cardiac ultrasound

Emergency Cardiac Ultrasound

Phillip D. Levy, MD, MPH, FACEPAssistant Professor of Emergency MedicineWayne State University, Detroit Receiving

Hospital

Introduction

• “Stethoscope of the future”• Rapid visualization of cardiac

structures and potential pathology• More sensitive and specific than

physical exam, ECG or CXR

Primary Indications

• Suspected pericardial effusion or tamponade

• Cardiac arrest– PEA– Asystole vs. fine ventricular fibrillation

• Acute hypotension• Thoraco-abdominal trauma

Secondary Indications

• Acute chest pain– Myocardial infarction– Pulmonary embolism– Aortic dissection

• Procedural guidance– Pericardiocentesis– Detection of transcutaneous pacer

capture – Placement of transvenous pacer

Primary Clinical Concerns

• Is there cardiac activity ?

• Is there an effusion ?

Anatomical Overview

• Right ventricle anterior, left posterior

• Lungs provide poor transit medium – Air = scatter– Use liver as acoustic window for

subxyphoid approach

• Images quality can be limited by bony thorax

From: Yale Center for Advanced Instructional Media, Yale University. 2000

Technique

• Probe selection important– Curved array: better contrast resolution– Phased array (sector): less rib shadowing

• Average frequency = 3.5 MHz– 2.5 MHz for larger patients– 5.0 MHz for smaller patients

• Decrease depth and dynamic range • Reverse screen for true cardiac

imaging

Normal Appearance

• Pericardium: uniform, brightly echogenic line

• Myocardium: bulky, heterogeneous, hyperechoic material

• Chambers: anechoic

Basic Image Planes

Subcostal

• Most useful overall• Standard view in FAST exam• Ideal for detection of effusion and

cardiac motion• Diagonal view of heart • Liver functions as acoustic window

Subcostal

• Probe marker to patient’s right

• Subxyphoid position• Shallow angle (~

15°)• Aimed at left

shoulder

Subcostal

Parasternal Views

• Probe placed in left parasternal region at 2nd to 4th intercostal space– Left lateral decubitus position improves

images• Long axis (right shoulder to left hip)• Short axis (left shoulder to right hip)• Enables differentiation between

pericardial and pleural effusions

From: Gray, H. Anatomy of the Human Body 20th ed. 2000

Short axis

Long axis

Parasternal Long Axis

• Clearly displays– Posterior wall of LV– Free wall of RV– Mitral and aortic

valves– Proximal ascending

aorta

• Probe marker faces left hip

Parasternal Long Axis

Parasternal Short Axis

• Cross-sectional view through ventricles

• Rotate probe 90° toward right hip

• Tilting probe cephalad to caudad allows imaging from aortic valve to apex

Apical Views

• Left lateral decubitus position• Probe at apex (4th or 5th intercostal

space) facing right shoulder• More difficult to obtain• Provides good images of chamber

dimensions

Apical 4-chamber

• Good for evaluation of– Wall motion – Masses or clots

• Probe marker toward right hip

Apical 4-chamber

Apical 2-chamber

• Less commonly used in ED setting

• Shows anterior and inferior walls simultaneously

• Rotate probe 90°– Marker faces

anterior and cephalad

Apical 2-chamber

Functional Assessment

• Observation of dynamic changes of cardiac cycle

• Estimation of ejection fraction• Evaluation of wall motion

abnormalities– Characterized as global or segmental– Hypokinesis: reduced movement– Akinesis: absent movement– Dyskinesia: paradoxical movement

Normal Cardiac Cycle

Cardiac Measurements

• Chamber diameter– Measured at right angle to long axis

in both systolic and diastolic phases– Provide some functional information– Most useful as indication of

ventricular strain

• Wall thickness– Determination of hypertrophy

Clinical Indications

Pericardial Effusion

• High degree of accuracy for EP’s 1

– Sensitivity 99.9%– Specificity 98.1 %

• Anechoic stripe between visceral and parietal pericardium– May be echogenic if malignant or

coagulated• Usually surrounds heart completely

– If anterior only, likely pericardial fat

1 Plummer D, et al. Abstract, SAEM Scientific Assembly 1995.


• Cardiac impairment dependent of rate of accumulation of fluid in pericardial space, not amount – Up to 50 cc may be physiologic; usually

not visible– Small collection < 1 cm thick– Large collections 1-2 cm thick

• Heart may swing freely with large effusions

Pericardial Fat

Pericardial Blood Clot

Tamponade

• Cardiac compromise from effusion• Beck’s triad seen in only 30 % 1 • Pulsus paridoxus late, non-specific• Ultrasound findings

– Systolic right atrial collapse– Diastolic right ventricular collapse– Equalization of ventricular pressures– Increased central venous pressure

1 Guberman BA, et al. Circulation 1981

Tamponade

• Respiratory variance in IVC can be used to estimate central venous pressure 1

IVC sizeResp change RA pressure< 1.5 cm Total collapse 0-5 cm/H201.5-2.5 > 50 % collapse 5-101.5-2.5 < 50 % collapse 11-15>2.5 < 50 % collapse 16-20>2.5 No change > 20

1 Ma, OJ and Mateer JR. Emergency Ultrasound, p 111. 2003

Effusion with Normal Dynamic Function

Tamponade with RV Collapse

Acute Hypotension

• Determination of etiology may allow rapid intervention

• Tamponade• Cardiogenic shock

– Global hypokinesis– Left ventricular distention (MI)– Right ventricular distention

• PE or RV infarct

Acute Hypotension

• Hypovolemic shock– Hyperdynamic cardiac activity– Small right chambers– Collapsed IVC

• Septic shock– Hyperdynamic activity

Cardiac Arrest Applications

• Can be used while CPR is in progress• Evaluate for cardiac activity• Treatment guidance for PEA

– Rule out tamponade– Dynamism of cardiac contraction

• Hyperdynamic may indicate hypovolemia• Hypodynamic may be ischemia or PE

• Assess capture by transthoracic pacemaker 1

1 Ettin D, et al. JEM 1999

Blunt Thoracic Trauma

• Pericardial effusion • Traumatic aortic rupture

– Not ideal diagnostic modality (CT or TEE)– Look for

• Hematoma• Intimal flaps• Changes in vessel contour

• Sternal or rib fractures– Associated with underlying cardiac injury

Blunt Thoracic Trauma

• Cardiac contusion– Majority (73%) have signs of trauma 1

– Rarely associated with long-term impairment 2

– Limited diagnostic value of formal echo 3

– Screening ED ultrasound sufficient to rule out severe underlying injury 4

• Assess for wall motion abnormalities and RV hypokinesis

1 Snow, et al. Surgery 19822 Sturaitis M, et al.. Arch Intern Med 19863 Maenza RL, et al. Am J Emerg Med 19964 Welch RD. Emerg Med Clin North Am 2001

Penetrating Thoracic Trauma

• Goal is early detection of pericardial effusion BEFORE clinical signs develop

• Hemopericardium is anechoic initially– Echogenicity develops as blood coagulates

• Imaging may be limited – Subcutaneous emphysema– Pneumopericadium– Mechanical ventilation

Penetrating Thoracic Trauma

• Study of utilization in 261 pts 1

– Sensitivity 100%, specificity 96.9%– PPV 81%, NPV 100%– Time to OR 12.1 +/- 5.9 min

• Comparison of outcomes 2

– 28 pts with ED cardiac ultrasound, 21 without

– Survival: 100% in echo, 57.1% in non-echo– Time to diagnosis

• 15 min echo, 42 min non-echo

1 Rozycki GS, et al. J Trauma 19992 Plummer D et al. Ann Emerg Med 1992

Myocardial Infarct

• Determined by appearance of wall motion abnormalities– Poor sensitivity 1,2

– Better specificity, but difficult to assess age of pathology 3,4

• ED cardiac ultrasound may be most useful in ruling out other potential diagnoses

1 Levitt MA, et al. Ann Emerg Med 1996

2 Muttreja M. Echocardiography 19993 Horowitz RS, et al. Circulation 19824 Sabia P, et al. Circulation 1991

Pulmonary Embolism

• Large PE may cause sonographically identifiable right heart strain

• Wide range in accuracy 1-4

– Sensitivity 50-93%– Specificity 81-98%

• Right heart strain: potential criteria for thrombolytic administration? 5

1 Kasper W, et al. Am Heart J 19862 Nazeryollas P, et al. Eur Heart J 19963 Perrier A, et al. Int J Cardiol 19984 Rudoni R, et al. J Emerg Med 20015 Konstantinides S, et al. NEJM 2002

PE - Sonographic Findings

• Right ventricular dilation– Parasternal long axis view– Normal diameter 21±1 mm– Abnormal > 25-30 mm

• Septal deviation to left ventricle– Apical 4-chamber view

• Tricuspid regurgitation• Right ventricle hypokinesis, with wall

thinning

Massive Pulmonary Embolism

From: Goldhaber, SZ. NEJM 2002

Resolution After Thrombolytics

From: Goldhaber, SZ. NEJM 2002

Aortic Dissection

• Difficult to detect by transthoracic echocardiogram– Best seen on parasternal long axis

view

• Appears as echogenic, mobile, linear flap within aorta lumen

• May visualize double lumen

Other Findings

• Atrial myxoma– Globular and echogenic, adherent to

wall• Mural thrombi

– Varying echogenicity• Valvular vegetations

– Echogenic with irregular appearance• Valvular dysfunction

– Best seen with color flow Doppler

Atrial Myxoma

Mural Thrombus

Bacterial Endocarditis

Procedural Applications

• Pericardiocentesis– Left parasternal approach or entry

into largest area of fluid collection adjacent to the chest wall

– Lower risk of cardiac or hepatic injury

• Transvenous pacing – Allows highly accurate placement of

pacing wire 1

1 Aguilera P, et al. Ann Emerg Med 2000

Pericardiocentesis

Cardiac Ultrasound Pitfalls

• Not optimizing gain, depth and dynamic range

• Settling for inferior images due to technical difficulty

• Improper probe positioning• Mistaking pericardial fat for effusion• Mistaking clotted blood for normal

anatomy

Case 1

• 77 yo female with hx of breast CA, in remission for 2 yrs, presents with gradually worsening SOB and CP

• BP 90/50 HR 100 RR 26 T 99 SpO2 82 %• Lungs with faint crackles, heart sounds

distant• Abd exam nl; ext 2 + edema; neuro nl

• Management ?

Case 2

• 22 yo old male, with stab wound to left chest, vital signs stable in field

• Loses consciousness of arrival in ED• BP 60/palp HR 130 RR 6 T 98 SpO2 80%• 2 cm stab wound over L 4th intercostal

space; no other injury• Shallow breaths, no audible heart sounds

• Management ?

Take Home Points

• Learn the skill but know your limitations !

• Be sure to observe dynamic function

• Tilt, rotate or angulate probe to obtain optimal images

• Use early, use often!

cardiac ultrasound

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