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Hemothorax 437

Etiology and Pathophysiology • Blood pressure (p. 1065): if compensated, • Unless due to neoplastic cause, autotrans-
Hemothorax occurs as a result of a primary may be normotensive or could be hypotensive fusion allows RBCs in hemorrhagic fluid
VetBooks.ir is vital to appropriate therapy. • Arterial blood gas (p. 1058): metabolic/ (through a blood filter) to the patient’s Diseases and Disorders
with massive hemorrhage
disease process. Determination of this cause
removed from the chest to be returned
peripheral circulation.
• Hemothorax (p. 1230)
lactic acidosis, hypoxemia, elevated alveolar
• Trauma to the lung, heart, mediastinum, or
to arterial gradient
great vessels • Coagulation testing (p. 1325): if hypoco- Chronic Treatment
• Coagulopathic: hypocoagulable agulable, expect After initial stabilization, further therapy and
○ Toxic (e.g., anticoagulant rodenticide ○ Prothrombin/partial thromboplastin time monitoring may be necessary.
toxicity) (PT/aPTT): prolonged (PT before aPTT • Serial TFAST scans to evaluate for recurrent/
○ Acquired (e.g., anticoagulants such as if rodenticide intoxication) ongoing hemorrhage
heparin, rivaroxaban), hepatic failure, ○ Activated clotting time (ACT): pro- ○ If continued hemorrhage, may need to
disseminated intravascular coagulopathy longed with severe depletion of clotting consider chest tube placement
(DIC), induced by anaphylaxis (e.g., factors • In anticoagulant rodenticide patients, vitamin
heartworm disease) ○ Thromboelastography (TEG): prolonged R K 1 2.5 mg/kg PO q 12h (p. 69)
○ Congenital (e.g., hyperfibrinolytic syn- time +/− smaller maximal amplitude (MA) • Refractory traumatic hemothorax
drome, hemophilia) with thrombocytopenia +/− normal to ○ Evaluate for hyperfibrinolytic ATC
• Coagulopathic: hypercoagulable larger MA with anemia, hyperfibrinolysis with TEG and subsequent antifibrino-
○ Pulmonary thromboembolism (PTE) with trauma/disseminated intravascular lytic therapy (e.g., aminocaproic acid
• Neoplastic (primary or metastatic): pleural, coagulation 50-100 mg/kg PO q 8h for 5 days) if
mediastinal, pulmonary, ruptured abdominal present
neoplasm Advanced or Confirmatory Testing ○ If cannot identify underlying source
• Infectious (e.g., viral, bacterial, parasitic, • Fluid analysis with cell count/cytology of hemorrhage, may require thoracic
fungal) (see Risk Factors above) (p. 1343): erythrophagocytosis, no platelets exploratory surgery
• Iatrogenic (typically clotted blood with +/− clumping of neoplastic cells +/− pink • Neoplasia: palliative or definitive therapy,
no erythrophagocytosis) (see Risk Factors supernatant if spun down (hemolysis) depending on type and location
above) • Thoracic radiographs (preferably after • If patient has retained blood clots, consider
• Miscellaneous therapeutic thoracocentesis): loss of detail fibrinolytic agent administration (humans).
○ Lung lobe torsion due to remaining effusion, interstitial to
○ Pancreatitis alveolar pattern consistent with parenchymal Behavior/Exercise
○ Subpleural arteriovenous malformations hemorrhage +/− mass effect (pulmonary, The patient should be kept calm until definitive
○ Aneurysms (aorta, pulmonary artery) mediastinal), depending on cause therapy is instituted. Gentle patient handling
○ Pulmonary bulla rupture • CT and thoracic ultrasound: if trauma and is necessary to minimize further hemorrhage.
○ Vascular rupture (Ehlers-Danlos syndrome) coagulopathy have been ruled out, neces-
○ Thymic brachial cyst sary in 90% cases to confirm suspicion of Possible Complications
○ Thyroglossal cyst neoplasia Numerous complications noted in human
○ If mass present, consider aspiration/biopsy literature: retention of blood clots in the
DIAGNOSIS (p. 1113) pleural space, pyothorax/empyema (1%-4%
• Anticoagulant rodenticide screening (spec- overall, 26.8% traumatic cases [humans]), and
Diagnostic Overview trophotometry) to confirm rodenticide fibrothorax. Hemorrhage can recur/progress or
Hemothorax is confirmed by thoracentesis with coagulopathy (rarely performed) may not be able to be removed safely.
fluid analysis. After ensuring hemodynamic
stability of the patient, evaluation can proceed TREATMENT Recommended Monitoring
and usually should include coagulation testing. Serially monitor heart and respiratory rates,
Treatment Overview respiratory effort as well as blood pressure,
Differential Diagnosis The therapeutic steps highly depend on the PCV, and TS. If tolerated, monitor pulse
Pleural effusion (p. 791) cause of hemothorax but generally include oximetry and/or arterial oxygenation. Serial
blood products, therapeutic thoracocentesis, and TFAST exams are recommended to evaluate
Initial Database definitive therapy for the primary condition. for recurrence or progression of hemorrhage.
• Thoracic-focused assessment with sono-
graphic evidence of trauma (TFAST [p. Acute General Treatment PROGNOSIS & OUTCOME
1102]): hypoechoic fluid that may have a • For every patient, immediately: oxygen
hyperechoic texture if highly cellular (similar supplementation (p. 1146), obtain intrave- • Highly depends on the underlying cause
to smoke appearance) nous access, and begin fluid resuscitation (if of hemothorax, with the best prognosis
• Thoracocentesis (p. 1164): cage-side evalu- hypotensive [p. 911]) associated with rodenticide anticoagulant
ation • If coagulopathic, administer frozen plasma intoxication (98.6% survival) and self-
○ Spun packed cell volume (PCV) > 25% (15 mL/kg IV over 4 hours) limited or correctable causes of traumatic
of the animal’s peripheral blood PCV • Thoracocentesis to remove enough volume hemothorax.
○ Unless peracute, effusion does not clot to ease respiration (after any coagulopathy • Prognosis for infectious causes depends on
○ Peracute hemorrhage (<1 hour) is very is addressed) the response to supportive care and treatment
similar to peripheral blood ○ Not necessary or beneficial to remove all of particular pathogen.
• CBC or initial peripheral blood PCV and effusion • Prognosis for neoplastic causes of hemothorax
total solids (TS) ○ Generally, removal of 10 mL/kg adequate depends on the type of neoplasia: that for
○ May be normal in peracute period, fol- to improve clinical signs solitary primary pulmonary neoplasia ame-
lowed by anemia • If anemic, administer blood products nable to surgery can be good with follow-up
○ Total solids below reference range (p. 1169). chemotherapy; mediastinal lymphoma cases
○ Thrombocytopenia possible, depending • Packed red blood cells (RBCs) or whole blood have short survival times (days to months);
on cause of hemothorax typical and metastatic neoplasia/carcinomatosis

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