1
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Lambert D, Binkley M, Gaskill Z. Underwater and Scuba Diving Accidents. Emerg Med Clin North Am 2024; 42:551-563. [PMID: 38925774 DOI: 10.1016/j.emc.2024.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2024]
Abstract
The evaluation and care of an injured scuba diver requires an understanding of the different types of underwater activities that may be deemed scuba diving. Such activities may range from the complex (eg, commercial or technical diving) all the way up to basic recreational scuba or snorkeling. A thorough physical examination should be completed as early as possible with a focus on specific areas at risk for injury and etiology, such as a detailed cardiopulmonary, skin, and neurologic examination. Serial reassessments and supportive care are as equally important as consultation with a dive medicine expert, especially one with hyperbaric capabilities.
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Affiliation(s)
- David Lambert
- Division of Undersea and Hyperbaric Medicine, University of Pennsylvania, 3610 Hamilton Walk, 1 John Morgan Building, Philadelphia, PA 19104, USA.
| | - Mark Binkley
- Division of Undersea and Hyperbaric Medicine, University of Pennsylvania, 3610 Hamilton Walk, 1 John Morgan Building, Philadelphia, PA 19104, USA
| | - Zachary Gaskill
- Division of Undersea and Hyperbaric Medicine, University of Pennsylvania, 3610 Hamilton Walk, 1 John Morgan Building, Philadelphia, PA 19104, USA
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2
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Vezzoli A, Mrakic-Sposta S, Brizzolari A, Balestra C, Camporesi EM, Bosco G. Oxy-Inflammation in Humans during Underwater Activities. Int J Mol Sci 2024; 25:3060. [PMID: 38474303 DOI: 10.3390/ijms25053060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 02/22/2024] [Accepted: 03/01/2024] [Indexed: 03/14/2024] Open
Abstract
Underwater activities are characterized by an imbalance between reactive oxygen/nitrogen species (RONS) and antioxidant mechanisms, which can be associated with an inflammatory response, depending on O2 availability. This review explores the oxidative stress mechanisms and related inflammation status (Oxy-Inflammation) in underwater activities such as breath-hold (BH) diving, Self-Contained Underwater Breathing Apparatus (SCUBA) and Closed-Circuit Rebreather (CCR) diving, and saturation diving. Divers are exposed to hypoxic and hyperoxic conditions, amplified by environmental conditions, hyperbaric pressure, cold water, different types of breathing gases, and air/non-air mixtures. The "diving response", including physiological adaptation, cardiovascular stress, increased arterial blood pressure, peripheral vasoconstriction, altered blood gas values, and risk of bubble formation during decompression, are reported.
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Affiliation(s)
- Alessandra Vezzoli
- Institute of Clinical Physiology-National Research Council (CNR-IFC), 20142 Milano, Italy
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| | - Simona Mrakic-Sposta
- Institute of Clinical Physiology-National Research Council (CNR-IFC), 20142 Milano, Italy
| | - Andrea Brizzolari
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
| | - Costantino Balestra
- Environmental, Occupational, Aging (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), 1160 Brussels, Belgium
- Physical Activity Teaching Unit, Motor Sciences Department, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
- DAN Europe Research Division (Roseto-Brussels), 1160 Brussels, Belgium
| | | | - Gerardo Bosco
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy
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3
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Šegrt Ribičić I, Valić M, Lušić Kalcina L, Božić J, Obad A, Glavaš D, Glavičić I, Valić Z. Effects of Oxygen Prebreathing on Bubble Formation, Flow-Mediated Dilatation, and Psychomotor Performance during Trimix Dives. Sports (Basel) 2024; 12:35. [PMID: 38275984 PMCID: PMC10820603 DOI: 10.3390/sports12010035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/16/2024] [Accepted: 01/19/2024] [Indexed: 01/27/2024] Open
Abstract
Introduction: This research was performed to examine the effects of air and oxygen prebreathing on bubble formation, flow-mediated dilatation, and psychomotor performance after scuba dives. Methods: Twelve scuba divers performed two dives using a gas mixture of oxygen, nitrogen, and helium (trimix). In a randomized protocol, they breathed air or oxygen 30 min before the trimix dives. Venous bubble formation, flow-mediated dilatation, and psychomotor performance were evaluated. The participants solved three psychomotor tests: determining the position of a light signal, coordination of complex psychomotor activity, and simple arithmetic operations. The total test solving time, minimum single-task solving time, and median solving time were analyzed. Results: The bubble grade was decreased in the oxygen prebreathing protocol in comparison to the air prebreathing protocol (1.5 vs. 2, p < 0.001). The total test solving times after the dives, in tests of complex psychomotor coordination and simple arithmetic operations, were shorter in the oxygen prebreathing protocol (25 (21-28) vs. 31 (26-35) and 87 (82-108) vs. 106 (90-122) s, p = 0.028). Conclusions: In the oxygen prebreathing protocol, the bubble grade was significantly reduced with no change in flow-mediated dilatation after the dives, indicating a beneficial role for endothelial function. The post-dive psychomotor speed was faster in the oxygen prebreathing protocol.
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Affiliation(s)
- Ivana Šegrt Ribičić
- Department of Pulmonary Diseases, University Hospital Center Split, 21000 Split, Croatia;
| | - Maja Valić
- Department of Neuroscience, University of Split School of Medicine, 21000 Split, Croatia;
| | - Linda Lušić Kalcina
- Department of Neuroscience, University of Split School of Medicine, 21000 Split, Croatia;
| | - Joško Božić
- Department of Pathophysiology, University of Split School of Medicine, 21000 Split, Croatia;
| | - Ante Obad
- Department of Health Studies, University of Split, 21000 Split, Croatia;
| | - Duška Glavaš
- Department of Internal Medicine, University of Split School of Medicine, 21000 Split, Croatia;
| | - Igor Glavičić
- Department of Marine Studies, University of Split, 21000 Split, Croatia;
| | - Zoran Valić
- Department of Physiology, University of Split School of Medicine, 21000 Split, Croatia;
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4
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Balestra C, Bosco G, Cialoni D, Kot J, Pelliccia R, Marroni A. Editorial: Physiological telemonitoring and interventional telemedicine in extreme environments. Front Physiol 2024; 14:1353731. [PMID: 38250658 PMCID: PMC10797047 DOI: 10.3389/fphys.2023.1353731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 12/19/2023] [Indexed: 01/23/2024] Open
Affiliation(s)
- C. Balestra
- DAN Europe Research Division, Brussels, Italy
- Environmental, Occupational, Aging (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
- Motor Sciences Department, Physical Activity Teaching Unit, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - G. Bosco
- Environmental Physiology and Medicine Lab, Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - D. Cialoni
- DAN Europe Research Division, Brussels, Italy
- Environmental Physiology and Medicine Lab, Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - J. Kot
- National Centre for Hyperbaric Medicine Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Gdynia, Poland
| | | | - A. Marroni
- DAN Europe Research Division, Brussels, Italy
- Environmental, Occupational, Aging (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
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5
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Muth T, Schipke JD, Brebeck AK, Dreyer S. Assessing Critical Flicker Fusion Frequency: Which Confounders? A Narrative Review. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:medicina59040800. [PMID: 37109758 PMCID: PMC10141404 DOI: 10.3390/medicina59040800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/13/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023]
Abstract
The critical flicker fusion frequency (cFFF) refers to the frequency at which a regularly recurring change of light stimuli is perceived as steady. The cFFF threshold is often assessed in clinics to evaluate the temporal characteristics of the visual system, making it a common test for eye diseases. Additionally, it serves as a helpful diagnostic tool for various neurological and internal diseases. In the field of diving/hyperbaric medicine, cFFF has been utilized to determine alertness and cognitive functions. Changes in the cFFF threshold have been linked to the influence of increased respiratory gas partial pressures, although there exist inconsistent results regarding this effect. Moreover, the use of flicker devices has produced mixed outcomes in previous studies. This narrative review aims to explore confounding factors that may affect the accuracy of cFFF threshold measurements, particularly in open-field studies. We identify five broad categories of such factors, including (1) participant characteristics, (2) optical factors, (3) smoking/drug use, (4) environmental aspects, and (5) breathing gases and partial pressures. We also discuss the application of cFFF measurements in the field of diving and hyperbaric medicine. In addition, we provide recommendations for interpreting changes in the cFFF threshold and how they are reported in research studies.
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Affiliation(s)
- Thomas Muth
- Institute of Occupational, Social, Environmental Medicine, Faculty of Medicine, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Jochen D Schipke
- Research Group Experimental Surgery, University Hospital Düsseldorf, 40225 Düsseldorf, Germany
| | | | - Sven Dreyer
- Hyperbaric Oxygen Therapy, University Hospital Düsseldorf, 40225 Düsseldorf, Germany
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6
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Bosco G, Giacon TA, Paolocci N, Vezzoli A, Noce CD, Paganini M, Agrimi J, Garetto G, Cialoni D, D'Alessandro N, Camporesi EM, Mrakic-Sposta S. Dopamine/BDNF loss underscores narcosis cognitive impairment in divers: a proof of concept in a dry condition. Eur J Appl Physiol 2023; 123:143-158. [PMID: 36214902 DOI: 10.1007/s00421-022-05055-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 09/18/2022] [Indexed: 01/20/2023]
Abstract
PURPOSE Divers can experience cognitive impairment due to inert gas narcosis (IGN) at depth. Brain-derived neurotrophic factor (BDNF) rules neuronal connectivity/metabolism to maintain cognitive function and protect tissues against oxidative stress (OxS). Dopamine and glutamate enhance BDNF bioavailability. Thus, we hypothesized that lower circulating BDNF levels (via lessened dopamine and/or glutamate release) underpin IGN in divers, while testing if BDNF loss is associated with increased OxS. METHODS To mimic IGN, we administered a deep narcosis test via a dry dive test (DDT) at 48 msw in a multiplace hyperbaric chamber to six well-trained divers. We collected: (1) saliva samples before DDT (T0), 25 msw (descending, T1), 48 msw (depth, T2), 25 msw (ascending, T3), 10 min after decompression (T4) to dopamine and/or reactive oxygen species (ROS) levels; (2) blood and urine samples at T0 and T4 for OxS too. We administered cognitive tests at T0, T2, and re-evaluated the divers at T4. RESULTS At 48 msw, all subjects experienced IGN, as revealed by the cognitive test failure. Dopamine and total antioxidant capacity (TAC) reached a nadir at T2 when ROS emission was maximal. At decompression (T4), a marked drop of BDNF/glutamate content was evidenced, coinciding with a persisting decline in dopamine and cognitive capacity. CONCLUSIONS Divers encounter IGN at - 48 msw, exhibiting a marked loss in circulating dopamine levels, likely accounting for BDNF-dependent impairment of mental capacity and heightened OxS. The decline in dopamine and BDNF appears to persist at decompression; thus, boosting dopamine/BDNF signaling via pharmacological or other intervention types might attenuate IGN in deep dives.
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Affiliation(s)
- Gerardo Bosco
- Department of Biomedical Sciences, University of Padova, 35131, Padova, Italy
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD, USA
- Institute of Clinical Physiology, National Research Council (CNR), 20162, Milano, Italy
- ATIP Center for Hyperbaric Medicine, Padova, Italy
| | | | - Nazareno Paolocci
- Department of Biomedical Sciences, University of Padova, 35131, Padova, Italy
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - Alessandra Vezzoli
- Institute of Clinical Physiology, National Research Council (CNR), 20162, Milano, Italy
| | - Cinzia Della Noce
- Institute of Clinical Physiology, National Research Council (CNR), 20162, Milano, Italy
| | - Matteo Paganini
- Department of Biomedical Sciences, University of Padova, 35131, Padova, Italy
| | - Jacopo Agrimi
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | | | - Danilo Cialoni
- Department of Biomedical Sciences, University of Padova, 35131, Padova, Italy
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD, USA
- Institute of Clinical Physiology, National Research Council (CNR), 20162, Milano, Italy
- ATIP Center for Hyperbaric Medicine, Padova, Italy
- Dan Europe Foundation, Research Division, Roseto degli Abbruzzi, Teramo, Italy
| | | | | | - Simona Mrakic-Sposta
- Institute of Clinical Physiology, National Research Council (CNR), 20162, Milano, Italy.
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7
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Comment on Mankowska et al. Critical Flicker Fusion Frequency: A Narrative Review. Medicina 2021, 57, 1096. Medicina (B Aires) 2022; 58:medicina58060739. [PMID: 35744002 PMCID: PMC9227080 DOI: 10.3390/medicina58060739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/18/2022] [Accepted: 05/18/2022] [Indexed: 12/02/2022] Open
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8
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Oxygen-enriched air reduces breathing gas consumption over air. Curr Res Physiol 2022; 5:79-82. [DOI: 10.1016/j.crphys.2022.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/14/2022] [Accepted: 01/27/2022] [Indexed: 11/22/2022] Open
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9
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Pleil JD, Wallace MAG, Davis MD, Matty CM. The physics of human breathing: flow, timing, volume, and pressure parameters for normal, on-demand, and ventilator respiration. J Breath Res 2021; 15:10.1088/1752-7163/ac2589. [PMID: 34507310 PMCID: PMC8672270 DOI: 10.1088/1752-7163/ac2589] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/10/2021] [Indexed: 11/12/2022]
Abstract
Normal breathing for healthy humans is taken for granted; it occurs without conscious effort using ambient (1-atmosphere) pressure with 21% oxygen (O2) concentration. The body automatically adjusts for stress, exercise, altitude, and mild disease by increasing the volume and frequency of breathing. Longer term adaptations for exercise and altitude include increases in red blood cell counts and higher concentrations of capillaries in muscle tissue. When more challenging external environmental conditions or pulmonary illnesses exceed the capability for these adaptations, the human system requires technology to maintain sufficient ventilation to preserve life. On the environmental side there are two conditions to be addressed: toxicity of the surrounding atmosphere and changes in external pressure and O2concentration. On the medical side, mechanisms for assisting breathing include O2supplementation at ambient pressure, positive pressure/flow without additional O2, or a combination of both. This overview describes the various technologies applied to maintaining a safe breathing environment. Topics for environmental intervention include filter-based and flowing air-supply masks for toxic environments (occupational and laboratory protection), and on-demand gas supply systems for firefighters, self-contained underwater breathing apparatus divers, and altitude (high performance aircraft, spacecraft) applications. The topics for medical intervention include nasal cannula, continuous positive airway pressure, and medical ventilators. The primary purpose of this article is to provide a basic understanding of normal human breathing and the adaptation of breathing in different environments using available technologies.
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Affiliation(s)
- Joachim D. Pleil
- Gillings School of Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - M. Ariel Geer Wallace
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Michael D. Davis
- Herman B. Wells Center for Pediatrics Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Christopher M. Matty
- Johnson Space Center, National Aeronautics and Space Administration, Houston, TX, USA
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10
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Piispanen WW, Lundell RV, Tuominen LJ, Räisänen-Sokolowski AK. Assessment of Alertness and Cognitive Performance of Closed Circuit Rebreather Divers With the Critical Flicker Fusion Frequency Test in Arctic Diving Conditions. Front Physiol 2021; 12:722915. [PMID: 34447319 PMCID: PMC8384076 DOI: 10.3389/fphys.2021.722915] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/12/2021] [Indexed: 12/29/2022] Open
Abstract
Introduction: Cold water imposes many risks to the diver. These risks include decompression illness, physical and cognitive impairment, and hypothermia. Cognitive impairment can be estimated using a critical flicker fusion frequency (CFFF) test, but this method has only been used in a few studies conducted in an open water environment. We studied the effect of the cold and a helium-containing mixed breathing gas on the cognition of closed circuit rebreather (CCR) divers. Materials and Methods: Twenty-three divers performed an identical dive with controlled trimix gas with a CCR device in an ice-covered quarry. They assessed their thermal comfort at four time points during the dive. In addition, their skin temperature was measured at 5-min intervals throughout the dive. The divers performed the CFFF test before the dive, at target depth, and after the dive. Results: A statistically significant increase of 111.7% in CFFF values was recorded during the dive compared to the pre-dive values (p < 0.0001). The values returned to the baseline after surfacing. There was a significant drop in the divers’ skin temperature of 0.48°C every 10 min during the dive (p < 0.001). The divers’ subjectively assessed thermal comfort also decreased during the dive (p = 0.01). Conclusion: Our findings showed that neither extreme cold water nor helium-containing mixed breathing gas had any influence on the general CFFF profile described in the previous studies from warmer water and where divers used other breathing gases. We hypothesize that cold-water diving and helium-containing breathing gases do not in these diving conditions cause clinically relevant cerebral impairment. Therefore, we conclude that CCR diving in these conditions is safe from the perspective of alertness and cognitive performance.
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Affiliation(s)
- Wilhelm W Piispanen
- Faculty of Medicine, University of Turku, Turku, Finland.,DAN Europe Research Division, Finnish Branch, Helsinki, Finland
| | - Richard V Lundell
- The Centre for Military Medicine, The Finnish Defense Forces, Helsinki, Finland.,Department of Pathology, Helsinki University, Helsinki, Finland
| | - Laura J Tuominen
- Department of Pathology, Helsinki University, Helsinki, Finland.,Anesthesia and Intensive Care Unit, Tampere University Hospital, Tampere, Finland
| | - Anne K Räisänen-Sokolowski
- DAN Europe Research Division, Finnish Branch, Helsinki, Finland.,The Centre for Military Medicine, The Finnish Defense Forces, Helsinki, Finland.,Department of Pathology, Helsinki University and Helsinki University Hospital, Helsinki, Finland
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11
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Dugrenot E, Balestra C, Gouin E, L'Her E, Guerrero F. Physiological effects of mixed-gas deep sea dives using a closed-circuit rebreather: a field pilot study. Eur J Appl Physiol 2021; 121:3323-3331. [PMID: 34435274 DOI: 10.1007/s00421-021-04798-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 08/19/2021] [Indexed: 12/11/2022]
Abstract
PURPOSE Deep diving using mixed gas with closed-circuit rebreathers (CCRs) is increasingly common. However, data regarding the effects of these dives are still scarce. This preliminary field study aimed at evaluating the acute effects of deep (90-120 msw) mixed-gas CCR bounce dives on lung function in relation with other physiological parameters. METHODS Seven divers performed a total of sixteen open-sea CCR dives breathing gas mixture of helium, nitrogen and oxygen (trimix) within four days at 2 depths (90 and 120 msw). Spirometric parameters, SpO2, body mass, hematocrit, short term heart rate variability (HRV) and critical flicker fusion frequency (CFFF) were measured at rest 60 min before the dive and 120 min after surfacing. RESULTS The median [1st-3rd quartile] of the forced vital capacity was lower (84% [76-93] vs 91% [74-107] of predicted values; p = 0.029), whereas FEV1/FVC was higher (98% [95-99] vs 95% [89-99]; p = 0.019) after than before the dives. The other spirometry values and SpO2 were unchanged. Body mass decreased from 73.5 kg (72.0-89.6) before the dives to 70.0 kg (69.2-85.8) after surfacing (p = 0.001), with no change of hematocrit or CFFT. HRV was increased as indicated by the higher SDNN, RMSSD and pNN50 after than before dives. CONCLUSION The present observation represents the first original data regarding the effects of deep repeated CCR dives. The body mass loss and decrease of FVC after bounce dives at depth of about 100 msw may possibly impose an important physiological stress for the divers.
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Affiliation(s)
- Emmanuel Dugrenot
- TEK diving SAS, F-29200, Brest, France
- Univ Brest, ORPHY, IBSAM, 6 avenue Le Gorgeu, F-29200, Brest, France
| | - Costantino Balestra
- Environmental and Occupational Physiology Laboratory, (ISEK), Haute Ecole Bruxelles-Brabant (HE2B), 1160, Brussels, Belgium
| | | | - Erwan L'Her
- Médecine Intensive et Réanimation, CHRU de Brest, Brest, NA, France
| | - François Guerrero
- Univ Brest, ORPHY, IBSAM, 6 avenue Le Gorgeu, F-29200, Brest, France.
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12
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Möller F, Jacobi E, Hoffmann U, Muth T, Schipke JD. Oxygen-enriched Air Decreases Ventilation during High-intensity Fin-swimming Underwater. Int J Sports Med 2021; 43:230-236. [PMID: 34399427 PMCID: PMC8885326 DOI: 10.1055/a-1554-5093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Oxygen-enriched air is commonly used in the sport of SCUBA-diving and might affect ventilation and heart rate, but little work exists for applied diving settings. We hypothesized that ventilation is decreased especially during strenuous underwater fin-swimming when using oxygen-enriched air as breathing gas. Ten physically-fit divers (age: 25±4; 5 females; 67±113 open-water dives) performed incremental underwater fin-swimming until exhaustion at 4 m water depth with either normal air or oxygen-enriched air (40% O
2
) in a double-blind, randomized within-subject design. Heart rate and ventilation were measured throughout the dive and maximum whole blood lactate samples were determined post-exercise. ANOVAs showed a significant effect for the factor breathing gas (F(1, 9)=7.52; P=0.023; η
2p
=0.455), with a lower ventilation for oxygen-enriched air during fin-swimming velocities of 0.6 m·s
−1
(P=0.032) and 0.8 m·s
−1
(P=0.037). Heart rate, lactate, and time to exhaustion showed no significant differences. These findings indicate decreased ventilation by an elevated oxygen fraction in the breathing gas when fin-swimming in shallow-water submersion with high velocity (>0.5 m·s
−1
). Applications are within involuntary underwater exercise or rescue scenarios for all dives with limited gas supply.
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Affiliation(s)
- Fabian Möller
- Department of Exercise Physiology, German Sport University Cologne, Cologne, Germany
| | - Elena Jacobi
- Department of Exercise Physiology, German Sport University Cologne, Cologne, Germany
| | - Uwe Hoffmann
- Department of Exercise Physiology, German Sport University Cologne, Cologne, Germany
| | - Thomas Muth
- Occupational, Social, Environmental Medicine, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
| | - Jochen D Schipke
- Research Group Experimenal Surgery, University Hospital Düsseldorf, Dusseldorf, Germany
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13
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Vrijdag XC, van Waart H, Sleigh JW, Mitchell SJ. Reply: Commentary on using critical flicker fusion frequency to measure gas narcosis. Diving Hyperb Med 2021; 51:228-229. [PMID: 34157743 DOI: 10.28920/dhm51.2.228-229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 04/26/2021] [Indexed: 11/05/2022]
Affiliation(s)
- Xavier Ce Vrijdag
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.,Address for correspondence: Xavier CE Vrijdag, Department of Anaesthesiology, School of Medicine, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand,
| | - Hanna van Waart
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
| | - Jamie W Sleigh
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.,Department of Anaesthesia, Waikato Hospital, Hamilton, New Zealand
| | - Simon J Mitchell
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.,Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand
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14
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Tetzlaff K, Lemaitre F, Burgstahler C, Luetkens JA, Eichhorn L. Going to Extremes of Lung Physiology-Deep Breath-Hold Diving. Front Physiol 2021; 12:710429. [PMID: 34305657 PMCID: PMC8299524 DOI: 10.3389/fphys.2021.710429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 06/16/2021] [Indexed: 01/03/2023] Open
Abstract
Breath-hold diving involves environmental challenges, such as water immersion, hydrostatic pressure, and asphyxia, that put the respiratory system under stress. While training and inherent individual factors may increase tolerance to these challenges, the limits of human respiratory physiology will be reached quickly during deep breath-hold dives. Nonetheless, world records in deep breath-hold diving of more than 214 m of seawater have considerably exceeded predictions from human physiology. Investigations of elite breath-hold divers and their achievements revised our understanding of possible physiological adaptations in humans and revealed techniques such as glossopharyngeal breathing as being essential to achieve extremes in breath-hold diving performance. These techniques allow elite athletes to increase total lung capacity and minimize residual volume, thereby reducing thoracic squeeze. However, the inability of human lungs to collapse early during descent enables respiratory gas exchange to continue at greater depths, forcing nitrogen (N2) out of the alveolar space to dissolve in body tissues. This will increase risk of N2 narcosis and decompression stress. Clinical cases of stroke-like syndromes after single deep breath-hold dives point to possible mechanisms of decompression stress, caused by N2 entering the vasculature upon ascent from these deep dives. Mechanisms of neurological injury and inert gas narcosis during deep breath-hold dives are still incompletely understood. This review addresses possible hypotheses and elucidates factors that may contribute to pathophysiology of deep freediving accidents. Awareness of the unique challenges to pulmonary physiology at depth is paramount to assess medical risks of deep breath-hold diving.
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Affiliation(s)
- Kay Tetzlaff
- Department of Sports Medicine, University Hospital of Tübingen, Tübingen, Germany
| | - Frederic Lemaitre
- Faculte des Sciences du Sport et de l'Education Physique, Universite de Rouen, Rouen, France
| | - Christof Burgstahler
- Department of Sports Medicine, University Hospital of Tübingen, Tübingen, Germany
| | | | - Lars Eichhorn
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
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15
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Karakaya H, Aksu S, Egi SM, Aydin S, Uslu A. Effects of Hyperbaric Nitrogen Narcosis on Cognitive Performance in Recreational air SCUBA Divers: An Auditory Event-related Brain Potentials Study. Ann Work Expo Health 2021; 65:505-515. [PMID: 33942846 DOI: 10.1093/annweh/wxaa132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 11/21/2020] [Accepted: 12/01/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The narcotic effect of hyperbaric nitrogen is most pronounced in air-breathing divers because it impairs diver's cognitive and behavioral performance, and limits the depth of dive profiles. We aimed to investigate the cognitive effects of simulated (500 kPa) air environments in recreational SCUBA divers, revealed by auditory event-related potentials (AERPs). METHODS A total of 18 healthy volunteer recreational air SCUBA divers participated in the study. AERPs were recorded in pre-dive, deep-dive, and post-dive sessions. RESULTS False-positive score variables were found with significantly higher differences and longer reaction times of hits during deep-dive and post-dive than pre-dive sessions. Also, P3 amplitudes were significantly reduced and peak latencies were prolonged during both deep-dive and post-dive compared with pre-dive sessions. CONCLUSION We observed that nitrogen narcosis at 500 kPa pressure in the dry hyperbaric chamber has a mild-to-moderate negative effect on the cognitive performance of recreational air SCUBA divers, which threatened the safety of diving. Although relatively decreased, this effect also continued in the post-dive sessions. These negative effects are especially important for divers engaged in open-sea diving. Our results show crucial implications for the kinds of control measures that can help to prevent nitrogen narcosis and diving accidents at depths up to 40 msw.
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Affiliation(s)
- Huseyin Karakaya
- Department of Underwater and Hyperbaric Medicine, Istanbul Faculty of Medicine, Istanbul University, Capa, Istanbul, Turkey
| | - Serkan Aksu
- Department of Physiology, Istanbul Faculty of Medicine, Istanbul University, Capa, Istanbul, Turkey
| | - Salih Murat Egi
- Department of Computer Engineering, Faculty of Engineering and Technology, Galatasaray University, Ortakoy, Istanbul, Turkey
| | - Salih Aydin
- Department of Underwater and Hyperbaric Medicine, Istanbul Faculty of Medicine, Istanbul University, Capa, Istanbul, Turkey
| | - Atilla Uslu
- Department of Physiology, Istanbul Faculty of Medicine, Istanbul University, Capa, Istanbul, Turkey
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16
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Kirshenboim I, Aviner B, Itskovits E, Zaslaver A, Broday L. Dopamine-dependent biphasic behaviour under 'deep diving' conditions in Caenorhabditis elegans. Proc Biol Sci 2021; 288:20210128. [PMID: 33715430 PMCID: PMC7944115 DOI: 10.1098/rspb.2021.0128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Underwater divers are susceptible to neurological risks due to their exposure to increased pressure. Absorption of elevated partial pressure of inert gases such as helium and nitrogen may lead to nitrogen narcosis. Although the symptoms of nitrogen narcosis are known, the molecular mechanisms underlying these symptoms have not been elucidated. Here, we examined the behaviour of the soil nematode Caenorhabditis elegans under scuba diving conditions. We analysed wild-type animals and mutants in the dopamine pathway under hyperbaric conditions, using several gas compositions and under varying pressure levels. We found that the animals changed their speed on a flat bacterial surface in response to pressure in a biphasic mode that depended on dopamine. Dopamine-deficient cat-2 mutant animals did not exhibit a biphasic response in high pressure, while the extracellular accumulation of dopamine in dat-1 mutant animals mildly influenced this response. Our data demonstrate that in C. elegans, similarly to mammalian systems, dopamine signalling is involved in the response to high pressure. This study establishes C. elegans as a powerful system to elucidate the molecular mechanisms that underly nitrogen toxicity in response to high pressure.
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Affiliation(s)
- Inbar Kirshenboim
- Department of Cell and Developmental Biology, School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
| | - Ben Aviner
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
| | - Eyal Itskovits
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Alon Zaslaver
- Department of Genetics, Silberman Institute of Life Science, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Limor Broday
- Department of Cell and Developmental Biology, School of Medicine, Tel Aviv University, Tel Aviv, Israel
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17
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Vrijdag XC, van Waart H, Sleigh JW, Balestra C, Mitchell SJ. Investigating critical flicker fusion frequency for monitoring gas narcosis in divers. Diving Hyperb Med 2020; 50:377-385. [PMID: 33325019 PMCID: PMC7872789 DOI: 10.28920/dhm50.4.377-385] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 07/28/2020] [Indexed: 01/14/2023]
Abstract
INTRODUCTION Critical flicker fusion frequency (CFFF) has been used in various studies to measure the cognitive effects of gas mixtures at depth, sometimes with conflicting or apparently paradoxical results. This study aimed to evaluate a novel automatic CFFF method and investigate whether CFFF can be used to monitor gas-induced narcosis in divers. METHODS Three hyperbaric chamber experiments were performed: 1) Automated and manual CFFF measurements during air breathing at 608 kPa (n = 16 subjects); 2) Manual CFFF measurements during air and heliox breathing at sea level (101.3 kPa) and 608 kPa (n = 12); 3) Manual CFFF measurements during oxygen breathing at sea level, 142 and 284 kPa (n = 10). All results were compared to breathing air at sea level. RESULTS Only breathing oxygen at sea level, and at 284 kPa, caused a significant decrease in CFFF (2.5% and 2.6% respectively compared to breathing air at sea level. None of the other conditions showed a difference with sea level air breathing. CONCLUSIONS CFFF did not significantly change in our experiments when breathing air at 608 kPa compared to air breathing at sea level pressure using both devices. Based on our results CFFF does not seem to be a sensitive tool for measuring gas narcosis in divers in our laboratory setting.
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Affiliation(s)
- Xavier Ce Vrijdag
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
- Deep Dive Dubai, Dubai, United Arab Emirates
- Corresponding author: Xavier Vrijdag, Department of Anaesthesiology, School of Medicine, University of Auckland, Private bag 92019, Auckland 1142, New Zealand,
| | - Hanna van Waart
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
| | - Jamie W Sleigh
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
- Department of Anaesthesia, Waikato Hospital, Hamilton, New Zealand
| | - Costantino Balestra
- Environmental, Occupational and Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
| | - Simon J Mitchell
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
- Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand
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18
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Berenji Ardestani S, Matchkov VV, Eftedal I, Pedersen M. A Single Simulated Heliox Dive Modifies Endothelial Function in the Vascular Wall of ApoE Knockout Male Rats More Than Females. Front Physiol 2019; 10:1342. [PMID: 31695628 PMCID: PMC6817487 DOI: 10.3389/fphys.2019.01342] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 10/09/2019] [Indexed: 12/19/2022] Open
Abstract
Introduction The number of divers is rising every year, including an increasing number of aging persons with impaired endothelial function and concomitant atherosclerosis. While diving is an independent modulator of endothelial function, little is known about how diving affects already impaired endothelium. In this study, we questioned whether diving exposure leads to further damage of an already impaired endothelium. Methods A total of 5 male and 5 female ApoE knockout (KO) rats were exposed to simulated diving to an absolute pressure of 600 kPa in heliox gas (80% helium, 20% oxygen) for 1 h in a dry pressure chamber. 10 ApoE KO rats (5 males, 5 females) and 8 male Sprague-Dawley rats served as controls. Endothelial function was examined in vitro by isometric myography of pulmonary and mesenteric arteries. Lipid peroxidation in blood plasma, heart and lung tissue was used as measures of oxidative stress. Expression and phosphorylation of endothelial NO synthase were quantified by Western blot. Results and Conclusion A single simulated dive was found to induce endothelial dysfunction in the pulmonary arteries of ApoE KO rats, and this was more profound in male than female rats. Endothelial dysfunction in males was associated with changing in production or bioavailability of NO; while in female pulmonary arteries an imbalance in prostanoid signaling was observed. No effect of diving was found on mesenteric arteries from rats of either sex. Our findings suggest that changes in endothelial dysfunction were specific for pulmonary circulation. In future, human translation of these findings may suggest caution for divers who are elderly or have prior reduced endothelial function.
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Affiliation(s)
- Simin Berenji Ardestani
- Department of Clinical Medicine, Comparative Medicine Lab, Aarhus University, Aarhus, Denmark.,Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, NTNU: Norwegian University of Science and Technology, Trondheim, Norway
| | | | - Ingrid Eftedal
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, NTNU: Norwegian University of Science and Technology, Trondheim, Norway.,Faculty of Nursing and Health Sciences, Nord University, Bodø, Norway
| | - Michael Pedersen
- Department of Clinical Medicine, Comparative Medicine Lab, Aarhus University, Aarhus, Denmark
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19
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De Bels D, Pierrakos C, Bruneteau A, Reul F, Crevecoeur Q, Marrone N, Vissenaeken D, Borgers G, Balestra C, Honoré PM, Theunissen S. Variation of Cognitive Function During a Short Stay at Hypobaric Hypoxia Chamber (Altitude: 3842 M). Front Physiol 2019; 10:806. [PMID: 31316394 PMCID: PMC6611417 DOI: 10.3389/fphys.2019.00806] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 06/06/2019] [Indexed: 12/12/2022] Open
Abstract
Objective To observe the effects of a fast-acute ascent to high altitude on brain cognitive function and transcranial doppler parameters in order to understand the physiological countermeasures of hypoxia. Methods 17 high-altitude-naïve male subjects (mean age was 26.3 ± 8.1 years) participated in the study. We measured Critical Flicker Fusion Frequency (CFFF), blood oxygen saturation, Psychology Experiment Building (PEBL) including three tests (Modified Math Processing Task, Perceptual Vigilance Task, and Time Estimation Task), as well as Cerebral Blood Flow index (CBFi), mean cerebral artery Systolic and diastolic velocities, Cerebral Pulsatility index (CPi), and heart Rate. All were measured at sea level, at least 1 h after arrival at the hypobaric hypoxia equivalent of 3842 m and 1 h after return to sea level. Results Under acute exposure to hypobaric hypoxic conditions, significant decrease in CFFF [42.1 ± 1 vs. 43.5 ± 1.7 Hz at sea level (asl), p < 0.01], CBFi (611 ± 51 vs. 665 ± 71 asl, p < 0.01) and blood oxygen saturation (83 ± 4% vs. 98 ± 1% asl, p < 0.001) as compared to pre-ascent values were observed. Physiological countermeasures to hypoxia could be involved as there was no significant change in neuropsychometric tests, Systolic and Diastolic velocities and CPi. A significant increase in Heart Rate (81 ± 15 bpm vs. 66 ± 15 bpm asl, p < 0.001) was observed. All parameters returned to their basal values 1 h after regaining sea level. Conclusion Hypoxia results in a decrease in CFFF, CBFi and oxygen saturation and in an increase in heart rate. As it decreased, Cerebral Blood Flow index does not seem to be the physiological measurement of choice to hypoxia explaining the maintenance of cognitive performance after acute exposure to hypobaric hypoxia and requires further investigation. Cerebral oxygen delivery and extraction could be one of the underlying mechanisms.
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Affiliation(s)
- D De Bels
- Department of Intensive Care Medicine, Brugmann University Hospital, Brussels, Belgium.,Unit of Oxygen Study, Translational Research Laboratory, Université Libre de Bruxelles, Brussels, Belgium.,Laboratory of Integrative Physiology, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
| | - C Pierrakos
- Department of Intensive Care Medicine, Brugmann University Hospital, Brussels, Belgium.,Unit of Oxygen Study, Translational Research Laboratory, Université Libre de Bruxelles, Brussels, Belgium
| | - A Bruneteau
- Laboratory of Integrative Physiology, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
| | - F Reul
- Faculty of Medicine, Université catholique de Louvain, Brussels, Belgium
| | - Q Crevecoeur
- Laboratory of Integrative Physiology, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
| | - N Marrone
- Laboratory of Integrative Physiology, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
| | - D Vissenaeken
- Hypobaric Chamber, Queen Astrid Military Hospital, Brussels, Belgium
| | - G Borgers
- Hypobaric Chamber, Queen Astrid Military Hospital, Brussels, Belgium
| | - C Balestra
- Laboratory of Integrative Physiology, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
| | - P M Honoré
- Department of Intensive Care Medicine, Brugmann University Hospital, Brussels, Belgium
| | - S Theunissen
- Laboratory of Integrative Physiology, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
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20
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Lafère P, Hemelryck W, Germonpré P, Matity L, Guerrero F, Balestra C. Early detection of diving-related cognitive impairment of different nitrogen-oxygen gas mixtures using critical flicker fusion frequency. Diving Hyperb Med 2019; 49:119-126. [PMID: 31177518 DOI: 10.28920/dhm49.2.119-126] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 03/08/2019] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Cognitive impairment related to inert gas narcosis (IGN) is a threat to diving safety and operations at depth that might be reduced by using enriched air nitrox (EANx) mixtures. Using critical flicker fusion frequency (CFFF), a possible early detection of cognitive abilities/cerebral arousal impairment when breathing different oxygen (O2) fractions was investigated. METHODS Eight male volunteers performed, in random order, two dry chamber dives breathing either air or EANx40 (40% O₂-60% nitrogen) for 20 minutes (min) at 0.4 MPa. Cognition and arousal were assessed before the dive; upon arrival at 0.4 MPa; after 15 min exposure at 0.4 MPa; on surfacing and 30 min post-dive using behavioural computer-based testing psychology experiment building language (PEBL) and by CFFF while continuously recording brain oxygenation with near-infrared spectroscopy. RESULTS In both breathing conditions, CFFF and PEBL demonstrated a significant inverse correlation (Pearson r of -0.90, P < 0.0001), improved cognitive abilities/cerebral arousal occurred upon arrival at 0.4 MPa followed by a progressive deterioration. Initial brain activation was associated with a significant increase in oxyhaemoglobin (HbO2) and a simultaneous decrease of deoxyhaemoglobin (HHb). The magnitude of the changes was significantly greater under EANx (P = 0.038). CONCLUSIONS Since changes were not related to haemodynamic variables, HbO₂ and HHb values indicate a significant, O₂-dependent activation in the prefrontal cortex. Owing to the correlation with some tests from the PEBL, CFFF could be a convenient measure of cognitive performance/ability in extreme environments, likely under the direct influence of oxygen partial pressure, a potent modulator of IGN symptoms.
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Affiliation(s)
- Pierre Lafère
- DAN Europe Research Division, Roseto, Italy.,Laboratoire ORPHY, EA 4324, UFR sciences et techniques, Université de Bretagne Occidentale, Brest, France.,Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium.,Corresponding author: Pierre Lafère, Laboratoire ORPHY, EA 4324, UFR sciences et techniques, Université de Bretagne Occidentale, 6 Avenue Le Gorgeu - CS 93837, 29238 Brest Cedex 3, France,
| | - Walter Hemelryck
- DAN Europe Research Division, Roseto, Italy.,Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium
| | - Peter Germonpré
- DAN Europe Research Division, Roseto, Italy.,Centre for Hyperbaric Oxygen Therapy, Military Hospital 'Queen Astrid', Brussels
| | | | - François Guerrero
- DAN Europe Research Division, Roseto, Italy.,Laboratoire ORPHY, EA 4324, UFR sciences et techniques, Université de Bretagne Occidentale, Brest, France
| | - Costantino Balestra
- DAN Europe Research Division, Roseto, Italy.,Environmental, Occupational, Ageing (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), Brussels, Belgium.,Anatomical Research and Clinical Studies (ARCS), Vrije Universiteit Brussel (V.U.B.), Brussels.,Anatomical Research Training and Education (ARTE), Vrije Universiteit Brussel (V.U.B.).,Motor Sciences, Université Libre De Bruxelles (U.L.B.), Brussels
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21
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Mirasoglu B, Aktas S. Comments on unresponsive decompression illness case. J Intensive Care 2018; 6:77. [PMID: 30479773 PMCID: PMC6251120 DOI: 10.1186/s40560-018-0347-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 11/14/2018] [Indexed: 12/02/2022] Open
Abstract
We have read the case report about a decompression sickness that was unresponsive to hyperbaric oxygen treatment in your journal. Presented case is intriguing; however, we think there are some contradictive issues in the discussion of the case. In this letter, we aim to comment on these issues that may raise further question. Bubble formation plays a very important role for decompression sickness, but proposed mechanism is incorrect as nitrogen does not change state during decompression. Use of terminology for diving-related diseases and comments on properties of helium may cause misunderstandings. Also importance of history of the dive in evaluating an accident should be emphasized.
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Affiliation(s)
- Bengusu Mirasoglu
- Underwater and Hyperbaric Medicine Department, Istanbul Faculty of Medicine, Istanbul, Turkey
| | - Samil Aktas
- Underwater and Hyperbaric Medicine Department, Istanbul Faculty of Medicine, Istanbul, Turkey
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