Triage by definition is ‘the sorting of patients for treatment priority when resources are insufficient for all to be treated immediately in an emergency setting’. This concept originated in the 1700s in warfare to treat mass casualties, and has been applied to organise human emergency rooms to maximise the available staff and facilities while optimising patient outcome. A veterinary triage system, modified from the Manchester Triage Group, was validated to be more effective than subjective assessment of patients when sorting emergency patients. One system the author has used which summarises these systems is described in the table below:

Although these systems are available, it is challenging to develop a universal consensus triage system due to the variability in hospital size, staffing and facilities. In developing a system for your hospital the key elements of triage should be considered:

• Being prepared and well equipped at all times.
• Rapid assessment and treatment of the respiratory, cardiovascular and neurological systems; using brief history, physical exam and minimal diagnostics.
• Training of veterinarians and technicians/nurses in triage.
• Good communication between staff and with clients.

Respiratory Assessment

Physical Examination

Initial assessment involves observation of respiratory rate, effort and pattern. Normal respiratory rate is 8–40 breaths per minute. Upper respiratory tract disease results in inspiratory dyspnoea, while lower respiratory tract disease usually results in expiratory dyspnoea.

If cyanosis is observed, this indicates presence of severe hypoxemia (PaO₂<60 mm Hg; SpO₂<90%) and requires immediate oxygen therapy.

Auscultation should be performed by dividing the thorax into 9 quadrants. Decreased lung sounds ventrally can be due to pleural effusion, dorsally due to pneumothorax, while decreased or displaced lung sounds can be due to diaphragmatic hernia/rupture.

Thoracocentesis

If ultrasound is unavailable, and physical examination indicates a possible pleural effusion or pneumothorax, thoracocentesis can be a lifesaving therapeutic and diagnostic tool.

Pulse Oximetry

Pulse oximetry provides a minimally invasive assessment of a patient’s oxygen levels. Normal is 98–100%, hypoxaemia is <93–95%, and severe hypoxaemia is <90%. Any value below 95% must receive oxygen therapy. Another advantage of pulse oximetry is that response to oxygen can be monitored. However, its use can be limited in the emergency room as movement, hypoperfusion, icterus, pigmentation, oedema, and severe hypoxaemia can result in inaccurate readings.

Respiratory Stabilisation

Oxygen

There are many methods of oxygen delivery including flow-by, oxygen mask, oxygen hood, nasal prongs and oxygen cages. Care must be taken to minimise stress during oxygen administration. Flow-by oxygen provides the least concentration of oxygen (though potentially up to FiO₂ of 40%), but is well tolerated while being able to examine and treat the patient at the same time. Mask oxygen provides greater concentration of oxygen compared to flow by, though may not be tolerated by some; in addition, contraindicated in hyperthermia and hypercapnia. Human nasal prongs are a useful hands-free approach to oxygen administration to dogs who are not significantly open mouth breathing. Oxygen chambers can be useful in stressed animals requiring larger concentration of oxygen (up to FiO₂ of 60%), however, contraindicated in hyperthermia and hypercapnic patients. Oxygen flow rates should be set at 50–100 mL/kg/min.

Sedation

Sedation will decrease oxygen demand, help with respiratory stabilisation, and help facilitate procedures. Intramuscular sedation may be necessary if IV catheterization is too stressful.

Intubation and Ventilation

Despite oxygen supplementation and sedation/analgesia, some patients may require immediate intubation and ventilation. It is important to be prepared by having an anesthetic machine with rebreathing bag or oxygen cylinder with Ambu bag; endotracheal tube with tie and cuff syringe; IV catheter; induction agent; and monitoring equipment including ECG, pulse oximetry, and capnography.

Cardiovascular Assessment

Assessment of heart rate and rhythm should be performed while concurrently palpating the pulses for pulse quality and deficits. If there are any abnormalities, ECG is recommended to diagnose any urgent cardiac disease as well as to monitor the patient easily while you are attending to other body systems.

Being able to assess for cardiovascular shock rapidly is also important. There are 4 types of shock:

• Hypovolemic (hemorrhage, dehydration, 3rd space loss of fluid).
• Cardiogenic (heart failure, arrhythmia)
• Obstructive (GDV, pericardial effusion, pneumothorax)
• Vasodilatory (systemic inflammatory response syndrome, sepsis, anaphylaxis)

Rapid clinical assessment involves the following parameters:

It is important to remember:

• If a dog is bradycardic and in decompensated shock, immediate treatment is necessary as further decompensation can lead to cardiac arrest.
• Cardiogenic shock should be identified, as it’s the only group not treated by fluids.

Cardiovascular Stabilisation

Shock

Other than in cardiogenic shock and pericardial effusion, a fluid bolus should be administered rapidly over 15 minutes at the following doses and the above parameters to be reassessed for improvement. Fluid boluses can be given up to 4 times except for hypertonic saline:

• Isotonic crystalloids (e.g., Lactated Ringer’s): dogs: 10–20 mL/kg; cats: 5–10 mL/kg
• Artificial colloids (e.g., Volulyte): dogs: 5 mL/kg; cats: 2.5–5 mL/kg (contraindicated in patients with kidney injury, coagulopathy or pulmonary disease)
• Hypertonic saline (e.g., 7% NaCl): Dogs and cats: 2–4 mL/kg (contraindicated if severely dehydrated, sodium abnormalities; must give with isotonic crystalloids)

Large breed dogs may require a pressure bag to administer a bolus within 15 minutes. Care should be taken when administrating a bolus to cats, as incorrect use of fluid pumps can lead to fluid over load. As a safety measure, the author uses a 50 mL syringe and administers the fluids manually. Other options are the use of a syringe driver, or a paediatric burette attached to a fluid pump. Care should be taken in administering large volumes of fluid in patients prone to heart failure, pulmonary disease, anuric or oliguric renal failure, geriatric cats, hypoalbuminemia and sepsis or systemic inflammatory response syndrome.

Bradycardia and Tachycardia

Treatment of individual causes of bradycardia/tachycardia is beyond the scope of this lecture; however, it is important to identify bradycardia and place and ECG. Critical bradycardia requiring specific urgent treatment includes decompensated shock, hyperkalemia, bradyarrhythmias, and intracranial hypertension.

Neurologic

Seizures/Tremors

Seizures should be initially controlled by IV or per rectal diazepam. If seizures are not controlled with diazepam, propofol should be administered to effect followed by phenobarbitone. If the patient is recumbent with no gag reflex, intubation is required to maintain a patent airway and prevent aspiration pneumonia.

Increased Intracranial Pressure

Increased intracranial pressure (ICP) can occur with any intracranial disease, traumatic brain injury, and seizures. Cushing reflex characterised by hypertension and bradycardia, as well as abnormal respiratory patterns can occur. Modified Glascow Coma Score can be used to assess patients with traumatic brain injury, which includes assessment of motor activity, brainstem reflexes, and level of consciousness. Treatment involves maintaining normal perfusion (blood pressure) and oxygenation, elevating the head 30 degrees being careful not to kink the neck, in addition to reducing intracranial hypertension with mannitol or hypertonic saline.

Spinal Injury

It is important to keep the spine immobilised by securing the animal to a back board.

Other Considerations

Analgesia

Identifying and providing analgesia to patients is an important part of triage.

Temperature

Rapid cooling of hyperthermic patients to 39.5°C is important. Active cooling should be instituted by running water, fan, bolus of intravenous fluids, flow-by oxygen, enemas, and keeping the animal on a cool surface and not in an enclosed space. Water baths and placing wet towels over animals are not effective methods of cooling.

Hypothermic animals must be warmed slowly by rewarming the trunk of the body by wrapping the body, applying hot packs indirectly, or a rewarming blanket. Rewarming (particularly rewarming of extremities) can lead to vasodilation and hypotension, therefore intravenous fluids should be administered at the same time.

References

References are available upon request.