Today's Veterinary Practice provides comprehensive information to keep every small animal practitioner up to date on companion animal medicine and surgery as well as practice building and management.
Issue link: http://todaysveterinarypractice.epubxp.com/i/591321
tvpjournal.com | November/December 2015 | ToDay's VeTeriNary PracTice aPProach To resPiraTory DisTress Peer reviewed 59 for reducing moderate to severe pulmonary hypertension if documented on echocardiography. PLEURAL SPACE DISEASE Etiology Pleural space disease refers to abnormal accumulations within the pleural space that impair lung expansion on inhalation. These accumulations can be associated with fuid (ie, pleural effusion), air (ie, pneumothorax), masses, or organs (ie, diaphragmatic hernia). Clinical Signs Animals with pleural space disease may have: • Inspiratory distress • Rapid shallow breathing • Paradoxical breathing pattern in which the chest falls on inspiration and the abdomen expands rather than the chest rising with inspiration • Decreased lung sounds on thoracic auscultation. Diagnostic Approach Thoracic imaging is the mainstay of diagnosis. In unstable patients, point-of-care ultrasound is particularly useful to confrm the presence of pleural fuid or air. 10 Radiographs can also confrm diagnosis but ideally, in unstable patients, thoracocentesis (see Stabilization & Management) should be performed after ultrasound and prior to radiographs. If ultrasound is not available, thoracocentesis should be performed based on clinical suspicion, in order to stabilize the patient prior to obtaining radiographs. Stabilization & Management In patients with pleural effusion or pneumothorax, therapeutic thoracocentesis should result in immediate improvement. Pleural fuid can then be submitted for analysis/cytology and, in cases of pyothorax, bacterial culture (both aerobic and anaerobic culture). Once therapeutic thoracocentesis has been performed, the next step is addressing the underlying disease. Specifc discussion of treatment of underlying diseases is beyond the scope of this article. FLAIL CHEST Etiology Flail chest refers to destabilization of a portion of the rib cage, which occurs if there are rib fractures in 2 different locations (proximal and distal) on the same rib(s). This condition often affects multiple ribs (at least 2 consecutive ribs), creating a fail segment. 11 Concurrent injuries, such as pulmonary contusions and pneumothorax, are common in dogs with fail chest and are generally the cause of respiratory compromise, rather than the fail chest itself. Clinical Signs & Diagnostic Approach Flail chest is usually visually obvious on examination, but radiographs are indicated to confrm the nature of the rib fractures and allow assessment of severity of the underlying pulmonary parenchymal damage. Rib fractures are extremely painful and may cause rapid, shallow breathing because big chest excursions cause more pain than little breaths. Stabilization & Management Management of fail chest is often supportive; the following should be provided: • Oxygen supplementation, given the high likelihood of underlying pulmonary contusions • Appropriate analgesia: » Usually in the form of systemic analgesia (eg, pure mu-opioid agonists, such as hydromorphone or fentanyl) ± local nerve blocks » Intercostal nerve blocks can be performed in dogs using 0.5% bupivacaine, with a total of 1 to 4 mg/kg divided between sites » If local anesthetic nerve blocks are used in cats, dose reduction to prevent toxicity is important; generally, the total local anesthetic dose should not exceed 0.2 to 0.5 mg/kg in cats; particular care should be taken to avoid inadvertent IV administration » Although use of nonsteroidal anti-infammatory drugs (NSAIDS) should be avoided in the initial stabilization and management of trauma patients, NSAIDs can be considered later in the course of hospitalization once the patient is hemodynamically stable. Additional supportive care may include: • Patient positioning in lateral recumbency, with the flail segment facing downwards • Bandaging the chest to reduce movement of the flail segment, although, extreme care must be taken to avoid further impeding inspiration. Surgery is not indicated unless penetrating thoracic wounds are present, in which case an exploratory thoracotomy should be performed. Assuming unilateral penetrating thoracic wounds, a lateral thoracotomy is performed to allow visualization of the affected thorax, a lung lobectomy if necessary, and thoracic lavage, prior to closure with placement of a chest tube. Diaphragmatic Hernia: emergency Management Patients with diaphragmatic hernia usually have a history of trauma; either acute, or at some time in the past. Surgery via a ventral midline laparotomy to replace the abdominal contents in the abdomen and repair the torn diaphragm is indicated as soon as possible.