Page 312 - Small Animal Internal Medicine, 6th Edition

284 PART II Respiratory System Disorders

Resting Respiratory Rate increased expiratory or inspiratory efforts, or both; and
Resting respiratory rate can be used as an objective indi- may have abnormal lung sounds on auscultation. Patients
VetBooks.ir cator of pulmonary function in patients that are not yet with intrathoracic large airway obstruction (intrathoracic
trachea and/or large bronchi) generally have normal to
in respiratory distress. The measurement is ideally made at
home by the owner, eliminating the effect of the stress of
ration; and audible or auscultable expiratory sounds (see
the veterinary hospital on the respiratory rate. The normal slightly increased respiratory rate; prolonged, labored expi-
respiratory rate of a dog or cat without stress, at rest, is less Chapter 25).
than 20 respirations per minute. A rate of up to 30 respira-
tions per minute is generally considered normal during a
routine physical examination. Panting is a distinct activity DIAGNOSTIC APPROACH TO DOGS
with respiratory rates often exceeding 200 breaths/minute. AND CATS WITH LOWER RESPIRATORY
Panting is primarily associated with the function of heat TRACT DISEASE
dissipation but can also be seen as a response to pain or
anxiety and in association with hyperadrenocorticism or INITIAL DIAGNOSTIC EVALUATION
steroid administration. The initial diagnostic evaluation of dogs or cats with signs of
lower respiratory tract disease includes a complete history,
Mucous Membrane Color physical examination, thoracic radiographs, and complete
Cyanosis, in which normally pink mucous membranes are blood count (CBC). Further diagnostic tests are selected on
bluish, is a sign of severe hypoxemia and indicates that the the basis of information obtained from these procedures;
increased respiratory effort is not sufficiently compensating these include tests for specific diseases, the evaluation of
for the degree of respiratory dysfunction. Pallor of mucous specimens collected from the lower respiratory tract, spe-
membranes is a more common sign of acute hypoxemia cialized imaging techniques, and pulmonary function tests
resulting from respiratory disease. (Fig. 19.1). Historical information was discussed in previous
paragraphs.
Breathing Pattern
Patients in respiratory distress resulting from diseases of Physical Examination
the lower respiratory tract, excluding the large airways, Measurement of respiratory rate, assessment of mucous
typically have rapid and often shallow respirations; have membrane color, and observation of the breathing pattern

INITIAL EVALUATION
History
Physical examination
Thoracic radiographs
CBC

TESTS FOR SPECIFIC COLLECTION OF SPECIALIZED IMAGING PULMONARY FUNCTION
DISEASES PULMONARY SPECIMENS TECHNIQUES TESTS
FOR CYTOLOGY,
HISTOLOGY, AND/OR
Serology MICROBIOLOGIC TESTING Specialized radiography Arterial blood gas analysis
Heartworm disease Fluoroscopy Pulse oximetry
Histoplasmosis Computed tomography
Blastomycosis Magnetic resonance imaging
Coccidioidomycosis Tracheal washing Ultrasonography
Toxoplasmosis Bronchoalveolar lavage Nuclear imaging
Feline coronavirus Transthoracic lung aspiration/
Canine influenza biopsy
Urine antigen tests Bronchoscopy and visually
Histoplasmosis guided specimen collection
Blastomycosis Bronchial brushing
PCR tests Bronchial biopsy
Respiratory infectious disease Bronchoalveolar lavage
panels Transbronchial biopsy
Various individual organisms Thoracotomy or thoracoscopy
Fecal examination for parasites with lung biopsy
Flotation
Baermann examination
Sedimentation
FIG 19.1
Diagnostic approach for dogs and cats with lower respiratory tract disease.