HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Georg D. A. Nollert Lennart F. Duebener Jason Sperling Mitsugi Nagashima Richard A. Jonas Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sakamoto, T. Articles by Jonas, R. A. Search for Related Content PubMed PubMed Citation Articles by Sakamoto, T. Articles by Jonas, R. A. Related Collections Cerebral protection

Ann Thorac Surg 2004;77:1656-1663
© 2004 The Society of Thoracic Surgeons

---

Original article: cardiovascular

Hemodilution elevates cerebral blood flow and oxygen metabolism during cardiopulmonary bypass in piglets

^a Department of Cardiovascular Surgery Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
^b Department of Biostatistics Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
^c Department of Neurology Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
^d Department of Radiology, Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA

Accepted for publication October 10, 2003.

^* Address reprint requests to Dr Jonas, Department of Cardiovascular Surgery, Children's Hospital, 300 Longwood Ave, Boston, MA, USA 02115
e-mail: richard.jonas{at}tch.harvard.edu

BACKGROUND: Hemodilution continues to be widely used during cardiopulmonary bypass (CPB) for both adults and children. Previous studies with nonbypass models have suggested that an increase in cerebral blood flow (CBF) compensates for the reduced oxygen-carrying capacity; however, this increased CBF is achieved by an increase in cardiac output. We hypothesized that even with the fixed-flow perfusion of CPB, CBF would be increased during hemodilution.

METHODS: Two experiments were conducted and analyzed separately. In each experiment, 10 piglets were randomized to two different groups, one with a total blood prime yielding a high hematocrit (25% or 30%), and the other with a crystalloid prime resulting in a low hematocrit (10% or 15%). Animals were cooled with pH-stat strategy at full flow (100 or 150 mL · kg^–1 · min^–1) to a nasopharyngeal temperature of 15°C, a period of low flow (50 mL · kg^–1 · min^–1) preceding deep hypothermic circulatory arrest (45 or 60 minutes), and a period of rewarming at full flow. Cerebral blood flow was measured at the beginning of CPB, at the end of cooling, at the end of low flow, 5 minutes after the start of rewarming, and at the end of rewarming by injection of radioactive microspheres.

RESULTS: Mean arterial pressure was significantly greater with higher hematocrit at each time point (p< 0.05). Cerebral blood flow and the cerebral metabolic rate of oxygen decreased during cooling and further during low flow bypass but were significantly greater with lower hematocrit during mild hypothermia and at the end of rewarming (p< 0.05).

CONCLUSIONS: Hemodilution is associated with decreased perfusion pressure, increased CBF and increased the cerebral metabolic rate of oxygen during hypothermic CPB.

This article has been cited by other articles:

				J. K. Shoemaker Hemodilution Impairs Cerebral Autoregulation, Demonstrating the Complexity of Integrative Physiology Anesth. Analg., November 1, 2007; 105(5): 1179 - 1181. [Full Text] [PDF]

				J. C. Halstead, M. Wurm, D. M. Meier, N. Zhang, D. Spielvogel, D. Weisz, C. Bodian, and R. B. Griepp Avoidance of hemodilution during selective cerebral perfusion enhances neurobehavioral outcome in a survival porcine model Eur. J. Cardiothorac. Surg., September 1, 2007; 32(3): 514 - 520. [Abstract] [Full Text] [PDF]

				E. Hickey, T. Karamlou, X. You, C. Komanapalli, T. Person, K. Wehrley, and R. Ungerleider The Use of a Miniaturized Circuit and Bloodless Prime To Avoid Cerebral No-Reflow After Neonatal Cardiopulmonary Bypass Ann. Thorac. Surg., March 1, 2007; 83(3): 895 - 901. [Abstract] [Full Text] [PDF]

				J. Steinbrink, T. Fischer, H. Kuppe, R. Hetzer, K. Uludag, H. Obrig, and W. M. Kuebler Relevance of depth resolution for cerebral blood flow monitoring by near-infrared spectroscopic bolus tracking during cardiopulmonary bypass. J. Thorac. Cardiovasc. Surg., November 1, 2006; 132(5): 1172 - 1178. [Abstract] [Full Text] [PDF]

				E. Hickey, T. Karamlou, J. You, and R. M. Ungerleider Effects of Circuit Miniaturization in Reducing Inflammatory Response to Infant Cardiopulmonary Bypass by Elimination of Allogeneic Blood Products Ann. Thorac. Surg., June 1, 2006; 81(6): S2367 - S2372. [Abstract] [Full Text] [PDF]