GettyImages/Simonkr As we discussed in part one of this series, the AFAST represents a method to evaluate the abdomen for fluid, not only at a single point in time, but also for serial monitoring, initially arose to assess and manage trauma patients. However, it emerged into much more. Since the chest cavity often accumulates fluid as well, the TFAST method soon followed (thoracic-focused assessment sonography for trauma, triage, and tracking). To determine if there is fluid (or air where it shouldn’t be) in the pleural or pericardial cavity and lung parenchyma, while also evaluating the caudal vena cava, we can easily assess this via a TFAST scan. If we want to delve a bit further and assess the lung surface pathology, we can consider using Vet BLUE, a regional lung ultrasound.1–4 However, remember that we can use these tests not only in acute trauma or at initial presentation, but also for serial monitoring. Radiographs may not always be feasible in patients in respiratory distress. Thoracic scanning is often much safer and less stressful for our patients. Gaining confidence in your ability to detect fluids in the thoracic cavity is a significant first step. However, would you like to be able to confidently confirm that your patient with respiratory distress has clinically significant wet lungs*? Conditions, such as non-cardiogenic pulmonary edema, pneumonia, CHF, pulmonary contusions, or hemorrhage, can be demonstrated using Vet BLUE and, in conjunction with a TFAST scan and radiographs, help guide therapy, prognosis, and additional diagnostics. TFAST origins In addition to his revolutionization of abdominal point-of-care ultrasound (POCUS), Gregory R. Lisciandro, DVM, Dipl. ABVP, Dipl. ACVECC, revolutionized the diagnostic ability of veterinarians when evaluating patients with trauma, and then helped guide the transformation of ultrasound use in assessing patients in the emergency setting to become much more advanced. AFAST, TFAST, followed by Vet BLUE, collectively known as Global FAST, Dr. Lisciandro and colleagues continue to update and refine techniques and methods, providing instruction through webinars, in-person training, asynchronous learning, and textbooks. These procedures equip veterinarians with essential skills to methodically, repeatedly, and confidently recognize and diagnose patients, facilitating immediate treatment and prognostic support.4–8 Clinical indications for use When should we use TFAST scanning to evaluate a patient at the clinic or in the field? Indications may include:1,8 Any respiratory distress patient Patients with acute or episodic collapse Penetrating trauma Blunt force trauma Patients with a risk of developing a PTX* Patients with hypotension of unknown origin Anemic patients To detect and monitor pulmonary edema (non-cardiogenic/cardiogenic) Patients with known heart disease who are decompensating To monitor progression or improvement of effusions or PTX Serial monitoring after rehydration in patients with concern for effusion risks Vomiting (Justine Lee, DVM, DACVECC, DABT, co-founder of VetGirl and Criticalist/toxicologist, said that, though uncommon, pericardial effusion may present with vomiting as the only outward sign.9) Concern for anaphylaxis Fever of unknown origin Any ADR patient How to perform a TFAST scan You could work at a small practice with limited volume or a high-volume emergency room. All vets, and ultimately, our patients, can benefit from taking the time to hone a skill. When adept, we can gather a lot of information in a brief yet comprehensive evaluation. There is always time for referral or a complete thoracic ultrasound once a patient is stable. However, in the face of respiratory distress, being able to determine cause, treatment course, and advise clients is paramount. Patient positioning For stable patients with mild respiratory changes that are not dyspneic and tolerate lateral recumbency, right lateral recumbency is preferred. However, many patients will only be able to be positioned either standing or in sternal recumbency, and we must work with whatever position is achievable. The patient’s comfort and ability to breathe without stress or increased effort should not be jeopardized. Dorsal recumbency is not recommended, as decompensation is highly likely.6,8 Evaluating the windows With our TFAST scan, we are looking for fluid (pleural or pericardial effusion), but we can also evaluate much more within our five windows. Always ensure appropriate contact between the patient and the transducer. Shaving is not usually necessary. Part the fur and ensure sufficient alcohol or ultrasound gel is used to minimize artifacts and provide adequate contact. Understand your machine’s capabilities and how to adjust depth, focus, gain, and be cognizant of your angle of insonation.*1 When scanning, do so systematically and consistently to avoid missing something and improve your proficiency (See: “The five acoustic windows”). For details on how to obtain the best image in each window, tricks of the trade, and additional information, see the provided references. A lot goes into each site, including various terminology that refers to the views obtained and what is evident within each axis. Things like the Bull’s eye, Batman sign, Mushroom, Windshield wipers, Fishmouth, and the Mercedes-Benz sign can all be found in the right short-axis PCS view. While on the left, we can see a Hammerhead and a Smiley face.1 The author in an externship at White Oak Conservation Center, Yulee, Fla., performing a pregnancy evaluation of a cheetah. Photo courtesy Dr. Erica Tramuta-Drobnis Vet BLUE: A brief introduction Vet BLUE, together with AFAST and TFAST, helps form the Global Fast, an evaluation that does more than just look for fluid or air where it should not be. When one attains proficiency, in a brief few minutes, we can glean valuable information for our patients, diagnosing conditions of “wet”* and “dry”* lungs, as well as primary cardiac versus primary respiratory or non-respiratory conditions (e.g. anaphylaxis, neoplasia), with minimal stress to our patients. Vet BLUE was developed as an adjunct to the TFAST to evaluate lung pathology at the surface level (if the pathology does not reach the surface level and is too deep in the lungs, the ultrasound waves cannot pick it up). Still, it provides an excellent “regional pattern-based approach”1 to the small animal respiratory patient. It aims to guide our therapy, and Dr. Lisciandro suggests it may be more sensitive than radiography when evaluating contusions, metastatic lesions, and alveolar-interstitial edema.1 Ideally performed in a standing or sternal position, Vet BLUE features nine acoustic windows (eight bilateral transthoracic) and the DH view used in AFAST and TFAST scans. Limitations and pitfalls Ensuring technique is practiced and systematic is paramount to accuracy of diagnosis and findings. However, limitations in TFAST use include:1 Inability to characterize any pleural or pericardial effusions found without centesis. Will never totally replace chest radiography, echocardiography, nor the benefits of CT. Cannot identify non-thoracic respiratory disease causes, e.g. acute anaphylaxis or hemoabdomen. (Though use of the AFAST and the DH view can help) along with other diagnostics. Because only two windows specific to pulmonary regions are utilized, limitations exist in our lung evaluation and in what we can discern. Compare this to the windows of Vet BLUE. Pitfalls we may encounter may include:1 Patient positioning challenges. For your cat or small dog in sternal, utilizing a towel rolled up under the forelimbs can help gain access to the chest. When using lateral recumbency, use caution that you do not scan too high or too low to identify air or fluid. The ribs can be pesky. Ensure you obtain the reference point or “gator sign”* by ensuring your probe is in the longitudinal orientation. SQ emphysema and pericardial fat can interfere with our ability to evaluate certain regions of the body. Although gentle, even pressure applied to SQ emphysema may spread it out enough to yield an appropriate image. TFAST is more than simply placing the probe on the patient and checking for fluid. However, unless you practice and refine your techniques, you aren’t truly serving your patients and may over- or underinterpret findings. Therefore, gain proficiency through texts, in-person and online classes, and various available resources. Practice on healthy patients first (at no charge to the client) to gain proficiency and understand normal findings before seeking out the abnormal. One doesn’t need to work in a busy ER to utilize this valuable skill (See: “Additional resources”). Additional resources Point-of-Care Ultrasound Techniques for the Small Animal Practitioner, Second Edition. ISBN: 978-1-119-46102-9 Focused Ultrasound Techniques for the Small Animal Practitioner. ISBN: 978-1-118-76077-2 FastVet.com https://fastvet.com/what-is-fastvet/ has continuing education, in-person and distance learning, and additional resources. Templates are available for free through FastVet. They are available for Global Fast Goal-Directed standing and right lateral recumbency, AFAST Goal-Directed with right lateral recumbency preferred; TFAST Goal-Directed and the Vet BLUE Goal-directed. Additional limitations may arise due to numerous factors. A TFAST scan depends on the skill of the sonographer, the quality and capabilities of the equipment, and its proper maintenance. GettyImages/BlueCinema A lot of info in a short scan Still a few things to garner and know that you may be able to glean from a TFAST® scan include:1,8 When scanning, try not to lift the probe from the patient's skin when moving between sites. Losing contact means you have to reacquire your acoustic window, which wastes valuable time and can harm your results. Ideally, use your non-probe hand to move the skin while keeping the probe in place. Always ensure you have enough depth to evaluate the entire heart fully. A-lines are a normal finding. Doing only one acoustic window is like taking a single radiographic view; it doesn’t give you the complete clinical picture. Always ensure that you scan in at least two locations. B-lines (alveolar-interstitial edema) in known trauma, until verified otherwise, are contusions. The presence of B-lines rules out a PTX. Check for PTX at the CTS view. For PTX, use the TFAST PTX 1/3s rule for lung point location: a) Upper third of the chest – Trivial, may be clinically normal; b) Middle third of the chest – Moderate, likely increased breathing effort; c) Not found along the chest – Inconclusive or most severe – check the patient When scanning for pericardial effusion, make sure to find the pericardium, the most hyperechoic structure in the far-field. That is your key landmark. When looking for pleural effusion, the DH and the PCS views are utilized. Remember, pleural effusion typically shows up much sooner on ultrasound than on radiographs. A LA:Ao (Left atrium to aorta) greater than 2:1 is always abnormal in the dog and cat. A RV:LV (right ventricle to left ventricle) of 1:1 is abnormal (RV should be less than LV, though variable with species and minor breed variations)) Fractioning shortening (FS%) of < 20 percent is abnormal in both the dog and cat. In addition to acute anaphylaxis, gallbladder striation can occur with right-sided CHF in dogs and cats, aka “cardiac gallbladder.” This represents gall bladder wall edema. Pericardial fat can trick you into thinking there is pulmonary effusion: a) A fat pad (echogenic triangle region) in the cardio-diaphragmatic pouch*; b) Linear anechoic strip at the left PCS between the intercostals and the heart Gaining proficiency with TFAST POCUS evaluations will give you a clinical edge for patients that present in respiratory distress, those with coughs, sudden collapse, and more. While we did not delve into specific details in this article, you can explore the provided resources for further information. While it may seem daunting, this invaluable skill benefits both the pet and its owner, guiding therapy and management. Glossary Terminology to be familiar with is noted with an asterisk (*).1 A-lines - Equidistant parallel lines emanating from a robust air-ultrasound interface signifying air reverberating artifacts, typically associated with normally aerated lung, pneumothorax (PTX), an air-filled GIT, or pneumoperitoneum. They are seen when in the far-field in the DH View from the caudal vena cava. Angle of insonation – “Defines the angle of incidence at which the ultrasound wave strikes the object.” It is how you are holding the probe and the angle relative to what you are scanning. B-lines – “Hyperechoic vertical artifacts that originate off the lung surface and extend through the far-field, obliterating A-lines while swinging like a pendulum in synchrony with inspiration and expiration.” Cardio-diaphragmatic pouch – “The most gravity-dependent region in the pleural cavity between the heart and the diaphragm, best imaged in the standing patient.” Caudodorsal transition zone (CdTZ) – “The region of the interface of the pleural and peritoneal cavity intified by the presence of the curtain sign.*” Curtain sign – “The term used when a linear border is created along the dirty shadowing created by lung moving to and fro over pleural effusion or abdominal structures at the transition zone of the pleural and peritoneal cavities.” Dry lung – Lung sliding* and A-lines Gator sign – “The intercostal orientation for all lung ultrasound in which the probe is placed perpendicular to the long axis of the ribs, creating the image of a partially submerged alligator peering over the water at the sonographer, with the eyes as the ribs and the bridge of the nose as the intercostal space.” Lung line – The location of the lung surface in the face of pleural space abnormalities. Lung point – “The location where the lung recontacts the thoracic wall, the transition zone of pneumothorax and reoposition of lung against the thoracic wall, as evidenced by any presence of lung immediately against the thoracic wall, most commonly by lung sliding* and b-lines,*” Lung sliding – “The ‘to and fro’ motion of the lung sliding in synchrony immediately adjacent to the intercostal space during inspiration and expiration”. Previously known as the glide sign. Pneumothorax (PTX) – “A-lines in the absence of lung sliding.”1 Racetrack sign – When we find pericardial effusion, we see a rounding in the DH view of the heart’s muscular apex. Wet lung – Represents interstitial-alveolar edema, evident with the presence of b-lines Erica Tramuta-Drobnis, VMD, MPH, CPH, is the CEO and founder of ELTD One Health Consulting, LLC. Dr. Tramuta-Drobnis works as a public health professional, emergency veterinarian, freelance writer, consultant, and researcher. She is passionate about One Health issues and believes pet health, food safety, agricultural health, and more can address the interconnection of human, animal, and environmental health. References Lisciandro GR. Point-of-Care Ultrasound Techniques for the Small Animal Practitioner. Second. Wiley-Blackwell; 2020. Accessed March 2, 2025. https://www.wiley.com/en-us/Point-of-Care+Ultrasound+Techniques+for+the+Small+Animal+Practitioner%2C+2nd+Edition-p-9781119461029 Lisciandro GR. Thoracic FAST (TFAST®) for Trauma, Triage, and Tracking. In: Southwest Veterinary Symposium, 2017. Southwest Veterinary Symposium; 2017:6. https://wendyblount.com/articles/ultrasound/2Article-TFAST-2017SWVS-Lisciandro.pdf Lisciandro GR. The Vet Blue Lung Scan. In: Focused Ultrasound Techniques for the Small Animal Practitioner. John Wiley & Sons, Ltd, 2014:166-188. doi:10.1002/9781118760772.ch10 Lisciandro GR. Abdominal and thoracic focused assessment with sonography for trauma, triage, and monitoring in small animals. J Vet Emerg Crit Care. 2011;21(2):104-122. doi:10.1111/j.1476-4431.2011.00626.x Lisciandro GR. Sonography in the Emergency Room. In: Drobatz KJ, Hopper K, Rozanski EA, Silverstein DC, eds. Textbook of Small Animal Emergency Medicine. First. John Wiley & Sons, Ltd; 2018:1183-1194. doi:10.1002/9781119028994.ch182 Lisciandro GR (Ed). Point-of-Care Ultrasound Techniques for the Small Animal Practitioner, 1st Edition. First. John Wiley & Sons, Incorporated; 2014. Lisciandro GR. Abdominal and thoracic focused assessment with sonography for trauma, triage, and monitoring in small animals. J Vet Emerg Crit Care. 2011;21(2):104-122. doi:10.1111/j.1476-4431.2011.00626.x Tramuta-Drobnis EL. Essential point-of-care tests for veterinarians, part 2: The tFAST3 scan. IndeVets. September 13, 2022. Accessed December 11, 2022. https://indevets.com/blog/essential-point-of-care-tests-for-veterinarians-part-2-the-tfast3-scan/ Lee J. Emergency Medicine/Toxicology. Lecture Series: Live presented at: Delaware Valley Academy of Veterinary Medicine; November 11, 2020, Virtual. Lisciandro GR. AFAST: Introduction and Its Target Organ Approach & Fluid Scoring System. Accessed July 26, 2025. https://fastvet.com/wp-content/uploads/2020/05/01-FASTVet-AVMA-01-AFAST-Introduction-and-Target-organ-Approach-AVMA-2020.pdf Lisciandro GR. Focused Ultrasound Techniques for the Small Animal Practitioner. John Wiley & Sons, Incorporated; 2014. Accessed July 26, 2025. https://onlinelibrary.wiley.com/doi/book/10.1002/9781118760772 Lisciandro G. FASTVet Free Resource: Blog Preview - Use of the AFAST®-TFAST® DH View for the Accurate Diagnosis of Pericardial Effusion - The Racetrack Sign. FASTVet. November 6, 2014. Accessed July 26, 2025. https://fastvet.com/blog-preview-use-fast-dh-view-diagnosis-pericardial-effusion/
