Pulmonary edema is a clinical term that refers to the abnormal buildup of fluids within the lung tissues that causes physiological disturbances to the patient. Patients usually present with severe left sided heart failure with pulmonary hypertension and alveolar flooding in the lungs.
Pulmonary edema from different causes can either present acutely or chronically. The following signs and symptoms are commonly seen with pulmonary edema:
Pulmonary edema is a medical emergency, thus initial diagnostic modalities are usually limited to the preliminary physical examination, chest X-ray, and electrocardiography (ECG). When patients are judged to be stable, they will be subjected to the different test and diagnostic procedures as a standard work up for pulmonary edema. The following tests are conducted to patients with pulmonary edema:
Patients presenting with pulmonary edema are usually attached to an oxygen source through mask or nasal cannula to allay the symptoms of dyspnea. Although severe cases presenting with respiratory failure may already require mechanical ventilation . For cardiogenic pulmonary edema, a cardiac preload unloader like furosemide can reduce the accumulation of fluids in the air sacs. In the same way, an afterload reducer like nitroprusside that dilates the systemic vessels and unloads the ventricular workload can mitigate the crisis. Morphine is sometimes given to control chest pain and severe anxiety in patients. Blood pressure regulating medications may also be given with the need arise during the resuscitative phase of pulmonary edema.
The prognosis for patients who subsequently develop congestive heart failure with hydrostatic pulmonary edema is poor. It carries a mean survival time of 1.7 years among males and 3.2 years in females from the time of diagnosis . Most cases of neurogenic pulmonary edema remains underdiagnosed due to the imposing primary disorder that undermines its existence. The relative morbidity of neurogenic pulmonary edema is as high as 50% while its relative mortality rating is as low as 7% .
The following etiologic factors and medical conditions predispose susceptible patients to pulmonary edema:
The American Heart Association (AHA) has reported at 550,000 new cases of cardiogenic pulmonary edema each year in the United States. Congestive heart failure has caused the death of at least 287,000 of these cases in 1999 alone . The lifetime risk for hydrostatic pulmonary edema has practically doubled beyond 40 years of age especially those with hypertension concomitant with congestive heart failure .
There is a slight predilection for the male population compared to the females due to the decreasing incidence of cardiogenic and neurogenic inciting events among females. In neurogenic pulmonary edema, more than half of patients have sustained a blunt trauma to the head with concussion. More than 71% of patient fatalities with subarachnoid hemorrhage complicates with neurogenic pulmonary edema. In at least of a third of the patients with status epilepticus develop neurogenic pulmonary edema .
The accumulation of the fluid within the alveoli is commonly brought about by cardiogenic causes. In the normal flow of blood, the atria receives the blood from the lungs where it is pumped outward by the left ventricle to the other organs of the body. Any pathology that endangers this balance and causes an increased pressure in the atria can cause a backflow of fluids to the air sacs due to the increased in ventricular and atrial pressure. Heart related pathologies that results in cardiogenic pulmonary edema include coronary artery diseases, cardiomyopathy, hypertension, and cardiac valvular problems. In non-cardiogenic pulmonary edema however, the capillaries within the lungs become more permeable or “leaky” due to inflammatory responses with infection, bleeding, and pressure. This are usually brought about by toxins, medications, contrast media , viral infections, barotrauma, near drowning, and neurogenic disorders.
The active control of the congestive heart failure is paramount in the prevention of the hydrostatic pulmonary edema. Lung infections like pneumonia must be treated promptly and monitored to prevent progressive accumulation of fluids within the lung spaces. Adequate acclimatization should be in place for high altitude athletes to prevent the occurrence of pulmonary edema. A preventive dose of the corticosteroid dexamethasone may avert the progression to pulmonary edema of patients diagnosed with pulmonary hypertension and barotrauma .
Pulmonary edema is a medical condition wherein there is an excessive fluid in the pulmonary space. The accumulating fluid in the lungs fills in the air sacs and manifest externally as dyspnea. Pulmonary edema is most commonly caused by heart failure although some non-cardiac causes like pulmonary infections, reactions to medications, external trauma, barotrauma from high altitudes, and toxins may predispose patients to this serious lung disorder. Pulmonary edema which occurs acutely is considered a serious medical emergency that could be potentially fatal if not treated immediately.
Pulmonary edema is a medical condition wherein there is an abnormal accumulation of fluid (exudates) in the alveoli. The accumulation of fluids in the lungs fill in the air sacs and manifest externally dyspnea, chest pain, and cyanosis.
The majority of cases of pulmonary edema are caused by cardiogenic factors like congestive heart failure, cardiomyopathy and valvular diseases. Non-cardiogenic causes include pneumonia, toxins, medications, and barotrauma.
Preliminary physical examination, ECG and Chest X-ray are routinely done in an emergency setting for patients suspected of pulmonary edema. Additional tests like pulse oximetry, blood tests, echocardiography, and pulmonary/cardiac catheterization are performed as soon as the patients are stabilized.
Treatment and follow-up
Oxygen inhalation is the primary intervention given to patients with pulmonary edema. Cardiogenic pulmonary edema patients are given preload unloaders and afterload reducers to allay the cardiogenic instability. Morphine may also be given to relieve the chest pain and severe anxiety in patients.