N exchanges in hyperbaric environments: towards a model based on physiological gas transport (O and CO).

Decompression sickness can occur in divers even when recommended decompression procedures are followed. Furthermore, the physiological state of individuals can significantly affect bubbling variability. These informations highlight the need for personalized input to improve decompression in SCUBA diving.

Scientific shallow saturation dive expedition using diving rebreathers and a specific dry habitat: medical management of the "Capsule" programme.

Background: Scientific underwater exploration could benefit from professional diving facilities. This could allow marine research for durations far exceeding anything currently possible. The closed-circuit rebreather expansion provides new perspectives by unleashing divers and their diving bell.

A new form of admissible pressure for Haldanian decompression models.

In this article, we propose and study a new form of admissible pressure in the Haldanian framework. We then use it to study the surjectivity of the Gradient Factors on the space of the reachable decompression profiles, and investigate a particular case. This case leads to the proposition of a decompression strategy, whose crucial parameter is the ascent rate.

Molecular hydrogen attenuates radiation-induced nucleobase damage to DNA in aerated aqueous solutions.

Purpose: The main aim of the present study is to gain mechanistic insights into the modulating effect of molecular hydrogen on the γ-radiation-induced alteration pathways of DNA nucleobases.

Materials And Methods: Aerated aqueous solutions of calf thymus DNA were exposed to a (60)Co source at doses ranging from 0 to 55 Gy under normoxic conditions, in the presence or not of 0.7 MPa hydrogen or helium.

Doppler detection in Ama divers of Japan.

Objective: Symptoms consistent with neurological decompression sickness (DCS) in commercial breath-hold (Ama) divers has been reported from a few districts of Japan. The aim of this study was to detect circulating intravascular bubbles after repetitive breath-hold diving in a local area where DCS has been reported in Ama divers.

Methods: The participants were 12 partially assisted (descent using weights) male Ama divers.

A closed-circuit rebreather for the characterization of denitrogenation.

Background: The denitrogenation methods currently used to characterize the washout kinetics of body nitrogen require costly devices that are not easily transportable for measurements in real conditions. An original and simple system to measure the denitrogenation kinetics of the human body at rest and at ambient pressure is presented here.

Methods: The nitrogen content accumulated in the loop of a closed-circuit rebreather supplied by pure oxygen was determined using galvanic oxygen sensors and a small size data logger for pressure, temperature, and relative humidity measurements.

Decompression sickness in breath-hold divers: a review.

Although it has been generally assumed that the risk of decompression sickness is virtually zero during a single breath-hold dive in humans, repeated dives may result in a cumulative increase in the tissue and blood nitrogen tension. Many species of marine mammals perform extensive foraging bouts with deep and long dives interspersed by a short surface interval, and some human divers regularly perform repeated dives to 30-40 m or a single dive to more than 200 m, all of which may result in nitrogen concentrations that elicit symptoms of decompression sickness. Neurological problems have been reported in humans after single or repeated dives and recent necropsy reports in stranded marine mammals were suggestive of decompression sickness-like symptoms.

Gender differences in circulating bubble production after SCUBA diving.

Objective: Differences in circulating bubble production have been described after exposures in altitude chambers between men and women. The present study was designed to examine gender differences in circulating bubble production after a dive.

Methods: Fifty-two men and 52 women performed the same dive profile (25 min to 35 m).

Circulating venous bubbles in children after diving.

Doppler ultrasonic detection of circulating venous bubbles after a scuba dive is a useful index of decompression safety in adults, since a relationship between bubbles and the risk of decompression sickness has been documented. No study, however, has investigated circulating venous bubbles in young recreational divers after their usual dives. The aim of this study was to determine whether these bubbles would be detected in children who performed a single dive without any modification in their diving habits.

Activity-based rate-adaptive pacemakers under hyperbaric conditions.

Objectives: The aim of this study was to test a variety of currently available activity-based rate-adaptive pacemakers under hyperbaric conditions.

Background: Sports divers with pacemakers can dive under certain circumstances. The rate response of activity-sensing pacing under hyperbaric conditions has rarely been evaluated.

Bubble incidence after staged decompression from 50 or 60 msw: effect of adding deep stops.

Objectives: The French Navy uses the Marine Nationale 90 (MN90) decompression tables for air dives as deep as 60 msw. The resulting incidence of decompression sickness (DCS) for deep dives (45-60 msw) is one case per 3000 dives.

Methods: Three protocols with experimental ascent profiles (EAPs) were tested in the wet compartment of a hyperbaric chamber.