EMS Canine Tactical Medicine Trauma Survey and Treatment

Etiology

Within the United States, WDs play an essential role in law enforcement, search and rescue, and many service-oriented positions. An estimated 50,000 non-military K9s operate in the US. Typical roles for WDs place them in unfamiliar and potentially dangerous environments, increasing their injury risk. Musculoskeletal injuries are the most common type of injury incurred by WDs, often due to tracking and apprehension tasks. These include sprains, strains, and fractures from repetitive stress. Due to their specific working environments, WDs are also at risk for heat-related illness. A working dog's drive to complete tasks and the increased thermal strain of protective equipment places them at high risk for heat-related pathology.[1] Lacerations, abrasions, and other injuries are also common in working dogs. Military WDs are more likely to suffer from penetrating or explosive injuries, while civilian WDs are more likely to be injured in motor vehicle accidents.[2] Many injuries require careful attention from the WD handler and transfer to veterinarians. Most diagnoses require veterinarian evaluation as owners only correctly identify 20% of injuries.[3] Rigorous training programs, regular veterinary check-ups, appropriate protective gear, and ongoing monitoring of their physical condition help minimize the risk of injuries.

Epidemiology

Most data collected on WDs come from military use in the operational environment, with much less information on how WDs are injured in the community setting. Over the past 20 years, the US military working dog (MWD) has most commonly been a German shepherd (56%) trained in explosives detection and patrol work (73%).[4] This is compared to the civilian WD, which has a broader range of breeds due to the variety of tasks required.[3] Both military and civilian WDs are more likely to be intact or not neutered, increasing the risk of hip dysplasia, ligamentous injuries, and increased incidence of some neoplasia in certain breeds.[3] Available data suggests a high injury rate within the civilian world. In one survey, injury incidence in WDs was 45.5%.[3] 

Search and rescue dogs incur the highest frequency of injuries. The most common injuries include musculoskeletal injuries (22%), phalanx and carpal bone fractures (20%), injuries to the pads and digits (10%), and cruciate ligament rupture (3%), followed by a variety of less common injuries.[3] Most injuries are identified within 12 to 72 hours of the incident. However, a veterinarian must make a specific diagnosis.[3]

History and Physical

Professional veterinary care is not always available in the acute or emergent setting. In most cases, it is not feasible to have on-site or on-call veterinary care. Human healthcare providers must be comfortable evaluating and managing the care of injuries sustained by WDs. A history can be obtained from the handler, including any allergies or medications they may be using. Additionally, handlers can aid in caring for the WD and provide recommendations on handling. Working dogs may have familiarity with medical procedures such as IV access. However, this should not be assumed.

Safety

An injured WD should be assessed with the WD's handler to prevent damage to the animal and responders. The WD should not be approached unless the handler is available. If unavailable, an additional provider should assist in restraining the dog. Provider safety is the priority; if an injured dog cannot be treated safely, providers must find a safer location for extrication or determine how to muzzle and control the wounded animal.[5] A WD should be approached while lowered or crouched from the front or side. A WD should be restrained in a position of comfort with a secured muzzle. Unresponsive WDs and those with a significant airway injury should not be muzzled.[5]

Vital Signs

Vital signs may vary based on the breed of dog encountered. A 25-35 kg German shepherd or Labrador retriever typically has a resting heart rate of 50-60 bpm. The pulse can be palpated at the medial femoral artery or the dorsal pedal artery. Blood pressure can be obtained at the dorsal pedal artery or forearm using a pediatric blood pressure cuff. Blood pressure measurements are slightly higher than in humans, with standard ranges from 110/60 to 160/90 mm Hg. The canine tongue can be used for pulse oximetry using a human finger probe and is only safe when the canine is sedated.[6] ECG pads should be applied to the animal's forelimbs and left rear limb foot pads. ECG tracings are similar to humans, as are many lab values.

Physical Exam

An efficient exam is essential to identifying evidence of traumatic injuries. Providers should start by observing the dog's appearance and behavior, noting signs of distress, pain, or abnormal behavior. The dog's respiratory rate and effort should be assessed next, and signs of labored breathing or other abnormalities should be noted. The heart should be auscultated to check for irregular rhythms or murmurs. The dog's abdomen should be palpated for tenderness or swelling. The mucous membrane color and capillary refill time should be checked using the paws. Wounds, lacerations, or other signs of trauma should be assessed by closely checking the skin beneath the coat. The dog's extremities should be checked for any evidence of trauma or pain symptoms. Finally, a dog's neurological status should be assessed by observing its coordination, reflexes, and responsiveness. Frequent reevaluation ensures the WD receives the necessary care to optimize its well-being and performance.

Evaluation

The primary trauma assessment of a WD is similar in organization to that used in human trauma evaluation and focuses on airway, circulation, and hemorrhage control. During this primary survey, any life-threatening findings should be immediately addressed. This trauma survey involves a systematic and rapid assessment to identify life-threatening injuries and initiate immediate interventions to stabilize the animal's condition. Personnel conducting the primary survey should carefully evaluate the dog's airway, breathing, circulation, and neurological status to address immediate threats to life. Any signs of airway obstruction, respiratory distress, or abnormal bleeding are promptly identified and managed during this process. Special attention is given to assessing the dog's mental status and responsiveness to determine the extent of neurological involvement. The primary trauma survey sets the foundation for further diagnostic evaluation and appropriate treatment, ensuring these devoted working dogs receive the urgent care they need to enhance their chances of successful recovery and return to critical roles in future missions.

Once the ABCs are addressed, providers should perform a secondary survey to evaluate for cardiopulmonary dysfunction and chest, abdomen, head, or extremities injuries. The specifics dictated by the environment will determine when and how this will occur. Providers should have a high index of suspicion for internal injuries or musculoskeletal dysfunction. Given their inability to communicate, performing a thorough evaluation and frequently reassessing injured WDs is essential.

Treatment / Management

Airway Management

Unresponsive or apneic WDs should be placed in the recovery position, lateral recumbent with the head and neck in a straight line, mouth open, and pulling the tongue forward. This prevents airway obstruction without the threat of spinal injury.[7] WDs should be ventilated at 8-10 breaths/min.

Orotracheal intubation may be required in unresponsive canines, those with injuries requiring airway protection, or severe shock and cardiac arrest. The recommended technique is a face-to-face approach where the provider directly faces the canine, positioned in sternal recumbency, lying on its chest with its head extended and neck straightened to create a clear pathway to the trachea. Ensure the dog's head is supported correctly to maintain alignment and facilitate airway visualization. A laryngoscope is used to lift the dog's tongue, visualize the back of the throat, and locate the glottis. Once inserted, confirm correct tube placement by observing chest rise and fall with ventilation. Proper positioning and rapid execution are critical to successful canine intubation, providing the necessary airway support to stabilize the dog's condition and improve its chances of recovery.

When a WD cannot be ventilated or intubated, trained providers should perform an emergency cricothyrotomy. While tracheostomy is considered the gold standard in a canine airway, it is not a skill prehospital providers or most physicians are familiar with. Additionally, cricothyrotomy is as fast or faster than tracheostomy in canines.[8] There are several commercially available cricothyrotomy kits for dogs. However, a bougie-assisted technique frequently used in humans can quickly adapt to canine anatomy.[9]

Intravenous and Intraosseous Access in Working Dogs

All of the following conditions may require IV or IO access. While human providers may be unfamiliar with canine anatomy, most working dogs have prominent veins, including the cephalic vein in the front leg or the saphenous vein at the rear leg. These veins typically permit 20-gauge IV access, while the external jugular provides more significant bore access.[10] When feasible, fur should be shaved and the area disinfected. Access should be well secured, especially if the site cannot be shaved. Access can often be obtained faster via IO access.[11] Most commonly, the trochanteric fossa of the femur or the medial, flat portion of the tibia is used.[12] Providers assigned to care for WDs should consider additional training in canine IV and IO access. (B3)

Pneumothorax

Decompression of a pneumothorax can relieve the accumulation of air in the pleural cavity, which can cause a life-threatening condition. The WD should be restrained and positioned in lateral recumbency on the affected side. A decompression needle should be inserted into the chest wall between the ribs in the seventh to ninth intercostal spaces within the dorsal third of the thorax.[13] The provider should aim toward the opposite shoulder. As the needle penetrates the pleural space, a rush of air may be felt or heard, indicating the successful decompression of the pneumothorax. Monitor the dog closely for signs of improvement, such as improved respiratory effort and reduced respiratory distress. The catheter should remain in place while further stabilization and transport efforts continue.(B3)

It is important to note that dogs can often suffer from gastric dilatation and volvulus (GDV). When this occurs, a WD can suffer from significant gas trapping within the GI system.[13] This may present with similar signs and symptoms of a pneumothorax. However, gas trapping will likely also present with abdominal distention and intact lung sounds in the thorax.(B3)

Hemorrhagic Shock

WDs can quickly succumb to hemorrhage from arterial bleeding or penetrating injuries. Blood loss can be difficult to measure accurately, and compensatory physiology changes may cause blood pressure and heart rate to remain normal until 15-20% of blood volume has been lost. Clinically, WDs may exhibit elevated heart rates, pale mucus membranes, slowed capillary refill time, and rapidly weakening pulses as compensation diminishes. The shock index (SI=heart rate/systolic blood pressure) can assist in identifying shock.[14] WDs who require transfusion or volume resuscitation are at significant risk for death.[15] Although impractical in the prehospital setting, transfusions are performed in a 1:1 ratio of RBCs:pRBC in the appropriate setting.[14] Volume resuscitation prevents acidosis and worsening coagulopathy while improving oxygen delivery. Volume resuscitation should be performed with a crystalloid fluid, with a goal of permissive hypotension. IV fluids should be given at 10-50 mg/kg/hr, with a goal systolic blood pressure of 40 mm Hg. There is an ongoing debate about synthetic colloids; however, it is unlikely to be available in the prehospital emergent setting and outside the scope of a typical prehospital provider.[14][16] K9-TECC guidelines recommend low-volume hypertonic saline and synthetic colloid in patients with altered mental status due to a traumatic brain injury. Research has shown that permissive hypotension decreases mortality compared to standard normotensive resuscitative canine efforts. However, a specific pressure goal has not been defined.(B2)

Bleeding should be managed in an escalating manner. Direct pressure should be applied to the injury site. This is the most straightforward approach for initial hemorrhage control and is easily accessible in most injuries. Manual pressure above the injury may help slow arterial blood flow to the wound and should be used when direct pressure alone cannot control bleeding. Finally, a tourniquet should be applied to the affected limb when a hemorrhage cannot be controlled. Tourniquet selection for canines is important; tourniquets designed for human use can fail on WDs and are not recommended for first-line treatment of hemorrhagic shock. Instead, a stretchable tourniquet is preferred, such as the SWAT-T. This device can better conform to canine anatomy and provide more effective pressure. Providers should provide direct pressure and wound packing in WDs with junctional bleeding or incompressible location. The committee on tactical combat casualty care currently does not recommend using junctional tourniquets on WDs, as these have not been evaluated. Non-compressible wounds will typically result in the death of the WD unless the specific vessel can be rapidly controlled.[10](B3)

Additional medications may be provided in specific cases of hemorrhagic shock, but only under a veterinarian's direction. Despite a lack of evidence, steroids are considered a standard of care in hemorrhage management.[10] Severe hemorrhagic shock may require treatment with pressor agents such as dopamine. Clot promoters, such as tranexamic acid (TXA), appear to have low rates of side effects in canines; it is unclear if there is any impact on outcomes.[17][18] Providing 10 mg/kg of TXA over 15 minutes in canines that may need blood transfusions is recommended. An artificial blood alternative, a hemoglobin-based oxygen carrier, is also available and safe in canines.[19] This thermally stable medication may be feasible for providers in high-risk situations.(B2)

Cardiac Arrest

WDs who suffer a traumatic arrest are unlikely to survive. Overall rates of ROSC with acceptable function are about 5% and lower in traumatic arrests.[6] In most traumatic incidents, human healthcare providers should not provide CPR unless veterinary personnel is leading the resuscitation. Such care should not take precedence over the treatment of human patients. Repeated resuscitation attempts are unlikely to be successful.

Canine CPR should be considered in non-traumatic arrests, such as hypothermia, drowning, or electrocution. BLS care is performed on unresponsive, apneic WDs; providers do not need to check for pulses. Chest compressions are performed at the same rate as human CPR. The WD should be placed in a lateral recumbent position, and compressions should compress one-third to one-half of the chest width.[6] Ventilation should be performed after intubation or tracheostomy and should not interfere with continued compressions.

Advanced life support consists of ACLS therapy similar to AHA guidelines, including ECG, EtCO2 monitoring, and antiarrhythmic medications. 30% of canines will present in a shockable rhythm, and defibrillation is performed with pads on each side of the chest.

Musculoskeletal Injuries

Musculoskeletal injuries are common in WDs and are more often due to repetitive work and aging. Degenerative disc disease and overuse are frequent causes of discharge for MWDs. WDs can also suffer acute sprains, fractures, and wounds due to environmental factors, ballistic, or blast injuries.[20] Injured WDs may present with "lameness" or inability to walk, while mild or less severe injuries may decrease performance. Treatment is similar to human patients; WDs should be removed from tasks and allowed to rest. Major extremity injuries should be splinted or protected while definitive care is sought.(B3)

When managing significant musculoskeletal injuries, it is essential to consider provider safety; sedation or analgesia should be provided before manipulating the fracture site. Sedation may be required to reduce fractures, manage potentially unstable spinal injuries, or manage multisystem trauma. TECC guidelines recommend oral tramadol for mild or moderate analgesia (3-5 mg/kg every 6-8 hours) or IV opiates for severe pain. In situations where a WD may be continuing a mission despite an injury, opioid medications should be avoided. When indicated, antibiotics should be considered early in WD care to prevent significant delays while awaiting definitive care.

Heat-Related Illness

Even during work in temperate climates, WDs need frequent access to water to maintain their intravascular volume and assist with thermal management. Dogs can require up to 15 liters per day of oral rehydration in arid environments.[10] Heat-related illness is the most common cause for early discharge of a MWD, and many civilian WDs are at high risk for heat-related illness.[20] WDs who have suffered heat illnesses previously are more likely to experience heat illnesses in the future. Older canines are most likely to have severe or fatal illnesses.[21] Those who suffer acute neurologic changes of heat stroke have a mortality rate of 50%.[20] (B3)

WDs may begin having symptoms after losing only 8-10% vascular volume. WDs commonly present with panting and hypersalivation when hyperthermia is due to a nonpyrogenic cause. Canines suffering from heatstroke or shock pool blood in the intestinal tissues, which quickly and easily can lead to GI bleeding and unidentified blood loss.[10] Rectal temperatures are often higher than 108 °F and often exceed the detectable range of many digital thermometers.(B3)

Treatment for heat-related illness includes removal from the heat source and passive cooling through environmental changes. Active cooling can also be provided with convective heat transfer with fans. Cool water baths are very effective at cooling if not contraindicated due to other injuries. Cool IV fluid therapy, or subcutaneous fluid administration, is also recommended. Subcutaneous administration is appropriate when IV access is not available. Like humans, cooling efforts should be discontinued when the patient's temperature is below 103 °F (39.4 °C).

Differential Diagnosis

Canines with traumatic injuries must be assessed for medical illness or toxidrome while identifying wounds. A comprehensive evaluation is essential to identify potential underlying medical issues or toxic exposures. Veterinary professionals, the dog's handlers, and EMS personnel are vital in conducting a thorough assessment. This includes a detailed history-taking to identify recent exposures, changes in diet, or any potential ingestion of toxic substances. Ruling out medical illnesses or toxidromes allows for prompt treatment to be initiated and can prevent secondary contamination of responders.

Prognosis

Working dogs are at high risk for poor outcomes from traumatic injuries. Given the lack of developed systems for canine injuries, rapid evaluation and management of traumatic injuries is essential to preventing death or disability. Military studies have revealed mortality rates for WDs injured in combat settings as high as 50%.[22] Guidelines for combat care of MWDs recommend that providers consider euthanasia when a dog's injuries appear unsurvivable.[6] Given the limitations of available data, it is not easy to provide reliable prognostic information in the prehospital setting. 

Complications

Return to Work

Accidents and injuries affecting WDs can prevent them from performing tasks acutely, leading to prolonged recovery, extensive rehabilitation, and possible surgery. Injuries can be emotionally taxing for the canine. Both physical and emotional trauma may lead to poor performance in future roles. Injured WDs who return to work without appropriate mental and physical rehabilitation are at increased risk for reinjury. The animals may experience fear, anxiety, or behavioral changes following their injuries, affecting their confidence and performance in future operations. Building their trust and retraining them to regain their previous efficiency takes considerable time and expertise. If working dogs are not appropriately supported and rehabilitated after an injury, they may be prone to recurrent injuries or may have to be retired from service prematurely, causing further strain on the resources and capabilities of the organization relying on their assistance. Therefore, preventing and promptly addressing traumatic injuries in working dogs is critical to ensure the animals' well-being and maintain their invaluable contributions to various lifesaving and security operations.

Provider Safety

Evaluation and treatment of WDs put providers and handlers at risk for injuries from the working dog being cared for. WDs should be considered dangerous when injured or in a stressful environment.[6] Providers should use caution and discuss any physical exam steps or procedures with the handler before any attempts. Working dogs are trained to wear muzzles to prevent them from biting in high-stress cases, such as during medical procedures or in pain. Muzzles should be placed and maintained except in certain specific situations.[23] Finally, providers should limit any unneeded contact with WDs, especially during courses or examinations when the WD may be distracted or under duress.

Dog bites can cause fractures and soft tissue infections that require surgical correction. In most cases, the use of safety precautions can prevent bites. Providers should avoid rapid movements, direct eye contact, or loud noises, as these can trigger a defensive response in dogs. Healthcare providers who frequently contact WDs should receive training on handling and understanding WD behavior.