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.
Copyright: This article is the copyright of the authors who grant Diving and Hyperbaric Medicine a non-exclusive licence to publish the article in electronic and other forms.
Professor Simon Mitchell is the Editor of Diving and Hyperbaric Medicine. He took no part in the peer-review and decision-making processes for this paper, which were managed entirely by the Deputy Editor, Dr Lesley Blogg. There were no other conflicts of interest.
The second and third experiments of this study were supported by funding from the Office for Naval Research Global (ONRG), United States Navy (N62909-18-1-2007).
Figures
Figure 1
Flow diagram of critical fusion…
Figure 1
Flow diagram of critical fusion frequency manual (left) and automatic (middle) modes during…
Figure 1
Flow diagram of critical fusion frequency manual (left) and automatic (middle) modes during experiment one and manual mode (right) during experiments two and three
Figure 2
Diagram summarising procedures in all…
Figure 2
Diagram summarising procedures in all three experiments
Figure 2
Diagram summarising procedures in all three experiments
Kot J, Winklewski PJ.Kot J, et al.Diving Hyperb Med. 2021 Jun 30;51(2):227-228. doi: 10.28920/dhm51.2.227-228.Diving Hyperb Med. 2021.PMID: 34157742Free PMC article.No abstract available.
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