Point-of-Care Ultrasound Techniques for the Small Animal Practitioner. Группа авторов
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especially AFS 3 and 4Combine AFAST (or Global FAST) with other clinical findings and surgical indications (hernia, pneumoperitoneum, septic abdomen, refractory pain, etc.)Sample fluid when safely accessible and characterize the effusion with fluid analysis and cytologyCT is the gold standard imaging test
Pearl: If an AFS 1, 2 (modified AFS system <3) “small‐volume bleeder” dog or cat without preexisting anemia becomes anemic, the attending clinician should explore other sites as potential sources of hemorrhage, including the retroperitoneal space, pericardial sac, pleural cavity, and lung, using the Global FAST approach along with a good physical exam.
Decision Making Using the AFS for the Hemoabdomen
Tables 7.2 and 7.3 will aid decision making based on the AFAST AFS score in dogs and cats.
In summary, the following general guidelines apply.
Blunt Trauma (BT)
Bleeding is most commonly medically treated with titrated fluid therapy, blood transfusion(s), and replacement of clotting factors in patients that require more than one transfusion or that are or have become coagulopathic. Surgery is uncommon so think medical treatment first.
Computed tomography (CT) is the gold standard for detecting injury, whereas AFAST provides indirect evidence through the detection of free fluid.
Radiography is an unreliable test for free fluid not only in terms of its presence or absence but also its inability to semiquantitate volume (Lisciandro et al. 2009).
Penetrating Trauma (PT)
Any positive is potentially a surgical problem and thus exploratory laparotomy should be considered post resuscitation. There are no veterinary studies evaluating positive AFAST studies and the frequency of medical versus surgical injuries; however, exploratory laparotomy is recommended in people with positive FAST examinations (Udobi et al. 2001).
Computed tomography is the gold standard for detecting injury, whereas AFAST provides only indirect evidence through the imaging of free fluid.
Other imaging options include radiography, which is standard of care for PT, for the detection of pneumoperitoneum, herniations, fractures and body wall abnormalities.
Table 7.3. Flowchart providing general guidelines regarding the decision‐making process for acutely bleeding dogs and cats when applying the abdominal fluid score (AFS) during AFAST. Note the algorithm assumes the patient is noncoagulopathic or, when coagulopathic, the coagulopathy is corrected.
Source: Reproduced with permission of Dr Gregory Lisciandro, Hill Country Veterinary Specialists and FASTVet.com, Spicewood, TX.
Postinterventional Trauma
Apply the “small‐volume bleeder versus large‐volume bleeder” principle to determine if the case is medical or surgical. The postinterventional patient includes any invasive procedure in which internal bleeding is a possible complication, such as percutaneous aspirations, needle and Tru‐Cut biopsy, laparoscopy, exploratory laparotomy, etc.
Small‐Volume AFS 1 and 2 Bleeders
In general, the “small‐volume bleeder” (AFS 1 and 2; modified AFS system <3) is not immediately surgical and serial AFAST with an assigned AFS is an important monitoring tool for detecting increasing AFS often before overt decompensation, referred to as the “crump” (Bilello et al. 2011).
In stable AFS 1 and 2 (modified AFS system <3) patients, the author routinely repeats AFAST with an assigned AFS ~1 hour post admission and then again four hours post admission, and then as clinical course dictates.
AFAST with an assigned AFS should continue during patient rounds every 12–24 hours or during recheck examination until ascites resolution, that is, AFS returns to 0, negative.
In questionable or unstable patients, serial AFAST with an assigned AFS are performed as often as necessary. The Global FAST approach is important to rule in and rule out other internal sites of bleeding and comorbidities in the thorax, including heart and lung.
Large‐Volume AFS 3 and 4 Bleeders (AFS ≥3)
In general, postinterventional bleeding in noncoagulopathic patients will not stop without a surgical intervention, in other words, the ligation of the bleeder(s). Many “large‐volume bleeders” are not initially anemic in the acute setting because patients can compensate, especially dogs which have a unique large splenic blood reservoir.
AFS 3 and 4 (modified AFS system ≥3) initially or on serial examinations are “large‐volume bleeders” and in general should be explored or have another appropriate intervention to stop the bleeding as soon as possible, with the caveat that the patient has an acceptable coagulation profile.
The author follows the axiom “If it's an AFS of 3 or 4, you should explore (surgically intervene),” with the caveat that the patient has an acceptable coagulation profile.
Pearl: Waiting on a compensated postinterventional noncoagulopathic “large‐volume bleeder” (AFS ≥3) instead of surgically addressing the cause of bleeding often leads to increased morbidity and cost (e.g., transfusion products) and increased patient anesthetic risk, because “large‐volume bleeders” predictably become markedly to severely anemic and overtly decompensate in time. Thus, “If it's an AFS of 3 or 4, you should explore (surgically intervene),” with the caveat that the patient has an acceptable coagulation profile.
Nontrauma
Nontraumatic hemoabdomen requires a more cerebral approach and knowledge base. Coagulopathy should always be ruled out, including minimally performing basic testing of prothrombin time (PT), activated partial thromboplastin time (aPTT), and a buccal mucosal or nail clip bleed time (platelet function test), readily available onsite tests at most practices. In coagulopathic cases, the coagulopathy generally needs to be corrected before invasive procedures. In noncoagulopathic cases, a bleeding mass is most common in dogs and cats and surgical intervention is required for definitive care. However, canine anaphylaxis must also be considered in all dogs with hemorrhagic effusions, some of which may have PT and aPTT times of <25% over the upper reference