# Veterinary Trauma: Secondary Survey and Diagnostic Imaging ## Key Takeaways - The secondary survey is a systematic head-to-tail examination performed *after* primary survey and ABC stabilization to identify all injuries, including occult ones, and guide further diagnostics. - Focused Assessment with Sonography for Trauma (FAST) scans (AFAST/TFAST) rapidly detect free fluid in body cavities and pleural spaces but do not exclude solid organ injury; serial scans are crucial for monitoring hemorrhage. - Radiography is the first-line imaging modality for stable trauma patients, providing excellent detail for appendicular skeleton, spine, and thoracic evaluation, with three views recommended for thoracic imaging to detect pneumothorax and effusion. - Computed Tomography (CT) is the gold standard for head trauma, complex fractures, and polytrauma when hemodynamically permissible, offering superior sensitivity for intracranial hemorrhage, skull fractures, and subtle axial skeleton injuries. - Repeat physical examinations and imaging (e.g., serial FAST, thoracic radiographs) are mandatory within 12-24 hours, or sooner if clinical status changes, to detect delayed hemorrhage, evolving pulmonary contusions, or expanding pneumothoraces. - Imaging decisions are dictated by patient stability; unstable patients require resuscitation before imaging, and imaging results must directly influence immediate management to be indicated. --- The secondary survey is the structured, head-to-tail examination performed after the primary survey and initial resuscitation have stabilized the patient's airway, breathing, and circulation. Its purpose is to identify all injuries, including those that are occult or delayed in presentation, and to prioritize further diagnostic testing. This article addresses the practising veterinarian's diagnostic reasoning during the secondary survey, with emphasis on the selection and interpretation of imaging modalities across species. It does not cover immediate life-saving interventions, which are addressed in the primary survey. The clinical question this article answers is practical: once the patient is stable enough for a complete examination, which injuries must be actively sought, and which imaging tool is most appropriate for each body region and patient type? The answer depends on injury mechanism, hemodynamic status, species, and the availability of advanced imaging. The evidence base for trauma imaging in veterinary medicine is heterogeneous, and much of the guidance derives from human trauma protocols adapted to veterinary patients, supported by consensus guidelines and institutional references such as the [MSD Veterinary Manual](https://www.msdvetmanual.com/) and the [RECOVER Initiative guidelines](https://recoverinitiative.org/). ## At a Glance | Parameter | Decision or Fact | |---|---| | Timing of secondary survey | After primary survey and stabilization of ABCs, before definitive treatment planning | | Examination sequence | Head to tail, both sides, including oral cavity, ears, perineum, and distal extremities | | FAST scan role | Rapid detection of free fluid in thorax and abdomen, does not exclude solid organ injury | | Radiography role | First-line for appendicular skeleton, spine, and thoracic evaluation in stable patients | | CT role | Gold standard for head trauma, complex fractures, and polytrauma when hemodynamically permissible | | Repeat examination | Mandatory within 12 to 24 hours, serial FAST and physical exams detect delayed hemorrhage | | Contraindication to imaging | Unstable patient: resuscitate first, image only if the result changes immediate management | ## The Rationale for a Structured Secondary Survey Trauma patients deteriorate from missed injuries more often than from failure of initial resuscitation. The secondary survey exists because physical examination alone detects only a fraction of significant injuries, particularly in the thorax, abdomen, and axial skeleton. A retrospective survey of hospitalized dogs from developing communities found that trauma accounted for 22% of admissions, with a mortality rate of 30%, figures that underscore the need for systematic injury detection in settings where advanced imaging may be limited [Eckersley et al., disease status of hospitalized dogs](https://pubmed.ncbi.nlm.nih.gov/1569535/). The survey must be performed in a fixed order to prevent omission. Begin with the head, examining the eyes, ears, nasal passages, and oral cavity. Palpate the cervical spine and trachea. Move to the thorax, auscultating both lung fields and both cardiac sides. Palpate all ribs and the sternum. Examine the abdomen for distension, pain, or palpable masses. Palpate the pelvis and all four limbs, including joints and paws. Finally, examine the perineum and tail. Each region requires both visual inspection and palpation, and the patient should be turned to examine the dependent side. Analgesia is a prerequisite for an accurate examination. A patient that cannot be handled safely without sedation or pain relief will not permit adequate palpation, and the resulting examination is unreliable. The examiner should record all findings immediately, including negative findings, because the trajectory of clinical change over time is as informative as the initial examination. ## Physiology of Injury Detection The secondary survey is guided by the physiology of trauma. Hemorrhage into body cavities can be occult until substantial blood loss has occurred, because the compliant abdomen and pleural space accommodate large volumes before clinical signs appear. The cardiovascular response to hypovolemia, including tachycardia, vasoconstriction, and reduced pulse pressure, is initially compensatory. By the time hypotension is measurable, the patient has typically lost 30% or more of circulating volume. Inflammation and edema evolve over hours. A pulmonary contusion may be radiographically invisible immediately after injury and become apparent within 6 to 12 hours. Similarly, a small pneumothorax can expand as the patient breathes against a damaged visceral pleura. These temporal patterns explain why serial examination and repeat imaging are central to trauma care. The [RECOVER Initiative](https://recoverinitiative.org/) guidelines emphasize that monitoring is continuous and that deterioration at any point should trigger reassessment instead of a fixed imaging schedule. ## Focused Assessment with Sonography for Trauma The FAST scan is a point-of-care ultrasound examination that detects free fluid in the peritoneal, pleural, and pericardial spaces. In veterinary patients, the abdominal FAST (AFAST) examines four to five dependent regions, and the thoracic FAST (TFAST) examines the chest for pleural effusion, pericardial effusion, and pneumothorax via the glide sign. The technique is performed with the patient in lateral recumbency, and each region is imaged in both transverse and longitudinal planes. FAST is not a screening test for organ injury. It detects fluid, and in the trauma patient that fluid is presumed to be blood until proven otherwise. A positive FAST in a hypotensive patient is an indication for surgical exploration or ongoing resuscitation, depending on the patient's response. A negative FAST does not exclude injury: solid organ lacerations can bleed slowly, and retroperitoneal hemorrhage may not reach the dependent peritoneal spaces. Serial FAST examinations, performed at intervals of 15 to 30 minutes in the unstable patient and at 6 to 12 hours in the stable patient, improve sensitivity. The principal limitation of FAST is operator dependence. The technique requires training and regular practice, and its sensitivity for small volumes of fluid is limited. In experienced hands, volumes of 5 to 10 mL can be detected in the dog, but this varies with body condition and patient cooperation. For the stable patient with a negative FAST and persistent clinical suspicion, computed tomography or diagnostic peritoneal lavage may be indicated. ## Radiography in Trauma Radiography remains the first-line imaging modality for the stable trauma patient in most practice settings. It is widely available, relatively inexpensive, and provides excellent spatial resolution for bone and lung. The thoracic radiograph is the single most useful projection in trauma: it detects pneumothorax, pleural effusion, pulmonary contusions, rib fractures, and mediastinal abnormalities. Three views, including both lateral projections and a dorsoventral or ventrodorsal view, are recommended because a pneumothorax or a small effusion may be visible on only one projection. Spinal radiography is indicated when neurologic deficits are present or when the history suggests a high-energy mechanism. The entire spine must be imaged, because multiple vertebral fractures occur in a substantial proportion of cases. Sedation or general anesthesia may be required for positioning, and the examiner must protect the spine during positioning to avoid exacerbating an unstable fracture. Appendicular radiography is performed when lameness, swelling, or crepitus is detected. Two orthogonal views are mandatory, and joints must be included at both ends of the imaged bone. Radiography has limitations: it underestimates the extent of pulmonary contusions, cannot reliably distinguish active hemorrhage from static effusion, and provides limited detail of the abdomen. For abdominal trauma, radiography is useful for detecting free gas, loss of serosal detail, and radiopaque foreign bodies, but it does not characterize solid organ injury. ## Computed Tomography in Polytrauma Computed tomography provides the most complete assessment of the trauma patient and is the imaging modality of choice when available and when the patient is hemodynamically stable enough to tolerate anesthesia and positioning. CT is superior to radiography for the detection of pulmonary contusions, small pneumothoraces, and occult fractures of the axial skeleton. In head trauma, CT identifies intracranial hemorrhage, skull fractures, and brain edema with a sensitivity that radiography cannot approach. The decision to use CT must balance diagnostic yield against the risks of anesthesia in a compromised patient. A patient that requires escalating vasopressor support or ongoing fluid resuscitation is not a candidate for CT. The [AAHA/AAFP fluid therapy guidelines](https://www.aaha.org/resources/2024-aaha-fluid-therapy-guidelines-for-dogs-and-cats/) emphasize that hemodynamic stabilization precedes any non-emergent diagnostic procedure. When CT is performed, the study should be planned to answer specific clinical questions, and the anesthetist must be prepared for deterioration during the scan. The availability of CT varies widely between practices and regions. In settings where CT is unavailable, the secondary survey and radiography must suffice, and the clinician should acknowledge the limits of the information obtained. Referral for advanced imaging should be considered when the findings would change management, such as suspected spinal instability or intracranial hemorrhage, and when the patient is stable enough to travel. ## The Secondary Survey: Sequence and Priorities The secondary survey begins only after the primary survey, resuscitation, and stabilization are complete. Its purpose is to identify all injuries, including those that were not immediately life-threatening or were masked by the patient's initial presentation. The survey proceeds from head to tail, with deliberate attention to body regions where injuries are commonly missed. Start with the head. Examine the eyes for anisocoria, dyscoria, hyphema, and lens luxation. Assess the maxillofacial region for fractures, dental trauma, and nasal discharge. Palpate the mandible and temporomandibular joints. In cats, concurrent thoracic trauma is common with head trauma, so thoracic auscultation and imaging should follow promptly. Move to the neck. Palpate the trachea, larynx, and cervical vertebrae. Check for subcutaneous emphysema, which suggests tracheal or esophageal rupture. Evaluate jugular vein distension, which may indicate cranial vena cava obstruction or pericardial effusion. Examine the thorax systematically. Auscult all lung fields and both cardiac sides. Percuss the chest wall to detect dullness or hyperresonance. Palpate the ribs and sternum for fractures. Note any paradoxical breathing, which indicates flail chest. In small animals, the thoracic cavity can accommodate significant hemorrhage or pneumothorax before clinical signs become obvious. Palpate the abdomen for distension, pain, or fluid wave. Assess the urinary bladder and kidneys. In ruminants and horses, perform a rectal examination to evaluate the pelvic canal, urethra, and caudal abdomen. In all species, examine the external genitalia for lacerations or swelling. Evaluate the musculoskeletal system. Palpate all four limbs from the digits to the scapula and pelvis. Assess the spine for pain, swelling, or step deformities. Perform a neurologic examination, including postural reactions and deep pain perception in the pelvic limbs. Pelvic fractures in dogs and cats are frequently accompanied by urinary tract injury, so bladder integrity must be confirmed. Finally, examine the skin and integument. Clip and clean all wounds to assess their true depth. Search for puncture wounds in the axillae, inguinal region, and between the toes. Document all wounds photographically or with diagrams, noting their location, size, and degree of contamination. ## Imaging Selection: A Decision Framework The choice of imaging modality depends on the patient's stability, the suspected injuries, and the equipment available. The following table provides a framework for selecting the appropriate modality. | Clinical question | First-line modality | When to escalate | Notes | |---|---|---|---| | Free abdominal fluid | AFAST | CT if unstable or if fluid is present and source unclear | AFAST is sensitive for clinically significant hemorrhage | | Pneumothorax or pleural effusion | Thoracic radiographs | CT if radiographs are inconclusive or if pulmonary contusions are suspected | Obtain radiographs before positive pressure ventilation if possible | | Pulmonary contusions | Thoracic radiographs | CT for quantification or if surgical planning is needed | Radiographs may underestimate severity in the first 6 hours | | Skull or spinal trauma | Radiographs | CT for all suspected skull fractures and spinal fractures | CT is superior for evaluating the cranial vault and vertebral canal | | Pelvic fractures | Radiographs | CT for surgical planning or if acetabular reconstruction is considered | Radiographs identify most fractures but miss some sacroiliac luxations | | Suspected diaphragmatic hernia | Radiographs | Ultrasound or CT if radiographs are equivocal | Positive contrast studies may be needed in small patients | | Bladder rupture | Radiographs with contrast cystography | CT cystography if available | Retrograde contrast studies are more reliable than excretory studies | The patient's cardiovascular status should guide imaging decisions. A hypotensive patient with a positive AFAST should proceed to surgery or angiography instead of CT. A stable patient with suspected pulmonary contusions can undergo thoracic radiography without delay. In equine patients, standing radiography is often possible for limb injuries, but thoracic and abdominal imaging may require sedation or general anesthesia. ## Common Findings and Their Interpretation The secondary survey and imaging will identify a range of injuries. Some findings require immediate intervention, while others can be managed conservatively. **Pneumothorax** appears as retraction of the lung lobes from the thoracic wall, with an increased radiolucent space. Tension pneumothorax causes contralateral mediastinal shift and flattening of the diaphragm. In small animals, needle thoracocentesis is both diagnostic and therapeutic. In large animals, a chest tube may be required. **Pulmonary contusions** appear as patchy alveolar or interstitial opacities, often in the caudodorsal lung fields. They may not be visible for several hours after trauma. Contusions typically resolve within 72 hours if the patient survives. The presence of contusions should prompt careful fluid management, as overhydration can worsen oxygenation. **Hemothorax** appears as a homogeneous opacity in the dependent thorax. The underlying lung may be atelectatic. Hemothorax is often associated with rib fractures or pulmonary laceration. In dogs and cats, most hemothoraces are managed conservatively with thoracocentesis as needed. In horses, hemothorax is uncommon but carries a guarded prognosis. **Free abdominal fluid** on AFAST appears as anechoic or hypoechoic fluid in the dependent abdomen. The presence of fluid in a hypotensive patient indicates hemorrhage until proven otherwise. Serial AFAST examinations can track ongoing bleeding. A positive AFAST in a stable patient warrants abdominocentesis or diagnostic peritoneal lavage to characterize the fluid. **Bladder rupture** is suspected when the bladder is not palpable and the patient is anuric or dysuric. Contrast cystography will show leakage of contrast into the peritoneal cavity. In male dogs, urethral obstruction from pelvic fractures can mimic bladder rupture. Retrograde urethrography is indicated when urethral injury is suspected. **Diaphragmatic hernia** is identified by the presence of abdominal organs in the thoracic cavity. Radiographs may show loss of the diaphragmatic line, gas-filled loops of bowel in the thorax, or a soft tissue opacity obscuring the cardiac silhouette. Ultrasound can confirm the diagnosis by identifying the liver or spleen within the thorax. Herniation of the stomach can cause gastric dilation and requires immediate decompression. **Skull fractures** are often subtle on radiographs. CT is the modality of choice for evaluating the cranial vault, temporomandibular joints, and nasal cavity. In patients with head trauma, CT can identify intracranial hemorrhage, cerebral edema, and fractures that may require surgical intervention. **Spinal fractures** require careful handling. Radiographs should be obtained with the patient under heavy sedation or anesthesia to minimize movement. CT provides superior detail of the vertebral canal and is indicated when surgical stabilization is planned. Neurologic status should be documented before and after imaging. ## Documentation and Communication Accurate documentation is essential for monitoring the patient's progress and for medicolegal purposes. Record the following for each injury: - Anatomic location and laterality - Estimated size or severity - Degree of contamination for wounds - Neurologic status for spinal injuries - Serial measurements for thoracic or abdominal effusions - Imaging findings with a description of the technique used Use a standardized body diagram to mark wounds and fractures. Photographs are valuable but should not replace written descriptions. In production animal practice, document the animal's identification number and the owner's instructions for follow-up. Communication with the owner or handler should include a clear explanation of the injuries, the planned diagnostic and therapeutic steps, and the prognosis. In cases where the patient's condition is deteriorating, repeat the secondary survey to identify missed injuries. The [first aid, transport, and triage guidance](https://pubmed.ncbi.nlm.nih.gov/7879363/) emphasizes that the secondary survey is not a single event but a process that continues throughout the patient's hospitalization. ## Species-Specific Considerations The secondary survey must be adapted to the species and production system. In cattle, the most common trauma mechanisms are kicks, crushing injuries, and calving-related trauma. The [survey of veterinarian injuries](https://pubmed.ncbi.nlm.nih.gov/3411647/) documents that bovine patients are the most frequent source of injury to veterinarians, so restraint and safety are paramount during the examination. In horses, trauma often involves the distal limbs, head, and thorax. Standing sedation may be required for radiography of the limbs, but thoracic and abdominal imaging generally requires general anesthesia. Horses with suspected colic after trauma should undergo abdominal ultrasonography to evaluate for splenic or hepatic injury. In small ruminants and pigs, trauma is often related to handling and transport. These patients are prone to fractures and soft tissue injuries. Radiography may require heavy sedation or anesthesia, and the small size of the patient limits the volume of contrast agents that can be administered. In all species, the availability of advanced imaging should not delay the identification of life-threatening injuries. The [MSD Veterinary Manual](https://www.msdvetmanual.com/) provides species-specific guidance on imaging techniques and interpretation. When CT is not available, radiography and ultrasound performed by a skilled operator will identify most clinically significant injuries. The decision to transport a patient to a referral center for CT should be based on the patient's stability and the likelihood that CT will change the treatment plan. ## Recognized Complications and Early Detection The secondary survey itself can induce harm if performed without attention to patient stability. Repeated handling of an unstable pelvis or thorax can precipitate cardiovascular collapse. Serial assessments should be spaced to allow recovery between interventions, and any deterioration during examination warrants immediate return to the primary survey and resuscitation phase. Specific failure modes deserve named attention. Occult pneumothorax may be missed on initial radiography if the patient is positioned in dorsal recumbency, which can shift free gas dorsally and obscure the classic retraction of the lung margin. Repeat imaging in sternal or lateral recumbency, or ultrasound identification of the glide sign, resolves this ambiguity. Pulmonary contusions typically worsen over the first 24 to 48 hours after injury, so a normal initial thoracic radiograph does not exclude clinically significant contusion. Serial radiographs or continuous pulse oximetry with blood gas correlation provide the necessary surveillance. Pericardial effusion with tamponade can develop slowly after blunt trauma. Echocardiography or focused ultrasound showing a non-collapsing right atrium in diastole, combined with progressive hypotension and muffled heart sounds, should trigger immediate pericardiocentesis instead of further imaging. Similarly, uroperitoneum from bladder rupture may present with only mild azotaemia and progressive abdominal distension over 12 to 24 hours. Ultrasound-guided abdominocentesis with fluid creatinine and potassium measurement against peripheral blood confirms the diagnosis. Coagulopathy after massive trauma, including hemorrhage-induced consumption and dilutional coagulopathy, can be detected early through serial platelet counts, prothrombin time, and activated partial thromboplastin time. Mucosal bleeding, persistent oozing from venipuncture sites, or expanding hematomas are clinical signals that laboratory confirmation should follow immediately. | Observation | Likely Cause | Discriminating Check | |---|---|---| | Progressive hypoxemia, normal initial radiograph | Pulmonary contusions evolving | Repeat thoracic radiograph at 24 h, arterial blood gas | | Sudden hypotension after positioning | Occult hemorrhage or tamponade | Repeat FAST, echocardiography, packed cell volume trend | | Rising creatinine, abdominal distension | Uroperitoneum | Fluid creatinine and potassium vs peripheral blood | | Persistent tachycardia despite fluid therapy | Ongoing blood loss or pain | Serial lactate, repeat FAST, reassess analgesia | | Worsening respiratory effort, absent lung slide | Pneumothorax | Thoracic ultrasound, repeat radiograph in lateral recumbency | ## Common Errors and Corrective Actions Less experienced clinicians frequently mistake the absence of external wounds for the absence of internal injury. Blunt trauma can produce pulmonary contusion, splenic rupture, or diaphragmatic rupture with minimal cutaneous evidence. The corrective action is to image the thorax and abdomen in every polytrauma patient regardless of external findings. A second recurring error is performing a complete radiographic study before stabilization. A patient that is hypotensive or dyspnoeic should receive immediate intervention, not a 20-minute imaging session. The decision framework in the earlier section applies: ultrasound and targeted radiographs first, computed tomography only after hemodynamic and respiratory stability is achieved. Students often over-interpret incidental findings. Spondylosis deformans, renal mineralization, and hepatic nodular hyperplasia are common in older patients and may be unrelated to the traumatic presentation. Correlation with clinical signs and laboratory results prevents unnecessary diagnostic pursuit. The [MSD Veterinary Manual](https://www.msdvetmanual.com/) provides species-specific guidance on distinguishing incidental from clinically significant findings. A third error involves inadequate serial monitoring after the initial survey. A single normal examination does not clear a patient. Repeat vital parameters, repeat FAST, and repeat radiographs at defined intervals are required to detect delayed hemorrhage or progressive contusion. ## Evidence Limitations and Divergent Expert Opinion The evidence base for trauma imaging in veterinary medicine is largely extrapolated from human literature and single-center retrospective studies. Prospective randomised comparisons of imaging strategies in veterinary trauma patients are scarce. Expert opinion differs on the optimal timing of computed tomography in stable polytrauma patients, with some advocating immediate whole-body imaging and others favouring staged, problem-directed imaging. The role of focused ultrasound has expanded considerably, but its sensitivity for solid organ injury is lower than computed tomography. A negative FAST does not exclude intra-abdominal hemorrhage, particularly when hemorrhage is retroperitoneal or when the patient is hypovolemic and bleeding is slow. Clinicians should communicate this limitation to owners when discussing diagnostic options. Consensus guidelines exist for resuscitation, including the [RECOVER Initiative veterinary CPR guidelines](https://recoverinitiative.org/) and the [AAHA and AAFP fluid therapy guidelines](https://www.aaha.org/resources/2024-aaha-fluid-therapy-guidelines-for-dogs-and-cats/), but neither addresses imaging selection in trauma directly. Practitioners must therefore integrate these resources with local expertise and available equipment. ## Referral, Consultation, and Reporting Referral to a specialty center is warranted when computed tomography is indicated but unavailable, when surgical intervention is likely, or when the patient requires mechanical ventilation or continuous hemodynamic monitoring. Early telephone consultation with a specialist can guide stabilization before transfer and reduce the risk of deterioration during transport. Laboratory involvement extends beyond routine hematology and biochemistry. Coagulation panels, blood gas analysis, lactate measurement, and cross-matching for transfusion should be requested early in severe trauma. A veterinary clinical pathologist can assist with interpretation of fluid analysis, particularly when distinguishing transudate from exudate or confirming uroperitoneum. Regulatory reporting obligations vary by jurisdiction and species. Bite wounds involving humans, suspected animal abuse, and notifiable diseases require reporting to the appropriate authorities. The [AVMA practice resources](https://www.avma.org/resources-tools) and [WOAH terrestrial animal health standards](https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/) provide guidance on professional obligations, though practitioners must confirm the specific requirements in their region. In production animal trauma, withdrawal periods and food safety considerations may also influence diagnostic and therapeutic decisions, and consultation with the relevant regulatory body is advised where doubt exists. ## Frequently Asked Questions ### How Do I Prioritize Imaging When Computed Tomography Is Unavailable or Cost-Prohibitive? Begin with the physical examination and serial re-evaluation to direct imaging choices. Perform a focused assessment with sonography for trauma (FAST) first to detect free fluid, then obtain orthogonal radiographs of the region most likely injured based on examination findings. Thoracic radiographs are indicated in any patient with respiratory compromise, suspected pulmonary contusions, or unexplained hypoxemia. Abdominal radiographs add value when gastrointestinal perforation or retroperitoneal injury is suspected. If only one imaging modality is affordable, choose the one that answers the highest-risk question: ultrasound for hemorrhage, radiography for fractures and pneumothorax. Document the limitation in the medical record and state which injuries could not be excluded. ### When Should I Repeat the FAST Scan or Radiographs During Hospitalization? Repeat the FAST scan at 30 to 60 minutes after the initial study if hemorrhage is suspected, because a negative scan does not exclude delayed bleeding. Serial FAST is also indicated when packed cell volume or blood pressure deteriorates without an obvious source. Repeat thoracic radiographs 12 to 24 hours after admission in patients with known or suspected pulmonary contusions, as radiographic opacities may not appear for several hours after injury. Re-imaging is not required in stable patients with normal findings and no clinical change. The decision to repeat imaging should be driven by a change in clinical status, not by a fixed schedule. ### How Does the Imaging Approach Differ in Large Animals Compared with Small Animals? Large animal trauma patients present practical constraints that alter the imaging plan. Standing radiography is often the only option for horses and cattle, which limits the ability to obtain perfect orthogonal views and makes thoracic and abdominal studies difficult. Ultrasound is highly useful in large animals because it can be performed standing and provides real-time assessment of the diaphragm, bladder, and peritoneal fluid. Computed tomography in large animals generally requires general anesthesia and specialised tables, so it is reserved for cases where surgical planning demands it, such as complex skull or sinus fractures. Portable equipment quality varies, and image interpretation must account for the larger body mass and tissue thickness. ### What Should I Document in the Medical Record Regarding Imaging Decisions? Record the indication for each imaging study, the technique used, the person performing and interpreting the study, and the specific findings. State which clinically important injuries were excluded and which could not be excluded due to modality limitations. Document the rationale when imaging is declined or deferred, including financial constraints or patient instability. Include serial re-evaluation findings and any changes in the imaging plan. This record supports continuity of care and provides a defensible basis for clinical decisions if the outcome is poor. A structured template for trauma imaging documentation reduces omissions and improves consistency across clinicians. ### How Do I Explain Imaging Recommendations to a Client Who Is Concerned About Cost? Frame the discussion around the specific diagnostic question each study answers and how that answer changes treatment. Explain that a FAST scan detects free fluid quickly and can guide the decision for surgery or medical management. Radiographs identify fractures and lung injury that cannot be detected by palpation or auscultation alone. Computed tomography provides the most complete assessment of polytrauma but is not always necessary. Offer a staged approach: perform the highest-yield study first and reassess. Be transparent about what each modality cannot detect and what risks remain if imaging is declined. Written estimates before imaging help clients make informed decisions. ### What Are the Limitations of Ultrasound in Detecting Solid Organ Injury? Ultrasound is sensitive for free peritoneal fluid but is unreliable for identifying parenchymal lacerations, contusions, or retroperitoneal hemorrhage. A negative FAST scan does not rule out solid organ injury, particularly in the early minutes after trauma when bleeding is ongoing but not yet voluminous. Gas-filled bowel loops obscure the pancreas and portions of the kidneys and spleen. Obesity and patient movement degrade image quality. In hemodynamically stable patients with suspected solid organ injury, computed tomography is the preferred modality when available. In unstable patients, a positive FAST scan supports the decision for exploratory surgery without further imaging. ## Related Clinical & Scientific Guides * [Toxicology in Emergency Practice: Common Poisons and Diagnostic Approach](/knowledge/veterinary-medicine/emergency-critical-care/toxicology-emergency-practice-common-poisons-diagnostic-approach) * [Veterinary Cardiopulmonary Resuscitation: Post-Cardiac Arrest Care](/knowledge/veterinary-medicine/emergency-critical-care/veterinary-cardiopulmonary-resuscitation-post-cardiac-arrest-care) * [Fluid Therapy Guidelines for Dogs and Cats: A Practical Update](/knowledge/veterinary-medicine/emergency-critical-care/fluid-therapy-guidelines-dogs-cats-practical-update) ## References and Further Reading - [Spontaneous histologic lesions of the adult naked mole rat (Heterocephalus glaber): a retrospective survey of lesions in a zoo population.](https://pubmed.ncbi.nlm.nih.gov/23355517/). 2013. - [Professional quality of life among Spanish veterinarians.](https://pubmed.ncbi.nlm.nih.gov/36419745/). 2022. - [First aid, transport, and triage.](https://pubmed.ncbi.nlm.nih.gov/7879363/). 1994. - [A comparison between the disease status of hospitalized dogs from developed and those from developing communities.](https://pubmed.ncbi.nlm.nih.gov/1569535/). 1992. - [Trauma and the veterinarian.](https://pubmed.ncbi.nlm.nih.gov/3411647/). 1988. - [RECOVER Initiative Veterinary CPR Guidelines](https://recoverinitiative.org/). Veterinary Emergency and Critical Care Society. - [AAHA/AAFP Fluid Therapy Guidelines for Dogs and Cats](https://www.aaha.org/resources/2024-aaha-fluid-therapy-guidelines-for-dogs-and-cats/). AAHA. - [MSD Veterinary Manual, Professional Edition](https://www.msdvetmanual.com/). MSD Veterinary Manual. - [American Veterinary Medical Association Practice Resources](https://www.avma.org/resources-tools). American Veterinary Medical Association. ## Related Articles - [Trauma Triage and Primary Survey in Small Animals](/knowledge/veterinary-medicine/emergency-critical-care/trauma-triage-primary-survey-small-animals) - [Veterinary Trauma: Primary Survey and Immediate Stabilization](/knowledge/veterinary-medicine/emergency-critical-care/veterinary-trauma-primary-survey-immediate-stabilization) - [Sepsis in Dogs: Early Recognition and Diagnostic Criteria](/knowledge/veterinary-medicine/emergency-critical-care/sepsis-dogs-early-recognition-diagnostic-criteria) - [Salvage Resuscitation in Severe Trauma: When to Stop or Continue](/knowledge/veterinary-medicine/emergency-critical-care/salvage-resuscitation-severe-trauma-veterinary) - [Toxicology in Emergency Practice: Common Poisons and Diagnostic Approach](/knowledge/veterinary-medicine/emergency-critical-care/toxicology-emergency-practice-common-poisons-diagnostic-approach) > This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.