Measuring whole body inert gas wash-out.

Introduction: Quantifying inert gas wash-out is crucial to understanding the pathophysiology of decompression sickness. In this study, we developed a portable closed-circuit device for measuring inert gas wash-out and validated its precision and accuracy both with and without human subjects.

Methods: We developed an exhalate monitor with sensors for volume, temperature, water vapor and oxygen.

Proposed Thalmann algorithm air diving decompression table for the Swedish Armed Forces.

The Swedish Armed Forces (SwAF) air dive tables are under revision. Currently, the air dive table from the U.S.

Agreement between ultrasonic bubble grades using a handheld self-positioning Doppler product and 2D cardiac ultrasound.

Introduction: Intravascular bubble load after decompression can be detected and scored using ultrasound techniques that measure venous gas emboli (VGE). The aim of this study was to analyse the agreement between ultrasonic bubble grades from a handheld self-positioning product, the O'Dive™, and cardiac 2D ultrasound after decompression.

Methods: VGE were graded with both bilateral subclavian vein Doppler ultrasound (modified Spencer scale) and 2D cardiac images (Eftedal Brubakk scale).

Randomised, controlled, open label, multicentre clinical trial to explore safety and efficacy of hyperbaric oxygen for preventing ICU admission, morbidity and mortality in adult patients with COVID-19.

Introduction: COVID-19 may cause severe pneumonitis and trigger a massive inflammatory response that requires ventilatory support. The intensive care unit (ICU)-mortality has been reported to be as high as 62%. Dexamethasone is the only of all anti-inflammatory drugs that have been tested to date that has shown a positive effect on mortality.

The performance of 'temperature stick' carbon dioxide absorbent monitors in diving rebreathers.

Introduction: Diving rebreathers use canisters containing soda lime to remove carbon dioxide (CO2) from expired gas. Soda lime has a finite ability to absorb CO₂. Temperature sticks monitor the exothermic reaction between CO₂ and soda lime to predict remaining absorptive capacity.

Measurement and modeling of oxygen content in a demand constant mass ratio injection rebreather.

Mechanical semi-closed rebreathers do not need oxygen sensors for their functions, thereby reducing the complexity of the system. However, testing and modeling are necessary in order to determine operational limits as well as the decompression obligation and to avoid hyperoxia and hypoxia. Two models for predicting the oxygen fraction in a demand constant mass ratio injection (DCMRI) rebreather for underwater use were compiled and compared.

Measuring Uptake and Elimination of Nitrogen in Humans at Different Ambient Pressures.

Background: To measure nitrogen (N2) wash-out and uptake requires elaborate set-ups, especially when doing the measurements at increased or decreased ambient pressure. Here we present a transportable device for quantifying N2 turnover in humans which can be used at different ambient pressures.

Methods: A modified close-circuit electronic rebreather was used to assess N2 turnover.

A metabolic simulator for unmanned testing of breathing apparatuses in hyperbaric conditions.

Background: A major part of testing of rebreather apparatuses for underwater diving focuses on the oxygen dosage system.

Methods: A metabolic simulator for testing breathing apparatuses was built and evaluated. Oxygen consumption was achieved through catalytic combustion of propene.

Nitrox permits direct exit for attendants during extended hyperbaric oxygen treatment.

Background: Intermittent breathing of oxygen-enriched air, nitrox (1:1 air:oxygen, 60.5% O2), for attendants in multiplace hyperbaric chambers should enable treatment protocols (HOPAN - hyperbaric oxygen protocol attendants' nitrox) of up to 200 minutes at 2.8 atmospheres absolute (ATA), while retaining the option of a direct decompression and exit.

Investigation of a demand-controlled rebreather in connection with a diving accident.

This paper describes the examination of a Halcyon RB80 semi-closed underwater breathing apparatus used in a diving accident in 2007. The apparatus was supplied with trimix (oxygen, nitrogen and helium) containing 31% oxygen. The duration of the dive was 105 minutes at 28 meters' average depth in fresh water, with a 19-minute oxygen decompression stop at 6 meters.