Cardiopulmonary disease may be a common predisposing factor in IPE in the recreational swimming/diving population, whereas pulmonary hypertension due to extreme exertion may be more important in military cases. Individuals with past history of IPE in our case series had a greater proportion of comorbidities compared to published cases. The role of underlying cardiopulmonary dysfunction may be underestimated, especially in older swimmers and divers. We conclude that an episode of IPE should prompt the evaluation of cardiac and pulmonary function.

Background Swimming-induced pulmonary edema (SIPE) occurs during swimming or scuba diving, often in young individuals with no predisposing conditions, and its pathophysiology is poorly understood. This study tested the hypothesis that pulmonary artery and pulmonary artery wedge pressures are higher in SIPE-susceptible individuals during submerged exercise compared to the general population and are reduced by sildenafil. Methods and Results Ten study subjects with a history of SIPE (mean age 41.6 years) and 20 control subjects (mean age 36.2 years) were instrumented with radial artery and pulmonary artery catheters and performed moderate cycle ergometer exercise for 6–7 minutes while submersed in 20°C water. SIPE-susceptible subjects repeated the exercise 150 minutes after oral administration of 50 mg sildenafil. Work rate and mean arterial pressure during exercise were similar in controls and SIPE-susceptibles. Average VO2 and cardiac output (CO) in SIPE-susceptibles and controls were: VO2 2.42 L.min−1 vs. 1.95 L.min−1, P=0.2; CO 17.9 L.min−1 vs. 13.8 L.min−1, P=0.01). Accounting for differences in CO between groups, mean pulmonary artery pressure (MPAP) at CO=13.8 L.min−1 was 22.5 mmHg in controls vs. 34.0 mmHg in SIPE-susceptibles (P=0.004) and the corresponding pulmonary artery wedge pressure (PAWP) 11.0 mmHg vs. 18.8 mmHg (P=0.028). After sildenafil, there were no statistically significant differences in MPAP or PAWP between SIPE-susceptibles and controls. Conclusions These observations confirm that SIPE is a form of hemodynamic pulmonary edema. The reduction in pulmonary vascular pressures after sildenafil with no adverse effect on exercise hemodynamics suggests that it may be useful in SIPE prevention. Clinical Trial Registration Information ClinicalTrials.gov. Identifier: NCT00815646.

Background/aimTo address the question as to whether immersion pulmonary oedema (IPO) may be a common cause of death in triathlons, markers of swimming-induced pulmonary oedema (SIPO) susceptibility were sought in triathletes' postmortem examinations.MethodsDeaths while training for or during triathlon events in the USA and Canada from October 2008 to November 2015 were identified, and postmortem reports requested. We assessed obvious causes of death; the prevalence of left ventricular hypertrophy (LVH); comparison with healthy triathletes.ResultsWe identified 58 deaths during the time period of the review, 42 (72.4%) of which occurred during a swim. Of these, 23 postmortem reports were obtained. Five individuals had significant (≥70%) coronary artery narrowing; one each had coronary stents; retroperitoneal haemorrhage; or aortic dissection. 9 of 20 (45%) with reported heart mass exceeded 95th centile values. LV free wall and septal thickness were reported in 14 and 9 cases, respectively; of these, 6 (42.9%) and 4 (44.4%) cases exceeded normal values. 6 of 15 individuals (40%) without an obvious cause of death had excessive heart mass. The proportion of individuals with LVH exceeded the prevalence in the general triathlete population.ConclusionsLVH—a marker of SIPO susceptibility—was present in a greater than the expected proportion of triathletes who died during the swim portion. We propose that IPO may be a significant aetiology of death during the swimming phase in triathletes. The importance of testing for LVH in triathletes as a predictor of adverse outcomes should be explored further.

Swimming-induced pulmonary edema (SIPE) occurs during swimming and scuba diving, usually in cold water, in susceptible healthy individuals, especially military recruits and triathletes. We have previously demonstrated that pulmonary artery (PA) pressure and PA wedge pressure are higher during immersed exercise in SIPE-susceptible individuals versus controls, confirming that SIPE is a form of hemodynamic pulmonary edema. Oral sildenafil 50 mg 1 h before immersed exercise reduced PA pressure and PA wedge pressure, suggesting that sildenafil may prevent SIPE. We present a case of a 46-yr-old female ultratriathlete with a history of at least five SIPE episodes. During a study of an exercise submerged in 20°C water, physiological parameters before and after sildenafil 50 mg orally were as follows: O2 consumption 1.75, 1.76 L·min; HR 129, 135 bpm; arterial pressure 189/88 (mean 121.5), 172/85 (mean 114.3) mm Hg; mean PA pressure 35.3, 28.8 mm Hg; and PA wedge pressure 25.3, 19.7 mm Hg. She has had no recurrences during 20 subsequent triathlons while taking 50 mg sildenafil before each swim. This case supports sildenafil as an effective prophylactic agent against SIPE during competitive surface swimming.

High-grade VGE are increased by mild ambulation conducted under a supersaturated state (Group I vs. II); however, no increase was observed with mild ambulation during the saturated state alone (control vs. Group II).Conkin J, Pollock NW, Natoli MJ, Martina SD, Wessell JH III, Gernhardt ML. Venous gas emboli and ambulation at 4.3 psia. Aerosp Med Hum Perform. 2017; 88(4):370-376.