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Veterinary Specialists Of South Florida Presents…. Near Drowning and Noncardiogenic Pulmonary Edema. VETERINARY SPECIALISTS OF SOUTH FLORIDA Tyler Foreman, DVM. “Luke”. 2.5 year old MN American Bulldog Presented with increased RR/RE Became acutely dyspnic after playing in the ocean
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Near Drowning and Noncardiogenic Pulmonary Edema VETERINARY SPECIALISTS OF SOUTH FLORIDA Tyler Foreman, DVM
“Luke” • 2.5 year old MN American Bulldog • Presented with increased RR/RE • Became acutely dyspnic after playing in the ocean • Owner described Luke “biting” at the waves • He had two episodes of vomiting and diarrhea shortly after leaving the beach
Physical Exam • 5% dehyrdated • MM light pink to pale and slightly tacky • Increased to harsh bronchovesicular sounds in all lung fields • RR = 132 • SpO2 = 81% on room air
Diagnostics • Stress leukogram • HCT = 50.5 • TP = 8.4 • K+ = 3.2 (range from 3.8 – 5.3) • Radiographs
Normal Alveolar Fluid Physiology • Collodial oncotic pressure (COP)and hydrostatic pressures interact to create a mild negative fluid pressure in the interstitial tissues. • Lymphatic drainage primarily responsible for removing excess fluid • Low normal hydrostatic pressures • Surfactant within the alveoli • Can withstand 20-40 mmHg hydrostatic pressure without leaking into the alveolus
Pathophysiology • 3 Main Causes of Pulmonary Edema • Increased hydrostatic pressure • Increased capillary permeability • Mixed • Initial fluid accumulation on capillary side opposite gas exchange • Eventually, fluid moves into alveolus, altering ventilation • Acts as diffusion barrier to gas exchange • Increases vascular resistence • End result is hypoxemia
Noncardiogenic Pulmonary Edema • Definition – Fluid accumulation in the pulmonary interstitium and alveoli caused by a disorder other than congestion resulting from heart disease.
Typically a result of increased capillary permeability • Can also result from impaired lymphatic drainage (neoplasia, lymphangitis) • Decreased plasma oncotic pressure is rarely a cause of pulmonary edema
Near Drowning • Both a form of noncardiogenic pulmonary edema and an aspiration event • Usually small volumes aspirated • Dilutes surfactant • Collapses avleoli • Decreases lung compliance • Salt water increases fluid flux into alveoli due to hypertonicity
Clinical Signs/PE Findings • Respiratory Distress • Tachypnea • Cough • Expectoration of fluid • Crackles may be ausculted at varying times and places • Cyanosis
Risk Factors/Underlying Conditions: Noncardiogenic Edema • Upper airway obstruction • Laryngeal paralysis, foreign body, mass, brachycephalic, etc. • Systemic Inflammatory response syndrome (SIRS) or Acute Respiratory Distress syndrome (ARDS) • Sepsis, pancreatitis, pneumonia, severe tissue trauma, Immune-mediated disease, metastatic neoplasia • Systemic vasculitis • Pulmonary Thromboembolism • Ventilator-associated lung injury • Volatile hydrocarbons • Cisplatin in cats • Recent history of being in water
Diagnosis • R/O Heart Disease first • Thoracic Radiographs • CBC/Chem • Hunt for causes of underlying disease
Therapy • Oxygen therapy • Positive pressure ventilation • Thoracocentesis if pleural effusion present • Medical Management • Furosemide • Decreases pulmonary hydrostatic pressure • Increases COP secondary to hemoconcentration • Evidence that it acts as a vasodilator and bronchodilator
Therapy Continued • Vasodilators (Nitroprusside, Nitroglycerin) • More for use in cardiogenic edema • Decrease afterload and preload • Beta-2 agonists (Terbutaline) • Increase cAMP which increases fluid reabsorption from the alveolar space • Fluid Therapy • Generally avoided • Use with caution if necessary • Sedatives, if patient is overtly anxious
Luke’s Therapy • Furosemide CRI • 0.2-0.4 mg/kg/hr • Best administered as a CRI for 6 hours • Oxygen therapy • 40% O2 overnight • Weaned off in the morning after RR/RE had stabilized • IV Fluids • Started at ¾ maintenance • Increased to 1.0x maintenance • Added 30 mEq/L KCl
Outcome • Luke dramatically improved overnight • Went home the next day
Summary • Important to first R/O Cardiogenic Edema • Determine origin of Noncardiogenic edema • Treat underlying cause and symptoms • Noncardiogenic edema does not usually respond as well to therapy as cardiogenic edema
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References • Noncardiogenic Pulmonary Edema. Clinical Veterinary Advisor. Pg 913-914 • Pulmonary Edema. Small Animal Critical Care Medicine. Pg 82-84 • Noncardiogenic Pulmonary Edema. Textbook of Veterinary Internal Medicine. pg 1240 • Near Drowning. Textbook of Veterinary Internal Medicine. pg 1260-1261 • http://www.pathologyatlas.ro/pathology_atlas_imagini/pulmonary_edema_detail.jpg • Chest. 2007 Apr;131(4):964-71 • Schweiz Arch Tierheilkd. 2010 Jul;152(7):311-7 • Anesthesiology. 2010 Jul;113(1):104-15