Bubble Formation After a 20-m Dive: Deep-
Stop vs. Shallow-Stop Decompression Profiles
Authors: Schellart, Nico A.M.
; Brandt Corstius, Jan-Jaap
; Germonpré, Peter
; Sterk, Wouter
Source: Aviation, Space, and Environmental Medicine, Volume 79, Number 5, May , 2008 , pp.
Publisher: Aerospace Medical Association
Schellart NAM, Brandt Corstius J-J, Germonpré P, Sterk W. Bubble formation after a 20-m
dive: deep-stop vs. shallow-stop decompression profiles. Aviat Space Environ Med 2008; 79:488-
Objectives: It is claimed that performing a “deep stop,” a stop at about half of maximal diving depth
(MDD), can reduce the amount of detectable precordial bubbles after the dive and may thus diminish
the risk of decompression sickness. In order to ascertain whether this reduction is caused by the deep
stop or by a prolonged decompression time, we wanted to test the “deep stop” theory without increas-
ing the total decompression time. From a modeling point of view, Haldanian theory states that this
situation would increase the probability of observable bubbles, because of a longer stay at depth. Un-
der these conditions, we examined whether a “deep-stop dive” (DSD) produces more bubbles or less
than a “shallow-stop dive” (SSD).
Methods: Recreational divers performed either a DSD or a SSD. Both groups were matched biometri-
cally. MDD was 20 msw, bottom time 40 min and total diving time 47 min. In DSD, the “deep” stop
(10 msw) replaced 3 min of the 7 min stop at 4 msw of SSD.
Results : DSD produced significantly more precordial bubbles than SSD after knee bends (P-
values ranging from 0.00007 to 0.038).
Discussion: Our results indicate that at least for the tested dive profile, the higher supersaturations af-
ter surfacing overruled any possible beneficial effects of the deep stop on bubble formation. The use-
fulness of substituting a shallow stop with a deep stop in dives up to 20 msw can be questioned; at the
least, more research is needed.
References: 12 references open in new window
Articles that cite this article?
Keywords: diving; shallow stop; deep stop; VGE; bubble grade; decompression theory
Document Type: Research article
Affiliations: 1: From the Department of Medical Physics, Academic Medical Centre, University of
Amsterdam, The Netherlands (N. A. M. Schellart); Foundation of Diving Research, Amsterdam, The
Netherlands (N. A. M. Schellart); Scott Haldane Foundation, Loosdrecht, The Netherlands (J-J.
Brandt Corstius); Centre for Hyperbaric Oxygen Therapy, Military Hospital Brussels, Belgium (P.
Germonpré); and Dadcodat, Zuidwolde, The Netherlands (W. Sterk).