{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,13]],"date-time":"2026-03-13T21:00:55Z","timestamp":1773435655869,"version":"3.50.1"},"reference-count":0,"publisher":"Diving and Hyperbaric Medicine Journal","issue":"4","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diving Hyperb Med"],"abstract":"<jats:p>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: In a dry environment 20 participants wore three types of snorkel equipment in random order: Subea Easybreath FFSM; QingSong 180-degree panoramic FFSM; and a Beuchat Spy conventional snorkel (with nose clip), in three conditions: rest in a chair; light; and moderate intensity exercise on a cycle ergometer. Peripheral oxygen saturation, partial pressure of carbon dioxide (PCO2) and oxygen (PO2) in the end tidal gas and FFSM eye-pockets, respiratory rate, minute ventilation, were measured continuously. Experiments were discontinued if oxygen saturation dropped below 85%, or if end-tidal CO2 exceeded 7.0 kPa. Results: Experimental runs with the FFSMs had to be discontinued more often after exceeding 7.0 kPa end-tidal CO2 compared to a conventional snorkel e.g., 18\/40 (45%) versus 4\/20 (20%) during light intensity exercise, and 9\/22 (41%) versus 3\/16 (19%) during moderate intensity exercise. Thirteen participants exhibited peripheral oxygen saturations below 95% (nine using FFSMs and four using the conventional snorkel) and five fell below 90% (four using FFSMs and one using the conventional snorkel). The PCO2 and PO2 in the eye-pockets of the FFSMs fluctuated and were significantly higher and lower respectively than in inspired gas, which indicated rebreathing in all FFSM wearers. Conclusions: Use of FFSMs may result in rebreathing due to non-unidirectional flow, leading to hypercapnia and hypoxaemia.<\/jats:p>","DOI":"10.28920\/dhm53.4.313-320","type":"journal-article","created":{"date-parts":[[2023,12,14]],"date-time":"2023-12-14T22:32:56Z","timestamp":1702593176000},"page":"313-320","source":"Crossref","is-referenced-by-count":3,"title":["Full-face snorkel masks increase the incidence of hypoxaemia and hypercapnia during simulated snorkelling compared to conventional snorkels"],"prefix":"10.28920","volume":"53","author":[{"name":"Department of Anaesthesiology, University of Auckland, Auckland, New Zealand","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6931-0168","authenticated-orcid":false,"given":"Janneke","family":"Grundemann","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xavier CE","family":"Vrijdag","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"name":"Department of Anaesthesiology, University of Auckland, Auckland, New Zealand","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nicole YE","family":"Wong","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"name":"Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nicholas","family":"Gant","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"name":"Department of Exercise Sciences, University of Auckland, New Zealand","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Simon J","family":"Mitchell","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"name":"Department of Anaesthesiology, University of Auckland, Auckland, New Zealand","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"name":"Department of Anaesthesia, Auckland City Hospital, Auckland, New Zealand","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"name":"Slark Hyperbaric Unit, North Shore Hospital, Auckland, New Zealand","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hanna","family":"van Waart","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"name":"Department of Anaesthesiology, University of Auckland, Auckland, New Zealand","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"11463","published-online":{"date-parts":[[2023,12,20]]},"container-title":["Diving and Hyperbaric Medicine Journal"],"original-title":[],"deposited":{"date-parts":[[2023,12,14]],"date-time":"2023-12-14T22:33:00Z","timestamp":1702593180000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.dhmjournal.com\/index.php\/journals?view=article&id=325"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,12,20]]},"references-count":0,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2023,12,20]]}},"URL":"https:\/\/doi.org\/10.28920\/dhm53.4.313-320","relation":{},"ISSN":["2209-1491"],"issn-type":[{"value":"2209-1491","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,12,20]]}}}