Diagnostic and therapeutic efforts in emergency situations are directed by the nature and severity of the trauma.
Blunt trauma (from vehicular trauma, hits, falls, etc) is commonly associated with thoracic and abdominal bleeding, organ rupture, fractures, and neurological injuries. Falls from a height, a particular type of blunt trauma, may cause long bone and facial bone fractures as well as thoracic and abdominal injuries.
Penetrating trauma is typically localized to the path of the penetrating object (eg, stick, bullet, knife, antlers) and rarely occurs in a straight line.
An animal attacked by another animal (bitten, gored, kicked, envenomated by snakes or arthropods, quilled, etc) can have deep, penetrating wounds; spinal injuries; and major cervical (including tracheal or vessel rupture), abdominal, and thoracic trauma (even without penetrating wounds) from the shearing forces sustained during thrashing motions (see image of cervical trauma from bite wound, dog).
Resuscitation of the airway, breathing, and circulation; control of hemorrhage; and pain relief are followed by a careful evaluation of the nervous system, thorax, abdomen, integument, and ocular and musculoskeletal systems.
Courtesy of Dr. Andrew Linklater.
The traumatized animal should be approached as if multiple injuries are present.
The neck and spine should be immobilized until a thorough examination for spinal fractures or luxations has been completed.
Thoracic auscultation for cardiac arrhythmias and the presence and quality of lung sounds should be performed to identify thoracic injuries.
The abdomen and inguinal and rectal regions should be palpated for pain, fluid, or hernias.
Extremity fractures should be supported by bandages or splinted to prevent further injury until definitive care is performed.
Substantial swelling of any body part may indicate ongoing hemorrhage.
Delayed injury or illness can occur with penetrating injuries or loss of blood supply to tissues and may sometimes take days to become evident.
Because many internal injuries are not apparent for hours or sometimes days after the initial trauma occurs, close monitoring of the patient is essential to allow early detection of potentially life-threatening problems. A patient that appears normal and stable on initial examination may have substantial underlying injury, making, at a minimum, hospitalization for monitoring physical examination parameters (eg, respiratory and heart rates, mucous membrane color, and mentation) appropriate.
The Rule of 20 is a list of 20 critical parameters that should be evaluated regularly in all critically ill patients.
Initial diagnostic evaluation should include the minimum database before fluids are administered, if possible. Point-of-care tests should minimally include measurement of PCV and concentrations of total solids, BUN (or other assessment of renal function), and blood glucose.
When hemorrhage first occurs, peripheral blood PCV may be normal or even increased, with a relative normal or decreased total protein concentration. This is a clinical indication of hemorrhagic shock in dogs; splenic contraction releases RBCs into circulation, maintaining PCV temporarily. Serial PCV and total solids concentration measurements should be monitored after trauma; PCV and total solids concentrations both will decrease as hemorrhage and fluid resuscitation continues.
An extended initial database includes arterial or venous blood gases, electrolyte panel, blood lactate, and assessment of coagulation. This information is used to create the initial treatment plan and to provide the baseline for subsequent monitoring.
Radiographs of the thorax and abdomen can demonstrate the initial changes resulting from thoracic and abdominal trauma or can be useful to provide a baseline, if normal. Orthogonal views (minimum of two) should always be obtained, as long as the animal can tolerate the diagnostic testing; additional views (or stressed views of limbs/joints) may provide additional insight.
In addition, ultrasonographic examination of the abdominal and thoracic cavities may provide more information about internal injuries and can often be performed while resuscitation is initiated.
Some scoring systems have been developed for trauma, such as the animal trauma triage (ATT) score; this system assigns a number from 0 (slight or no injury) to 3 (severe injury) in each of the following categories:
perfusion
cardiac
respiratory
eye-muscle-integument
skeletal
neurological
In two retrospective studies, evaluating data from more than 20,000 dogs and more than 3,800 cats having sustained blunt and penetrating trauma, higher ATT scores were associated with a higher mortality rate (1, 2).
The modified Glasgow coma score (mGCS) and the composite Glasgow pain scale are useful tools to objectively reassess patients from baseline or to evaluate their response to therapy.
The Veterinary Committee on Trauma (VetCOT) has certified veterinary trauma centers around the US that promote defining standards of care and disseminating information to improve trauma care. With the development of VetCOT, more information has been published regarding the outcome of trauma patients.
Several factors have been associated with worse outcomes in trauma (depending on signalment and type of trauma), including the following categories:
signalment: older age, intact status, patient size (smaller patients have worse outcomes)
altered electrolytes, including ionized hypercalcemia and hyperkalemia
altered clinicopathological parameters, including hyperlactatemia, elevated BUN concentration, lower serum pH, increasing base excess, lower SpO2
assessment scores, including increased ATT score, lower mGCS
location of trauma: head trauma and spinal injury
type of trauma: penetrating trauma better than blunt; either type better than both
imaging: higher abdominal fluid scores
development of a variety of organ disorders (pneumonia, need for pressors, DIC)
need for surgery or blood products
As noted above, hospitalizing a patient for observation provides a method of continual evaluation of vital signs (temperature, pulse, respiration, blood pressure), reassessment of scores, clinicopathological parameters (PCV, total solids concentration, lactate concentration, etc), neurological injury, as well as observation of ability to ambulate, urinate, defecate, eat, and drink.
Thoracic Trauma in Emergency Medicine
Some potentially life-threatening complications considered in thoracic trauma include the following:
pulmonary contusions
pneumothorax
cardiac arrhythmias
pleural hemorrhage
pericardial hemorrhage
rib fractures
flail chest
diaphragmatic hernia
Oxygen supplementation and analgesics allow for careful physical examination.
An ECG, thoracic radiographs, or thoracic point-of-care ultrasound (TPOCUS) examination, arterial blood gas analysis, and diagnostic or therapeutic centesis can help to determine the extent and severity of the trauma.
Analgesics administered in the acute setting often include pure mu-opioid receptor agonists, such as fentanyl (3–10 mcg/kg, IV, often followed by a CRI), methadone (0.1–0.5 mg/kg, IV, SC, or IM), and hydromorphone (0.05–0.2 mg/kg, IV, SC, or IM).
Additional treatments, such as local blocks, continuous infusions, neuroleptanalgesia, and adjuvant medications (lidocaine, ketamine, alpha-2 adrenergic receptor agonists, NSAIDs), are patient- and situation-dependent.
Severe pulmonary contusions cause hypoxemia, labored breathing, and crackles or rales on pulmonary auscultation. If the patient does not improve with supplemental oxygen (of any type; see Treatment With Oxygen in Breathing Disorders), pain medications, and fluid therapy, then tracheal intubation and positive pressure ventilation with 100% oxygen are indicated.
The airway should be suctioned to evacuate any obstructing blood or debris. Sedation or general anesthesia is often necessary to accomplish this unless the patient is comatose; balanced analgesia and anesthesia techniques should be used.
Labored breathing, with asynchronous movement of the chest and abdomen and dull or quiet lung sounds, is consistent with pleural air or fluid and warrants immediate thoracocentesis. Because animals with respiratory distress can decompensate quickly, thoracocentesis should not be delayed to perform radiography; assessment with TPOCUS may be less stressful than positioning for radiography but also should not delay therapy.
When negative pressure cannot be achieved during thoracocentesis, repeated centesis or continuous drainage of the pleural space by thoracostomy tube is required (see image of thoracostomy tube, dog). Large quantities of whole blood removed on thoracocentesis or ongoing leakage of air after 72 hours of pleural drainage is an indication for surgical exploration of the thorax.
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Large volumes of blood aspirated during a centesis may be collected in an aseptic fashion into an IV bag or blood transfusion bag as it may be used for autologous blood transfusion (see image of autologous blood transfusion).
An open chest cavity requires placement of an occlusive bandage to limit airflow and may require intubation with positive pressure ventilation or urgent surgical correction.
Courtesy of Dr. Andrew Linklater.
Courtesy of Dr. Andrew Linklater.
The TPOCUS technique can help diagnose pneumothorax, pleural effusion, or thoracic wall trauma and provides an alternative to radiographs when performed by a skilled sonographer.
The thoracic cavity should be palpated for rib fractures or avulsions, flail segments, torn intercostal muscles, and herniations.
When a flail segment impairs ventilation, the segment is stabilized by securing it to an external frame or cast, formed to the shape of the thorax.
Penetrating wounds over the chest should be explored under anesthesia for debridement and repaired after the patient is stabilized; the thorax may need to be surgically entered to inspect damage to underlying tissues, repair or debride tissue as necessary, lavage the thoracic cavity, and place a thoracostomy tube. Samples for bacterial culture should be collected and antimicrobial therapy initiated; these should be altered based on culture and susceptibility testing as soon as results are available.
Some patients may have altered thoracic wall integrity, with air escaping into the subcutaneous space without a true flail chest, which can often be managed with a bandage.
As the animal's condition allows, thoracic radiographs (three views) should be obtained to assess for injury to the lungs, diaphragm, thoracic wall, and extrathoracic tissues. In many cases, a dorsoventral view will help decrease undue stress on a patient with thoracic trauma. Many injuries may show up on routine radiographs; however, radiographic evidence of pulmonary contusions may not appear until 12–24 hours after the initial injury.
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CT scans provide additional information and can be used as an alternative to radiographs.
The heart should be auscultated and an ECG evaluated for arrhythmias. Arrhythmias may not be present at the time of injury but can develop up to 48 hours after the event, as myocardial contusions and hypoxemia affect the cardiac conduction system. Common arrhythmias after thoracic trauma include sinus tachycardia, ventricular premature contractions, and ventricular tachycardia.
Treatment for ventricular arrhythmias with lidocaine (dogs: 2 mg/kg or cats: 0.2–0.5 mg/kg, IV) or other antiarrhythmic medications is warranted if the following situations occur:
arrhythmias impair perfusion
rate is rapid and sustained (> 180 bpm in dogs)
ventricular contractions are multiform
prefibrillatory rhythms are present:
R on T phenomenon
torsades de pointes
ventricular flutter
Abdominal Trauma in Emergency Medicine
The extent and severity of abdominal injuries may not be apparent on initial examination, unless there is visceral herniation outside the body cavity. The abdominal surface should be examined closely for evidence of bruising, abrasions, lacerations, protrusions, localized swelling, herniations, distention, and pain.
Animals with evidence of abdominal pain that are in shock are considered to have intra-abdominal hemorrhage until proven otherwise. Rupture (crush) and laceration of the spleen or liver are the most common sources of intra-abdominal hemorrhage. However, all abdominal organs are susceptible to the shearing and crushing forces from blunt or penetrating trauma.
Other common sources of abdominal bleeding include avulsed mesenteric vessels, damaged muscle, penetration of organs, and avulsion of the kidneys in the retroperitoneal space (see images of dog with abdominal and thoracic trauma and dog with trauma from car collision).
Courtesy of Dr. Andrew Linklater.
Courtesy of Dr. Andrew Linklater.
Approximately 40 mL/kg (just less than half of the circulating blood volume) must accumulate before free blood in the abdominal cavity will be evident by palpation or external visual inspection; this volume is associated with clinical signs of poor perfusion (shock). Smaller volumes of abdominal fluid may be identified with abdominocentesis or radiographic or ultrasonographic examination.
Abdominal distention from hemorrhage may become apparent if aggressive fluid resuscitation increases blood pressure and disrupts blood clots that provided hemostasis. Small volume fluid resuscitation to achieve a low-normal blood pressure end point (systolic arterial blood pressure 90 mm Hg, mean arterial blood pressure 60–80 mm Hg) is indicated to avoid sudden increases in arterial or venous pressures.
When ongoing abdominal hemorrhage is confirmed, hindlimb and abdominal binding is indicated early to decrease the amount of hemorrhage until hemostasis is accomplished.
After injury of any abdominal organ, clinical signs of organ dysfunction or hollow viscus rupture typically develop over a period of hours but can be longer or shorter depending on the nature and severity of the injury. Acute abdominal pain is a key physical finding.
Survey abdominal radiographs can demonstrate organ displacement, distention, rotation, or free abdominal gas or fluid. Fluid can be recovered by four-quadrant abdominocentesis. Using the abdominal POCUS (APOCUS) technique, even small amounts of free fluid in the abdomen can be identified and aspirated using ultrasonographic guidance (see APOCUS image).
Courtesy of Dr. Andrew Linklater.
When free fluid is not readily identified, diagnostic peritoneal lavage (DPL) can be done; however, given availability of ultrasonography and clinician familiarity with APOCUS and guided centesis, DPL is rarely performed.
To perform DPL, a fenestrated catheter is placed into the peritoneal space, and warm saline solution (0.9% NaCl; 20 mL/kg) is infused into the abdomen. The fluid is allowed to dwell for several minutes and distribute throughout the abdomen; it is then drained and evaluated. Clear fluid indicates that the possibility of substantial abdominal hemorrhage is minimal. Fluid with a 1% PCV indicates mild abdominal hemorrhage, whereas fluid with a PCV > 5% indicates substantial abdominal hemorrhage that warrants careful monitoring.
Fluid obtained from the abdomen should be examined cytologically for evidence of WBCs, plant or meat fibers, and extracellular or intracellular microorganisms (see photomicrograph, septic abdominal effusion).
Biochemical evaluation of abdominal fluidcan help identify various conditions:
Creatinine concentration (> 2X serum) and potassium concentration (> 1.4X [dog] or > 1.9X [cat] serum) may help to identify urinary system rupture.
Bilirubin concentration or bile acids concentrations higher than serum may help to identify gallbladder rupture; however, RBC lysis in the fluid can increase bilirubin concentrations.
Amylase activity (> 1050 U/L) and lipase activity (> 500 U/L) may help to identify pancreatic injury.
Phosphorus concentration may help to identify ischemic bowel.
Abdominal fluid glucose that is 20 mg/dL (approximately 1.1 mmol/L) or more below peripheral blood glucose is characteristic of septic peritonitis and warrants exploratory surgery. Abdominocentesis, peritoneal lavage, or APOCUS scan can be repeated in several hours if fluid from the first assessment did not indicate a notable problem but the clinical signs continue or progress.
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Retroperitoneal, fascial, or intramuscular (body wall) hemorrhage or hemorrhage into the GI system can be more challenging to identify.
Courtesy of Dr. Andrew Linklater.
Criteria for emergency exploratory laparotomy include the following:
ongoing hemorrhage
inability to stabilize shock
organ rotation, entrapment, rupture, avulsion or ischemia
clinical signs of diaphragmatic hernia
evidence of bacterial peritonitis
Some simple urinary bladder ruptures may be amenable to medical management by placement of an indwelling urinary catheter connected to a closed urinary collection system and close patient monitoring of urine production, abdominal fluid accumulation, and biochemical measurements.
Surgery to repair a diaphragmatic hernia should not be delayed, particularly with gastric displacement into the thoracic cavity, respiratory compromise, or ongoing hemorrhage.
Retroperitoneal hemorrhage, severe fascial compartment hemorrhage (associated with pelvic fractures), or hemorrhage into a hollow viscus is suspected in acutely traumatized animals that have declining PCV and total solids concentration, nonresponsive hemorrhagic shock, and no noteworthy findings on abdominocentesis, peritoneal lavage, or APOCUS. Radiographs typically show expansion of soft tissue and loss of detail and/or expansion of the retroperitoneal space.
An IV pyelogram should be done to help delineate disruption in the renal vascular supply or in the retroperitoneal portion of the ureter before proceeding with exploratory surgery in this situation; alternatively, urine production can be identified intraoperatively with a cystotomy and observation of the ureteral papilla.
Damage control resuscitation paired with damage control surgery may help optimize the outcome for patients with severe trauma. Damage control resuscitation includes early use of blood products to hypotensive end points to avoid the development of a lethal triad of acidosis, coagulopathy, and hypothermia common in severely traumatized patients. Damage control surgery is a limited laparotomy designed only to control hemorrhage and/or to minimize contamination but not to perform definitive surgical repair to avoid similar clinical complications.
Definitive care is delayed until the patient is able to tolerate extended anesthesia and surgery.
Acute traumatic coagulopathy can occur in patients with severe trauma. This syndrome, which develops due to tissue injury, hypoperfusion, hypothermia, hemodilution, metabolic acidosis, and systemic inflammation, results in increased bleeding, most often due to consumption of clotting factors and/or hyperfibrinolysis.
Acute traumatic coagulopathy may be diagnosed via thromboelastography.
Acute traumatic coagulopathy is treated with a combination of blood products to address hypocoagulation, along with antifibrinolytic agents (eg, tranexamic acid [10 mg/kg, IV, followed by 10 mg/kg/h, IV, for 3 hours] or aminocaproic acid [50–100 mg/kg, slow IV, every 8 hours or 15 mg/kg/h CRI]) to address hyperfibrinolysis (3). These medications are usually discontinued after 24 hours.
Key Points
Analgesia is necessary, and oxygen is commonly administered during stabilization and with respiratory compromise.
Hypothermia, hypocoagulation, hypotension, and acidosis should be minimized.
Definitive care may need to be delayed to stabilize the patient through damage control resuscitation or surgery.
Regular patient scoring and assessment of perfusion, respiration, and neurological status is needed.
The Rule of 20 is useful for monitoring of any critically ill patient.
For More Information
Registry publications. Veterinary Committee on Trauma.
Ash K, Hayes GM, Goggs R, Sumner JP. Performance evaluation of the animal trauma triage score and modified Glasgow Coma Scale with suggested category adjustments in dogs: a VetCot registry study. J Vet Emerg Crit Care. 2018;28(3):192-200.
Lapsley J, Hays GM, Sumner JP. Performance evaluation of the animal trauma triage score and modified Glasgow Coma Scale with suggested category adjustments in dogs: a Veterinary Committee on Trauma registry study. J Vet Emerg Crit Care (San Antonio). 2019;29(5):478-483.
Also see pet owner content regarding emergency care for dogs and cats and emergency care for horses.
Also see the chapter Monitoring the Critically Ill Small Animal Using the Rule of 20.
References
Davros AM, Gregory CW, Cockrell DM, Hall KE. Comparison of clinical outcomes in cases of blunt, penetrating and combination trauma in dogs: a VetCOT registry study. J Vet Emerg Crit Care (San Antonio). 2023;3(1):74-80
Lee JA, Huang C-M, Hall KE. Epidemiology of severe trauma in cats: an ACVECC VetCOT registry study. J Vet Emerg Crit Care. 2022;32(6):705-713.
Brown JC, Brainard BM, Fletcher DJ, Nie B, Arnold RD, Schmiedt CW. Effect of aminocaproic acid on clot strength and clot lysis of canine blood determined by use of an in vitro model of hyperfibrinolysis. Am J Vet Res. 2016;77(11):1258-1265. doi:10.2460/ajvr.77.11.1258
