The aim of this study was to assess the effect of the ascent rate on the production
of venous circulating bubbles during the decompression following a recreational dive.
Twenty-eight recreational divers performed two open water dives at 35 m during 25
minutes. Ascent rate up to the decompression stop was in one case 9 meter per minute
(m/min) and in the other case 17 m/min. Circulating venous bubbles were screened using
continuous wave Doppler every 10 minutes during one hour after surfacing. Bubbles
Doppler signals were graded according to the Spencer scale (from 0 to IV), and the
Kisman integrated severity score (KISS) was calculated. Statistical analysis demonstrated
a significantly higher bubbles grade and a significantly higher KISS following the
rapid decompression compared to the slow one (respectively p = 0.001 and p = 0.0001).
In conclusion, these results demonstrate that a 9 m/min ascent rate is safer than
a 17 m/min one.
Gas emboli, diving, Doppler, decompression.
