[Effects of variations in the ascending speed on the production of circulating gas bubbles after compressed-air diving]. / Effetti della variazione della velocità di risalita sulla produzione di bolle gassose circolanti dopo immersioni ad aria compressa.

ABSTRACT

Ninety-seven compressed air divers at depths of 20 to 52 msw were done. Every dive reached a tissue nitrogen saturation level greater than or equal to M value according to U.S. Navy decompression schedules and respected all prescribed decompression stop. Dives were divided in two groups according to the speed of ascent--1st group 33 dives (18 simulated, 15 open water) with ascent at 18 msw/min. for the first half of the distance and 10 msw/min. for the second half. No work on the bottom. Average ascent rate 14 msw/min. This profile was due to the flow limits of the outlet of our chamber during the second part of the ascent, and it was repeated in open water diving.--2nd group 64 dives (4 simulated, 60 open water) with linear ascent at 10 msw/min. Half the open water dives were repetitive within 4 hours from the first one. Medium to heavy work on the bottom. Ultrasound Doppler bubble detection at rest and after exercise was performed at five minutes intervals and during 40 minutes after surfacing.