Severe hemodilutional anemia increases cerebral tissue injury following acute neurotrauma
Anemia may worsen neurological outcomes following traumatic brain injury (TBI) by undefined mechanisms. We hypothesized that hemodilutional anemia accentuates hypoxic cerebral injury following TBI. Anesthetized rats underwent unilateral TBI or sham injury (n ≥ 7). Target hemoglobin concentrations between 50 and 70 g/l were achieved by exchanging 40-50% of the blood volume (1:1) with pentastarch. The effect of TBI, anemia, and TBI-anemia was assessed by measuring brain tissue oxygen tension (PbrO ), regional cerebral blood flow (rCBF), jugular venous oxygen saturation (SjvO ), cerebral contusion area, and nuclear staining for programmed cell death. Baseline postinjury PbrO values in the TBI and TBI-anemia groups (9.3 ± 1.3 and 11.3 ± 4.1 Torr, respectively) were lower than the uninjured controls (18.2 ± 5.2 Torr, P < 0.05 for both). Hemodilution caused a further reduction in PbrO in the TBI-anemia group relative to the TBI group without anemia (7.8 ± 2.7 vs. 14.8 ± 3.9 Torr, P < 0.05). The rCBF remained stable after TBI and increased comparably after hemodilution in both anemia and TBI-anemia groups. The SjvO was elevated after TBI (87.4 ± 8.9%, P < 0.05) and increased further following hemodilution (95.0 ± 1.6%, P < 0.05). Cerebral contusion area and nuclear counts for programmed cell death were increased following TBI-anemia (4.1 ± 3.0 mm and 686 ± 192, respectively) relative to TBI alone (1.3 ± 0.3 mm and 404 ± 133, respectively, P < 0.05 for both). Hemodilutional anemia reduced cerebral PbrO and oxygen extraction and increased cell death following TBI. These results support our hypothesis that acute anemia accentuated hypoxic cerebral injury after neurotrauma. Copyright © 2007 the American Physiological Society. 2 2 2 2 2 2 2 2
Journal of Applied Physiology
Digital Object Identifier (DOI)
Hare, Gregory M.T.; Mazer, C. David; Hutchison, James S.; McLaren, Anya T.; Liu, Elaine; Rassouli, Alipasha; Ai, Jinglu; Shaye, Rachel E.; Lockwood, Julia A.; Hawkins, Cynthia E.; Sikich, Nancy; To, Kevin; and Baker, Andrew J., "Severe hemodilutional anemia increases cerebral tissue injury following acute neurotrauma" (2007). Neurobiology. 1006.