and Pitfalls, The Final Say
AFAST is a standardized ultrasound examination with exact clarity of its five acoustic windows and how each is performed. AFAST has been shown to be superior to radiography for not only the detection of free intraabdominal fluid but also the volume through its AFAST‐applied fluid scoring system (Lisciandro et al. 2009, 2015, 2019). Moreover, the AFAST DH view is an important source of patient information for free fluid, volume status, pericardial and pleural effusion and lung conditions. Chapter 7 covers clinical integration of AFAST‐acquired information.
AFAST has exact clarity to its five acoustic windows.
AFAST and its acoustic windows are exactly the same no matter the patient positioning.
Each view has target organs that are imaged while looking for free fluid (intraabdominal, retroperitoneal, pleural, pericardial) and lung conditions.
AFAST should be part of any POCUS abdominal examination to make sure that effusions or other obvious target organ pathology are not missed.
Serial AFAST and an assigned abdominal fluid score should be repeated, called the serial exam, four hours after the initial AFAST in all stable patients and sooner if the patient is unstable or questionable.
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 categorize small‐volume bleed/effusion from large‐volume bleed/effusion, AFS at each respective 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 as originally published, with the categorization of small‐volume bleed/effusion defined as AFS <3 (AFS ranges from 0 to 2½, thus including AFS of 1, 1½, 2 and 2½) and large‐volume bleed/effusion defined as AFS ≥3 (AFS ranges from 3 to 4, including AFS of 3, 3½ and 4).
Expect that ~50% of adult dogs will 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).Figure 6.35. AFAST‐focused spleen. The spleen represented by the banana is interrogated by the “slide and fan” approach, overlapping each section as scanning cranially until there is no more spleen and then scanning caudally until there is no more spleen. The author repeats the technique twice. Its hyperechoic capsule and the blood vessels splitting the capsule as in (A) identify the spleen. (B–E) A scan in a dog that has a splenic mass. In (B) and (C) the spleen is unremarkable until at (D) and (E) a mass that disrupts the contour of the splenic capsule is noted, a serious finding.Source: Reproduced with permission of Dr Gregory Lisciandro, Hill Country Veterinary Specialists and FASTVet.com, Spicewood, TX.
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).
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).
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; 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 caudal vena cava may be grouped as a “bounce” and fluid responsive, “FAT” and fluid intolerant, and “flat” and hypovolemic.
Maximum heights at the FAST DH view may be used to additionally characterize the caudal vena cava (see Tables 7.6 and 36.3).
References
1 American College of Emergency Physicians. 2001. ACEP emergency ultrasound guidelines 2001. Ann Emerg Med 38:470–481.
2 Bilello JF, Davis JW, Lemaster D, et al. 2011. Prehospital hypotension in blunt trauma: identifying the “crump factor.” J Trauma 70(5): 1038–1042.
3 Birkbeck R, Greensmith T, Humm K, et al. 2019. Haemoabdomen due to suspect anaphylaxis in four dogs. Vet Rec Case Rep 7:e000734.
4 Blackbourne LH, Soofer D, McKenney M, et al. 2004. Secondary ultrasound examination increases the sensitivity of the FAST exam in blunt trauma. J Trauma 57(5): 934–938.
5 Boysen SR, Lisciandro GR. 2013. The use of ultrasound in the emergency room (AFAST and TFAST). Vet Clin North Am Small Anim Pract 43(4):773–797.
6 Boysen SR, Rozanski EA, Tidwell AS, et al. 2004. Evaluation of a focused assessment with sonography for trauma protocol to detect free abdominal fluid in dogs involved in motor vehicle accidents. J Am Vet Med Assoc 225(8):1198–1204.
7 Caldwell DJ, Petras KE, Mattison BL, et al. 2018. Spontaneous hemoperitoneum and anaphylactic shock associated with Hymenoptera envenomation in a dog. J Vet Emerg Crit Care 28(5):476–482.
8 Candotti C, Arntfield R. Pericardial effusion. 2014. In: Point‐of‐Care Ultrasound, edited by Soni NJ, Arntfield R, Kory P. Philadephia: Elsevier, pp 130–134.
9 Darnis E, Boysen S, Merveille AC, et al. 2018. Establishment of reference values of the caudal vena cava by fast‐ultrasonography through different views in healthy dogs. J Vet Intern Med 32(4):1308–1318.
10 Ferrada P, Vanguri P, Anand RJ, et al. 2012a. Flat inferior vena cava: indicator of poor prognosis in trauma and acute care surgery patients. Am Surg 78(12):1396–1398.
11 Ferrada P, Anand RJ, Whelan J, et al. 2012b. Qualitative assessment of the inferior vena cava: useful tool for the evalutaion of fluid status in criticall ill patients. Am Surg 78(4):468–470.
12 Grimes JA, Fletcher JM, Schmiedt CW. 2018. Outcomes in dogs with uroabdomen: 43 cases (2006–2015). J Am Vet Med Assoc 252(1):92–97.
13 Hnatusko A, Gicking JC, Lisciandro GR. 2019. Anaphylaxis‐related hemoperitoneum in 11 dogs. J Vet Emerg Crit Care, in press.
14 Hoffberg JE, Koenigshof AM, Guiot LP. 2016. Retrospective evaluation of concurrent intra‐abdominal injuries in dogs with traumatic
