title: A bovine hemoglobin-based oxygen carrier as pump prime for cardiopulmonary bypass: reduced systemic lactic acidosis and improved cerebral oxygen metabolism during low flow in a porcine model.
abstract: OBJECTIVE
  Cerebral ischemia can occur during cardiopulmonary bypass, especially during low flow. HBOC-201 (OPK Biotech, Cambridge, Mass) is a hemoglobin-based oxygen-carrying solution that enhances oxygen delivery. This project evaluated the benefits on total body and cerebral oxygen delivery and consumption using HBOC-201 during cardiopulmonary bypass.
  
  
  METHODS
  Twelve immature swine were assigned to one of 2 groups. One group used HBOC-201 in pump prime, and the other used donor porcine blood. Cardiopulmonary bypass was initiated and then flow was serially decreased from 100% to 75%, to 50%, and then back to full flow. At each interval, (15)O positron emission tomographic analysis was performed, and blood was collected. Total body and cerebral oxygen delivery and consumption were calculated. Statistical analysis was performed with a Tukey-Kramer adjusted P value based on a repeated measures linear model on log-transformed data.
  
  
  RESULTS
  Total and plasma hemoglobin levels were higher in the HBOC-201 group. Oxygen delivery and consumption were not statistically different but did tend to be higher in the HBOC-201 group. Mixed venous saturation was lower in the HBOC-201 group but not significant. Mild metabolic acidosis with increased lactate levels developed in the blood group. Mean cerebral blood flow decreased in both groups when total flow was 50%. In the HBOC-201 group cerebral oxygen metabolism was maintained.
  
  
  CONCLUSIONS
  The addition of HBOC-201 for cardiopulmonary bypass appears to improve oxygen use and minimize anaerobic metabolism. Cerebral oxygen use was preserved in the HBOC-201 group, even during decrease in blood flow. These findings support the reported improved oxygen-unloading properties of HBOC-201 and might provide a benefit during cardiopulmonary bypass.
authors.affiliation: Department of Surgery, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA. mcneil@uthscsa.edu
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: McNeil
authors.forename: Brandon
authors.initials: B
authors.lastname: Propper
authors.forename: Joshua
authors.initials: J
authors.lastname: Walker
authors.forename: Lauren
authors.initials: L
authors.lastname: Holguin
authors.forename: Lauren
authors.initials: L
authors.lastname: Evans
authors.forename: Kihak
authors.initials: K
authors.lastname: Lee
authors.forename: Peter T
authors.initials: PT
authors.lastname: Fox
authors.forename: Joel E
authors.initials: JE
authors.lastname: Michalek
authors.forename: Clinton E
authors.initials: CE
authors.lastname: Baisden
mesh_terms: D000140:Acidosis, Lactic / Q000517:prevention & control*; D000818:Animals; D001802:Blood Substitutes / Q000627:therapeutic use*; D001921:Brain / Q000378:metabolism*; D002315:Cardiopulmonary Bypass; D002560:Cerebrovascular Circulation; D006454:Hemoglobins / Q000032:analysis / Q000627:therapeutic use*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D013552:Swine
chemical_list: D001802:Blood Substitutes; D006454:Hemoglobins; C096798:HBOC 201; D010100:Oxygen