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.
