From the Guidelines
Pulmonary edema and congestion are primarily caused by heart failure, particularly left-sided heart failure, where the heart cannot effectively pump blood, leading to fluid backup in the lungs, as supported by the most recent guidelines from the European Society of Cardiology 1. Other cardiac causes include mitral valve disease, severe hypertension, and myocardial infarction. Non-cardiac causes include acute respiratory distress syndrome (ARDS), pneumonia, sepsis, drug overdose (especially opioids and aspirin), high-altitude exposure, and near-drowning. Certain medications like chemotherapy agents (bleomycin) and NSAIDs can also trigger pulmonary edema. Fluid overload from kidney failure or excessive IV fluid administration may contribute as well. The underlying mechanism involves increased hydrostatic pressure in pulmonary capillaries or damage to the alveolar-capillary membrane, allowing fluid to leak into the alveolar spaces and interstitial tissue. This fluid accumulation impairs gas exchange, causing symptoms like shortness of breath, cough with frothy sputum, and hypoxemia. Treatment depends on addressing the underlying cause while providing supportive care with oxygen, diuretics like furosemide (40-80mg IV), and in severe cases, mechanical ventilation, as recommended by the European Heart Journal 2 and the European Respiratory Journal 3. Key considerations in management include the use of i.v. loop diuretics to improve breathlessness and relieve congestion, high-flow oxygen to correct hypoxemia, and thrombo-embolism prophylaxis to reduce the risk of deep venous thrombosis and pulmonary embolism, as outlined in the guidelines for the diagnosis and treatment of acute and chronic heart failure 2012 1. In patients with acute heart failure syndromes, the European Society of Cardiology recommends an individualized approach to management, taking into account the patient's specific clinical presentation and underlying cause of heart failure 1. Overall, the management of pulmonary edema and congestion requires a comprehensive approach that addresses the underlying cause, provides supportive care, and prevents complications, with the goal of improving morbidity, mortality, and quality of life for patients with these conditions.
From the Research
Causes of Pulmonary Edema and Congestion
- High-altitude exposure is a primary cause of pulmonary edema, as seen in High-Altitude Pulmonary Edema (HAPE) 4, 5, 6
- Individual susceptibility, altitude, speed and mode of ascent are important determinants for the occurrence of HAPE 5
- Exaggerated pulmonary hypertension is a hallmark of HAPE and is thought to play an important part in its pathogenesis 5, 7
- Pulmonary vascular endothelial dysfunction and augmented hypoxia-induced sympathetic activation may be underlying mechanisms contributing to exaggerated pulmonary vasoconstriction in HAPE 7
- A defect in transepithelial sodium transport could act as a sensitizer to pulmonary edema at high-altitude 7
- Inflammatory response with increased capillary permeability may also contribute to the development of HAPE, although it is unclear whether this is a primary cause or a consequence of edema formation 5