introduction to basic ultrasound in emergency...
TRANSCRIPT
Eberhard KE, Sundskard M, Sørensen EM © SATS Copenhagen ⎟ emss15.sats-kbh.dk
Introduction to ultrasound in emergency medicine 1. ULTRASOUND PHYSICS
What is ultrasound and how does it work? Ultrasound is high frequency sound waves of 2-17 MHz far - above what the human ear can register. The ultrasound probe emits a sound wave impulse, then waits until it receives the reflected wave. The waves are reflected when passing from one density of tissue to another. A reflection will be imaged as a white spot e.g. the high density of bone will reflect all sound waves creating a very clear white line with a black shadow behind. If no waves are reflected the spot will be black e.g. when passing through water or blood. The gray-tones in between show the degree of reflection. Frequency and choice of probe: The higher frequency waves the better the picture. The down side of high frequency and high resolution is low penetration. Therefore, always choose the highest possible frequency depending on the depth you need to reach. Abdominal probe
Linear probe
Heart probe
Penetration High Low Low Resolution Low High High Choose it when… Abdominal scans
FAST Superficial structures Vascular access Blockade
FATE Echocardiography
Eberhard KE, Sundskard M, Sørensen EM © SATS Copenhagen ⎟ emss15.sats-kbh.dk
Orientation of image Ultrasound follows the basic principles of imaging: the right side of the patient is on the left side of the image and the left side of the patient is on the right side of the image. 2. BUTTONOLOGY
Preset: always remember to choose the right preset settings, e.g. choose abdominal if doing a FAST. Depth: adjust depth so the area of interest is as large as possible, and in the middle of the image. Focus: adjust focus to be on or just below your organ of interest. It will automatically optimize the image in that level of depth. This button is not always available. Gain: is the enhancement of the signal that the ultrasound machine receives. It is visualized as the brightness of the image. Be careful not using too much gain unless you do echocardiography. 3. INTRODUCTION TO eFAST and FATE
• Extended Focused Assessment with Sonography for Trauma (eFAST) key points:
o A quick point-of-care test to check for free fluid in the abdomen, pleural cavity and pericardium as well as pneumothorax.
o Abdominal probe and abdominal settings. Remember to adjust the scanning setting, to slide the probe in all 4 directions.
o Five different locations: 1. Anterior thoracic view – not included in the non-extended regular FAST scan 2. Subxiphoid view
(https://youtu.be/BEofsBzfOOw?list=PL2AGl6-lzXJTRn113DAv1Iybh_AFHBwFX) 3. The hepato-renal view
(https://youtu.be/0VTRm_DNW8s) 4. The spleno-renal view
(https://youtu.be/IuRklL3cWJU?list=PL2AGl6-lzXJTRn113DAv1Iybh_AFHBwFX) 5. Pelvic view
(https://youtu.be/6Srf0briZSU?list=PL2AGl6-lzXJTRn113DAv1Iybh_AFHBwFX) (https://youtu.be/HxQE2gYH3Sk?list=PL2AGl6-lzXJTRn113DAv1Iybh_AFHBwFX)
o Don’t let the name of the protocol fool you! An eFAST exam is not only useful for trauma patients, but for all patients with an unexplained condition eg. hypotension.
o For a detailed walk-through please go to: http://www.sonoguide.com/FAST.html (you may just scroll down to the explanations, images and videos of the windows).
o For a short version take a look at the eFAST protocol pocket card!
Eberhard KE, Sundskard M, Sørensen EM © SATS Copenhagen ⎟ emss15.sats-kbh.dk
• Focus Assessed Transthoracic Echocardiography (FATE) key point:
o A focused point-of-care test to check cardio-pulmonal status as pericardial effusion, tamponade, cardiac contractility, intravascular volume status and free fluid in the pleural cavity.
o Cardiac probe and cardiac setting o Four different locations:
1. Subxipoid view (https://youtu.be/Mkc6tUVRgKo?list=PL2AGl6-lzXJRp3Dh0t1YZ2qsyic0msYDd)
2. Parasternal long-axis view (PLAX) (https://youtu.be/4qerzEW_ASU?list=PL2AGl6-lzXJRp3Dh0t1YZ2qsyic0msYDd)
3. Parasternal short-axis view (PSAX) (https://youtu.be/EaLuCBXXINg?list=PL2AGl6-lzXJRp3Dh0t1YZ2qsyic0msYDd)
4. Apical 4-chamber view (https://youtu.be/_eHZz-OCc_M?list=PL2AGl6-lzXJRp3Dh0t1YZ2qsyic0msYDd)
5. Pleural view o For a detailed walk-through please go to: http://www.sonoguide.com/cardiac.html o For a short version take a look at the FATE protocol pocket cards!