Northern California Emergency Ultrasound Course Objectives The Extended FAST Exam Rimon Bengiamin, MD, RDMS UC SF 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 Focused Assessment e With Sonography In Trauma (FAST) 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 Focused Assessment e With Sonography In Trauma (FAST) 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 Not a good definitive test if your suspicion is high and the test is negative
Focused Assessment e With Sonography In Trauma (FAST) 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 Focused Assessment e With Sonography In Trauma (FAST) When should it be done? Part of the primary survey, particularly when evaluating circulation Examples Hypotensive, tachycardic patient and you find pericardial al 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! Focused Assessment e With Sonography In Trauma (FAST) 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- Liver Morison s Pouch Kidney
Right Upper Quadrant -Positive Free Fluid- RUQ Diaphragm -Probe Orientation- Text Free fluid appears black Counterclockwise probe rotation will help decrease rib shadows Right Upper Quadrant -Diaphragm- Pelvic View Diaphragm Look for mirror artifact - equal echo on both sides of the diaphragm 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- Pelvic View -Normal Male- Uterus Bladder Cervix First place free fluid collects Location of potential free fluid What is this?
Pelvic View -Free Fluid- Left Upper Quadrant Free Fluid Clot 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- Left Upper Quadrant -Free Fluid- Spleen Diaphragm 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- Cardiac (Parasternal) -Probe Orientation- Is this tamponade?
Cardiac -Parasternal Long Axis- Cardiac Parasternal -Effusion with Clot- Tamponade and pericardiocentesis 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 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)- Chest X-ray vs Ultrasound 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 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- Sliding Lung Sign 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 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 Thoracic Ultrasound -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 -Lung Point- 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
Thoracic Ultrasound -Hemothorax- Thoracic Ultrasound -Hemothorax- Hemothorax Ma et al. (11) 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 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 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. Questions? (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.