Should be a routine add‐on for all POCUS abdominal exams (Global FAST is an even better approach).
Should be standard of care for all bluntly traumatized small animals, as it is in people.
Should be used in penetrating trauma cases with the understanding that AFAST is generally thought to be very specific for detecting intraabdominal injury (by finding free fluid), but lacks high sensitivity.
Serial exams should always be performed in bluntly traumatized animals, after rehydration and resuscitation in trauma and nontrauma including suspect peritonitis cases.
The use of the AFAST‐applied abdominal fluid scoring system may be effective in bleeding traumatized and nontraumatized dogs to predict degree of anticipated anemia and may be used also for peritonitis or other effusive conditions as a monitoring tool by scoring (AFS 0–4).
The diagnosis of anaphylaxis in dogs may be supported with the finding of a sonographic striation of the gallbladder wall (halo effect or double rim effect). However, a Global FAST (including TFAST and Vet BLUE) helps rule out pericardial effusion/cardiac tamponade and right‐sided cardiac failure, and placing the constellation of patient information (history, physical examination, laboratory findings, imaging) within the complete clinical picture is important to avoid mistakes and “satisfaction of search error.”
Quick Reference of Normals and Rules of Thumb
Adult dogs and cats should have no free fluid within their peritoneal cavity or retroperitoneal space (or within the pleural cavity or pericardial sac); however, recent research evaluating anesthetized adult dogs and cats, and puppies and kittens has documented small pockets of free intraabdominal fluid in clinically normal canines and felines.
The originally published AFAST‐applied abdominal fluid scoring system was scored according to number for positive AFAST views (range 0–4) excluding the bonus 5th view that is not part of the AFS. However, to better distinguish small‐volume bleeder/effusion from large‐volume bleeder/effusion, AFS at each AFAST view now ranges from 0 (negative) to ½ (small pocket <5 mm in cats and <10 mm in dogs) to 1 (>5 mm cats and >10 mm dogs).
Total AFS remains similar as originally published with the categorization of small‐volume bleeder/effusion defined as AFS <3 (AFS ranges from 0 to 2½, thus including AFS of 1, 1½, 2 and 2½) and large‐volume bleeder/effusion defined as AFS ≥3 (AFS ranges from 3 to 4, including AFS of 3, 3½, and 4).
Expect ~50% of adult dogs to have an AFS of ½ along the diaphragm at the DH view with maximum dimensions of <3 mm that may not be noticeable in unsedated, unanesthetized adults (Lisciandro et al. 2019).
Expect ~90% of puppies <6 months of age to have an AFS of ½ to 1 along the diaphragm at the DH view and then with fairly equal distribution between the other three AFAST views of ½ to 1 with maximum dimensions of <3 mm (Lisciandro et al. 2019).Figure 7.16. AFAST goal‐directed template.Source: Reproduced with permission of Dr Gregory Lisciandro, Hill Country Veterinary Specialists and FASTVet.com, Spicewood, TX.
Expect that ~70% of adult cats and kittens <6 months of age will have AFS of ½ along the diaphragm at the DH view and then next most commonly positive in both age groups at the most gravity‐dependent umbilical view (SR view in left lateral recumbency) with maximum dimensions at either of these AFAST views of <3 mm that may or may not be noticeable in unsedated, unanesthetized adult cats and kittens (Lisciandro et al. 2015).
Any mass found to deform the splenic capsule on a focused spleen view should always be considered a serious finding.
The FAST DH view should be considered nearly 100% sensitive and 100% specific for the detection of clinically relevant PCE in both dogs and cats in standing or sternal positioning.
Serial examinations should always be performed after resuscitation and rehydration of the patient with at least one more AFAST examination (or a Global FAST) and whenever the patient is failing inpatient or outpatient care.
The finding of sonographic striation of the canine gallbladder wall should be considered abnormal in the acute setting (acute collapse and weakness) even when the thickness is in the normal range of 1–3 mm and anaphylaxis, “anaphylactic gallbladder,” and right‐sided congestive heart failure, “cardiac gallbladder,” should be ruled out using the Global FAST approach.
Although rare in cats, a “cardiac gallbladder” may occur with feline congestive heart failure.
Characterization of the CVC may be categorized as a “bounce” and fluid responsive, “FAT” and fluid intolerant, or “flat” and hypovolemic.
Maximum heights at the FAST DH view may be used to additionally characterize the CVC (see Tables 7.6 and 36.3).
References
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