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29 A Respiratory Pattern‐Based Approach to Dyspnea 295

segment) during respiration. Splinting due to pain tial in patients presented with respiratory signs, and
VetBooks.ir associated with respiration leads to a decreased cough appropriate cooling measures should be implemented
when hyperthermia is documented.
reflex, hypoventilation, hypoxemia, and atelectasis.
Intracranial diseases may directly stimulate the respir-
Several techniques for stabilization of flail chest have
been reported, but the primary focus should be on oxy- atory center located in the medulla. Patients with trau-
gen supplementation, underlying intrathoracic injuries, matic brain injury, intracranial neoplasia, and/or
and multimodal analgesia. inflammatory/infectious central nervous system diseases
may have abnormal respiratory patterns. Neurological
examination typically identifies other deficits that may
Diaphragm aid in determining a definitive diagnosis. Pain and acid–
base disorders may also induce tachypnea without
As a major respiratory muscle responsible for the crea- hypoxia in patients. Distension of the abdominal cavity is
tion of subatmospheric intrathoracic pressure, the dia- another common cause of tachypnea and dyspnea in
phragm is essential for adequate oxygen and ventilation. dogs and cats, chiefly through elevation of intraabdomi-
Many conditions may induce partial or complete nal hypertension and development of abdominal
diaphragmatic paralysis, including pleuroperitoneal her- compartment syndrome; specifically, intraabdominal
nias, botulism, and phrenic nerve damage or degenera- hypertension impairs diaphragmatic contraction,
tion. The classic respiratory pattern of a patient with a thereby impeding the ability to generate subatmospheric
dysfunctional or ruptured diaphragm is tachypnea with intrathoracic pressure. Additionally, pulmonary paren-
marked inspiratory excursion of the cranial half of the chyma may be compressed, leading to decreased oxygen
thorax. Paradoxical abdominal movement is also com- transport across the pulmonary capillary membrane,
mon, and may be due to either thoracic displacement of increased alveolar dead space, and alveolar atelectasis.
abdominal viscera during vigorous inspiration or an ina- Common examples of intraabdominal pathology that
bility to maintain abdominal girth during inspiration. may cause and/or contribute to respiratory compromise
include severe paralytic ileus, marked abdominal dis-
comfort inducing splinting of abdominal musculature,
Nonrespiratory Causes large‐volume peritoneal effusion, intraabdominal neo-
plasia, and gastric dilation‐volvulus. Whenever possible,
There are multiple causes of tachypnea and dyspnea that abdominal decompression should be performed, and
do not directly arise from the respiratory tract. Perhaps possible decompression methods include peritoneocen-
the most common example is nonpyogenic hyperther- tesis, therapy for ileus and capillary leak, adequate anal-
mia which may be the sole cause of respiratory signs or gesia to allow for abdominal muscle relaxation, and
be secondary to a concurrent medical condition. surgical decompression.
Accordingly, measurement of body temperature is essen-

Further Reading

Algren JT, Price RD, Buchino JJ, et al. Pulmonary edema Hackner SG. Pulmonary thromboembolism. In: King LG,
associated with upper airway obstruction in dogs. ed. Textbook of Respiratory Disease in Dogs and Cats. St
Pediatr Emerg Care 1993; 9: 332–7. Louis, MO: Saunders, 2004, pp. 526–41.
Amis TC, Kurpershoek C. Pattern of breathing in Johnson LR, Lappin MR, Baker DC. Pulmonary
brachycephalic dogs. Am J Vet Res 1986; 47: 2200–4. thromboembolism in 29 dogs: 1985–1995. J Vet Intern
Baker JL, Havas KA, Miller LA, et al. Gunshot wounds in Med 1999; 13: 338–45.
military working dogs in Operation Enduring Freedom Krebs A, Marks SL. Brachycephalic airway syndrome.
and Operation Iraqi Freedom: 29 cases (2003–2009). Standards Care Emerg Crit Care Med 2007; 9(6): 9–15.
J Vet Emerg Crit Care 2013; 23: 47–52. Lamb CR, Parry AT, Baines EA, et al. Does changing the
Byers CG, Dhupa N. Feline bronchial asthma: orientation of a thoracic radiograph aid diagnosis of rib
pathophysiology and diagnosis. Compend Contin Educ fractures? Vet Radiol Ultrasound 2011; 52: 75–8.
Pract Vet 2005; 27: 418–25. Lisciandro GR. Abdominal (AFAST) and thoracic
DeTroyer A, Kirkwood PA, Wilson TA. Respiratory actions (TFAST) focused assessment with sonography for
of the intercostal muscles. Physiol Rev 2005; 85: 717–56. trauma, triage, and tracking (monitoring) in small
Giggs R, Benigni L, Fuentes VL, et al. Pulmonary animal emergency and critical care. J Vet Emerg Crit
thromboembolism. J Vet Emerg Crit Care 2009; 19: 30–52. Care 2011; 21(2): 104–19.