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Immersion Pulmonary Edema in Scuba Diving: Understanding The IPE Risk

Immersion Pulmonary Edema (IPE), also known as immersion pulmonary oedema (IPO), is a condition that divers need to be aware of due to its potential risks.

During or after scuba diving, IPE involves the abnormal leakage of fluid into the lungs. It can occur suddenly and present symptoms such as shortness of breath, coughing, and blood-tinged sputum.

Immersion pulmonary edema can be life-threatening, causing respiratory distress and increasing the risk of drowning. Divers with pre-existing cardiac conditions or hypertension may be more susceptible to IPE.

In this article, I will comprehensively describe the causes, symptoms, risks, advice given by diving organizations and research on IPE.

Immersion Pulmonary Edema: What You Must Know

  • IPE is a medical condition where fluid leaks into the lungs during or after swimming or diving.
  • Symptoms include shortness of breath, coughing, and blood-tinged sputum.
  • IPE poses risks such as respiratory distress and drowning.
  • Divers with pre-existing heart or blood pressure conditions are more vulnerable to IPE.
  • Ongoing research aims to understand the causes, risk factors, and treatment of IPE.

Causes of Immersion Pulmonary Edema

The exact cause of IPE is not fully understood. However, it is believed to involve a combination of factors that can lead to increased pressure in the alveolar capillaries and subsequent leakage of fluid. Some of the possible causes of IPE include:

  1. Hydrostatic pressure changes: Immersion in water causes an increase in hydrostatic pressure, leading to the redistribution of blood from the extremities to the chest. This increased central blood volume can elevate cardiac filling pressures and result in higher pressure in the alveolar capillaries.
  2. Increased pulmonary blood flow: The immersion effect causes increased blood flow to the lungs, further contributing to the increased pressure in the alveolar capillaries.
  3. Increased vascular permeability: It is believed that certain individuals may have increased vascular permeability in their lungs, making them more susceptible to fluid leakage during immersion.
  4. Pre-existing cardiac conditions and hypertension: Individuals with pre-existing cardiac conditions or hypertension may have a higher risk of developing IPE. These conditions can lead to higher baseline alveolar capillary pressures, making them more prone to fluid leakage.
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Overhydration and Immersion Pulmonary Edema

Overhydrating before swimming or diving increases the risk of immersion pulmonary edema (IPE). Excessive fluid intake can disrupt the hydrostatic pressure balance in the lungs, potentially causing IPE.

Divers should be cautious about overhydration, particularly in hot climates during diving vacations. It is important to follow guidelines for proper hydration.

  • Overhydration before diving is associated with increased IPE risk.
  • Overhydration contributes to an elevated hydrostatic pressure gradient, potentially leading to the development of IPE.
  • Proper hydration practices are important for reducing the risk of IPE.
Immersion Pulmonary Edema (Oedema) IPE and IPO in scuba diving
X-ray of pulmonary edema. Attribution: Frank Gaillard, Radiopaedia, Wiki Commons.

Symptoms of Immersion Pulmonary Edema

Recognizing the symptoms of IPE is crucial for prompt identification and appropriate management. The symptoms of IPE may include:

  1. Rapid onset of shortness of breath: Individuals affected by IPE often experience sudden and severe shortness of breath, making it difficult to breathe normally.
  2. Coughing: Coughing is a common symptom of IPE. The cough may be persistent and accompanied by blood-tinged or frothy sputum.
  3. Chest pain: Some individuals may experience chest pain, which can range from mild discomfort to severe.
  4. Fatigue: Fatigue or a general feeling of weakness may be present in individuals with IPE.
  5. Sense of anxiety or impending doom: Some individuals may experience a sense of anxiety or a feeling that something is seriously wrong.

It is important to note that the symptoms of IPE can vary in severity, and in some cases, unconsciousness and cardiac arrest can occur due to hypoxia (low oxygen levels).

Risks Associated with Immersion Pulmonary Edema

IPE can pose significant risks, especially in the diving environment. The impaired gas exchange in the lungs can lead to respiratory distress and make it challenging to breathe properly underwater. This can increase the risk of drowning for individuals affected by IPE. It is crucial to be aware of the potential dangers and take appropriate actions to ensure safety while diving.

Certain factors can increase the risk of developing IPE, including:

  • Pre-existing cardiac conditions: Individuals with pre-existing heart conditions, such as cardiomyopathy or heart valve disorders, may have an increased risk of IPE.
  • Hypertension: High blood pressure can contribute to higher alveolar capillary pressures, making individuals more susceptible to fluid leakage in the lungs.
  • Cold water immersion: Immersion in cold water can lead to increased peripheral vasoconstriction, which raises afterload on the left ventricle and further increases filling pressures in the lungs.
  • Exertion and stress: Physical exertion and stressful events during immersion can elevate blood pressure and contribute to the development of IPE.
  • Inspiring against a negative pressure: Breathing against a negative pressure relative to the pressure at the lung centroid, such as when using a snorkel or certain scuba equipment, can increase the risk of fluid transudation into the alveoli.

It is important to note that even individuals without these risk factors can develop IPE, highlighting the complex nature of the condition.

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Treatment for Immersion Pulmonary Edema

Prompt recognition and appropriate management are crucial when dealing with immersion pulmonary edema (IPE). The primary goals of treatment for IPE are to stabilize the individual, improve oxygenation, and prevent further complications. Here are the key aspects of treatment for IPE:

First Response for Immersion Pulmonary Edema:

  1. Remove from water: If a diver or swimmer exhibits symptoms suggestive of IPE, it is essential to get them out of the water immediately. Continuing the activity in the water can exacerbate the condition.
  2. Ensure safety: Once out of the water, ensure the individual’s safety by keeping them in an upright position if conscious. Do not lie the victim down. A sitting position can improve breathing and gas exchange.
  3. Administer oxygen: Provide the affected individual with 100 percent supplemental oxygen if available. Oxygen therapy helps improve oxygenation and alleviate symptoms associated with hypoxia.
  4. Keep warm: Maintain a warm environment for the individual to reduce peripheral vasoconstriction, which can worsen symptoms.

Medical Treatment for Immersion Pulmonary Edema:

  1. Evaluation by a healthcare professional: It is crucial to seek immediate medical attention for anyone suspected of having IPE. A healthcare professional can assess the severity of the condition and provide appropriate treatment.
  2. Supplemental oxygen: Oxygen therapy should continue as part of medical treatment. This may involve the use of a nasal cannula or a non-rebreather mask to deliver high-flow oxygen.
  3. Diuretics: In some cases, diuretics (commonly known as “water pills”) may be prescribed to help reduce fluid accumulation in the lungs. Diuretics promote increased urine output, which can aid in eliminating excess fluid from the body.
  4. Vasodilators: Medications that help dilate blood vessels, such as nitrates, may be administered to reduce the workload on the heart and improve blood flow.
  5. Mechanical ventilation: In severe cases of IPE, where respiratory distress is severe and oxygenation cannot be adequately maintained, mechanical ventilation may be necessary. This involves using a ventilator to assist with breathing and oxygenation.

It is important to note that the specific treatment approach may vary based on the severity of the condition and individual patient factors. Treatment decisions should be made by a healthcare professional experienced in managing pulmonary edema.

IPE Recurrence and Medical Follow-up:

Individuals who have experienced IPE are at an increased risk of recurrence. Therefore, it is crucial to consider further evaluation and follow-up with a healthcare professional. The underlying causes and potential risk factors should be thoroughly assessed to determine the individual’s suitability to return to diving or swimming activities.

Prevention of Recurrence:

Preventing the recurrence of IPE involves identifying and addressing any underlying risk factors. This may include:

  • A comprehensive evaluation of cardiac function
  • Assessment of blood pressure and management of hypertension
  • Evaluation of lung function
  • Avoidance of overhydration before diving
  • Ensuring appropriate fitness levels and physical conditioning

Returning to diving after an episode of IPE should be approached cautiously and on a case-by-case basis.

IPE Advice from Diving Organizations

Diving organizations play a crucial role in providing advice and guidance to divers regarding the management and prevention of IPE. Here are some recommendations from prominent diving organizations:

  1. Divers Alert Network (DAN): DAN advises that anyone experiencing sudden shortness of breath or persistent cough while diving should abort the dive in a safe manner and breathe 100 percent oxygen on the surface. Further diving should be postponed until a physician can be consulted.
  2. British Sub-Aqua Club (BSAC): The BSAC recognizes the importance of IPE and has been actively raising awareness of the condition within the diving community. They emphasize the need for divers to be aware of the symptoms and seek immediate medical attention if they occur during or after a dive.

By following the advice provided by these organizations, divers can take proactive steps to manage and prevent IPE and ensure their safety while exploring the underwater world.

Research on IPE

Various organizations and researchers have conducted studies to better understand IPE, its causes, and risk factors. Here are some notable research efforts:

  1. Divers Alert Network (DAN): The DAN Medical Information department receives reports of symptoms suggestive of IPE and provides information and guidance to divers. Through their ongoing efforts, they aim to gather data and insights to enhance the understanding of IPE.
  2. United Kingdom Diving Medical Committee (UKDMC): The UKDMC recognizes IPE as a life-threatening condition affecting swimmers and divers. They contribute to research by gathering and analyzing data to improve knowledge about IPE and its implications for divers’ health and safety.
  3. Case reports and studies: Numerous case reports and studies have been published, investigating risk factors, potential mechanisms, and treatment options for IPE. These studies aim to shed light on the condition and provide valuable insights for medical professionals and the diving community.

Research on IPE is ongoing, and the findings contribute to the continuous improvement of diving safety protocols and guidelines.

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Be aware of Immersion Pulmonary Edema (IPE)

Immersion pulmonary edema (IPE) is a condition characterized by the abnormal leakage of fluid into the lungs during or after swimming or diving activities.

  • It can present with symptoms such as a rapid onset of shortness of breath, cough, and blood-tinged, frothy sputum.
  • IPE can be life-threatening and poses risks of respiratory distress and drowning.
  • Avoid over-hydrating before diving.
  • Diving organizations, such as DAN and BSAC, provide advice on managing IPE and raising awareness within the diving community.
  • Research on IPE is ongoing by various organizations and researchers to better understand the condition, its causes, and risk factors.

By staying informed and taking appropriate precautions, divers can mitigate the risks associated with IPE and ensure a safe and enjoyable diving experience. Remember, safe diving practices, adequate physical fitness, and regular medical check-ups are essential for an enjoyable and safe diving experience.

Further Reading on Immersion Pulmonary Edema

DAN ‘Immersion Pulmonary Edema’, Expert Comments on IPE

Dive Magazine ‘Immersion Pulmonary Oedema: the silent killer

UK Diving Medical Committee ‘Immersion Pulmonary Oedema

Shearwater Research ‘IPE by Richard Moon MD

BSAC ‘The hidden killer: Immersion pulmonary oedema (IPO)

Immersion Pulmonary Edema Studies

  1. Wilmshurst PT, Nuri M, Crowther A, Webb-Peplow MM. Cold-induced pulmonary oedema in scuba divers and swimmers and subsequent development of hypertension. Lancet 1989;I:62-65.
  2. Pons M, Blickenstorfer D, Oechslin E, Hold G, Greminger P, Franzeck UK, et al. Pulmonary oedema in healthy persons during scuba-diving and swimming. Eur Respir J 1995;8:762-7.
  3. Weiler-Ravell D, Shupak A, Goldenberg I, Halpern P, Shoshani O, Hirschhorn G et al. Pulmonary oedema and haemoptysis induced by strenuous swimming. BMJ 1995;311:361-2.
  4. Hampson NB, Dunford RG. Pulmonary oedema of scuba divers. Undersea Hyperb Med 1997;24:29-33.
  5. Slade JB, Hattori T, Ray CS, Bove AA, Cianci P. Pulmonary edema associated with scuba diving. Chest 2001;120:1686-94.
  6. Mahon RT, Kerr S, Amundson D, Parrish JS. Immersion pulmonary oedema in special forces combat swimmers. Chest 2002;122:383-4.
  7. Lund KL, Mahon RT, Tanen DA, Bakhda S. Swimming-induced pulmonary edema. Ann Emerg Med 2003;41:251-6.
  8. Wilmshurst PT. Pulmonary oedema induced by emotional stress, by sexual intercourse, and by exertion in a cold environment in people without evidence of heart disease. Heart 2004;90:806-7.
  9. Miller CC, Calder-Becker K, Modave F. Swimming-induced pulmonary edema in triathletes. Am J Emerg Med 2010;28:941-6.
  10. Moon RE, Martina SD, Peacher DF, Kraus WE. Deaths in triathletes: immersion pulmonary oedema as a possible cause. BMJ Open Sport Exerc Med 2016;2:e000146.
  11. Arborelius M, Balldin UI, Lilja B, Lundgren CEG. Hemodynamic changes in man during immersion with the head above water. Aerosp Med 1972;43:592-8.
  12. Shupak A, Guralnik L, Keynan Y, Yahir Y, Adir Y. Pulmonary oedema following closed-circuit oxygen diving and strenuous swimming. Aviat Space Environ Med 2003;74:1201-4.
  13. Gempp E, Louge P, Blatteau JE, Hugon M. Descriptive epidemiology of 153 diving injuries with re-breathers among French military divers from 1979 to 2009. Mil Med 2011;176:446-50.

Learn More About Dive Medicine

As a technical instructor and avid, safety-conscious, diver, I have found the following books to be especially useful:


Andy Davis Technical Sidemount Wreck Diving Subic Bay Philippines RAID Courses Training

About The Author

Andy Davis is a RAID, PADI TecRec, ANDI, BSAC, and SSI-qualified independent technical diving instructor who specializes in teaching sidemount, trimix, and advanced wreck diving courses.

Currently residing in Subic Bay, Philippines; he has amassed more than 10,000 open-circuit and CCR dives over three decades of challenging diving across the globe.

Andy has published numerous diving magazine articles and designed advanced certification courses for several dive training agencies, He regularly tests and reviews new dive gear for scuba equipment manufacturers. Andy is currently writing a series of advanced diving books and creating a range of tech diving clothing and accessories.

Prior to becoming a professional technical diving educator in 2006, Andy was a commissioned officer in the Royal Air Force and has served in Iraq, Afghanistan, Belize, and Cyprus.

In 2023, Andy was named in the “Who’s Who of Sidemount” list by GUE InDepth Magazine.

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A Comprehensive Guide to Backplate & Wing BCDs
Diving Psychology The Path to Proficiency: Mental Strategies for Scuba Divers (eBook)

Originally posted 2023-07-10 13:57:42.

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