title: A randomized controlled pilot study of VO2max testing: a potential model for measuring relative in vivo efficacy of different red blood cell products.
abstract: Randomized trials, for example, RECESS, comparing "young" (median, 7-day) versus "middle-aged" (median, 28-day) red blood cells (RBCs), showed no difference in outcome. These data are important; however, they do not inform us about the safety and effectiveness of the oldest RBCs, which some patients receive. It may not be feasible to conduct a clinical trial randomizing patients to receive the oldest blood. Therefore, we propose strenuous exercise (VO2max testing) as a model to study the relative efficacy to increase oxygen delivery to tissue of different RBC products, for example, extremes of storage duration.
  
  
  
  In this pilot study, eight healthy subjects had 2 units of leukoreduced RBCs collected by apheresis in AS-3 using standard methods. Subjects were randomized to receive both (2) units of their autologous RBCs at either 7 or 42 days after blood collection. VO2max testing on a cycle ergometer was performed 2 days before (Monday) and 2 days after (Friday) the transfusion visit (Wednesday). This design avoids confounding effects on intravascular volume from the 2-unit blood transfusion. The primary outcome was the difference in VO2max between Friday and Monday (delta VO2max).
  
  
  
  VO2max increased more in the 7-day RBC arm (8.7 ± 6.9% vs. 1.9 ± 6.5%, p = 0.202 for comparison between arms). Exercise duration (seconds) increased in the 7-day RBC arm (8.4 ± 1.7%) but actually decreased in the 42-day arm (-2.6 ± 3.6%, p = 0.002).
  
  
  
  This pilot study suggests that VO2max testing has potential as a rigorous and quantitative in vivo functional assay of RBC function. Our preliminary results suggest that 42-day RBCs are inferior to 7-day RBCs at delivering oxygen to tissues.
authors.affiliation: Stony Brook University Medical Center, Stony Brook, New York.
authors.forename: Elliott
authors.initials: E
authors.lastname: Bennett-Guerrero
authors.affiliation: University of New Mexico Health Science Center, Albuquerque, New Mexico.|Duke University Medical Center, Durham, North Carolina.
authors.forename: Evelyn L
authors.initials: EL
authors.lastname: Lockhart
authors.affiliation: Duke University Medical Center, Durham, North Carolina.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Bandarenko
authors.affiliation: Duke University Medical Center, Durham, North Carolina.
authors.forename: Mary L
authors.initials: ML
authors.lastname: Campbell
authors.affiliation: Duke University Medical Center, Durham, North Carolina.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Natoli
authors.affiliation: York University, Toronto, Ontario, Canada.
authors.forename: Veronika K
authors.initials: VK
authors.lastname: Jamnik
authors.affiliation: UNC Rex Hospital, Raleigh, North Carolina.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Carter
authors.affiliation: Duke University Medical Center, Durham, North Carolina.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Moon
mesh_terms: D000328:Adult; D001793:Blood Preservation; D001804:Blood Transfusion, Autologous; D017707:Erythrocyte Transfusion; D004912:Erythrocytes; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D010100:Oxygen / Q000097:blood*; D010865:Pilot Projects; D013997:Time Factors
chemical_list: D010100:Oxygen