FAST – Focus on the RUQ – False +ve

Text and images  Genevieve Carbonatto

There is a BAT call. A young 35 year old has fallen from a 3 story building and essentially landed on his feet.  He has extensive leg injuries and possible chest and abdominal injuries. BP 95/60 HR 110/min RR 25/min Saturating 96% on RA. He will hit your emergency department in 5 minutes.

OK. The trauma team is called. Roles are allocated to different doctors and nurses. You are given the task of doing the EFAST scan because you have been to a course recently and have done  scans since then. You set up the machine.

The patient gets wheeled in. He has both legs in splints and a pelvic binder on.  He has extensive injuries to his legs, femoral, fibular and tibial fractures with ankle fractures on the right. Probable foot fractures on the left.  He is pale and complaining of pain. The history is taken while the patient is transferred to the bed. His BP is 90 systolic his HR 120/min.  IV lines are inserted fluids are started. The massive transfusion protocol is activated. Your task is to do the EFAST exam. Your BP is probably hitting 180 systolic and your HR is close to what the patient’s HR is. Why ? Because your findings will determine whether this patient has (other than the obvious significant long bone injuries) any life threatening injuries, such as a pneumothorax or haemothorax (requiring chest tube insertion and possibly thoracotomy), free fluid in the abdomen (requiring a laparotomy) or pericardial fluid (requiring a pericardiocentesis or thoracotomy) and above all you don’t want to miss something. You get the probe. You start with the RUQ and your get this.

fat-around-liver

You see the black stripe  between the liver and kidney. You call it a +ve FAST. There are at least 10 people milling around the patient. Surgeons, anesthetists, intensivitists, emergency physicians, nurses and now  the radiographers for a chest Xray. You look at the chest and heart. You do not finish the abdominal exam because you have identified fluid in this hypotensive patient. The orthopaedic surgeon and general surgeons take the patient to theatre. He has a laparotomy – it is negative. No fluid in the abdomen. His haemodynamic instability was all related to his extensive legs injuries.

So how did you get it wrong? You overshot the mark.

Error  #1

You were  given the responsibility of the EFAST scan and you are not accredited. The result of your scan should have been discussed with an accredited person first

Error #2

You did not enter what I call “the Zone”.  The zone is that mental state where, however much the noise is around you, you can maintain total objectivity during your scan. You need to find the eye of the storm as it were. That place where you don’t want to find anything (ie fluid in a hypotensive patient), you just want to look. The zone is a place where all that matters is the image. This is where sonographers who have nothing to do with the clinical management of a patient are better than doctors because they have no interest in the management of the patient. We juggle two hats, a clinical hat and a sonography hat. We need to take the clinical hat off in trauma and just look.

Error # 3

You did not look elsewhere to corroborate your findings. What you saw was fat. Perihepatic fat.
fat

Had you scanned carefully through this area you would have seen the following.
fat-around-liver-2

There is clearly no fluid here. There is some echogenicity within the hypoechoic stripe. There are no sharp lines seperating fluid from liver. There is no fluid  at the tip of the liver.

Still unconvinced?

What about this. Fat or fluid?

fat-or-fluid

First of all there is some rib shadowing that is obscuring the view if that liver edge. You want to be able to scan through this area and check.

There is clearly no fluid in this scan of the liver

Still unconvinced?

Ok – this is what small amounts of fluid between the liver and the kidney in this area looks like. Click on the image below to get it running.

The hypoechoic areas are well defined. The liver edge is clearly visible as seperate from the fluid.

Now try the following 2 images

Fluid or fat?

fry

Fat

Fluid or fat?

fluid-tip-of-liver

Fluid

Discussion

You can overcall fluid or undercall it. The former leads to unecessary operations which have inherent risks, the latter, delay in potentially life saving procedures. It is important  to scan carefully and properly, know your false +ves and always ask if you are not accredited.

Teaching point: When you are performing an EFAST during a trauma, keep calm, get into the mental “zone”, corroborate your findings in several views, change your gain, your frequency, your depth or your dynamic range if you are having difficulty getting good images. 

 

 

 

 

 

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