Triage

When a trauma patient arrives, the availability and ability of the staff to appropriately triage patients is crucial to a successful outcome. Triage is the process of determining the priority of patients’ needs based on the severity of their condition. This is a coordinated effort starting with the front desk. Guidelines are needed to ensure medical personnel evaluate all patients in a timely manner and any patient necessitating stabilization must be recognized and receive immediate medical attention. Taking the time to establish and create guidelines for the following items can significantly improve recognition and treatment of emergent trauma patients:

1.  A phone triage protocol: where signalment, mechanism of injury, and awareness are relayed in transit to allow the medical team to prepare. Phone triage personnel should also be versed in simplistic measures that can be lifesaving:

a.  Do not get bit! Warn owners that animals in pain can behave differently.

b.  Put pressure on bleeding areas, especially if blood is spurting.

c.  Position animals with breathing concerns upright (rescue position/sternal recumbency) and minimize stress in transport.

2.  Notification of medical personnel immediately upon arrival of an emergent patient.

3.  Establishing timelines, criteria, and locations for placement of all emergent patients, including immediate evaluation by a triage nurse. The triage nurse should be skilled in the primary survey and must recognize patients requiring immediate medical attention and direct transfer to the treatment area.

4.  Customer service or technical personnel can obtain authorization for emergency treatment, with a standardized estimate for initial stabilization expenses. This allows the clinician to focus on the primary and secondary survey of the patient.

5.  A staging area should be available for resuscitation and emergent procedures. In a busy hospital, two to three tables should be reserved for critical patients, with at least one table dedicated to resuscitation of patients in shock and/or CPR.

6.  A trauma or triage board that summarizes the staff members involved, working diagnosis(es), diagnostics, and placement of all patients. This minimizes confusion with respect to patient and staffing needs.

Blunt Trauma

Blunt trauma implies the force applied to the body is not sharp, with the most common cause in veterinary medicine being motor vehicle accidents (MVA). Some awareness of the scene can raise one’s index of suspicion for severity of injury, as the velocity of the vehicle determines the damage (force = mass × acceleration). Since the dog or cat is close to the ground, they often hit the bumper, then are thrown by the vehicle, hit the pavement, and may or may not be run over. Extremity fractures and lacerations are common. Impact to the chest may result in rib fractures and possible hemothorax, secondary to shearing forces which tear or avulse vessels. If the breadth is held on impact, a pneumothorax may result due to pressure applied on the lungs against a closed glottis. Blunt impact on the abdomen again results in shearing forces and tearing of vessels, as well as transfer of kinetic energy to internal organs. The most vulnerable or friable organs in the abdomen are the spleen and liver, which typically suffer tearing of the visceral surface and potential splitting of the parenchyma with absorption of energy, leading to continuous oozing from the vascular beds. In this manner, hemoabdomen is the most common abdominal injury encountered.

Imaging

Point of care ultrasonography has become a mainstay in most veterinary emergency rooms. Adapted from human medicine, and developed specifically for veterinary patients, the global (abdomen and thorax) point of care ultrasound (POCUS) allows for rapid assessment of the trauma patient without excessive patient handling. One veterinary study evaluated traumatized (motor vehicle accident [MVA]) dogs, of which 45 out of 100 (45%) were positive for free abdominal fluid, as a marker of intra-abdominal injury, with a sensitivity of 96% and a specificity of 100%. In 40 of those 45 dogs, abdominocentesis was performed, and hemoperitoneum and uroperitoneum were diagnosed in 38 and 2 dogs, respectively, with 9 of 45 (23%) requiring a blood transfusion. A second study designed to evaluate abdominal fluid scoring in dogs that suffered from a MVA found free abdominal fluid in 27 of 101 (27%) dogs. Dogs with AFS scores of 3 or 4, out of 4, (14/27 [52%] AFS-positive dogs) experienced a more marked decreases in packed cell volume and total plasma protein, increases in alanine aminotransferase, and needed more blood transfusions. This methodology has also been assessed as having moderate to excellent correlation with computed tomography (CT) and has a gentle learning curve for novice users. For these reasons, emergent and serial use of ultrasound patient assessment has been advocated for informing clinical decisions in trauma patients, especially when CT is not readily available.

Hemostatic Resuscitation

In the setting of massive trauma with significant hemorrhage, damage control resuscitation (DCR) has been implemented to treat intravascular volume deficits, address acute coagulopathy of trauma, preserve oxygen-carrying capacity, and prevent dilutional coagulopathy through overzealous crystalloid administration. A mainstay of DCR is rapid hemorrhage control through the early administration of blood products, thereby limiting the deleterious effects of crystalloids. Fluid responsiveness can initially be assessed with the use of hypertonic solutions or a bolus of a replacement crystalloid, with subsequent small volume boluses. If appropriate endpoints are not achieved (see table 1 [VIN editor: table 1 not available 7/11/22]) within a total crystalloid dosage of 30–40 mL/kg in the dog or 15–20 mL/kg in the cat, blood product administration should be considered.

Much debate has been generated regarding the appropriate ratio of blood products used in human medicine. In an observational cohort study involving major trauma transfusion in 10 level one United States centers (PROMMTT study), the usage of higher plasma and platelet ratios early in resuscitation (<24 hours) were associated with decreased mortality. A subsequent and more recent randomized, controlled, clinical trial (PROPPR trial) of 680 severely injured trauma patients showed that using a plasma:platelet:red blood cell blood product ratio of 1:1:1 was superior to a ratio of 1:1:2 with respect to achieving hemostasis. No overall difference in mortality was found, but exsanguination, which was the predominant cause of death in the 24 hours, was significantly decreased in the 1:1:1 group. This has led to the conclusion that fresh whole blood may likely be best in these scenarios. However, the concern with fresh whole blood is the ability to obtain it and ensure compatibility in a timely manner. For this reason, autotransfusion is often offered as an acceptable alternative. Autotransfusion does help to restore oxygen carrying capacity but is unable to fulfill the other tenants of DCR, namely treatment of coagulopathy and prevention of dilution, and may have variable effects on inflammation. In a study of five dogs undergoing autotransfusion from experimental hemothorax, the hemothorax blood showed markedly prolonged PT and PTT, low platelets and fibrinogen, elevated fibrin/fibrinogen split products and marked reduction in several coagulation factors. Once transfused back into the same dog, arterial blood demonstrated 20–30% reductions in clotting factors, platelets, and fibrinogen. Although these dogs did not develop a demonstrable coagulopathy, they had normal baseline values and were not in a compromised state. Autotransfusion in people has similar findings, with shed blood being defibrinated, thrombocytopenic, and anemic. As such, it cannot substitute for whole blood or fresh frozen plasma. Once administered back to patient, the effects with respect to hemostasis can vary dependent upon the patient’s hemostatic profile at the time. Cell salvage devices in people were developed to facilitate rapid autotransfusion and are still in use, but newer technologies allow for the separation and rapid concentration of shed blood to eliminate several of the aforementioned factors. Although not routinely used in veterinary medicine, this technology should be considered. Until then, when time permits, the processing of shed blood into a packed red blood cell unit can also suffice.

General Principles

An organized approach to rapid triage and treatment are needed. Point of care imaging of the thorax and abdomen are recommended.

• If ultrasound is used, repeat imaging and abdominal fluid scoring (AFS) may help to guide therapy. Greater than or equal to 3 out of 4 positive AFS with hemoperitoneum warrants concern for the need for transfusion. With noncompressible hemorrhagic shock secondary to blunt trauma, consider hypertonic saline (3–5 mL/kg of 7% saline IV, over 10–20 mins) or a replacement crystalloid, such Ringer’s lactate, for initial resuscitation. Crystalloid boluses/challenges of 10–20 or 5–10 mL/kg for a dog or cat, respectively, should be used, with a total maximum dosage of 30–40 mL/kg in the dog and 15–20 mL/kg in the cat.
• If resuscitation remains incomplete or imaging indicates progressive hemorrhage, administration of whole blood (20–30 mL/kg) or packed red cells and plasma (10–15 mL/kg each) in a 1:1 ratio is recommended.
• Autotransfusion may be considered, especially if financial limitations are present. However, this will promote coagulopathic tendencies and plasma may still be needed. With hemorrhagic shock and no evidence of brain injury, one can target hypotensive resuscitation with a target MAP of 70 or systolic of 80–90 mm Hg. This is temporary while allowing hemostasis to occur and pressures should still slowly be brought to normal over the next several hours. With hemorrhagic shock and concurrent TBI, normotension should be pursued, as cerebral perfusion pressure is reliant on the mean arterial pressure. Refer to table 1 in “Prehospital Care and the Primary Survey” proceedings from this author for an overview of dynamic markers of intravascular fluid volume assessment.

Note: the in-person seminar will focus on blunt trauma/mechanism of injury recognition and stabilization. Triage is addressed in the proceedings as a vital component but will only be briefly touched upon due to time constraints.

References

1.  Boysen SR, Lisciandro GR. The use of ultrasound for dogs and cats in the emergency room: AFAST and TFAST. Vet Clin North Am Small Anim Pract. 2013;43(4):773–797.

2.  Edwards TH, Rizzo JA, Pusateri AE. Hemorrhagic shock and hemostatic resuscitation in canine trauma. Transfusion. 2021;61(Suppl 1):S264–S274.

3.  Holcomb JB, delJunco DJ, Fox EE, et al. The prospective, observational, multicenter, major trauma transfusion (PROMMTT) study: comparative effectiveness of a time-varying treatment with competing risks. JAMA Surg. 2013;148(2):127–136.

4.  Holcomb JB, Tilley BC, Baranuik S, et al. Transfusion of plasma, platelets, and red blood cells in a 1:1:1 vs a 1:1:2 ratio and mortality in patients with severe trauma: the PROPPR randomized clinical trial. JAMA. 2015;313(5):471–482.

5.  Lisciandro GR, Lagutchik MS, Mann KA, et al. Evaluation of an abdominal fluid scoring system determined using abdominal focused assessment with sonography for trauma in 101 dogs with motor vehicle trauma. J Vet Emerg Crit Care. 2009;19(5):427–437.

6.  Palmer LE. Clinical update: concepts of prehospital traumatic hemorrhage control in the operational K9. J Spec Oper Med. 2018;18(4):123–130.

7.  Napoli VM, Symbas PJ, Vroon DH, et al. Autotransfusion from experimental hemothorax: levels of coagulation factors. J Trauma. 1987;27(3):296–300.

8.  Salhanick M, Corneille M, Higgins R, et al. Autotransfusion of hemothorax blood in trauma patients: is it the same as fresh whole blood? Am J Surg. 2011;202(6):817–822.