Combined effects of mild hypothermia and nitrous-oxide-induced narcosis on manual and cognitive performance

Figures

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  Figure 1.. Overview of the experimental protocol of the two ∼12-h test sessions, during which subjects were breathing either normal air or a normoxic gas mixture containing 30% N2O. AIR, normal air; CWIA, 1st cold-water immersion; CWIB, 2nd cold-water immersion; CWIC, 3rd cold-water immersion; NIRS, near-infrared spectroscopy; N2O, nitrous oxide.

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  Figure 2.. Box and whiskers plot (5–95% percentile) and individual values of total mood disturbance derived from the Profile of Mood States-Short Form (A) and mean (SD) and individual values of thermal sensation (B) and comfort (C) obtained during the 3 repeated cold-water immersions (CWIA, 1st cold-water immersion; CWIB, 2nd cold-water immersion; CWIC, 3rd cold-water immersion), while subjects (n = 14 men) were breathing either room air (AIR) or a normoxic gas mixture containing 30% nitrous oxide (N2O). All baseline recordings were performed in room-air breathing conditions. AU, arbitrary units. Data were analyzed with linear mixed-effect models with best-fit covariance structure, followed by Bonferroni post hoc testing (P < 0.05). †Significantly different from baseline. *Significantly different from AIR.

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  Figure 3.. Mean (SD) and individual values of the total number of correctly filled pinholes in the 3-min finger dexterity test performed during the 3 repeated cold-water immersions (CWIA, 1st cold-water immersion; CWIB, 2nd cold-water immersion; CWIC, 3rd cold-water immersion), while subjects (n = 14 men) were breathing either room air (AIR) or a normoxic gas mixture containing 30% nitrous oxide (N2O). Baseline recordings were performed in room-air breathing conditions. Data were analyzed with linear mixed-effect models with best-fit covariance structure, followed by Bonferroni post hoc testing (P < 0.05). †Significantly different from baseline. *Significantly different from AIR.

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  Figure 4.. Mean (SD) and individual values of the composite score derived from the cognitive [Spaceflight Cognitive Assessment Tool for Windows (WinSCAT)] test performed during the 3 repeated cold-water immersions (CWIA, 1st cold-water immersion; CWIB, 2nd cold-water immersion; CWIC, 3rd cold-water immersion), while subjects (n = 14 men; except for AIR CWIA and N2O CWIB where n = 13) were breathing either room air (AIR) or a normoxic gas mixture containing 30% nitrous oxide (N2O). Baseline recordings were performed in room-air breathing conditions. AU, arbitrary units. Data were analyzed with linear mixed-effect models with best-fit covariance structure, followed by Bonferroni post hoc testing (P < 0.05). †Significantly different from baseline. *Significantly different from AIR.

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  Figure 5.. Mean (SD) and individual values of the throughput score for the code substitution (A), the running memory (B), the mathematical processing (C), the match to sample (D), and the delayed code substitution (E) subtests derived from the cognitive (WinSCAT) test performed during the 3 repeated cold-water immersions (CWIA, 1st cold-water immersion; CWIB, 2nd cold-water immersion; CWIC, 3rd cold-water immersion), while subjects (n = 14 men; except for AIR CWIA and N2O CWIB where n = 13) were breathing either room air (AIR) or a normoxic gas mixture containing 30% nitrous oxide (N2O). Baseline recordings were performed in room-air breathing conditions. Data were analyzed with linear mixed-effect models with best-fit covariance structure, followed by Bonferroni post hoc testing (P < 0.05). †Significantly different from baseline. *Significantly different from AIR. §Significantly different from CWIA.