Trauma cases have the potential to be overwhelming and stressful for clinicians and owners alike. This lecture will provide some practical tips that may help you logically and confidently approach trauma cases presented to you even if budgets are tight.
Tip 1: Major Body Systems Matter Most
The initial goal with trauma is to triage major body systems even if other injuries might be more eye catching. Specifically, the neurological system (brain), cardiovascular system (heart), and respiratory system (lungs). Derangements of these systems can result in patient death and addressing issues with these systems are treatment priorities. Major body systems can be assessed rapidly (within a few minutes) and should provide objective ‘yes-no’ style pieces of data. A careful physical examination provides lots of helpful information that can then be supplemented with other diagnostics.
Neurological System
Assessment of patient mentation/level of consciousness is often done quickly and somewhat unconsciously. Level of mentation can be classified as normal, obtunded, stuporous, or coma. When traumatic brain injury is suspected, additional physical examination parameters (i.e., pupil size, motor ability, oculocephalic reflex) may be assessed to formulate the modified Glasgow Coma Scale. Animals with intracranial hypertension secondary to traumatic brain injury may exhibit the Cushing’s response (i.e., systemic hypertension with inappropriate bradycardia). This is vitally important to recognize, as it suggests critical elevations of intracranial pressure, and emergent treatment (e.g., hypertonic saline, mannitol) should be instituted immediately.
Cardiovascular System
Identification of haemorrhage is the most important initial priority after trauma. Cardiovascular stability is determined by assessment of the perfusion parameters, specifically heart rate, pulse quality, mucous membrane color, capillary refill time, mentation, and temperature. Dogs tend to have a predictable response to hypovolaemia, characterized by progressive sinus tachycardia, alterations in pulse quality (hyperdynamic initially, progressing to weaker), progressive pallor, prolongation of CRT, diminishing mentation, and cold periphery compared to core. Cats with advanced hypoperfusion are more likely to have muted responses, characterized by hypothermia, bradycardia, and hypotension. When the possibility of cardiovascular instability is detected, it is usually appropriate to start some treatment (e.g., fluid resuscitation) concurrent to performing ancillary diagnostics. Tachycardia may develop after trauma for several reasons other than haemorrhage (e.g., pain, anxiety).
Respiratory System
Initial assessment should include respiratory rate and effort. A variety of traumatic injuries may be encountered (e.g., pulmonary contusions, pneumothorax, diaphragmatic hernia). It is also important to consider non-respiratory lookalikes that could alter the respiratory character of a patient (e.g., pain, anxiety, hypovolaemia, compensation for acidaemia). In the emergent setting, it is always reasonable to provide supplemental oxygen until you can confidently separate respiratory from non-respiratory causes of tachypnoea. Not all cases of true respiratory dysfunction improve considerably with oxygen administration however. For example, significant pleural space disease will require emergency therapeutic thoracocentesis in order to relieve the distress in an affected patient.
Tip 2: Are the Limbs Functioning Normally?
As an extension of the triage neurological exam, it is important to assess spinal cord function early on. Triage questions that need to be answered quickly and confidently are (1) is the dog ambulatory or non-ambulatory? and (2) if the dog is non-ambulatory, do they have intact motor and/or sensation? Any locomotor abnormalities can then be further characterized as ataxia, paresis, or plegia. If an animal has motor ability, it is not necessary to assess for deep pain, but checking if sensation is present is prognostically very important for plegic patients. Recognition of the Schiff Sherrington response is seen with severe thoracolumbar lesions (e.g., fractures, luxations, traumatic disks) but is not synonymous with only irreparable lesions. Two important points are worth considering here - firstly analgesia may confuse your neurological examination. In the time it takes for a colleague to calculate a dose and draw up analgesia, it should be possible to tell if the pet has intact motor and/or sensation. Secondly, animals that have sustained trauma may be unable to stand for a non-neurological lesion including fractures (especially pelvic and femoral) or haemodynamic compromise (e.g., internal bleeding causing hypovolaemia).
Tip 3: PCV and Total Solids Are Cheap and Helpful
Even when budgets are tight, spinning a PCV and assessing a total solids with a refractometer should be considered essential information for any trauma case. After acute haemorrhage, the PCV takes time to equilibrate and is not a sensitive indicator of acute blood loss. A drop in total solids will occur rapidly, however, and is a very useful, inexpensive hint towards blood loss. As a guide, identification of a TS <60 g/L (6 g/dL) in an acute trauma case should prompt the clinician to hunt for haemorrhage. Reasonably common sites of haemorrhage include the abdominal cavity, pelvic fracture sites, and femur fractures. Haemothorax is a fairly uncommon injury but may be encountered in larger dogs and may be a fatal lesion in cats and small dogs. In the absence of a definitive physical bleed, presence of coagulopathy should be considered. Spontaneous endogenous coagulation dysfunction is recognized in severely traumatized people and may also develop in some dogs. Haemostatic dysfunction following resuscitation with large volumes of crystalloids and synthetic colloids (i.e., resuscitation associated coagulopathy) may also be encountered from time to time.
Tip 4: A-FAST Usually Help More Than Abdominal Radiographs
Focused assessment with sonography for trauma or point-of-care ultrasound has revolutionized bedside assessment of patients in the ER. It has become an extension of the physical exam in the triage setting. For trauma, abdominal or A-FAST is a sensitive means of identifying free peritoneal effusion. Effusion following trauma usually represents haemorrhage but other fluids (e.g., urine, bile) may also be encountered. In comparison, abdominal radiographs are generally less sensitive than ultrasonography for identification of effusion. There are some specific situations where radiographs of the abdomen may prove to be very helpful, however (e.g., identifying displaced abdominal organs, diagnosing ruptured abdominal walls/hernias).
Tip 5: Thoracic Radiographs Probably Help More Than TFAST
The disclaimer to the above statement will depend on your experience and comfort level with ultrasound! Focused ultrasound of the thorax (T-FAST) is a convenient and rapid way of identifying pleural effusion. As mentioned above, haemothorax is not an especially common lesion in traumatized animals since internal thoracic bleeds are often catastrophic. Ultrasound is also very helpful for identifying large and overt diaphragmatic rents (e.g., identify abdominal organs in the thorax). Basic echocardiography skills may also aid your interpretation of a patient’s volume status via left ventricular end diastolic diameter (LV-EDD) and confirm the presence of pericardial effusion. Many of the common thoracic injuries seen after trauma are reliably identified with radiographs (e.g., contusions, pneumothorax). While there will be a radiographic lag time associated with the severity of pulmonary contusions on radiographs, they are often clearly seen in clinically compromised pets shortly after trauma. With training and practice, T-FAST can help rule out pneumothorax by visualizing a convincing glide sign (movement of lung relative to the chest wall) and ultrasound can be used to identify lung infiltrates (i.e., B lines). In some cases, radiographs and ultrasound may still prove inconclusive for some thoracic injuries (e.g., small diaphragmatic defects) and CT scans may be recommended if available.
Tip 6: Lactate May Be More Helpful Than Blood Pressure
Lactate, as a byproduct of anaerobic respiration, may be elevated following trauma in animals with haemodynamic instability. Hyperlactataemia can be used to gauge patient illness severity and may clue clinicians in to situations where patients are more compromised than they appear. Serial monitoring may provide even more insight into patient stability and progress, since failure for lactate to improve despite treatment is considered a negative prognostic indicator in people. Blood pressure is used as another clinical correlate to haemodynamic stability and indicator of systemic perfusion. It is a quite late stage marker of hypoperfusion, so the blood pressure may be preserved during the compensated stages of shock. The accuracy of blood pressure is also dependent on the modality used (i.e., direct, Doppler vs. oscillometric) and should be interpreted in the light of the individual patient (e.g., anxiety level, patient cooperation). Simplistically, a low blood pressure reading in the face of a collapsed dog or cat with signs suggestive of haemodynamic instability is likely believable. There is a risk that blood pressure readings may be reassuringly normal, however, even when occult haemodynamic compromise is present.
Tip 7: Hypertonic Saline Is Helpful
Resuscitation with isotonic crystalloids is reasonable for many cases of trauma. Hypertonic saline can also be very helpful in a select population of patients. Proprietary 7.2% hypertonic saline can be provided 3–4 mL/kg as both a low volume resuscitation strategy and as a hyperosmolar therapy for traumatic brain injury/brain oedema. The low volume can be convenient when resuscitating large breed dogs, since a considerably lower volume can be administered rapidly compared to isotonic fluids. As a rule of thumb, 3–4 mL/kg is expected to have a similar volume expansive effect to 20 mL/kg of isotonic crystalloids. The actual haemodynamic endpoints are unlikely to be superior with hypertonic or isotonic fluids however. Hypertonic saline functions by rapidly liberating water from other bodily sources (primarily from the interstitial space). Consequently, if hypertonic saline is administered the patient should have normal hydration (i.e., fluid in interstitial space available for movement) and isotonic fluids must be administered afterwards to replenish the interstitial deficit. Hypertonic saline is an attractive option for traumatized pets with suspected brain injury since it confers that volume expansive effect, whereas alternatives like mannitol are osmotic diuretics and could worsen volume status.
Tip 8: Transfuse Early!
For some animals, fluid resuscitation is not always sufficiently effective and blood products may be helpful in some of these patients especially those with acute haemorrhage (i.e., replacing ‘like with like’). Acute haemorrhage will result in the loss of red cells, platelets, and plasma. In many hospitals, blood components (i.e., packed cells or plasma) will be available but fresh whole blood may be obtained when needed by a donor. The latter is an attractive option in cases of acute haemorrhage since haemostasis may be improved as well as improved oxygen delivery by providing red cells. In addition, antifibrinolytic agents (e.g., aminocaproic acid, tranexamic acid) may prove helpful for acute traumatic haemorrhage.
Tip 9: Urinary Tract Trauma Can Be Sneaky
Some traumatic injuries can easily be overlooked at the time of initial exam with urinary tract trauma being particularly easy to overlook. Urinary tract trauma is typically initially associated with a low volume of effusion that progresses over time. Sampled effusion will usually be blood tinged, rather than an expected yellow color that can also confuse the likely source of fluid. Triage blood work may identify modest azotaemia initially, which will worsen overtime. Biochemical analysis of effusion will identify >2x concentrations of creatinine and potassium compared to peripheral values. Definitive identification of the anatomical lesion will require diagnostic imaging (e.g., contrast studies, ultrasound).
Tip 10: Pattern Recognition Can Help
For trauma cases, certain patterns do appear to crop up that may help with initial triage assessment and diagnostic prioritization. For example, roll over injuries (i.e., high impact low velocity trauma) can result in several serious injuries including urinary bladder rupture, pelvic fractures, body wall rupture, and diaphragmatic rupture. This approach, therefore, could help prioritize useful diagnostics in situations where the clinician has to be selective in the tests recommended due to financial concerns. Likewise, recognizing that most dogs affected by traumatic haemoabdomen typically can be managed conservatively rather than surgically.