💧 Chapter 40: Pulmonary Oedema

Hydrostatic (cardiogenic) vs permeability (non-cardiogenic/ARDS) · Pathophysiology · CXR findings (Kerley B lines, perihilar batwing) · BNP · Role of PEEP · Diuretics · Inotropes · Post-obstructive pulmonary oedema (POPE) · Neurogenic pulmonary oedema

🔍 Core Concepts: Pulmonary Oedema

📌 Types & Pathophysiology
Hydrostatic (cardiogenic): ↑ capillary pressure (LV failure, fluid overload). Permeability (non-cardiogenic): ↑ capillary leak (ARDS, sepsis, aspiration). Mixed: neurogenic, high-altitude, POPE.
🫀 Cardiogenic vs Non-cardiogenic
Cardiogenic: cool extremities, S3 gallop, JVD, CXR: perihilar batwing, Kerley B lines, cardiomegaly. Non-cardiogenic: warm extremities, normal heart size, diffuse bilateral infiltrates.
📊 Diagnostic Tests
BNP: <100 pg/mL suggests non-cardiogenic; >500 suggests cardiogenic. Echocardiography: assess LV function, valvular disease. CXR differentiates distribution.
💨 Positive Pressure Ventilation
PEEP/CPAP improves oxygenation by recruiting alveoli, reducing preload, improving compliance. NIPPV (CPAP) first-line for cardiogenic pulmonary oedema. Intubation if severe.
💊 Medical Management
Cardiogenic: diuretics (furosemide), vasodilators (nitroglycerin), inotropes (dobutamine/milrinone). Non-cardiogenic: treat underlying cause (sepsis, pancreatitis), lung-protective ventilation, conservative fluid management after shock.
⚠️ Special Types
Post-obstructive pulmonary oedema (POPE): after relief of UAO; treat with PEEP. Neurogenic pulmonary oedema: after brain injury (seizure, trauma); sympathomimetic surge.

🩺 Stepwise Approach: Pulmonary Oedema

1
Assess & stabilise ABCs
High-flow oxygen, upright position. Assess severity: mild (SpO2 >90% on low O2), moderate (SpO2 85-90%, tachypnoea), severe (respiratory failure, hypotension).
2
Differentiate cardiogenic vs non-cardiogenic
History (hypertension, CHF, sepsis, aspiration, trauma), exam (S3 gallop, JVP vs warm extremities), CXR (perihilar batwing vs diffuse bilateral), BNP, echocardiogram.
3
Non-invasive positive pressure ventilation (NIPPV)
CPAP (5-10 cmH2O) is first-line for cardiogenic pulmonary oedema — reduces preload, afterload, improves oxygenation. BiPAP if hypercapnia. Intubate if severe or NIPPV fails.
4
Cardiogenic pulmonary oedema management
Furosemide (1-2 mg/kg IV), vasodilators (nitroglycerin infusion if BP permits), afterload reduction (enalaprilat). Inotropes (dobutamine, milrinone) for low output. Morphine if severe distress (controversial).
5
Non-cardiogenic (ARDS) management
Treat underlying cause (sepsis, pancreatitis, aspiration). Lung-protective ventilation (low tidal volume 6 mL/kg, Pplat <30). Conservative fluid management after shock resolution. Consider prone positioning, ECMO if refractory.
6
Special types: POPE & neurogenic
Post-obstructive: after relief of UAO (croup, extubation). Treat with PEEP, diuretics if fluid overloaded. Neurogenic: after seizure/head injury. Supportive, often self-resolving.