Immersion Pulmonary Oedema

Background

Immersion pulmonary oedema is being increasingly recognised as a fatal complication of SCUBA diving. It can occur with any type of immersion, so is also worth bearing in mind in swimmers, and is especially recognised in open water triathlon swimmers.

Basic Science and Pathophysiology

When a body is immersed in water, the increased hydrostatic pressure causes redistribution of blood to the chest. This increases cardiac filling pressures and stroke volume, and decreases total lung capacity. This increases pulmonary alveolar capillary pressure, increasing transudation of fluid from capillaries to alveolar spaces, and causing pulmonary oedema.

Risk Factors

Any condition that predisposes to a relatively high left ventricular filling pressures. Most commonly this is hypertension and heart failure.

Clinical presentation

• Cough
• Dyspnoea
• Pink frothy sputum

Investigations

• Chest x-ray

Management

• Sit still, in an upright position
• Keep warm to reduce vasoconstriction
• High flow oxygen
• Vasodilators e.g. nitrates
• Diuretics
• Mechanical ventilation in severe cases
• These patients do not need recompression therapy