Immersion Pulmonary Edema
Immersion pulmonary edema is sudden-onset pulmonary edema that typically occurs early during a dive while at depth.
(See also Overview of Diving Injuries.)
Immersion pulmonary edema has become more common over the past 2 decades. This disorder is similar to negative pressure pulmonary edema encountered during induction of anesthesia or after extubation, when a patient with laryngospasm attempts to take deep breaths against a closed larynx, thereby causing negative intra-alveolar pressure. Abnormal left ventricular systolic or diastolic function may contribute. Immersion pulmonary edema is not related to pulmonary barotrauma or decompression sickness. Cold water and a history of hypertension are risk factors. This syndrome occurs in competitive open water swimmers.
Severe dyspnea develops. Divers usually ascend rapidly and have cough, frothy sputum, scattered crackles throughout both lung fields, and sometimes cyanosis. Hypoxia is present.
Chest x-ray shows typical pulmonary edema. Cardiac evaluation usually shows normal right and left ventricular function and normal coronary arteries. Diastolic dysfunction can be documented by echocardiography.
Diuretic therapy and oxygen by positive pressure mask are usually sufficient therapy. Mechanical ventilation may be necessary. Recompression therapy is not indicated.