Pericardial Effusion

Author: Ryan Gibbons, MD FAAEM, The Lewis Katz School of Medicine at Temple University

Editor: William Scheels, MD, The Medical College of Wisconsin

Objectives

  • To understand the role of cardiac point of care ultrasound (POCUS) also known as focused cardiac ultrasound (FOCUS)
  • To appreciate the anatomy of the heart
  • To learn the bedside ultrasound technique to evaluate the heart
  • To identify and classify pericardial effusions
  • To differentiate pericardial effusions from pleural effusions
  • To recognize tamponade physiology
  • To comprehend the challenges and limitations of bedside ultrasound
  • To know the appropriate ED population who would benefit from FOCUS

Introduction

“In the emergency department, focused cardiac ultrasound has become a fundamental tool to expedite the diagnostic evaluation of the patient at the bedside and to initiate emergent treatment and triage decisions by the emergency physician.”23

Emergency medicine providers have been utilizing focused cardiac ultrasound (FOCUS) for nearly thirty years.16,31,36,37,56  While similar in practice and theory, FOCUS differs from comprehensive echocardiography.46 As with most point of care ultrasound applications, focused transthoracic cardiac ultrasound is a goal-directed assessment of a symptomatic patient employed to answer specific clinical questions and serves as an adjunct to the physical exam.46,55 It is a rapid, safe and effective means to not only diagnosis numerous cardiac pathologies but expedite treatment as well.  In 2001, the American College of Emergency Physicians (ACEP) endorsed focused echocardiography as a fundamental skill for the emergency provider.1 Since that time, the Accreditation Council for Graduate Medical Education (ACGME) has mandated emergency medicine residency programs provide ultrasound training in eleven core applications.

Table 1 illustrates many of the basic and advanced applications of cardiac ultrasound.  This discussion will focus solely on pericardial effusions.  Echocardiography remains the diagnostic study of choice for the detection and evaluation of pericardial effusions.2 In fact, as of 2003 the AHA/ACC/ASE have a level 1 recommendation for the use of echocardiography in the evaluation of all pericardial disease.10 It not only provides qualitative and quantitative information but enables assessment of the patient’s hemodynamic status and guides pericardiocentesis as well.2,33,40

 Table 1 Roles of Focused Cardiac Ultrasound (FOCUS)

Basic (The Five Es of Echo)21 Advanced
Entrance (IVC)

 

Exit (Aortic outflow tract)

 

Equality (RV:LV)*

 

Ejection fraction

 

Effusion

 

Valvular pathology

Cardiac arrest

Volume assessment

Diastolic dysfunction

HOCM (hypertrophic cardiomyopathy)

Ischemia (RWMA)**

Thrombus & mass identification

eFAST*** (Trauma)

Undifferentiated

o    Chest pain

o    Dyspnea

o    Hypotension (RUSH protocol44)****

Procedural

o    Pericardiocentesis

o    Trans-venous pacer placement

*Typical size ratio RV:LV is 0.6:1.021

**Regional Wall Motion Abnormalities (RWMA)

***Extended Focused Assessment with Sonography for Trauma

****Rapid Ultrasound for Shock and Hypotension (RUSH)

Review

The pericardium is a hyperechoic sac which surrounds the heart and great vessels consisting of an outer fibrous parietal layer and inner serous visceral layer also known as the epicardium.2,40 Normally, a small amount of physiologic fluid (5-50ml) surrounds the heart to assist in function and protect against infection.2,18,40,55  With uncomplicated pericardial effusions, excess fluid initially accumulates in the most dependent areas, typically posteriorly and inferiorly around the right atrium which is normally the chamber with the lowest pressure.13  Effusions rarely accumulate only anteriorly without a history of prior scarring or cardiac surgery.18

Pericardial effusions fall on a spectrum from asymptomatic to severe hemodynamic compromise.  Effusions develop gradually or acutely depending on the clinical scenario.18,47 Etiologies are numerous as are their classifications.  Tables 2 and 3 provide a brief overview.

 Table 2 Pericardial Effusion Classifications12

Size (mm)* Composition Onset (weeks) Distribution** Definition
<10 small Transudative <1 acute Circumferential  

Simple

 

10-20 moderate Exudative <12 subacute Focal Complex
>20 large >12 chronic  

 

*Measured at end-diastole using visual estimation or M-mode.  Trace or physiologic <50cc is within normal limits.2,8,19,21,49 Others define effusion size as follows (in mm)27:  <10, 10-15, >15

**Utilize multiple cardiac views to assess for focal effusions8,11,21 

 Table 3 Causes of Pericardial Effusion*2,8,18,26,40-42,49

Common Less Common
Autoimmune

Neoplasm**

o    lung

o    breast

o    leukemia

o    lymphoma

o    melanoma

Idiopathic

o    20-86%, most thought to be viral

Infectious

o    >60% Tuberculosis (Tb) worldwide2,30

Ø  Often with HIV18,34

Iatrogenic**

Metabolic

o    hypothyroidism, uremia

Trauma

Myocardial Infarction

Aortic Dissection (AoD)

Coagulopathic

Radiation

Congestive Heart Failure

Valvular heart disease

Myopericardial disease

Systemic18

o    Cirrhosis

o    Nephrotic Syndrome

Medications

o    Antineoplastic

o    Lupus-like syndrome***

 

*An effusion with pericarditis, think malignancy or infection18

**Most likely to need a pericardiocentesis53

*** Procainamide, hydralazine, methyldopa, isoniazid, & phenytoin2

Ultrasound Technique21,27,49,55

image-1Imaging of the heart is done in real time.  The 1-5 mHzphased array (cardiac) probe (image 1) is utilized routinely given its small footprint which augments intercostal imaging.27 Hold the probe similar to a pencil resting your hypothenar eminence on the chest wall, which allows better manipulation of the probe. Typically, there are four standard cardiac views:21,49,55 parasternal long axis (PSLA or PLAX), parasternal short axis (PSSA or PSAX), apical four chamber (A4Ch), & subcostal or subxiphoid.  There are additional advanced views & applications beyond the scope of this review.

                                                                           Image 1 Phased Array (cardiac) probe

 

Parasternal long axis:  effusion, aortic outflow tractimage-2

 

Parasternal short axis:  ideal for global function

 

Apical four-chamber:  often best for pericardiocentesis

 

Subcostal:  effusion and global function                           Image 2 Standard Cardiac Windows & Indications

To begin, place the probe along the left parasternal border in the 2nd through 5th intercostal space.  Traditionally, the probe indicator (circled in image 1) is oriented to the patient’s right shoulder to obtain the PSLA view.  Rotate the probe 90° clockwise to acquire the PSSA image.  Maintain the indicator’s alignment towards the left shoulder or axilla while sliding in the direction of the cardiac apex or PMI (point of maximum impulse) to visualize the A4Ch, which is typically along the left lateral chest wall in the 5th intercostal space inferolateral to the nipple.  Have female patients lift their breasts to improve imaging.  Flatten your angle to optimize your A4Ch view.  You may need to position your hand over the probe to achieve the appropriate angle.  Place the patient in the left lateral decubitus position to augment the A4Ch view as well.

image-3

Image 3 Standard Cardiac Axes

http://www.barnardhealth.us/echocardiography/info-bvs.html

Used with the Creative Commons License 3.0 (http://www.barnardhealth.us/about/)

Parasternal Long Axis (PSLA) View

image-4

 Image 4 Parasternal Long Axis (PSLA) View

Left Ventricle (LV); Right Ventricle (RV); Left Atrium (LA); Aortic Outflow Tract (AOFT)

Video 1: PSLA normal

Video: 2: PSLA with effusion

Parasternal Short Axis (PSSA) View

 

image-5

 Image 5 Parasternal Short Axis (PSSA) View

Video 3: PSSA normal

Video 4: PSSA with effusion

Apical 4-Chamber (A4Ch) View

 

image-6 

Image 6 Apical Four Chamber (A4Ch) View

Left Ventricle (LV); Right Ventricle (RV); Left Atrium (LA); Right Atrium (RA)

Video 5: A4Ch normal

Video 6: A4Ch with effusion

Subxiphoid View

image-7

The subcostal view is typically the easiest and most reliable at detecting pericardial effusions since the most dependent portion of the heart is nearest to your probe.21 Additionally, it is often the best view to distinguish between pleural and pericardial effusions since there is no pleural reflection between the liver and the heart.49,55 Either the phased array or curvilinear (abdominal) probe (image 7) can be utilized to obtain the subcostal view.  Use an overhand grip to allow for a shallow approach of 5-15°.  Having the patient inhale deeply will bring the heart closer to the probe. Use the liver as your acoustic window and be sure to adjust your depth to visualize the entire heart.

                                                                                       Image 7 Curvilinear (abdominal) probe

When using the curvilinear probe, the indicator is positioned to the patient’s right, the traditional point of care ultrasound orientation, using the abdominal setting.

image-8

Image 8 Subcostal View; Curvilinear (abdominal) probe

When using the phased array probe with the cardiac setting, the indicator is positioned to the patient’s left to maintain the traditional view on the ultrasound screen.  With the abdominal setting, the probe is oriented towards the patient’s right.

image-9

 Image 9 Subcostal View; Phased Array (cardiac) probe

Video 7: Normal Subxiphoid View

Video 8: Subxiphoid View with Effusion

Focused cardiac ultrasound is the diagnostic study of choice for identifying pericardial effusions.1,2,10,23,46,54 It can detect as little as 15-35cc of pericardial fluid.8,56 Echocardiography can help clarify the type and extent of the effusion, as well as recognize tamponade physiology and guide treatment through pericardiocentesis.  An uncomplicated effusion appears as an anechoic stripe separating the heart from the parietal pericardium, initially accumulating dependently in the posterolateral and inferior sections.27,49 Complex effusions, such as infectious or traumatic, can appear echogenic with internal echoes or septations and may collect circumferentially or focally.  The size or amount of effusion is visually estimated or measured using M-mode at end-diastole.18,19

Overall, studies have demonstrated excellent sensitivities and specificities from 96-100% for the detection of pericardial effusions in both medical and trauma patients using focused cardiac ultrasound.1,23,28,36,37,50,51  Plummer, et al. not only demonstrated remarkable sensitivity but also a decreased time to the operating room (OR) from 42 to 15 minutes and an improved survival rate from 57% to 100% in patients with penetrating chest trauma with the diagnosis of traumatic pericardial effusions on bedside ultrasound.36,37  Tayal, et al. showed survival benefit as well in patients with non-traumatic PEA (pulseless electrical activity) arrest with a bedside ultrasound diagnosis of a pericardial effusion.

Technical Considerations

As with any ultrasound study, proper set up is key to obtaining accurate images.  The patient should be placed in the supine position at the level of the scanner’s waist with the head of the bed slightly raised to 30°.  Dim the lights as appropriate and apply adequate ultrasound gel, especially with the subcostal view to maintain suitable contact between the probe and skin.

Utilize the cardiac presets when scanning the heart.  Modify the gain, frequency, and depth to refine your images.  The initial depth should be maximized in order to display the entire heart, including the posterior pericardium.  Adequate depth is particularly important with the subxiphoid window.  Once the entire heart is visualized, the depth can be adjusted accordingly to optimize your view.

Have the patient lie in the left lateral decubitus position to enhance imaging, especially for the A4Ch.  Nonetheless, up to 25-30% of patients will not have an adequate A4Ch window.  Advanced imaging, such as transesophageal echocardiography (TEE), CT, or cardiac MRI, is then required based on the clinical indication and the patient’s hemodynamic stability.

Cardiac Tamponade

All individuals with pericardial effusions are at risk of developing tamponade, which is a potentially fatal complication resulting in obstructive shock.  The diagnosis is challenging to all physicians given that the signs and symptoms of both pericardial effusions and cardiac tamponade can be subtle and not always present.6,25 Many patients with pericardial effusions are asymptomatic or have nonspecific signs and symptoms, such as cough, fever, hiccups, fatigue, and abnormal vital signs (see Table 8).  Moreover, traditionally we are taught that tamponade is a clinical diagnosis and that patients will demonstrate the classic Beck’s triad of hypotension; muffled, distant heart sounds; and jugular venous distension (JVD).4 In reality though, this is a relatively rare and late finding.6,49,14,20,25,28 Less than 10-40% patients will present with this triad.14,40,38,49,56 Furthermore, medical patients will rarely present this way given the chronicity of their diseases.  Trauma patients are much more likely to depict Beck’s triad, although our clinical suspicion is already much higher in this subset of individuals.

Pulsus paradoxus, defined as a >10mmHg drop in systolic blood pressure (SBP) with inspiration, can be useful in diagnosing cardiac tamponade.  However, assessing for this can be time consuming and difficult with an unstable patient.  Frequently, it is not present with significant hypovolemia.   Furthermore, it is seen in numerous other conditions, such as emphysema, pulmonary embolism, congestive heart failure, mitral stenosis, aortic regurgitation, and in other forms of shock.2,8,9,20,24,40,47

Given the nonspecific complaints and unreliable exam findings, cardiac tamponade is NOT just a clinical diagnosis!  Utilize FOCUS in conjunction with lung and inferior vena cava (IVC) ultrasound17 as an adjunct to the physical exam to assess for causes of obstructive shock, such as tamponade, aortic dissection, and tension pneumothorax.

Cardiac tamponade occurs along a spectrum of hemodynamic changes when intrapericardial pressure exceeds intracardiac pressure causing impaired filling, chamber collapse, and decreased cardiac output (CO).8,47   This is a form of obstructive shock.  The most important factor in developing tamponade physiology is the rate of effusion buildup rather than its size.8,9,18,19,40 Gradual accumulation, seen commonly with chronic medical conditions, allows the pericardium to accommodate large volumes in excess of 1-2 liters.  Several non-traumatic effusions are more likely to develop tamponade though, including those caused by bacterial infections, neoplasms, and post-radiation.  Nearly 1/3 of chronic large effusions regardless of etiology progress to obstructive shock.18,19

image-10

 Image 10 Tamponade Pathophysiology47

    From New England Journal of Medicine, Spodick D, Acute cardiac tamponade, 349, 684-90. Copyright © 2003 Massachusetts Medical Society. Reprinted with permission from Massachusetts Medical Society

Traumatic effusions accrue rapidly preventing the pericardium to adapt.40 Subsequently, cardiac tamponade occurs in these situations with as little as 50-100cc of fluid.45 The pericardial compliance determines the amount of fluid which triggers tamponade.  Dr. David Spodick described tamponade as a “last-drop” phenomenon: “the final increment produces critical cardiac compression, and the first decrement during drainage produces the largest relative decompression.”47 (see image 10) Tables 4 and 5 review the common causes of tamponade as well as the characteristic ultrasound findings. 

 Table 4 Causes of Tamponade2,18,19

Common Less Common
Trauma

Iatrogenic

o    Cardiac surgery or catheterization

Neoplasm

o    >50% of tamponade cases

o    Lung cancer most common

Infectious

o    Tuberculous

Pericarditis

Autoimmune

Myocardial Infarction

Aortic Dissection (AoD)

Radiation

Uremia

 

 Table 5 Ultrasound Findings in Tamponade15,39 (see videos 9-12 & Images 11-14)

RV collapse

o    During ventricular-diastole

o    Hallmark finding

o    Increased specificity

o    RVOT* (PSLA view) is the most compressible area9

 

RA collapse9,18,19,22,47

o    During early ventricular systole

o    More common

o    Occurs earlier than RV collapse

o    >1/3 cardiac cycle highly specific

o    Extends to late ventricular end-diastole as well

 

IVC plethora**17-19

o    Decreased respirophasic variation <50%

o    No collapse

o    97% sensitive, lacks specificity

Increased respiratory variation of transvalvular peak inflow velocities***3,7,9,21,24,29,33,45

o    >25% inspiratory Decrease of mitral E-wave signal

o    >40% inspiratory Increase of tricuspid E-wave signal

 

Large effusion with swinging heart18,19,27,47

o    Usually >300-600cc

 

LA collapse 8

o    98% specificity

o    Generally, a late finding

o    Only 25% of cases

 

LV collapse8,27,33,45,47

o    Very rare

o    Most often loculated and/or post-surgical

 

*Right ventricular outflow tract (RVOT)

**Visual estimation or measured with M-mode about 2-3cm distal from its entrance into the right atrium

  or just distal to where the right hepatic vein joins the IVC (see image 11).

***Focused cardiac ultrasound finding equivalent to pulsus paradoxus.  Measure the E-wave amplitude with pulsed wave doppler in the A4Ch view during early diastolic filling.21

Pathologic ventricular chamber collapse occurs during ventricular diastole (atrial systole), whereas pathologic atrial collapse occurs during ventricular systole (atrial diastole).  Utilize M-mode in the PSLA or subxiphoid view to help identify diastole by correlating with the peak E-wave amplitude or replay videos to identify when the mitral (PSLA or A4Ch view) and/or tricuspid (A4Ch view) valves are fully open (see images 12-14).21,33 Many of these ultrasound findings can be challenging to identify on FOCUS, therefore consider tamponade strongly if the patient is hypotensive with a pericardial effusion.33 Transvalvular pulsed wave doppler inflow velocities are challenging even for advanced practitioners and routinely do not add much with respect to the diagnosis of tamponade pathology.33 The pathophysiology and method to measure these values are beyond the scope of this review.

image-11

 Image 11 M-mode to Evaluate IVC Respirophasic Variation (complete lack of variation; IVC plethora)

image-12

Image 12 PSLA view; M-mode to Evaluate for RV Collapse during Ventricular Diastole (no collapse present)

image-13

Image 13 PSLA view; Ventricular Diastole without Evidence of Tamponade; Large Circumferential Effusion

image-14

 Image 14 PSSA view; RV collapse during Ventricular Diastole; Large Circumferential Effusion

Videos of Cardiac Tamponade

Video 9: PSLA with large effusion & RV collapse consistent with tamponade physiology

Video 10: PSSA with large effusion & RV collapse consistent with tamponade

Video 11: Subcostal with large effusion and tamponade physiology

Video 12: IVC plethora without respirophasic variation

Pericardiocentesis

Emergent pericardiocentesis is a potentially life-saving procedure in the coding or hemodynamically unstable patient.  Unfortunately, it is a rare and risky procedure that few emergency physicians practice routinely.  Table 6 lists many of its complications.

image-15

Pericardiocentesis with Ultrasound

 Table 6 Complications from Pericardiocentesis9,49,53

Risk Factors
·         Hemothorax

·         Pneumothorax

·         Hepatic or splenic injury

·         Gastric injury

·         Cardiac puncture

·         Infection

·         Dysrhythmia

·         Neurovascular injury

·         Pneumopericardium

·         Pneumomediastinum

 

Traditionally, we are taught to use the blind subcostal approach.  However, Tsang et al. conducted a 20-year retrospective review at the Mayo clinic and demonstrated a 97% success rate with ultrasound guidance with substantially less complications.33,35,52,53 Furthermore, only 20% of the time was the subcostal approach the ideal one.  Providers had far greater success with the A4Ch method.

Multiple views are advised to identify the optimal approach which is wherever the fluid is closest to the probe.  The patient should be supine with the HOB slightly elevated.  The left lateral decubitus position may improve your visualization as well.9 Intravenous fluids can be given while prepping for the procedure in an effort to augment cardiac output.  Under sterile conditions, use a 16 or 18-gauge needle with ultrasound guidance to ensure its location within the pericardial sac.  Once in position, use the Seldinger technique to place a catheter for continued drainage since there is a 30% recurrence rate.52-53 Nagdev et al. described a novel in-plane technique via the PLSA.32 Refer to the reference section below for a detailed review.

If the patient is hemodynamically stable, defer pericardiocentesis to the cardiologist.

Surgical evacuation is optimal though for posterior, nonuniform (loculated or focal), complex, and thrombosed effusions.9 Traumatic effusions are best managed with surgical intervention as well.51 An emergent pericardiocentesis can be a temporizing measure56 though in the hemodynamically unstable patient without access to a cardiac catheterization lab or surgical specialties.  In a cardiac arrest patient with an effusion, pericardiocentesis is immediately warranted.

Videos of Pericardiocentesis

Video 13: Needle tip visualized during pericardiocentesis

Video 14: Needle tip visualized during pericardiocentesis; CPR in progress

Determining Who to Scan

Tables 7-9 review the risk factors, signs & symptoms, and classic ECG & chest x-ray findings that may warrant a focused cardiac ultrasound to assess for a pericardial effusion or other cardiac pathology.

Table 7 Risk Factors for Pericardial Effusions

Risk Factors
·         >50 years old

·         Male

·         Pericarditis

·         Trauma

·         Malignancy

·         Rheumatologic disorders

·         Congestive Heart Failure

·         Renal disease

 

·         Thyroid disorder

·         Hypertension

·         Smoking

·         Family History

·         Coronary Artery Disease (CAD)

·         Diabetes Mellitus (DM)

·         Hyperlipidemia

·         Peripheral Arterial Disease (PAD)

 Table 8 Signs and Symptoms of Pericardial Effusions

Symptoms Signs
Undifferentiated

o    Chest pain

Ø  Positional; relief when sitting forward with pericarditis

o    Back pain

o    Flank pain

o    Abdominal pain

·Undifferentiated

o    Dyspnea >13% with effusion5

o    Orthopnea

o    PND

Nonspecific/Constitutional

o    Nauseated

o    Dysphagia

o    Anorexia

o    Fatigue

 

·         Trauma (eFAST)

·         PEA cardiac arrest33,50

·         Beck’s Triad

o    Jugular venous distention (JVD)

o    Distant, muffled heart sounds

o    Hypotension

·         Pulsus paradoxus

·         Pericardial friction rub

·         Edema

·         Hepatojugular Reflex

·         Kussmaul’s sign*

·         Syncope

·         Cyanosis

·         Abnormal VS

o    Shock/Hypotension**

o    Tachycardia

o    Tachypnea

·         Thromboembolic events to the extremities***

o    Weak or absent pulses

·         Neurologic deficit of the extremities***

·         CVA and/or carotid dissection***

·         Nonspecific:  cough, fever, hiccups

 

*Venous distention with inspiration (JVD)

**Undifferentiated shock/hypotension (RUSH protocol44); Patients with chronic hypertension may not exhibit hypotension.

***Possible aortic dissection (pericardial effusion may be the only visible sign of an AoD on FOCUS) or abdominal aortic aneurysm (AAA)

 Table 9 Classic ECG and Chest X-ray Findings (see images 16-19)

ECG47 Chest X-ray
Effusion: Low voltage (nonspecific)

Pericarditis

o    Diffuse ST elevations (concave up)

o    Diffuse PR depressions

o    No reciprocal changes

o    TP segment down-sloping (Spodick sign)

Tamponade

o    Electrical Alternans (see videos 15-16)

Ø  Beat to beat variation of P, QRS, T wave amplitudes

Ø  Highly Specific47

Cardiomegaly

Enlarged cardiac silhouette

o    Water Bottle sign

o    >200-300cc minimum2,18,19,38

o    FOCUS detects as little as 15-35cc8,56

 

image-16

Image 16 Low Voltage

Image 17 EKG Findings of Pericarditis

https://i2.wp.com/lifeinthefastlane.com/wp-content/uploads/2011/03/pericarditis-3.jpg

Used with permission based on Creative Commons Attribution License (notations added)

image-18

 Image 18 Electrical Alternans

image-19

 Image 19 Enlarged Cardiac Silhouette

Videos of Electrical Alternans

Video 15: A4Ch electrical alternans

Video 16: PSLA electrical alternans

Pearls & Pitfalls

Patient body habitus and stability, lung artifact, chest wall injuries, and ongoing procedures or resuscitation can obscure cardiac visualization.55 Be sure to utilize all four standard views and make subtle changes to your probe placement and orientation along with patient positioning to optimize your views through the intercostal spaces.  Rotating, angling, and tilting your probe, as well as trying advanced views (as your training progresses), can facilitate your scans.55 Placing the patient’s left hand overhead may widened the intercostal spaces.27 Remember, patients’ anatomies vary.  Adjust your probe placement as needed by sliding cranially and caudally along the left parasternal border between the 2nd and 5th intercostal spaces.  Even moving to the right parasternal border may improve your images.

 Table 10 Maneuvers to Augment Cardiac Visualization27

  PSLA PSSA A4Ch Subcostal
Inhale       X
Exhale X X X  
Supine

(HOB 30° upright)

X X   X

(completely supine)

Left lateral decubitus X   X  

Table 11 Cardiac Anatomic Position in the Chest Cavity27

  Medial Lateral Higher Lower
Younger X   X  
Elderly   X   X
Low BMI       X
Obese     X  

The apical four chamber (A4Ch) view is the most technically challenging one.  Move the patient into the left lateral decubitus position to bring the heart closer to the chest wall in order to supplement your view.  Nonetheless, 25-30% of individuals will not have a visible A4Ch view.

Remember, only 10-40% of patients with cardiac tamponade will present with the classic Beck’s triad of distance, muffled heart sounds; jugular venous distension; and hypotension.  Utilize FOCUS in conjunction with lung and IVC ultrasound to supplement your physical exam.

Pulsus paradoxus is seen in numerous other conditions, such as emphysema, pulmonary embolism, congestion heart failure, mitral stenosis, and aortic regurgitation.  It is often absent in severe hypovolemia.

Rate of accumulation rather than size is the most important determinant of cardiac tamponade.  Traumatic, neoplastic, infectious, and iatrogenic effusions are most likely to precipitate obstructive shock.

Utilize all standard views (and non-standard) to avoid missing focal, loculated, and small effusions, which can all cause tamponade physiology.9,33,41-43

 Table 12 Pericardial Effusions

False Positives False Negatives
Epicardial fat pad

o    Anterior

o    @RVOT in PSLA view

o    Moves with cardiac activity

o    Best seen in systole

o    Not seen in diastole

Pleural effusion*

Ascites

Thrombus

Mass

Left Ventricular Aneurysm

Hemorrhagic effusion

 

Clot

 

Loculated effusion

 

Focal effusion

*Large pleural effusions can cause tamponade physiology.

Intrathoracic pressure is transmitted to pericardial sac.  Consider thoracentesis.9,40 

 Table 13 Cardiac Tamponade

False Positive False Negative
Right heart collapse*

o    Hypovolemia

Ø  Trauma

Ø  Dialysis

 

Lack of right heart collapse**

o    Chronic cor pulmonale

 

 

 

*IVC collapse therefore very unlikely tamponade                      

**IVC plethora at baseline

The anterior epicardial fat pad is a heterogenous hypoechoic tissue with internal echoes9 that moves in conjunction with cardiac activity.  It is not circumferential and not clinically significant.21 Normally, it is found in obese and elderly patients.8 The fat pad is best seen above the RVOT in the PSLA view.9 Again, employ multiple views to differentiate between the anterior fat pad and pericardial effusions.11 Loculated and focal effusions can be particularly challenging to distinguish from an epicardial fat pad.  The later normally will have no impact on the patient’s hemodynamic status whereas the former can cause hemodynamic compromise.

Differentiating between pleural and pericardial can be challenging.  Identify the descending aorta in the PSLA view (see image 20).  Pericardial effusions track along the heart and separate the aorta from the pericardium and cross the midline.  Pleural effusions do not and will accumulate posterolateral to the descending aorta.  Typically, effusions identified in the subcostal view will be pericardial given there is no pleural reflection between the heart and liver.49 Effusions posterolateral to the heart in the subxiphoid view are typically pleural whereas fluid between the liver and diaphragm is ascites.  Look for the falciform ligament (see video 21) attached to the diaphragm and utilize multiple lung and abdominal views to help distinguish between these pathologic entities.  Lung consolidation or collapsed lung from atelectasis may be seen as well to help identify a pleural effusion (see videos 17-21).

Videos of Pleural Effusions

Video 17: PSLA pleural effusion seen posterolateral to the heart; Small pericardial effusion

Video 18: PSSA with pleural effusion posterolateral to heart; Small pericardial effusion

Video 19: PSLA pleural effusion with lung consolidation; Small pericardial effusion

Video 20: Pleural effusion with lung collapse & spine sign in right hemithorax

Video 21: Ascites with visable falciform ligament

Sometimes it is necessary to differentiate a pericardial effusion from a pleural effusion.

image-20

Image 20 Pericardial vs Pleural Effusion

FOCUS findings in cardiac tamponade are challenging even for advanced practitioners.  If the patient is hypotensive with an effusion, consider cardiac tamponade.  Consult cardiology immediately and prepare for an emergent pericardiocentesis.  Supplement IVF can help augment cardiac output as a temporizing measure.

If the patient is hemodynamically stable, defer pericardiocentesis to the cardiologist.

Surgical evacuation is optimal for posterior, nonuniform (loculated or focal), complex, and thrombosed effusions.9 Traumatic effusions are best managed with surgical intervention as well.  An emergent pericardiocentesis can be a temporizing measure in the hemodynamic unstable without access to a cardiac catheterization lab or surgical specialties.  In the coding patient with an effusion, immediate pericardiocentesis is warranted with bedside ultrasound guidance ideally.

Diagnostic Approach

diagnostic-approach

References

  1. American College of Emergency Physicians. Emergency ultrasound guidelines – 2008. Ann Emerg Med. 2009; 53:550-570.
  2. Adler Y, et al (2015) ESC Guidelines for the diagnosis and management of pericardial diseases. Eur Heart J.
  3. Appleton C, et al. Cardiac tamponade and pericardial effusion: respiratory variation in transvalvular flow velocities studied by Doppler echocardiography.  J Am Coll Cardiol, 11 (1988), pp. 1020–1030.
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All ultrasound images are used with permission of Tom Costantino