Microbubble detection following hyperbaric chamber dives using dual-frequency ultrasound

Area of Science:

• Biomedical Engineering
• Physiology
• Ultrasound Technology

Background:

• Venous gas emboli (VGE) are detectable in blood using ultrasound.
• Current methods cannot detect microbubbles within tissues after decompression.

Purpose of the Study:

• To test the hypothesis that dual-frequency ultrasound (DFU) can detect decompression-induced microbubbles in tissue.
• To establish a novel method for monitoring tissue microbubbles.

Main Methods:

• DFU utilizes a low "pump" frequency and a high "image" frequency to detect microbubbles.
• Experiments were conducted on anesthetized swine subjected to hyperbaric conditions.
• DFU monitored microbubble signals at multiple tissue sites before and after simulated dives.

Main Results:

• A significant increase in DFU signals indicative of microbubbles was observed after hyperbaric exposure (P < 0.01).
• No significant signal changes occurred after a mock dive, confirming the dive-induced nature of the microbubbles.
• The DFU signal increase was sustained and detected at multiple sites across different swine.

Conclusions:

• DFU can detect decompression-induced microbubbles in tissue for the first time.
• DFU shows potential for monitoring microbubble presence and progression at multiple body sites.
• This technology could aid in understanding and managing decompression stress.