Pulmonary Edema

Pulmonary Edema

Pulmonary edema is defined as abnormal accumulation offluid in the lung tissue and/or alveolar space. It is a severe, life-threatening condition.

Pathophysiology

Pulmonary edema most commonly occurs as a result of increased microvascular pressure from abnormal cardiac function. The backup of blood into the pulmonary vasculature resulting from inadequate left ventricular function causes an increased micro-vascular pressure, and fluid begins to leak into the interstitial space and the alveoli. Other causes of pulmonary edema are hypervolemia or a sudden increase in the intravascular pressure in the lung. One example of this is in the patient who has un-dergone pneumonectomy. When one lung has been removed, all the cardiac output then goes to the remaining lung. If the pa-tient’s fluid status is not monitored closely, pulmonary edema can quickly develop in the postoperative period as the patient’s pulmonary vasculature attempts to adapt. This type of pul-monary edema is sometimes termed “flash” pulmonary edema. A second example is called re-expansion pulmonary edema. This may be due to a rapid reinflation of the lung after removal of air from a pneumothorax or evacuation of fluid from a large pleural effusion.

Clinical Manifestations

The patient has increasing respiratory distress, characterized by dyspnea, air hunger, and central cyanosis. The patient is usually very anxious and often agitated. As the fluid leaks into the alve-oli and mixes with air, a foam or froth is formed. The patient coughs up or the nurse suctions out these foamy, frothy, and often blood-tinged secretions. The patient has acute respiratory distress and may become confused or stuporous.

Assessment and Diagnostic Findings

Auscultation reveals crackles in the lung bases (especially in the posterior bases) that rapidly progress toward the apices of the lungs. These crackles are due to the movement of air through the alveolar fluid. The chest x-ray reveals increased interstitial markings. The patient may be tachycardic, the pulse oximetry values begin to fall, and arterial blood gas analysis demonstrates increasing hypoxemia.

Medical Management

Management focuses on correcting the underlying disorder. If the pulmonary edema is cardiac in origin, then improvement in left ventricular function is the goal. Vasodilators, inotropic med-ications, afterload or preload agents, or contractility medications may be given. Additional cardiac measures (eg, intra-aortic bal-loon pump) may be indicated if the patient does not respond. If the problem is fluid overload, diuretics are given and the patient is placed on fluid restrictions. Oxygen is administered to correct the hypoxemia; in some circumstances, intubation and mechan-ical ventilation are necessary. The patient is extremely anxious, and morphine is administered to reduce anxiety and control pain.

Nursing Management

Nursing management of the patient with pulmonary edema in-cludes assisting with administration of oxygen and intubation and mechanical ventilation if respiratory failure occurs. The nurse also administers medications (ie, morphine, vasodilators, ino-tropic medications, preload and afterload agents) as prescribed and monitors the patient’s response.