Decompression induced venous gas emboli in sport diving: detection with 2D echocardiography and pulsed Doppler

The aim of this study was to determine the utility of pulsed Doppler and 2D echocardiography for the detection and the quantification of circulating bubbles after decompression. Twenty-three sport divers performed 60 SCUBA dives (mean 32 msw). An evaluation of circulating bubbles was performed using 2D images one hour after diving. Circulating bubbles were also detected with pulsed Doppler. The sample volume was placed in the outflow area of the right ventricle 1-2 cm below the pulmonary valve. 2D echocardiography showed circulating bubbles in right cavities of the heart in 32 cases. Short axis parasternal view and right cavities long axis view were the best incidences. Pulsed Doppler confirmed the results in these 32 cases and detected circulating bubbles in seven other cases. Isometric contraction of muscle limb must be performed to increase the sensitivity of detection. The count of the bubbles may be evaluated when using a combination of Spencer's and Powell's grading. We conclude that 2D echocardiography is less accurate than pulsed Doppler in the detection of circulating bubbles after decompression. Further studies are needed to compare pulsed Doppler guided by 2D echocardiography to continuous Doppler for the detection of circulating bubbles.