Background: Acute pulmonary edema has been noted in swimmers and divers, and has been termed swimming-induced pulmonary edema (SIPE). The mechanisms and consequences of SIPE are unknown, and there are currently no series of carefully evaluated patients with this condition. Herein we report the clinical presentation, incidence of recurrence, findings on physical examination, chest radiography, and oxygen saturation in 70 trainees with a diagnosis of SIPE. We also report the results of forced spirometry in a subgroup of 37 swimmers.
Methods: SIPE was diagnosed when severe shortness of breath and cough were reported during or after swimming, and were associated with evidence of pulmonary edema. During the years from 1998 to 2001, 70 cases of SIPE were documented in young healthy male subjects participating in a fitness-training program. Physical examination and pulse oximetry were performed immediately. Chest radiographs were obtained in all cases 12 to 18 h following onset of symptoms. In 37 swimmers, spirometry was performed at the time of chest radiography and again after 7 days.
Results: All subjects complained of severe shortness of breath. Sixty-seven of the 70 subjects (95.7%) had a prominent cough; in 63 subjects (90%), there was significant sputum production. Hemoptysis was observed in 39 subjects (55.7%). Mean arterial oxygen saturation after swimming was 88.4 +/- 6.6% breathing air, compared with 98 +/- 1.7% breathing air at rest before the start of the swimming trial (mean +/- SD) [p < 0.001]. Chest radiographs obtained 12 to 18 h after swimming were normal in all cases. Sixteen trainees (22.9%) had a recurrence of SIPE. Spirometry demonstrated restrictive lung function, which persisted for a week.
Conclusions: In our trainee population, SIPE is a not uncommon, often recurrent phenomenon that significantly influences performance. It is not clear what predisposes to its occurrence or recurrence and what, if any, are its long-term effects.