The goal of triage is to identify patients with life-threatening conditions who require immediate attention from a veterinarian, and distinguish them from patients that are not as ill (Aldrich, 2005; Drobatz, 2010). Triage is the systematic evaluation and categorization of patients, and is derived from the French word trier, ‘to sort’. Human triage models use levels or codes that are assigned to each patient, and which differentiate those patients who require immediate care from those who can wait for medical intervention.
A triage examination should be completed in less than 2 minutes. Calm, clear, and controlled communication with the owner is essential, and questions should be brief and relevant; a more in depth history will be obtained at a later time (Aldrich, 2005). It is important to drive the discussion in a compassionate tone while remaining confident, to assure the owners that their pet is in good hands — yours. The person performing the triage examination must stay focused on the patient and owner regardless of the activity in the rest of the emergency waiting room (Bateman, 2007).
One way to direct the conversation is to focus on the owner's reason for bringing the pet in for evaluation. Helpful questions include: ‘why have you brought in your pet today?’ ‘When was he/she last completely normal?’ ‘How has his/her condition progressed since that point?’ It is also important to ask if the pet is regularly given any medications or dietary supplements or if the pet has access to and may have ingested a toxin. If a patient is not stable and requires further evaluation or intervention, permission from the owner should be obtained for emergency procedures such as intravenous catheter placement, initial blood work, and other interventions such as thoracocentesis (Bateman, 2007). In the authors' practice, verbal permission is adequate for initial stabilization.
The triage examination should focus on the assessment of four major body systems: respiratory; cardiovascular; neurological; and urinary (Drobatz, 2010). Many of these systems can be assessed at the same time. It is essential to be familiar with normal parameters and to be comfortable with physical examinations on many types of animals. Part 1 of this series will discuss respiratory and cardiovascular triage, and part 2 will cover triage of neurologic, urogenital, and other conditions.
Respiratory triage
Respiratory distress is a common scenario for which owners seek emergency treatment. Respiratory emergencies require rapid assessments and decisions. The patient's respiratory rate, effort, and noise should be evaluated. Some of this evaluation can be completed even on approach to the animal, and some animals with extreme diffculty breathing (commonly termed dyspnoea) may be triaged from a distance. Animals that are breathing comfortably without an obvious increase in effort or rate are characterized as eupnoeic. Normal respiratory rate in dogs and cats is 10–20 breaths per minute, but panting in an excited dog may still be normal. Open-mouthed breathing or panting in a cat is abnormal (Figure 1a), and the patient should be immediately assessed further and provided with supplemental oxygen during the remainder of the examination (Aldrich, 2005).
Respiratory rate can be described as increased (tachypnoeic) or absent (apnoeic). Tachypnoeic patients should be evaluated for associated respiratory effort. If an increased effort is not present, consideration should be given to the possibility that the increased rate may be due to elevated body temperature, pain, excitement, anxiety, or lung disease.
If increased respiratory effort (dyspnoea) is observed, the effort should be characterized as inspiratory, expiratory, or both. Inspiratory dyspnoea indicates upper airway obstructions such as laryngeal paralysis, foreign bodies, tracheal collapse, or neoplasia in the oropharynx or trachea. Animals with upper airway obstructions will frequently generate abnormal noises while breathing, and may develop hyperthermia due to increased respiratory effort (Rozanski and Chan, 2005). Owners may also comment on abnormal respiratory noise, or a change in vocalizations. Stertor is a snoring sound created by the vibration of excessive soft tissues in the oropharynx (e.g. due to an overlong soft palate), and may be normal in some breeds (e.g. English Bulldogs or Pugs), but may be abnormal in non-brachycephalic breeds. Stridor refers to a high pitched sound, created primarily on inspiration by the vibration of soft tissues as air passes through a small opening at a high rate. Stridor is commonly associated with animals with laryngeal paralysis; on inspiration the arytenoid cartilage from each side is pulled towards midline, creating a smaller aperture for air to travel through and consequently making a high-pitched noise (Holt, 2004).
Expiratory dyspnoea is frequently associated with restrictive diseases of the lower airways such as asthma or chronic obstructive pulmonary disease (COPD) (Brainard and King, 2010). Animals with these diseases frequently have a very short, fast inspiratory phase, and spend the majority of the respiratory cycle trying to exhale. The narrowing of the lower airways (bronchi) by inflammation makes it diffcult to push air out of the lungs, and increased effort is necessary to exhale (Silverstein, 2004). Cats with asthma frequently have a history of a chronic cough, and the owner may also reveal a history of exposure to allergens, such as might be released during home renovations (Dye et al, 1996; Rozanski and Chan, 2005). Siamese breed cats tend to be over represented among cats with bronchial disease (Venema and Patterson, 2010). On further examination, animals with lower airway disease may have wheezes heard during pulmonary auscultation.
Animals with mixed (inspiratory and expiratory) dyspnoea may have disease at any level of the respiratory tract, but frequently have a degree of pulmonary parenchymal disease (Lee and Drobatz, 2004). This is disease (such as pneumonia, pulmonary oedema, or lung contusions) that directly affects the ability of the lungs to exchange oxygen and carbon dioxide with the bloodstream. History may include episodes of vomiting or recent anaesthesia and surgery. These animals frequently have significant respiratory diffculty, and will likely require supplemental oxygen for stabilization and further examination. Thoracic auscultation may reveal increased pulmonary (broncho-vesicular) sounds, or may be characterized by a crackling noise that is thought to represent the opening and closing of collapsed airways and alveoli (Aldrich, 2005; Kogan et al, 2008).
Animals with pleural space disease (e.g. pneumothorax, haemothorax, chylothorax, pyothorax) frequently have breathing patterns characterized by tachypnoea, rapid inspirations, and minimal chest excursions (‘short and shallow’) (Rozanski and Chan, 2005). The presence of air or fluid in the pleural space restricts the ability to expand the lungs, and animals may also have an abdominal component to their breathing, as the diaphragm is displaced caudally during inspiration. Pleural space disease can be secondary to a number of conditions, including cardiac disease, thoracic trauma, infection, or intoxication. Pleural space disease may be life threatening, and the air or fluid that is restricting lung expansion must be removed via thoracocentesis.
Prolonged or severe respiratory diffculty can result in gradual fatigue of the respiratory muscles, and may result in respiratory arrest (Hendricks, 2004). The observation of postures such as orthopnoea, where an animal sits or stands with a base-wide stance and outstretched neck, necessitate immediate action (e.g. oxygen cage, thoracocentesis) (Figure 1b) (Rozanski and Chan, 2005). If the patient is dyspnoeic and showing signs of anxiety or pain, judicious sedation or anxiolysis may also help to calm them and alleviate one factor contributing to observed distress (Rozanski and Chan, 2005). Common sedative drugs (e.g. opioids) may also cause respiratory depression, and preparations should be made for immediate endotracheal intubation if the administration of sedation results in apnoea. Common drugs that can be used for sedation or anxiolysis include butorphanol, acepromazine, or midazolam. Drugs such as propofol are extreme respiratory depressants, and should not be given without the ability to intubate and ventilate for the patient. If the patient is unable to be calmed, however, it may be necessary to induce anesthesia and intubate the patient (Rozanski and Chan, 2005).
Cardiovascular triage
Triage examination of the cardiovascular system is concerned with the ability of the heart to perfuse the tissues of the body, and secondarily to assess the ability of that perfusion to deliver oxygen to the tissues. While perfusion cannot be assessed directly, markers of cardiovascular performance can be assessed quickly and easily during the triage examination. The triage cardiovascular examination concentrates on mucous membrane (MM) colour, capillary refill time (CRT), and the palpation of pulses (which also allows calculation of heart rate and assessment of pulse quality) (Boag and Hughes, 2005).
MM can provide much information about the patient's cardiovascular status. The most frequently accessed location is the gums. If the patient's gums are pigmented or not accessible, the vulva and prepuce also provide an area to assess membrane color and perfusion. The examination should note the colour of the membranes, the CRT and the moistness of the tissue. When evaluating the gum colour, be aware of the presence of gingivitis, as the associated inflammation can create bright pink or red MMs.
CRT may be used to assess general perfusion. The CRT is determined by first blanching the membrane using light pressure from a fingertip, and then observing the time it takes for the colour to return when the pressure is removed. Normal CRT in a healthy, well-perfused animal is 1–2 seconds (Aldrich, 2005). A CRT of 2 seconds or greater is indicative of poor perfusion. This may be caused by a decrease in cardiac output (i.e. there is not enough blood pressure to quickly refill the capillaries), or may be due to other systemic alterations such as vasoconstriction (which makes refill more difficult). Conversely, a CRT of less than 1 second indicates an increase in cardiac output or perfusion of the MM. Increased perfusion may result from vasodilation, which can indicate local (e.g. gingivitis) or systemic (e.g. septic shock) inflammation. Increased cardiac ouput with vasodilation (creating brick red MM with a very fast CRT) is indicative of compensatory or hyperdynamic shock.
Normal MM colour ranges from a light pink to darker pink (Aldrich, 2005). Cats tend to have more pale pink MM compared with dogs (Silverstein, 2004). Pale or white coloured MM may be indicative of anaemia, hypothermia or vasoconstriction, and when associated with shock, is frequently accompanied with a slow CRT (Aldrich, 2005). Patients presenting in this manner require immediate assessment for systemic disease. Yellow MM indicate increased amounts of circulating bilirubin (icterus or jaundice), which can occur with liver disease or haemolysis (Figure 2). If the patient is hypoxaemic (low level of oxygen in the blood), the MM will appear blue or grey (this is also termed cyanosis). MM will be red in the presence of vasodilation (Boag and Hughes, 2005). Red MM may also be indicative of carbon monoxide toxicity (Aldrich, 2005). Poor tissue perfusion, as associated with decompensatory shock, results in a muddy grey hue (Boag and Hughes, 2005). Acetaminophen ingestion in cats will result in brown MM due to the presence of methaemoglobin. Petechiae (small pinpoint haemorrhages) may also be noted on the MM, and can indicate thrombocytopenia (Figure 3).
Palpation of the pulse during triage allows not only the determination of heart rate and rhythm, but with experience, qualitative properties of the pulse are identified, and can lead to a more accurate initial examination. Bradycardia and tachycardia are often recognized in the emergency room. Pulse palpation is most easily accomplished using the femoral pulse, although the metatarsal pulses are also easily palpated in patients with adequate blood pressure (Hackett, 2009). Normal heart rates in dogs range from 60–100 beats per minute (bpm), with larger dogs tending to display slower heart rates. Normal heart rate in cats is usually between 160–200 bpm, but may be higher if they are stressed in a hospital situation (Boag and Hughes, 2005). Tachycardia may be associated with shock due to hypovolaemia (e.g. due to acute blood loss), cardiac disease, or sepsis (Boag and Hughes, 2005). In addition, tachycardia may be a physiologic response to pain or to the anxiety of being in a new environment (especially in cats). Certain cardiac arrhythmias may result in tachycardia as well; both ventricular and supraventricular (e.g. atrial fibrillation) tachyarrhythmias can be seen in the emergency room. Obstructive shock (e.g. due to pericardial effusion) will also result in tachycardia.
Detection of a low heart rate (bradycardia) may also be a cause for concern, especially in cats. Bradycardia can be associated with hyperkalaemia, which may occur secondary to urinary obstruction, Addison's disease (hypoadrenocorticism), or acute renal failure. Bradycardia in patients with head trauma is a serious emergency and may indicate impending herniation of the brain. Animals with cardiac arrhythmias (e.g. 2nd or 3rd degree atrioventricular (AV) block) may also display bradycardia. Unlike dogs, cats with shock or signs of systemic inflammation may present with bradycardias (heart rate between 140–160 bpm) (Brady et al, 2000). Any bradycardia in a cat should be immediately investigated, and all animals presenting with a bradycardia and signs of systemic illness should be evaluated using an electrocardiogram (ECG) to determine the features of the bradycardia.
In addition to the heart rate, abnormal cardiac rhythms that result in irregular pulses can be detected by pulse palpation (Aldrich, 2005). These ‘dropped beats’ may be due to cardiac arrhythmias such as ventricular premature contractions (VPC) or AV block. The strength of the pulse should also be palpated. Pulses of varying strength may be indicative of a cardiac arrhythmia or of a situation such as pericardial effusion where the cardiac output is compromised (Hackett, 2009). A normal pulse should feel round and full, and should be easily palpable, with the possible exception being patients who are overweight. Animals that have an acute decrease in blood flow to the hind limbs (e.g. due to an aortic thromboembolism) will not have palpable femoral pulses, and should be further evaluated (as with any patient with non-palpable pulses). Both femoral pulses should be palpated at the same time, and they should feel equal in pressure and duration (Aldrich, 2005).
The palpated pulse is actually the difference between the systolic and diastolic arterial blood pressure (Aldrich, 2005). Because of this, qualitative changes in the systolic or diastolic blood pressure, or both, may be palpated, and can indicate the presence of systemic disease. Animals with an increased cardiac output, especially in the presence of vasodilation (such as may be seen with compensatory septic shock) will have an increased systolic pressure (from the increased cardiac output) and a decreased diastolic blood pressure (from the vasodilation) (Boag and Hughes, 2005). Consequently, the pulse pressure will be greater, and will be sensed as a ‘bounding’ pulse (Aldrich, 2005). By the same token, patients with decompensatory shock, or those with low cardiac output from other causes will have a lower systolic blood pressure and a diastolic blood pressure that is the same or decreased. These pulses will have a weak, or ‘thready’ characteristic, and may be diffcult to palpate (Boag and Hughes, 2005).
Conclusions
Once the primary triage is completed and an action plan implemented to address identified abnormalities, the assessment does not end. The patient must be re-evaluated often for signs of improving or deteriorating conditions, and immediate action should be taken if no improvement is noted. The emergency room is dynamic and patient conditions may change rapidly. Observations are critical and assessments need to be timely and accurate.
Most patients treated in an emergency room and triaged with abnormalities of the above systems receive supplemental oxygen, an intravenous catheter, an ECG tracing, blood pressure measurement and FAST ultrasound scan (Boysen et al, 2004) to evaluate for the presence of free abdominal or thoracic fluid. Initial bloodwork evaluation may include measurement of a packed cell volume (PCV) and total solids by refractometry, blood glucose concentration, and electrolyte assessment. Plasma lactate concentration is also a helpful measure that can indicate the presence of decreased oxygen delivery to tissues in the body (Pang and Boysen, 2007). Depending on the disease and the stability of the patient, all treatments and bloodwork may not be able to be performed. If handling an unstable patient, especially one with respiratory disease, the above items may need to be staged to prevent decompensation of the patient. Just as with the triage examination, the specific procedures should be triaged so that the tests producing data most likely to help with diagnosis or treatment of the patient are performed first. All equipment should be ready and within reach. In extremely unstable patients, it may be necessary to induce anaesthesia and stabilize the patient prior to pursuing diagnostics. While not ideal, this may prevent excessive stress on the patient, and will allow for collection of all relevant samples in a short period of time. In general, when working with unstable patients, preparation for worst cast scenarios will make the care team ready for any complications that may arise during the post-triage evaluation.
If a triage examination does not provide a strong indication of whether the animal requires immediate attention or not, a safe default action is to have the patient assessed with haste. Seconds count and patients' conditions can rapidly change. After the patient has been stabilized or triaged as stable, the secondary survey can begin. A complete palpation, further injury assessment, and imaging can now happen to give the clinician more in-depth information about the patient.
An ideal triage examination should take no more than 2 minutes. The integration of historical questioning within the physical examination is a skill that should be practised. While assessing the four major body systems, questions should be short and direct, but compassionate. Knowledge of the signalment and common emergencies can help to direct questions. Most owners do not prepare for emergencies and could be visibly upset and may be distracted or even injured. Appropriate immediate action should be taken when necessary, based on triage history, physical examination, or both. Veterinary technicians/nurses and all members of the veterinary care team should instill confidence that the best possible care will be provided for their pet. Provide updates to the owners if applicable and allowed, especially if a pet was rapidly triaged for further diagnosics or interventions. Triage examinations and decision making are skills like any other and need practise to improve. A confident veterinary technician with a strong knowledge base, excellent communication skills and the ability to make quick triage decisions will strengthen the team, and contribute to the optimal care of the emergency patient.