Advanced Bubble Detection for Decompression Sickness

Despite decades of research, there are numerous unanswered questions regarding the genesis, evolution, prevention, and treatment of decompression sickness (DCS), a serious risk for individuals exposed to large environmental pressure changes such as divers, rescued submariners, aviators, and astronauts. The elusive nature of DCS partly results from a lack of instrumentation capable of detecting, sizing, and counting bubbles in both the blood stream and/or tissue. Present approaches to the study of DCS rely on a subjective assessment of conventional Doppler ultrasound to quantify the level of decompression stress. No information regarding the bubble size distribution is obtained, and the approach cannot detect the stationary bubbles that might be present in joints and/or tissue. We propose to address these issues by exploiting Creare-developed, pulse-echo ultrasound technology to deliver a novel, bubble detection and sizing instrument. The instrument exploits the resonant properties of gas-filled bubbles, not the Doppler shift associated with their motion. This approach permits the relatively unambiguous detection and sizing of both stationary and moving emboli. During Phase I, we will implement several key enhancements to the existing instrument that are needed for improved usability, and we will demonstrate the enhancements in vivo using a swine model for DCS.