Immersion pulmonary edema


  • Also known as Swimming-Induced Pulmonary Edema (SIPE)[1]
  • Populations affected: Combat swimmers (e.g. Navy SEALs), triathletes, and submersion divers (aka "breath-hold diving")[2]
    • Prevalence approximately 1.8% in combat swimmers
    • Very rare outside these groups
    • Similar to exertion-related pulmonary edema (best described in racehorses)
  • No good evidence-based risk factors identified, but hypertension appears to be associated[2]
    • There may also be some relation to overhydration.[3]
  • Immersion increases cardiac output and doubles pulmonary artery pressures compared to being out of water[2]
    • Blood is also redistributed from extremities to the thorax. This effect is greater in cold water.[4]

Clinical Features[4]

  • Cough, dyspnea and/or hemoptysis immediately after water immersion
  • No history of water aspiration or laryngospasm
  • Hypoxia (SpO2 <92% or A-a gradient >30)
  • CXR opacities consistent with interstitial pulmonary edema or alveolar filling process

Differential Diagnosis

Water-related injuries


Increased bronchial wall visibility (thickening), central peri-hilar haziness, slight alveolar filling, and Kerley B lines (red arrows) consistent with mild pulmonary edema. In this patient, swimming-induced pulmonary edema (SIPE). Also labeled: carina (white arrow) liver and spleen opacity in upper abdomen.
Central haziness with slight alveolar filling and Kerley B lines consistent with swimming-induced pulmonary edema (SIPE)
SIPE patient with greater patchy airspace opacities along and increased interstial markings.
  • Clinical diagnosis, based on history and physical examination
  • CXR
    • opacities consistent with interstitial pulmonary edema or alveolar filling process
  • CBC, BMP
  • May consider ABG


  • Primarily supportive care, including supplemental oxygen[3][5]
    • Remove from water
    • Remove cold clothes and place into a warm environment
    • Albuterol may be used for symptomatic relief
  • Typically resolves completely within 24-48 hours
  • Sildenafil may prevent progression of pulmonary edema[6]
    • Dosing uncertain, consider that the half-life is 4 hours


  • Discharge if asymptomatic or minimal symptoms, normal SpO2
  • Otherwise, admit for observation

See Also


  1. (Accessed 08/17/15)
  2. 2.0 2.1 2.2 Miller CC 3rd, Calder-Becker K, Modave F. Swimming-induced pulmonary edema in triathletes. Am J Emerg Med. 2010 Oct;28(8):941-6.
  3. 3.0 3.1 Yoder JA, Viera AJ. Management of swimming-induced pulmonary edema. Am Fam Physician. 2004 Mar 1;69(5):1046, 1048-9.
  4. 4.0 4.1 Ludwig BB, Mahon RT, Schwartzman EL. Cardiopulmonary function after recovery from swimming-induced pulmonary edema. Clin J Sport Med. 2006 Jul;16(4):348-51.
  5. Lund KL, Mahon RT, Tanen DA, Bakhda S. Swimming-induced pulmonary edema. Ann Emerg Med. 2003 Feb;41(2):251-6.
  6. Moon RE et al. Swimming-Induced Pulmonary Edema: Pathophysiology and Risk Reduction With Sildenafil. Circulation. 2016; CIRCULATIONAHA.115.019464.