DCS or DCI? The difference and why it matters.

Area of Science:

• Diving Medicine
• Hyperbaric Physiology
• Cardiovascular Physiology

Background:

• Historically, diving injuries were classified as decompression sickness (DCS) or arterial gas embolism (AGE) based on presumed pathophysiology.
• The discovery of patent foramen ovale (PFO) as a route for venous bubbles to enter arterial circulation challenged traditional DCS/AGE distinctions.
• This led to the development of "decompression illness" (DCI) as a descriptive clinical term encompassing both conditions.

Discussion:

• The distinction between DCS and AGE is often blurred, particularly when PFO allows venous bubbles to cause arterial symptoms.
• Using AGE to describe venous bubbles crossing a PFO is misleading, as it implies a different primary event (pulmonary barotrauma).
• Clinical observations suggest that small venous bubbles crossing a PFO are less likely to cause severe stroke-like events compared to large arterial bubbles from barotrauma.

Key Insights:

• A revised nomenclature recommends using DCS for bubble formation from dissolved gas and discourages labeling PFO-related arterial bubbles as AGE.
• The descriptive term DCI is useful for clinical management when pathophysiology is uncertain or irrelevant for treatment.
• Accurate terminology is crucial for clear communication in research and clinical practice regarding bubble-induced dysbaric disease.

Outlook:

• Adoption of standardized terminology will improve clarity in diving medicine research and clinical practice.
• Further research may refine the understanding of bubble dynamics and their specific manifestations in relation to PFO and barotrauma.
• Educating divers and medical professionals on appropriate terminology is essential for effective diagnosis and management of dysbaric injuries.