently be reassessed to monitor for findings that would suggest re-accumulation of the effusion and inadvertent procedural complications.
Most complications of pericardiocentesis are related to needle penetration of either the heart or surrounding structures. Studies have cited serious complication rates of 20-30% using the blind approach. The use of ultrasound has significantly decreased these complications. A study of 1127 ultrasound-guided pericardiocentesis at Mayo Clinic showed a procedure success rate of 97%. The rate of major complications, which were those requiring intervention, was 1.2%. The minor complication rate was 3.5%. Similar findings have been repeated in more recent studies.
Specific complications to be aware of include:
- Dry tap (often caused by blockage of the needle with clot or tissue)
- Dysrhythmias, though the literature suggests dysrhythmias related directly to the pericardiocentesis procedure itself are rare
- Myocardial or coronary artery puncture leading to hemopericardium
- Liver laceration
- Vascular injury, most likely the internal mammary artery and the intercostal neurovascular bundle
- Flash pulmonary edema from rapidly increase in left ventricular preload after pericardial decompression
- Suppurative pericarditis
References and Further Reading
- Little WC, Freeman, GL. Pericardial disease. Circulation. 2006;113(12):1622-1632.
- Loukas M, Walters A, Boon JM, Welch TP, Meiring JH, Abrahams PH. Pericardiocentesis: A clinical anatomy review. Clin Anat. 2012;25(7):872-881.
- Hatch N, Wu TS. Advanced ultrasound procedures. Critical Care Clinics. 2014;30(2):305-329.
- Roy CL, Minor MA, Brookhart MA, Choudhry NK. Does this patient with a pericardial effusion have cardiac tamponade? JAMA. 2007;297(16):1810-1818.
- Roberts JR, Custalow CB, Thomsen TW, Hedges JR, eds. Roberts and Hedges’ Clinical Procedures in Emergency Medicine. 6th ed. Philadelphia: Elsevier Health Sciences; 2014.
- Tirado A, Wu T, Noble VE, et al. Ultrasound-guided procedures in the emergency department-diagnostic and therapeutic asset. Emergency Medicine Clinics of NA. 2013;31(1):117-149.
- Gluer R, Murdoch D, Haqqani HM, Scalia GM, Walters DL. Pericardiocentesis – how to do it. Heart, Lung and Circulation. 2015;24(6):621-625.
- The Task Force on the Diagnosis and Management of Pericardial Diseases of the European Society of Cardiology. Guidelines on the diagnosis and management of pericardial diseases executive summary. European Heart Journal. 2004;25(7):587-610.
- Tsang TSM, Enriquez-Sarano M, Freeman WK, et al. Consecutive 1127 therapeutic echocardiographically guided pericardiocenteses: clinical profile, practice patterns, and outcomes spanning 21 years. Mayo Clin Proc. 2002;77(5):429-436.
- Akyuz S, Zengin A, Arugaslan E, et al. Echo-guided pericardiocentesis in patients with clinically significant pericardial effusion: outcomes over a 10 year period. Herz. 2014;40(S2):153-159.
- Kil UH, Jung HO, Koh YS, et al. Prognosis of large, symptomatic pericardial effusion treated by echo-guided percutaneous pericardiocentesis. Clin Cardiol. 2008;31(11):531-537.
Links To More Information
- New England Journal of Medicine Pericardiocentesis Video
- Sonoguide ultrasound-guided procedures in Emergency Medicine:
A review of the above information, plus helpful photos and video clips of probe placement and ultrasound images. – http://www.sonoguide.com/pericardiocentesis.html
- MD Anderson Cancer Center Pericardiocentesis Video
- Video – Subxiphoid view demonstrating pericardial effusion with diastolic collapse – link
- Video – Pericardial tamponade – link