Change in breath hydrogen concentration during fast PET. A) Hourly change in PET using standard dialysate. No significant changes were observed. B) Hourly change during PET using H2-enriched dialysate. The hydrogen concentration at 60 min was significantly higher in H2-enriched dialysate than in standard dialysate. C) Breath hydrogen concentrations before, just after, 15 min after, and 30 min after administration of H2-enriched dialysate in three cases. Hydrogen concentrations just after and 15 min after administration were significantly higher than that before administration.