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The Gradient Perfusion Model Part 2: Substantiation of the GPM with clinical cases
Michael B Strauss1, Lientra Q Lu2, Stuart S Miller1
1Long Beach Memorial Medical Center, Hyperbaric Medical Program, Long Beach, California U.S.
Summary
The Gradient-Perfusion Model (GPM) explains decompression sickness (DCS) causes, including previously unexplained cases. Disordered decompression events are identified as the cause, leading to a new diagnostic term.
Area of Science:
- Physiology
- Diving Medicine
- Biophysics
Background:
- Decompression sickness (DCS) is a risk in diving.
- The Gradient-Perfusion Model (GPM) was previously introduced to explain DCS.
- This study investigates cases initially labeled as unexplained DCS.
Observation:
- A cohort of 500 DCS cases managed over 50 years included initially unexplained presentations.
- Disordering events were identified as the likely cause for these cases.
- Analysis linked tissue involvement with dive history to gradient-perfusion imbalances.
Findings:
- Serious (Type 2) DCS presentations correlate with altered perfusion in fast tissues, where gradients overwhelm offloading capacity.
- Pain-only and neuropathy presentations are linked to gradient limitations in intermediate and slow tissues.
- The GPM successfully accounts for various DCS signs and symptoms.
Implications:
- The GPM provides a framework for understanding DCS etiology.
- It enables appropriate treatment strategies and informed return-to-diving recommendations.
- The term "unexplained DCS" should be replaced with "DCS due to disordered decompression" based on GPM findings.
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