Look, Listen and Feel! Initial Evaluation of the Emergency Respiratory Patient
World Small Animal Veterinary Association World Congress Proceedings, 2011
Christopher G. Byers, DVM, DACVECC, DACVIM (SAIM)
Midwest Veterinary Specialty Hospital, Omaha, NE, USA

The initial approach to a patient with respiratory distress is of utmost importance as it can determine whether these critical patients will live or die. Classic clinical signs of respiratory distress are listed in Table 1.

Table 1. Classic Signs of Respiratory Distress.


 Head and neck extension

 Opened mouth



 Nares flaring

 Abducted elbows


 Paradoxical movement of the chest and/or abdomen

Signs of respiratory distress are more commonly seen in dogs compared to cats. Unfortunately, cats readily mask disease severity and commonly the only evidence of respiratory dysfunction is tachypnea and prominent respiratory motions in sternal recumbency.

The first step in examining a patient with a respiratory emergency is to perform a primary survey efficiently evaluating airway, breathing, and circulation (ABCs). If the airway is not patent, it must be cleared of obstruction and immediate intubation performed. If an upper airway obstruction prevents orotracheal intubation, an emergency tracheostomy must be done.

If intubation is deemed necessary, rapid induction with minimal cardiopulmonary depression should be accomplished. Common induction drugs are listed in Table 2.

Table 2. Common Induction Drugs in Respiratory Emergencies.



Ketamine / Midazolam

5 mg/kg ketamine IV; 0.25 mg/kg midazolam IV

Midazolam / Fentanyl

0.25 mg/kg midazolam IV; 3–5 mcg/kg fentanyl IV


0.5–2.0 mg/kg IV


3–8 mg/kg IV


5–10 mg/kg IV

If there are no airway patency issues (or once they have been addressed), a clinician should evaluate the patient's breathing pattern. The initial evaluation of a patient begins from afar, as the breathing pattern may change with patient manipulation. Making an accurate assessment, after handling, can be far more challenging.

Anatomical localization of the cause of respiratory distress is assessed through a "look, listen and feel" approach (Table 3). Supplemental oxygen should be provided while performing a primary survey (Table 4).

Table 3. Classic Anatomical Localizations.

Anatomic location

Most common causes

Useful distinguishing features

Upper airway disease

Foreign body, nasopharyngeal polyp, pharyngeal/laryngeal edema, mass, hemorrhage, laryngeal paralysis, tracheal collapse, brachycephalic airway syndrome

Stertor, stridor, noisy breathing, paradoxical abdominal movement, cyanosis, anxiety, exaggerated respiratory movements without breathing sounds

Chest wall disease

Flail chest, opened chest wound

Palpable thoracic body wall defect, paradoxical movement of flail segment

Pleural space disease

Pneumothorax, hemothorax, diaphragmatic hernia, chylothorax, pyothorax, right-sided heart failure, mediastinal disease, pleuritis

Rapid shallow respirations, muffled breath & heart sounds, paradoxical abdominal movement

Small airway disease

Chronic bronchitis, feline asthma

Prolonged expiration; expiratory "grunt"

Parenchymal disease

Pneumonia, pulmonary neoplasia, infiltrative disease, pulmonary contusions, cardiogenic pulmonary edema, non-cardiogenic pulmonary edema

Labored inspiration and expiration, harsh lung sounds, crackles, wheezes, dysrhythmias, murmur

Dr. Steven Haskins previously coined the term "look alikes" to describe non-respiratory causes of increased respiratory effort. These problems, that do not cause hypoxemia, include hypotension, pain, acidosis, behavioral disorders, anemia, and drugs. All may frequently be mistaken for indicating respiratory pathology.

Table 4. Methods of Provided Supplemental Oxygen.







Inexpensive; simple

Requires high-flow rates (6–8 L/min; may upset stressed patient; requires an assistant to monitor patient

Face mask

35–95% depending on tightness of facemask

Inexpensive, convenient, easily administered

Some patients don't tolerate face mask; requires an assistant to monitor patient

Oxygen cage


Allows animal to receive oxygen without manipulation

Expensive; requires large volume of oxygen to fill cage; oxygen level drops when cage door is opened; potential for patient over-heating


Unilateral: 30–35% @ 50 mL/kg/min
Bilateral: 55–60% @ 100 mL/kg/min

Inexpensive, allows continuous supplementation during manipulation

Patient may not tolerate nasal line(s) or jetting of oxygen

Elizabethan collar with plastic wrap

30–40% @ 0.2–0.5 L/min


Patient may not tolerate collar; potential for hyperthermia; frequently requires an assistant to monitor patient


40–60% @ 50 mL/kg min

Method of provision for patients with upper airway obstruction

Airway irritation, potential for tube kinking, potential for sedation, insertion site complications

One attempt may be made to place a peripheral intravenous catheter in order to facilitate administration of emergency intravenous medications. The patient should then be placed in a temperature-controlled, oxygen-enriched environment (i.e., oxygen cage) for observation. Should inhaled medications not be available and/or should a patent IV catheter not be available, continued venipuncture should not be attempted. Instead, medications should be given via appropriate alternative routes (IM, SQ), and then the patient should be placed in an oxygen cage.

Patients with respiratory distress require frequent serial evaluations of multiple physical parameters, particularly respiratory rate, respiratory effort, and lung sounds. Additionally, critical care monitoring modalities, particularly pulse oximetry and arterial blood gas analyses, provide invaluable information to afford optimal patient management.


References are available upon request.


Speaker Information
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Christopher G. Byers, DVM, DACVECC, DACVIM (SAIM)
Midwest Veterinary Specialty Hospital
Omaha, NE, USA

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