Page 25 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

Chapter 2
VetBooks.ir

Emergency management of

respiratory distress

Daniel Holden and Kenneth Drobatz

Introduction Oxygen supplementation should be provided whilst
assessing the airway. The goal is to allow for continued
Respiratory distress is a life-threatening clinical syndrome assessment of the patient and the provision of further
that should be dealt with immediately. The principles of the therapy, without causing excessive patient distress. The
approach to these critically ill patients are the same authors’ first choice is mask or flow-by oxygen delivery
whether it is a first-time patient presenting, an inpatient or (see later). The work of breathing may cause the patient
the postoperative animal. Immediate oxygen supplementa- to consume more oxygen; breath-holding can rapidly
tion, a thorough physical examination and evaluation of decrease the animal’s inspired oxygen concentration and
clinical history and signs, and empirical localization of the can severely compromise some patients. Even struggling
lesion can help guide therapy when definitive diagnostics against restraint, the placement of an intravenous catheter,
cannot be obtained because of the critical nature of the or positioning for radiography can be devastating in
patient. Once the patient is stable, definitive diagnostics animals with respiratory compromise. Good clinical judge-
can be obtained and specific therapy can be instituted. ment is extremely important in weighing the advantages
What is done in the initial approach to these animals can and disadvantages of any diagnostic or therapeutic pro-
make the difference between life and death. cedure in these critically ill patients.
If possible, an intravenous catheter should be placed.
This procedure allows collection of three capillary tubes of
Initial assessment and blood for an emergency database (packed cell volume
(PCV), total solids (TS), dipstick blood urea nitrogen (BUN),
stabilization blood glucose and a blood smear) and administration of
intravenous emergency drugs or fluids.
Patients with respiratory distress are usually easily identified:
• Standing (dogs) or sternal recumbency (cats)
• Abducted elbows Pathophysiology
• Extended neck
• Tachypnoea Under normal physiological conditions, alveolar ventilation
• Weakness is primarily driven by changes in the partial pressure of
• Abnormal stridorous (laryngeal or tracheal) and/or carbon dioxide in arterial blood (P aCO 2). Increases in
stertorous (nasal/oropharyngeal) sounds carbon dioxide (hypercapnia) will stimulate ventilation, but
• Increased inspiratory and/or expiratory effort hypoxaemia (decreased partial pressure of oxygen in
• Abnormal abdominal wall motion arterial blood, P aO 2) needs to be more profound before a
• Vigorous resistance to restraint. stimulatory effect is achieved. Hypercapnic respiratory
disease involves a failure of the neural and/or muscular
Cats are much more adept than dogs at concealing component of the respiratory system, and is often asso-
signs of respiratory distress, and disease is often much ciated with a decrease in ventilatory effort. Hypoxaemic
more advanced on presentation in this species. respiratory disease involves failure of efficient alveolar
Initial assessment in a patient with severe respiratory oxygenation, usually due to pulmonary parenchymal or
distress is directed at assuring a patent airway and ade- airway-related disorders, and is often associated with
quate ventilation. If the airway is not clear or the patient is increased ventilatory effort.
not ventilating adequately, immediate attempts should be
made to clear the airway and intubate the patient.
If a patent airway cannot be obtained through intuba-
tion, tracheotomy should be performed IF it will bypass the Diagnostic approach
airway obstruction. It is extremely rare that an emergency
tracheostomy has to be performed (see Operative Tech- Signalment, history and physical examination often pro-
nique 2.1). In most instances, airway access can be vide enough information to localize the respiratory lesion.
achieved via orotracheal intubation and tracheostomy may Localization of the lesion can narrow down the differential
then be performed in a more controlled manner. diagnosis list and provide a basis for empirical therapy if

16 BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, second edition. Edited by Daniel J. Brockman, David E. Holt and Gert ter Haar. ©BSAVA 2018

Ch02 HNT.indd 16 31/08/2018 10:28