Oxygen Toxicity: Mechanisms in Humans

Summary

The goal of this clinical trial is to learn about the mechanisms of oxygen toxicity in scuba divers. The main questions it aims to answer are: * How does the training of respiratory muscles affect oxygen toxicity? * How do environmental factors, such as sleep deprivation, the ingestion of commonly utilized medications, and chronic exposure to carbon dioxide, impact the risk of oxygen toxicity? * How does immersion in water affect the development of oxygen toxicity? Participants will be asked to do the following: * Undergo a basic screening exam composed of health history, vital signs, and some respiratory function tests * Train their respiratory muscles at regular intervals * Exercise on a cycle ergometer both in dry conditions and underwater/under pressure in the context of medication, sleep deprivation, or carbon dioxide exposure Researchers will compare the performance of each subject before and after the possible interventions described above to see if there are changes in exercise performance, respiratory function, cerebral blood flow, and levels of gene expression.

Timeline

Start

2023-11-28

Primary completion

2026-08-31

Completion

2026-08-31

Publications

• Background Dunworth SA, Natoli MJ, Cooter M, Cherry AD, Peacher DF, Potter JF, Wester TE, Freiberger JJ, Moon RE. Hypercapnia in diving: a review of CO(2) retention in submersed exercise at depth. Undersea Hyperb Med. 2017 May-Jun;44(3):191-209. doi: 10.22462/5.6.2017.1.
• Background Drummond JC. Blood Pressure and the Brain: How Low Can You Go? Anesth Analg. 2019 Apr;128(4):759-771. doi: 10.1213/ANE.0000000000004034.
• Background Lucas SJ, Tzeng YC, Galvin SD, Thomas KN, Ogoh S, Ainslie PN. Influence of changes in blood pressure on cerebral perfusion and oxygenation. Hypertension. 2010 Mar;55(3):698-705. doi: 10.1161/HYPERTENSIONAHA.109.146290. Epub 2010 Jan 18.
• Background Wester TE, Cherry AD, Pollock NW, Freiberger JJ, Natoli MJ, Schinazi EA, Doar PO, Boso AE, Alford EL, Walker AJ, Uguccioni DM, Kernagis D, Moon RE. Effects of head and body cooling on hemodynamics during immersed prone exercise at 1 ATA. J Appl Physiol (1985). 2009 Feb;106(2):691-700. doi: 10.1152/japplphysiol.91237.2008. Epub 2008 Nov 20.
• Background Pendergast DR, Moon RE, Krasney JJ, Held HE, Zamparo P. Human Physiology in an Aquatic Environment. Compr Physiol. 2015 Sep 20;5(4):1705-50. doi: 10.1002/cphy.c140018.
• Background Linnarsson D, Ostlund A, Lind F, Hesser CM. Hyperbaric bradycardia and hypoventilation in exercising men: effects of ambient pressure and breathing gas. J Appl Physiol (1985). 1999 Oct;87(4):1428-32. doi: 10.1152/jappl.1999.87.4.1428.
• Background Oppersma E, Doorduin J, van der Hoeven JG, Veltink PH, van Hees HWH, Heunks LMA. The effect of metabolic alkalosis on the ventilatory response in healthy subjects. Respir Physiol Neurobiol. 2018 Feb;249:47-53. doi: 10.1016/j.resp.2018.01.002. Epub 2018 Jan 4.
• Background Cherry AD, Forkner IF, Frederick HJ, Natoli MJ, Schinazi EA, Longphre JP, Conard JL, White WD, Freiberger JJ, Stolp BW, Pollock NW, Doar PO, Boso AE, Alford EL, Walker AJ, Ma AC, Rhodes MA, Moon RE. Predictors of increased PaCO2 during immersed prone exercise at 4.7 ATA. J Appl Physiol (1985). 2009 Jan;106(1):316-25. doi: 10.1152/japplphysiol.00885.2007. Epub 2008 Sep 11.
• Background Dodson ME, Fryer JM. Postoperative effects of methylphenidate. Br J Anaesth. 1980 Dec;52(12):1265-70. doi: 10.1093/bja/52.12.1265.
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• Background Beecroft J, Duffin J, Pierratos A, Chan CT, McFarlane P, Hanly PJ. Enhanced chemo-responsiveness in patients with sleep apnoea and end-stage renal disease. Eur Respir J. 2006 Jul;28(1):151-8. doi: 10.1183/09031936.06.00075405. Epub 2006 Mar 1.
• Background Yao Q, Pho H, Kirkness J, Ladenheim EE, Bi S, Moran TH, Fuller DD, Schwartz AR, Polotsky VY. Localizing Effects of Leptin on Upper Airway and Respiratory Control during Sleep. Sleep. 2016 May 1;39(5):1097-106. doi: 10.5665/sleep.5762.
• Background Eynan M, Arieli Y, Taran B, Yanir Y. Symptoms of central nervous system oxygen toxicity during 100% oxygen breathing at normobaric pressure with increasing inspired levels of carbon dioxide: a case report. Diving Hyperb Med. 2020 Mar 31;50(1):70-74. doi: 10.28920/dhm50.1.70-74.
• Background Martin BJ. Effect of sleep deprivation on tolerance of prolonged exercise. Eur J Appl Physiol Occup Physiol. 1981;47(4):345-54. doi: 10.1007/BF02332962.

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Indications