a middle aged male is brought to your ED “found down”. You have no name, no age and he is not one of your regular attenders that you are on first name terms with. He is hypothermic, drowsy, non communicative, hypotensive and smells strongly of alcohol. There is no head injury and exam is largely unremarkable apart from inconsistent abdominal tenderness – it is not clear if he actually has a tender abdomen or just objects to your examination. You obtain the following images
He appears to object to your ultrasound examination as much as your physical examination. It is extremely common in POCUS to have difficulty obtaining diagnostic images. However we have the advantage of having the patient in front of us and putting the clinical images in context. Sometimes all we need is a less than optimal image to point us in the right direction. In this case there is free fluid noted in Morrisson’s pouch and the pelvis and maybe a hint surrounding the spleen.
that is entirely down to you. You most certainly have not made a diagnosis as yet but this is emergency medicine – limited information, a sick patient and a need to make a decision – free fluid in the belly of a sick patient should get you worried and perhaps occult trauma is high on the list here.
You are worried about an intrabdominal catastrophe and contact the surgical team and obtain a portable CXR below.
very little. the erect CXR has extremely limited diagnostic characteristics for something like a perforated viscus.
Given the huge diagnostic uncertainty he proceeds to a CT which shows free fluid and free air in the abdomen likely from a perf DU which is confirmed at surgery.
The FAST examination was originally designed for trauma – to detect free fluid and help with decision to go to theatre. As trauma care has developed and increased ease of access to CT (ie CT in the resus room), we find that we are frequently able to get the unstable patients to CT to get the injury defining info we need to know whether or not something like a laporotomy stands a chance of being therapeutic. Personally I find the FAST exam less use in trauma than I do in the sick undifferentiated medical patients.
Free fluid certainly can be blood that could be ectopic or in this case the free fluid of beer and kebab.
On the con side you could easily pick up the physiological free fluid of the menstrual cycle in a female and the chronic free fluid of a cirrhotic who happens to be sick with something else.
I like this quote the best via the EDE blog: