2-47
2-47. PULMONARY EDEMA
a. Pulmonary edema is an abnormal accumulation of fluid in the lungs. The most common cause of pulmonary edema is cardiac disease. When the pulmonary blood vessels receive more blood from the right heart than the left heart is able to receive in return, pulmonary congestion occurs. Pulmonary edema is the
end result of unrelieved pulmonary congestion. The congested pulmonary capillaries leak fluid into the nearby air spaces. As the pulmonary edema progresses, the escaping fluid mixes with alveolar air and a frothy sputum is produced, churning and gurgling with each respiration. This causes the characteristic "death rattle" associated with severe pulmonary edema. Fluid build-up in the lungs prevents air from entering the alveoli, causing severe hypoxia.
b. Treatment involves measures to improve ventilation and oxygenation and reduce lung congestion. The patient should be positioned in an upright position to decrease venous return to the right heart, thereby decreasing the right ventricular output to the lungs. Oxygen is used to relieve dyspnea and hypoxia. Administration of morphine in small doses will decrease the anxiety and dyspnea. Diuretics are used to decrease the fluid volume if necessary. Since pulmonary edema is a result of an imbalance between the left and right heart, treatment will also include those therapies and medications necessary to stabilize the heart dysfunction.
