Allocco August, van Waart Hanna, Connell Charlotte Jw, Wong Nicole Ye, Charukonda Abhi, Gant Nicholas, Vrijdag Xavier Ce, Mitchell Simon J
Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.
Department of Anesthesiology, Yale University, New Haven, CT, USA.
Diving Hyperb Med. 2025 Jun 30;55(2):136-144. doi: 10.28920/dhm55.2.136-144.
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-rescue.
Forty participants were randomised to receive either an information leaflet describing hypoxia symptoms or an unblinded hypoxia experience, prior to a blinded hypoxia testing exposure during a virtual reality dive over one month later. The primary outcome was the comparison of the proportion of participants in these two groups who initiated self-rescue before reaching a peripheral oxygen saturation of 70% in the blinded exposure. An individual's 'symptom profile' was assessed by comparing symptoms during the unblinded hypoxia experience and blinded testing exposures.
During the blinded hypoxia testing exposure, 18/20 (90%) participants in the hypoxia experience group performed a self-initiated rescue compared to 6/18 (33%) in the information leaflet group (P < 0.001). Participants in the information leaflet group had lower mean SpO₂ (73.4% vs 81.4%, mean difference 8% [95% CI = 2.5-13.5%, P = 0.005]) and lower inhaled oxygen fraction (7.6% vs 9.4%, mean difference 1.8% [95% CI = 0.6-3.1%, P = 0.005]) at self-rescue. The most frequent and severe symptoms were light-headedness and shortness of breath. Of the 20 participants completing both hypoxia exposures, 14 (70%) had a consistent hypoxia symptom profile, which was not related to the ability to recognise hypoxia.
Self-rescue was approximately three times more likely for participants who had previously experienced hypoxia compared to simply receiving information on relevant symptoms. Most participants exhibited a consistent pattern of individual symptoms, which did not result in earlier or improved detection of hypoxia.
潜水循环呼吸器的故障和人为失误可导致缺氧、氧中毒和/或高碳酸血症。我们评估了先前未设盲的缺氧经历是否能增强潜水员识别缺氧并启动自救的能力。
40名参与者被随机分为两组，一组在一个多月后的虚拟现实潜水中进行盲法缺氧测试暴露前，收到一份描述缺氧症状的信息手册，另一组经历未设盲的缺氧体验。主要结果是比较这两组参与者在盲法暴露中，在周围血氧饱和度降至70%之前启动自救的比例。通过比较未设盲的缺氧体验和盲法测试暴露期间的症状，评估个体的“症状特征”。
在盲法缺氧测试暴露期间，缺氧体验组的20名参与者中有18名（90%）进行了自救，而信息手册组的18名参与者中有6名（33%）进行了自救（P<0.001）。信息手册组的参与者在自救时平均SpO₂较低（73.4%对81.4%，平均差异8%[95%CI=2.5-13.5%，P=0.005]），吸入氧分数也较低（7.6%对9.4%，平均差异1.8%[95%CI=0.6-3.1%，P=0.005]）。最常见和严重的症状是头晕和呼吸急促。在完成两次缺氧暴露的20名参与者中，14名（70%）有一致的缺氧症状特征，这与识别缺氧的能力无关。
与仅接收相关症状信息的参与者相比，先前经历过缺氧的参与者进行自救的可能性大约高三倍。大多数参与者表现出一致且独特的症状模式，但这并未导致对缺氧的更早或更好的检测。
