Page 1588 - Cote clinical veterinary advisor dogs and cats 4th

798 Pneumothorax

• Rarely, foreign bodies (e.g., grass awns [p. • Analysis of pleural effusion obtained by Chronic Treatment
398], wooden toothpicks, porcupine quills) thoracocentesis (pp. 1164 and 1343) • Correction of the underlying cause if
VetBooks.ir pneumothorax. TREATMENT • If surgery is not an option, intrathoracic
may migrate intrathoracically and cause
applicable
installation of autologous fresh whole blood
Treatment Overview
DIAGNOSIS
The course and severity of the patient’s (i.e., “blood patch”) may help seal ongoing
pulmonary air leaks (p. 834).
Diagnostic Overview clinical signs and suspected inciting cause
The diagnosis is suspected based on a history help determine whether to pursue conservative Possible Complications
of thoracic trauma (field or surgical), dyspnea, management or thoracotomy. Treatment goals Ongoing pneumothorax or effusion
or both. The confirmatory test of choice is for conservative management include removal
thoracic radiography, although thoracic ultra- of air from the pleural space and measures that Recommended Monitoring
sound (p. 1102) is also useful for detecting encourage formation of a seal to prevent further • Respiratory rate and effort
pneumothorax (absence of the glide sign) and leakage; surgical treatment aims to eliminate • Pulse oximetry
may be performed without moving the animal. the source of the leak. • Keep track of volume of air removed
Differential Diagnosis Acute General Treatment PROGNOSIS & OUTCOME
Dyspnea after trauma: • Supplemental oxygen (p. 1146) produces
• Pleural effusion/diaphragmatic hernia more rapid resolution of a closed (not • Fair to good; often with trauma, the asso-
• Pulmonary contusions ongoing) pneumothorax because the trapped ciated injuries are more likely to predict
• Primary lung or airway disease air is higher in nitrogen, and if inhaled outcome.
• Pain oxygen is administered, the trapped air • Dyspnea and duration of intensive care are
• Hypovolemia moves more quickly down its concentration negative prognostic factors for dogs and cats
Dyspnea in absence of trauma: gradient. with pneumothorax.
• Pneumonia • Traumatic pneumothorax
• Congestive heart failure ○ No clinical signs and identified incidentally PEARLS & CONSIDERATIONS
• Neoplasia on radiographs: no treatment; monitoring
• Pulmonary thromboembolism is important Comments
• Pleural effusion ○ Clinical signs: thoracocentesis warranted • Traumatic pneumothorax rarely requires
• Upper airway disease (p. 1164). If large volumes (>200 mL/kg), surgical correction; most cases rapidly resolve
• Others no endpoint, or recurrent pneumothorax, (within 72 hours).
place thoracostomy tubes (p. 1082). Apply • Spontaneous pneumothorax in dogs com-
Initial Database the three-strikes rule: if three or more monly requires surgical treatment because
• Thoracic radiographs are the test of choice thoracocenteses are required within 24 many cases do not resolve without surgery.
for patients who can tolerate the procedure; hours after trauma, a thoracostomy tube Cats with spontaneous pneumothorax are
left lateral recumbency is the most sensitive should be placed. more likely to resolve without surgery.
view for detecting small volumes of air in the • Spontaneous pneumothorax (no trauma)
pleural space. Thoracic ultrasound can detect ○ If a bulla or bleb is suspected (no masses Prevention
pneumothorax as well and is less stressful. on radiographs), a thoracotomy is often Prevent free roaming of pets, and use caution
• In animals with suspected pneumothorax warranted (p. 834). when performing thoracocentesis.
when respiratory distress makes the animal ○ If a necrotic neoplasm or pulmonary
unstable for radiographs and ultrasound abscess is suspected, thoracic CT followed Technician Tips
is unavailable, thoracocentesis may be by thoracotomy is warranted. Technicians involved in caring for patients
diagnostic as well as therapeutic. ○ If underlying feline asthma or chronic with pneumothorax should be familiar with
• Arterial blood gas (ABG [p. 1058]) or pulse bronchitis is suspected, conservative management of chest tubes.
oximetry may help elucidate whether dyspnea therapy may be adequate.
in a traumatized animal with pneumothorax • Iatrogenic SUGGESTED READING
is due to the pneumothorax itself (e.g., PaO 2 ○ If there are no clinical signs (radiographic Mooney ET, et al: Spontaneous pneumothorax in 35
< 85 mm Hg on room air and/or SpO 2 diagnosis only or a small volume of air cats (2001-2010). J Feline Med Surg 14(6):384-391,
< 95%) or to pain, hypovolemia, or other was aspirated during thoracocentesis), 2012.
conditions associated with trauma. Pulmo- monitoring (e.g., regular respiratory rate, AUTHOR: Elizabeth Rozanski, DVM, DACVIM,
nary contusions may also cause hypoxemia effort, SpO 2) is adequate. DACVECC
and desaturation. ○ If the patient is showing clinical signs, EDITOR: Benjamin M. Brainard, VMD, DACVAA,
• Routine laboratory testing (CBC, serum repeating the thoracocentesis and monitor- DACVECC
chemistry profile, urinalysis): generally ing the animal closely are recommended.
unremarkable The animal may require a thoracostomy
tube or exploratory thoracotomy if not
Advanced or Confirmatory Testing responsive. Underlying disease may require
• CT often is useful for identification of specific treatment.
pulmonary bullae or abscesses.

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