Prehospital Care

Prehospital care encompasses emergent medical care delivered at the point of injury (POI) and in transport until handed off to a definitive medical provider in a hospital setting. An injury is defined as a harmful event that arises from the release of physical energy or barriers to the normal flow of energy. These forms of energy are numerous including chemical, thermal, radiation, electrical, and mechanical. Injury from mechanical forces occurs when a body in motion contains energy that is transferred fully or partially upon impact with another body. This is exemplified in the most common mechanisms of injury (MOI) experienced in veterinary medicine: blunt injury, acceleration/deceleration injury, or penetrating injury. According to the most recent registry report published by the American College of Veterinary Emergency and Critical Care Veterinary Committee on Trauma (VetCOT) in 2017, blunt trauma (in which they included acceleration/deceleration) was the most common source for injury in cats (56.7%), and penetrating trauma was the most common source for injury in dogs (52.3%). Surgery was performed in 43.8% of dogs and 36.2% of cats, and overall survival to discharge was 92.0% (dogs) and 82.5% (cats). This is the largest data set centered on trauma to date, incorporating 29 veterinary trauma centers in North America, Europe, and Australia, who contributed information from 17,335 dog and 3,425 cat trauma cases during a 42-month reporting period (2013–2017). Accrual of data such as this is a vital step in developing evidence-based guidelines for continual improvement in outcomes.

As we become more adept at recognizing and reporting the intricacies of MOI, our ability to triage these patients to appropriate trauma centers for care will improve. For example, an emergency medical services (EMS) provider for people is directed to choose the closest appropriate facility, meaning the facility most capable of providing appropriate definitive care within the first hour post-injury. Algorithms are established to dictate the types of injuries that warrant immediate transport to a trauma center, even if a non-trauma center hospital is closer. Examples of this include falls in adults over 20 feet and children over 10 feet, motor vehicle accidents (MVAs) with intrusion of >18 inches, ejection from the vehicle, or death in the same passenger compartment, auto versus pedestrian, or MVA at a velocity of >20 mph. The first step in veterinary medicine is working on a unified system to stratify available veterinary care while recording data on MOI, severity and extent of injury, and outcomes, which is being done through initiatives such as VetCOT. In this manner, we can provide prehospital care providers with more informed choices and algorithmic responses. Second, we need to establish guidelines and standardized training for EMS providers in the field. This is being done through organizations such as the National Association of Veterinary Emergency Medical Services (NAVEMS.org) and others. Through these efforts we can then develop common language and guidelines for veterinary and human EMS providers to work together, provide smooth handoffs, and allow for each to perform at the highest level within their scope of work for our veterinary patients.

Primary Survey

Upon arrival to the hospital, assuming prehospital care has not been rendered, the primary survey is conducted to identify and treat immediately life-threatening conditions. The priority is to contain these threats to life, even before you have a full history and assessment of the patient. It should take only a few minutes to conduct in a systematic fashion, taking note of items to be subsequently addressed in the secondary survey. There are several approaches with ABCD being one of the most accepted. In the setting of trauma, an XABCD approach is warranted. Although the items are listed in order of importance, in a team-based approach the clinician performs the action items and delegates part or all of the intervention(s) to a skilled nurse or assistant, while progressing through the primary and into the secondary survey.

• Exsanguination: the focus is on the identification of bleeding to prevent exsanguination, with particular emphasis on pulsatile, bright red, arterial bleeding. Any extremity venous bleed should also be noted along with signs of internal noncompressible hemorrhage (such as a distended, bruised abdomen).
• Action step(s): visual exam with blood sweep (running hands over and under body).
• Possible intervention(s): apply direct pressure with overwrap to any bleeding sites, consider application and incorporation of a hemostatic agent, and apply a tourniquet if needed (last resort).
• Airway: the focus is on the identification of obstruction or impedance to airflow. Listen for stridor (high pitch, implying air forced through a small orifice) or stertor (low pitch, reverberant sound due to redundant or excessive tissue swelling or obstruction), examine posture (tripod stance, abducted elbows, extended neck) or discolored mucous membranes (cyanosis).
• Action step(s): visual exam of posture and mucous membrane color and listening to breathing (without stethoscope).
• Possible intervention(s): ensure patient is in rescue position (sternal), extrude/grasp/flip pharyngeal object if present, intubate, flow-by oxygen, cricothyrotomy, or tracheotomy (upper airway obstruction).
• Breathing: observe pattern of breathing for lower airway compromise or restricted breathing with pleural space disease or rib fractures, observe rate and effort, auscult for presence/absence of breath sounds or abnormal sounds (crackles, wheezes, rales, etc.).
• Action step(s): visual exam of pattern, posture, and auscultation. Request point of care ultrasound (POCUS) machine for exam if not already present. Request equipment/kit for thoracocentesis or chest tube placement, if needed. Apply pulse oximetry.
• Possible intervention(s): thoracic POCUS exam (B lines, pleural effusion, shred, presence/absence of glide sign in a systematic fashion), diagnostic/therapeutic thoracocentesis +/- chest tube placement, and flow by oxygen. Occlusive dressing can be applied to sucking chest wounds, with subsequent observation for a tension pneumothorax.
• Circulation: consider MOI and possible impact on the cardiovascular system. Assess level of consciousness, mucous membrane color and capillary refill time, pulse character and quality as well as peripheral temperature (cold or warm extremities/paws).
• Action step(s): brief physical exam focusing on the aforementioned (pale, white, or muddy in color, low amplitude or thready pulses, CRT of <1 or >2 seconds, cool extremities, mental awareness). Request POCUS machine if not already present.
• Possible intervention(s): global POCUS exam (see thorax above, record abdominal fluid score of 4 quadrants), blood pressure, EKG, placement of an intravenous catheter and obtain PCV/TS/BG/lactate. Assess fluid responsiveness (see table 1).
• Disability: the goal is to assess for possible traumatic brain injury (TBI), so signs can be monitored for improvement or progression with therapy, and to determine the resuscitation endpoint of normotension or permissive hypotension. Evaluate mentation and cranial nerves prior to the administration of pain medications. Look for evidence of possible brain injury (fractured teeth, palpable skull fractures, etc.). Take note of obvious motor or sensory deficits (a full neuro exam should not be performed).
• Action step(s): document the Glasgow Coma Scale and record findings.
• Possible intervention(s): if TBI is present, seek normotension as an endpoint, monitor CO2 and glucose, avoid compression/pressure on jugulars and elevate head, consider advanced imaging once stable.

Table 1

Dynamic markers used to assess response to the administration of a preload challenge, which is typically a fluid bolus. A fluid challenge in the dog is 20 mL/kg with subsequent smaller challenges of 10 mL/kg. A fluid challenge in the cat is 10 mL/kg with subsequent smaller challenges of 5 mL/kg. Typically, more than one marker is applied (as no marker is 100% predictive). Please refer to “Stabilization of the Polytrauma Patient” by the same author for definitive goals.

In the 1960s, Dr. R Adams Cowley, a Baltimore thoracic and trauma surgeon, identified the critical time immediately after injury as a “golden hour,” and described shock as a “momentary pause in the act of death.” Although the above components appear obvious, the systematic usage of the primary and secondary survey in trauma help to halt the irreparable damage that is caused by even transient disruption in oxygenation and perfusion of organs and tissues.

Secondary Survey

The secondary survey is conducted once the action items for the primary survey have been completed and lifesaving and resuscitative interventions are underway. It encompasses:

1.  Assessing results of primary interventions.

2.  A head-to-toe exam identifying other critical and significant injuries that are not imminently life threatening.

3.  Identifying chronic issues that may warrant further investigation (poor BCS, skin nodules, etc.), after stabilization is complete.

To facilitate interventions as prescribed in the primary survey and appropriately evaluate ongoing response to therapy, a systematic approach to resuscitation with a standardized set of tools should be performed. One should set aside an area for resuscitation that is staffed and stocked in an organized and predictable manner. One way to remember the necessary tools is to think, I need Fluids and I can COPE!

• Fluids—a balanced replacement electrolyte solution, such as Ringer’s lactate, should be available along with obtaining vascular access. A PCV/TS/BG/lactate should be obtained during placement of the IV catheter.
• Crash cart—provides access to emergent drugs and intubation, but should also have a drawer dedicated to the equipment for emergent interventions listed above to include:
• Intraosseous access, IV access by cut down, thoracocentesis, cricothyrotomy, or tracheostomy.
• Oxygen—flow by oxygen is likely of benefit to any patient in shock.
• POCUS—Point of care ultrasound is needed for initial assessment and ongoing tracking of patient response to therapy.
• EKG—Offers the ability to identify a potential arrhythmia as well as easily gauge response to therapy. Most machines also offer concurrent blood pressure and pulse oximetry monitoring, which are beneficial.

References

Available upon request.