Merck Manual

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Parameters to Evaluate During Triage

Parameters to Evaluate During Triage




Mucous membrane color


Normal PCV and adequate perfusion

Pale or white

Anemia or shock


Severe hypoxemia


Increased serum bilirubin due to hepatic disease or hemolysis

Capillary refill time

1–2 sec

Normal perfusion and rapidity with which capillaries refill with blood

>2 sec

Poor perfusion or peripheral vasoconstriction

<1 sec

Hyperdynamic states; could be associated with fever, heat stroke, distributive shock, or early compensatory stage of hypovolemic shock

Heart rate

70–120 bpm (small dogs)

60–120 bpm (large dogs)

120–200 bpm (cats)

Normal heart rates; indicate that at least one component of cardiac output is normal


Decreased cardiac output and subsequent poor perfusion; cats in particular develop bradycardia (<120 bpm) in shock; an irregular, slow heart beat can be associated with imminent cardiac arrest, severe arrhythmias, or metabolic derangements ( hyperkalemia, hypocalcemia, etc)

Tachycardia (dogs >180 bpm, cats >220 bpm)

Compromised diastolic filling; sinus tachycardia often results from hypovolemic shock or pain; tachycardia that is irregular or associated with pulse deficits usually indicates an arrhythmia, and an ECG is indicated

Pulse rate and quality

Strong and synchronous with each heart beat

Normal; both femoral and digital pulses should be palpated


Usually indicative of a cardiac arrhythmia


Hyperdynamic (compensatory) state of shock

Weak or absent

Decreased cardiac output, peripheral vasoconstriction, decreased pulse pressure, or thromboses

Level of consciousness

Alert and responsive to surroundings

Normal overall neurologic and metabolic state

Depressed or obtunded (less responsive to visual and tactile stimuli, sleepy appearance but still arousable)

Can be caused by any illness or decreased perfusion; may be mild, moderate, or severe

Stupor (arousable only with painful stimuli)

Severe neurologic or metabolic derangements

Comatose (unarousable with any stimuli) or seizures (usually associated with whole body convulsions, salivation, facial tremors, possibly involuntary urination and defecation)

Abnormal cerebral electrical activity from primary neurologic disease or secondary to metabolic derangements seen in diseases such as diabetes, hepatic encephalopathy, hypoglycemia, or toxin exposure; accurate history or prior health problems, current medications, and possible toxin exposure important

Level of pain

Vocalization, changes in behavior (avoidance, aggression), or physical changes (tachycardia, dilated pupils, etc)

Clinical signs can be similar to those seen in compensatory stage of shock; pain delays healing and must be treated.