Figure 3.

Effect of the wavelength and irradiance of light on the carbon monoxide (CO) elimination rate. (A) Effect of phototherapy at 532 (n = 5), 570 (n = 3), 592 (n = 5), 628 (n = 7), and 690 nm (n = 6) wavelength and 54 mW ⋅ cm⁻² irradiance (I) on the time necessary to eliminate 90% of the CO absorbed during the poisoning period (T_90%CO). *P < 0.005 versus 100% O₂ alone, one-way analysis of variance (ANOVA). (B) Effect of phototherapy at 628 nm using either low (n = 4), medium (n = 5), or high (n = 5) power (I = 24, 54, and 80 mW ⋅ cm⁻²) on COHb half-life (COHb-t_1/2). *P < 0.001 versus 100% O₂ alone, ^†P < 0.05 versus low power; ^§P = 0.07 versus medium power, one-way ANOVA. (C) Effect of intermittent phototherapy at 532 nm, 80, 160, or 250 mW ⋅ cm⁻² I and pulse widths of 100, 500, 1,000 ms at a constant frequency of 1 Hz on the T_90%CO (n = 2–4 per treatment group). *P < 0.001 versus 100% O₂ alone, one-way ANOVA. ^†P < 0.001 versus pulse width 500 and 1,000 ms within the same irradiance, ^§P < 0.01 versus I 160 mW ⋅ cm⁻² within the same pulse duration, two-way ANOVA. (D) Relationship between the radiant exposure of light at 532 nm and the T_90%CO, R² = 0.93 (see text for details). All data represent mean ± SD. COHb = carboxyhemoglobin.