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ADDITIONAL MECHANISMS FOR THE ORIGIN OF BUBBLES IN ANIMALS DECOMPRESSED TO SIMULATED ALTITUDES
W E Berg1, M Harris, D M Whitaker
1Department of Biology, Stanford University.
The Journal of General Physiology
|October 30, 2009
Summary
High-fat meals do not cause decompression sickness. However, freezing body water or fracturing bones in frogs can create bubbles, a phenomenon relevant to high-altitude flight.
Area of Science:
- Physiology
- Biophysics
- Barotrauma
Background:
- Decompression sickness is a risk in diving and aviation.
- The formation of gas bubbles in tissues is the primary cause of decompression sickness.
- Understanding the nucleation and growth of bubbles is crucial for preventing decompression sickness.
Purpose of the Study:
- To investigate factors that contribute to bubble formation in vivo.
- To determine if high-fat diets increase susceptibility to bubble formation.
- To explore the role of physical trauma and temperature changes in bubble nucleation.
Main Methods:
- Rats and bullfrogs were fed emulsified fats and then subjected to decompression.
- Liquid caprylic acid was injected into bullfrog veins and subjected to cooling.
- Bullfrogs were cooled to induce freezing of body water, and bone fractures were induced.
- Bubble formation was observed following decompression in all experimental conditions.
Main Results:
- Ingestion of frothy, emulsified fats did not increase bubble formation susceptibility after decompression.
- Injection of liquid caprylic acid into veins led to crystallization and bubble formation upon cooling and decompression.
- Freezing body water in bullfrogs (e.g., to -10°C) resulted in bubble formation upon rewarming and decompression, even without exercise.
- Fracturing leg bones in frogs produced bubble nuclei that persisted for up to an hour, leading to bubble formation upon decompression.
Conclusions:
- High-fat diets do not appear to increase the risk of decompression sickness.
- Physical processes like crystallization of endogenous substances (e.g., water) and mechanical disruption (bone fracture) can create bubble nuclei.
- These findings have implications for understanding bubble formation in physiological conditions, particularly concerning high-altitude flight.
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