Explanipedia

An unblinded training exposure to hypoxia enhances subsequent hypoxia awareness Open

Xavier C. E. Vrijdag, Hanna van Waart, Charlotte J. W. Connell, Nicole Ye Wong, Abhi Charukonda , et al. · 2025

Introduction: Malfunctions and human errors in diving rebreathers can cause hypoxia, hyperoxia, and/or hypercapnia. We evaluated whether a prior unblinded hypoxia experience enhances a diver’s ability to recognise hypoxia and initiate self…

Electroencephalographic (EEG) changes accompanying normal breathing of concentrated oxygen (hyperoxic ventilation) by healthy adults: a systematic review Open

Xavier C. E. Vrijdag, Luke E. Hallum, Xavier C. E. Vrijdag · 2025

Introduction: Divers often increase their fraction of inspired oxygen (FIO2) to decrease their risk of decompression sickness. However, breathing elevated pressures of oxygen can cause central nervous system oxygen toxicity (CNS-OT). This …

A review of nutritional recommendations for scuba divers Open

Rhiannon J. Brenner, Kiran A. Balan, Marie P. L. Andersen, Emmanuel Dugrenot, Xavier C. E. Vrijdag , et al. · 2024

BACKGROUND: Scuba diving is an increasingly popular activity that involves the use of specialized equipment and compressed air to breathe underwater. Scuba divers are subject to the physiological consequences of being immersed in a high-pr…

Comparing the EMMA capnograph with sidestream capnography and arterial carbon dioxide pressure at 284 kPa Open

Xavier C. E. Vrijdag, Hanna van Waart, C Patrick Sames, Jamie Sleigh, Simon J Mitchell · 2023

Introduction: Capnography aids assessment of the adequacy of mechanical patient ventilation. Physical and physiological changes in hyperbaric environments create ventilation challenges which make end-tidal carbon dioxide (ETCO2) measuremen…

Full-face snorkel masks increase the incidence of hypoxaemia and hypercapnia during simulated snorkelling compared to conventional snorkels Open

Janneke Grundemann, Xavier C. E. Vrijdag, Nicole Ye Wong, Nicholas Gant, Simon J Mitchell , et al. · 2023

Introduction: Air flow in full-face snorkel masks (FFSMs) should be unidirectional to prevent rebreathing of exhaled air. This study evaluated rebreathing and its consequences when using FFSMs compared to a conventional snorkel. Methods: I…

A systematic review of electroencephalography in acute cerebral hypoxia: clinical and diving implications Open

Nicole Ye Wong, Hanna van Waart, Jamie Sleigh, Simon J Mitchell, Xavier C. E. Vrijdag · 2023

Introduction: Hypoxia can cause central nervous system dysfunction and injury. Hypoxia is a particular risk during rebreather diving. Given its subtle symptom profile and its catastrophic consequences there is a need for reliable hypoxia m…

Support-vector classification of low-dose nitrous oxide administration with multi-channel EEG power spectra Open

Xavier C. E. Vrijdag, Luke E. Hallum, E. Tonks, Hanna van Waart, Simon J Mitchell , et al. · 2023

Towards gas narcosis monitoring in compressed gas diving (PhD Academy Award) Open

Xavier C. E. Vrijdag · 2022

Does hyperbaric oxygen cause narcosis or hyperexcitability? A quantitative <span>EEG</span> analysis Open

Xavier C. E. Vrijdag, Hanna van Waart, C Patrick Sames, Simon J Mitchell, Jamie Sleigh · 2022

Divers breathe higher partial pressures of oxygen at depth than at the surface. The literature and diving community are divided on whether or not oxygen is narcotic. Conversely, hyperbaric oxygen may induce dose‐dependent cerebral hyperexc…

Comment on Mankowska et al. Critical Flicker Fusion Frequency: A Narrative Review. Medicina 2021, 57, 1096 Open

Xavier C. E. Vrijdag, Hanna van Waart, Jamie Sleigh, Simon J Mitchell · 2022

We have read with great interest the review by Mankowska et al. [...]

EEG functional connectivity is sensitive for nitrogen narcosis at 608 kPa Open

Xavier C. E. Vrijdag, Hanna van Waart, Rebecca M. Pullon, C Patrick Sames, Simon J Mitchell , et al. · 2022

Divers commonly breathe air, containing nitrogen. Nitrogen under hyperbaric conditions is a narcotic gas. In dives beyond a notional threshold of 30 m depth (405 kPa) this can cause cognitive impairment, culminating in accidents due to poo…

Reply: Commentary on using critical flicker fusion frequency to measure gas narcosis Open

Xavier C. E. Vrijdag, Hanna van Waart, Jamie Sleigh, Simon J Mitchell · 2021

Arterial blood gas measurements during deep open-water breath-hold dives Open

Tom Scott, Hanna van Waart, Xavier C. E. Vrijdag, David C. Mullins, Peter Mesley , et al. · 2021

Arterial blood gas measurements at both maximum depth and the surface before breathing on the same dive have not previously been obtained during deep breath-hold dives in cold open-water conditions and competition dive format. Such measure…

Investigating critical flicker fusion frequency for monitoring gas narcosis in divers Open

Xavier C. E. Vrijdag, Hanna van Waart, Jamie Sleigh, Costantino Balestra, Simon J Mitchell · 2020

(Vrijdag XCE, van Waart H, Sleigh JW, Balestra C, Mitchell SJ. Investigating critical flicker fusion frequency for monitoring gas narcosis in divers. Diving and Hyperbaric Medicine. 2020 December 20;50(4):377–385. doi: 10.28920/dhm50.4.377…

An Electroencephalogram Metric of Temporal Complexity Tracks Psychometric Impairment Caused by Low-dose Nitrous Oxide Open

Xavier C. E. Vrijdag, Hanna van Waart, Simon J Mitchell, Jamie Sleigh · 2020

Background Nitrous oxide produces non–γ-aminobutyric acid sedation and psychometric impairment and can be used as scientific model for understanding mechanisms of progressive cognitive disturbances. Temporal complexity of the electroenceph…

Pupillometry is not sensitive to gas narcosis in divers breathing hyperbaric air or normobaric nitrous oxide Open

Xavier C. E. Vrijdag, Hanna van Waart, Jamie Sleigh, Simon J Mitchell · 2020

Pupillometry is insensitive to the narcotic effect of air at 608 kPa in the dry hyperbaric environment and to the effects of low dose nitrous oxide. Pupillometry is not suitable as a monitoring method for gas narcosis in diving.

Deep anaesthesia: The Thailand cave rescue and its implications for management of the unconscious diver underwater Open

Hanna van Waart, Richard Harris, Nicholas Gant, Xavier C. E. Vrijdag, Craig J Challen , et al. · 2020

The CPAP function of the Interspiro Divator FFM works well configured with open-circuit scuba. This may have contributed to the success of the Thailand cave rescue. Caution is required in generalising this success to other diving scenarios.

Comments on: When neuroscience gets wet and hardcore: neurocognitive markers obtained during whole body water immersion Open

Xavier C. E. Vrijdag · 2017

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