Recipient pretreatment with HBO significantly, but transiently, reduces EPO serum levels at the time of UCB transplantation. (A) Serum EPO levels in mU/mL from individual patients who received myeloablative (blue line) and reduced-intensity preparative regimen (red line) plotted over time (in hours) from the start of HBO therapy. (B) The median serum EPO levels (mU/mL) in myeloablative (blue line) and reduced-intensity preparative regimen (red line) are plotted over time (in hours) from the start of HBO therapy. Baseline value (0-hour) was drawn just before HBO therapy. Blood levels were also drawn 6 hours, 8 hours, 24 hours, and 48 hours from the start of HBO.