Indicators of side-effects with low dose inhaled carbon monoxide.

<p><b>A</b>. Carboxyhemoglobin (COHb) level in blood of animals exposed to carbon monoxide (CO) for 24 hours both before and after lipopolysaccharide (LPS) instillation. Only COHb data from the first mouse removed from the chamber are shown to minimise the confounding effects of dropping the CO concentration upon opening the chamber. ***p<0.001 vs 0 ppm CO, n = 4–5/group. <b>B</b>. Percentage weight loss in the 24 hours following LPS instillation, in mice exposed to 0, 100, 200 or 500 ppm. ***p<0.001 vs 0 ppm CO, n = 8–12/group. <b>C</b>. CO₂ level in chamber. CO₂ levels were recorded every 30 minutes: data represent average level in the 24 hour period prior to LPS instillation (to avoid potential confounding effects of anesthetic/LPS). ***p<0.001 vs 0 ppm CO, n = 3–5 experiments, with 4 mice in the chamber each experiment.