Northern California Emergency Ultrasound Course

UCCSF

The Extended FAST Exam

Rimon Bengiamin, MD, RDMS

Objectives

• Discuss the components of the EFAST exam

• Evaluate the utility of the EFAST

• Review how to obtain and interpret the images

• Discuss the strengths and weaknesses of the EFAST

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• Abdominal sonography can detect as little as 50 cc of free fluid but generally you need about 200-250cc on average for a positive view

• An analysis of 62 publications with 18,167 patients revealed an overall sensitivity of 79% and a specificity of 99.2% for detecting free fluid, organ damage, or both. (1)

• Another study of emergency physicians showed a sensitivity of 90% and specificity of 99%. (2)

• Sensitivity increases with a repeat exam at 30 minutes. (3)

• Sensitivity is nearly 100 percent in the setting of hypotension and trauma

• What does this mean?

• It’s a good screening tool

• Not a good definitive test if your suspicion is high and the test is negative

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• Advantages of the FAST compared to DPL and CT

• Accurate - as a screening tool

• Rapid - the average time to perform a complete FAST examination of the thoracic and abdominal cavities is 2.1 to 4.0 minutes. (4,2)

• Noninvasive - less risk of infection/bleeding/other complications

• Repeatable - increases the sensitivity of the study

• Portable - convenient in unstable patients

• No contrast or radiation - renal failure and pregnant patients

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• Disadvantages of the FAST

• Inability to determine the exact etiology of free fluid in some cases

• Technically difficult in cases of obesity or bowel gas

• Cannot evaluate the retroperitoneum as well as CT

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• When should it be done?• Part of the primary survey, particularly when evaluating

circulation

• Examples

• Hypotensive, tachycardic patient and you find pericardial tamponade

• Hypotensive, tachypnic patient and you find a pneumo/hemothorax

• Do not let it hinder your treatment and stabilization!

• Should be done in conjunction/simultaneous with resuscitation

• FAST can be performed simultaneously as other things are being done!

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• What about cases when there isn’t trauma?

• AAA

• Ruptured ectopic pregnancy

What Is The Extended

FAST Exam?

• Also known as the EFAST

• The traditional FAST exam with the addition of evaluation of the thorax

• Thoracic exam includes looking for:

• Pneumothoraces

• Hemothoraces

Probe Choice

• You are looking at deep structures so you need a medium to low frequency probe

• These have better penetrance but lower resolution

Medium Low High

Right Upper Quadrant

• Evaluate three areas:

• Morison’s Pouch

• Most sensitive for detecting free fluid particularly if the patient is in Trendelenburg (6,7)

• Tip of the liver and pericolic gutter

• Slide the probe caudally

• Diaphragm

• Slide the probe cephalad and it may help to rotate the probe tip posteriorly (counterclockwise) to get through the ribs

Right Upper Quadrant

-Probe Orientation-

Right Upper Quadrant

-Morison’s Pouch-

Morison’s Pouch

Liver

Kidney

Right Upper Quadrant

-Positive Free Fluid-

Text

Free fluid appears black

RUQ Diaphragm

-Probe Orientation-

Counterclockwise probe rotation will help decrease rib shadows

Right Upper Quadrant

-Diaphragm-

Diaphragm

Look for “mirror” artifact - equal echo on both sides of the diaphragm

Pelvic View

• The traditional view is the transverse view

• However, evaluation of the pelvis in the saggital view, with the probe dot toward the head, can be more helpful

• Better delineation of the anatomy

• Helps with differentiation of free fluid

Pelvic View

-Probe Orientation-

Transverse vs.

Longitudinal

Longitudinal Transverse

Pelvic View

-Normal Female-

First place free fluid collects

Bladder

UterusCervix

Pelvic View

-Normal Male-

What is this?

Location of

potential free fluid

Pelvic View

-Free Fluid-

Clot

Free Fluid

Left Upper Quadrant

• Unlike Morison’s view, evaluation of the interface between the kidney and spleen is not as important

• Free fluid does not commonly collect in this space because of the phrenicocolic ligament running in this area

• Fluid commonly collects around the tip of the spleen, base of the spleen, or between the spleen and diaphragm

Left Upper Quadrant

-Probe Orientation- Left Upper Quadrant

• Need to have the probe oriented more cephalad and posterior than with Morison’s view

• Also may help to rotate the probe tip posteriorly (clockwise) to get through the ribs

Left Upper Quadrant

-Normal View-

Spleen

Diaphragm

Left Upper Quadrant

-Free Fluid-

Left Upper Quadrant

-Free Fluid-

Cardiac

• Two views

• Subxiphoid long axis

• Parasternal long axis

• Try to get comfortable with both windows

• Looking mainly for pericardial effusion

Cardiac (Subxiphoid)

-Probe Orientation-

Cardiac Subxiphoid

-Is this normal?-

Cardiac Subxiphoid

-Pericardial Effusion-

Is this tamponade?

Cardiac (Parasternal)

-Probe Orientation-

Cardiac

-Parasternal Long Axis-

Cardiac Parasternal

-Effusion with Clot-

Tamponade and

pericardiocentesis

• If there is tamponade you need to act now through pericardiocentesis

• Look for right atrial and ventricular collapse

• If there is clot, you should probably go straight to thoracotomy

Pericardiocentesis

• Direct visualization dynamic technique has far less complications

• Traditional subxiphoid approach has complication rate nearing 50% including wall puncture, coronary artery laceration, pneumothorax, diaphragm or organ injury

Pericardiocentesis

• Mayo Clinic 2002 (Teresa et al).

• 1127 ultrasound guided pericardiocentesis over the course of 21 years

• 97% success rate and 4.7% complication rate

• Much lower than blind

• Not an ideal study but take home message is it’s safer

Thoracic Ultrasound

• What does it add?

• Evaluation for pnuemothorax

• Sliding lung sign

• Leading edge

• Comet tail artifact

• Evaluation for hemothorax

• RUQ and LUQ windows

Thoracic Ultrasound

-Kirkpatrick et al. (8)-

• “EFAST has comparable specificity to CXR but is more sensitive for the detection of occult pneumothorax after trauma”

• Study of 225 patients

• EFAST more sensitive than CXR

• Picked up 63% of pneumothoraces missed on CXR

Chest X-ray vs

Ultrasound

• Why is ultrasound better in the setting of trauma?

• Patient is supine

• Air will layer anteriorly

• Blood will layer posteriorly

Thoracic Ultrasound

-Comparison to CXR-

• Makes sense that it would be more sensitive particularly in the supine patient since the air will be anterior

• Can be life saving in the case of the unstable patient

• Zhang et al. (9)

• 135 trauma patients, 83 mech. ventilated

• 29 had a pneumothorax

• US: sensitivity 86%, NPV 96%

• CXR: sensitivity 28%, NPV 84%

• US: 2.3 minutes CXR:10.3 minutes

Sliding Lung Sign

• Curvilinear (abdominal) or vascular probe

• The vascular probe tends to provide better quality images

• Position the probe:

• with the dot toward the head

• at the 2nd intercostal space

• at the midclavicular line

• Can use M mode to confirm - “waves crashing on a beach”

• Should see pleural lines

Thoracic Ultrasound

-Probe Position- Probe Position

• Should probably look at two spots

• Try to look at the most anterior part of the chest (likely around the nipple line - 4th intercostal space)

Thoracic Ultrasound

-Sliding Lung Sign-

Sliding Lung Sign

-M Mode-

Thoracic Ultrasound

-Lichtenstein et al (10)-

• “Ultrasound was a sensitive test for detection of pneumothorax, although false-positive cases were noted. The principal value of this test was that it could immediately exclude anterior pneumothorax.”

• 43 patients in an ICU setting

• Examination of sliding lung sign

• 95.3% sensitivity and 91.1% specificity

Thoracic Ultrasound

-Sliding Lung-

• Can use sliding lung to estimate the size of a pneumothorax

• Actually need to map out the lung by evaluating for sliding lung at each of the intercostal spaces

Comet Tail Artifact

• Artifact perpendicular to the pleura casting a hyperechoic line into the lung parenchyma

• Normally seen in fully expanded lung

• Can also be seen in pathologic states such as pulmonary edema or consolidation

Thoracic Ultrasound

-Comet Tail Artifact-

Thoracic Ultrasound

-Lung Point-

• An abrupt change from normal sliding lung or nonpathologic comet tail artifact to no sliding and/or pathologic comet tail artifact

• May or may not be present

Lung Point

Thoracic Ultrasound

-Hemothorax-

• Upright CXR - 100 cc

• Supine CXR - 200-300 cc

• CXR can miss large effusions

• US can pick up as little as 20 cc of effusion

Thoracic Ultrasound

-Hemothorax-

• Hemothorax

• Ma et al. (11)

• 240 patients

• Blunt and penetrating trauma

• Hemothorax confirmed by chest tube output or CT

• 99.6% accuracy

• Sisley et al. (12)

• 360 patients

• Blunt and penetrating trauma

• 40 hemothoraces confirmed by CT or chest tube

• Thoracic US had 97.5% sensitivity and 99.7% specificity

• Plain CXR had 92.5% sensitivity and 99.7% specificity

• Time for US: 1.3 min. Time for CXR: 14.8 min.

Thoracic ultrasound

-Hemothorax-

EFAST

-A Case-

EFAST

-A Case-

EFAST

-A Case-

EFAST

-A Case-

EFAST

-A Case-

EFAST

-A Case- Quiz!

• The most common place to see free fluid in the left upper quadrant is:

• A. Between the spleen and the kidney

• B. Between the spleen and the diaphragm

• C. Around the tip of the spleen

• D. B and C

EFAST

Questions?

References

• (1) Stengel D, Bauwens K, Rademacher G, et al: Association between compliance with methodological standards of diagnostic research and reported test accuracy: Meta-analysis of focused assessment of US for trauma. Radiology 2005; 236:102–111 nol 1996; 166:317–321 95.

• (2) Ma OJ, Mateer JR, Ogata M, Kefer MP, et al. Prospective analysis of a rapid trauma ultrasound examination performed by emergency physicians. J Trauma 1995;38:879-885.

• (3) Blackbourne LH, Soffer D, McKenney M, et al: Secondary ultrasound examination increases the sensitivity of the FAST exam in blunt trauma. J Trauma 2004; 57:934-938.

• (4) Thomas B, Falcone RE, Vasquez D, et al. Ultrasound evaluation of blunt abdominal trauma: program implementation, initial experience, and learning curve. J Trauma 1997;42:38-388.

• (5) Hoff WS, Holevar M, Nagy KK, et al. Practice management guidelines for the evaluation of blunt abdominal trauma: The EAST practice management guidelines work group. J Trauma 2002;53:602-615.

• (6) Sisley A, Rozycki G, Ballard R, et al: Rapid detection of traumatic effusion using surgeon performed ultrasound. J Trauma 1998;44:291-297.

• (7) Jehle D, Guarino J, Karamanoukian H: Emergency department ultrasound in the evaluation of blunt abdominal trauma. Am J Emerg Med 1993;11:342-346.

• (8) Kirkpatrick AW, Sirois M, Laupland KB, Liu D, et al: Hand-held thoracic sonography for detecting post-traumatic pneumothoraces: the extended focused assessment with sonography for trauma (EFAST). J Trauma 2004;57(2):288-295.

• (9) Zhang M, Liu ZH, Yang JX, Gan, JX, et al: Rapid detection of pneumothorax by ultrasonography in patients with multiple trauma. Critical Care 2006;10:R112.

• (10) Lichtenstein DA and Menu Y: A bedside ultrasound sign ruling out pneumothorax in the critically ill. Lung sliding. Chest 1995;108:1345-1348.

• (11) Ma OH, Mateer JR: Trauma ultrasound examination versus chest radiography in the detection of hemothorax. Annals of emergency medicine 2007;29:312-316.

• (12) Sisley A, Rozycki G, et al: Rapid detection of traumatic effusion using surgeon-performed ultrasonography. J Trauma 1998;44(2):291-297.