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Effects of pH management during selective antegrade cerebral perfusion on cerebral microcirculation and metabolism: alpha-stat versus pH-stat

Dahlbacka, S.; Alaoja, H.; Makela, J.; Niemela, E.; Laurila, P.; Kiviluoma, K.; Honkanen, Anna LU ; Ohtonen, P.; Anttila, V. and Juvonen, T. (2007) In Annals of Thoracic Surgery 84. p.847-855
Abstract
BACKGROUND: Selective cerebral perfusion (SCP) is used for extending the period during which surgical procedures can be safely performed. We sought to determine the direct effects of pH management on cerebral microcirculation and metabolism during SCP. METHODS: An experimental SCP porcine model was created by selectively allowing cold perfusate only into the bicarotid brachiocephalic trunk during the SCP period. Twenty-four piglets (6 to 8 weeks; mean weight, 26.1 +/- 4.1 kg) underwent 15-minute normothermic cardiopulmonary bypass, 45-minute cooling cardiopulmonary bypass, 60-minute SCP at 25 degrees C, and 45-minute rewarming cardiopulmonary bypass with either alpha-stat or pH-stat perfusion strategy randomly assigned. A cranial window... (More)
BACKGROUND: Selective cerebral perfusion (SCP) is used for extending the period during which surgical procedures can be safely performed. We sought to determine the direct effects of pH management on cerebral microcirculation and metabolism during SCP. METHODS: An experimental SCP porcine model was created by selectively allowing cold perfusate only into the bicarotid brachiocephalic trunk during the SCP period. Twenty-four piglets (6 to 8 weeks; mean weight, 26.1 +/- 4.1 kg) underwent 15-minute normothermic cardiopulmonary bypass, 45-minute cooling cardiopulmonary bypass, 60-minute SCP at 25 degrees C, and 45-minute rewarming cardiopulmonary bypass with either alpha-stat or pH-stat perfusion strategy randomly assigned. A cranial window was created over the parietal cortex for visualization of the cerebral vessels with intravital microscopy. Rhodamine-stained leukocytes were observed in cerebral postcapillary venules for adhesion and rolling. Microdialysis analysis was used for determination of brain metabolism. RESULTS: Brain concentration of lactate was significantly higher in the alpha-stat group at 45 minutes of SCP, and at 15- and 45-minute rewarming intervals (p = 0.03; p = 0.003; and p = 0.05; respectively), reaching borderline statistical significance when assessed throughout the experiment (p = 0.06 for differences between groups). Further, at the end of cooling, the oxygen delivery tended to be higher in the pH-stat group (p = 0.07), whereas at the 30-minute rewarming interval, the oxygen extraction tended to be higher in the alpha-stat group (p = 0.06). There were no statistically significant differences between the groups in leukocyte-endothelial interaction, arterial diameter, or tissue oxygenation. CONCLUSIONS: The higher concentration of brain lactate and the tendency to higher oxygen extraction levels during rewarming with alpha-stat strategy suggests anaerobic metabolism occurred during SCP. No major differences between pH management strategies in cerebral microcirculation could be shown during SCP. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Animals, Brain/metabolism, Cardiopulmonary Bypass, Cell Communication, Cerebrovascular Circulation, Dogs, Endothelial Cells/physiology, Female, Hydrogen-Ion Concentration, Lactic Acid/metabolism, Leukocyte Count, Leukocytes/physiology, Microdialysis, Oxygen/metabolism, Perfusion/methods
in
Annals of Thoracic Surgery
volume
84
pages
847 - 855
publisher
Elsevier
external identifiers
  • scopus:34548024029
ISSN
1552-6259
DOI
10.1016/j.athoracsur.2007.03.065
language
English
LU publication?
no
id
34589c89-f1da-4014-92a1-53cc18ecb6a1 (old id 5047039)
date added to LUP
2015-02-10 13:47:43
date last changed
2017-08-20 04:35:17
@article{34589c89-f1da-4014-92a1-53cc18ecb6a1,
  abstract     = {BACKGROUND: Selective cerebral perfusion (SCP) is used for extending the period during which surgical procedures can be safely performed. We sought to determine the direct effects of pH management on cerebral microcirculation and metabolism during SCP. METHODS: An experimental SCP porcine model was created by selectively allowing cold perfusate only into the bicarotid brachiocephalic trunk during the SCP period. Twenty-four piglets (6 to 8 weeks; mean weight, 26.1 +/- 4.1 kg) underwent 15-minute normothermic cardiopulmonary bypass, 45-minute cooling cardiopulmonary bypass, 60-minute SCP at 25 degrees C, and 45-minute rewarming cardiopulmonary bypass with either alpha-stat or pH-stat perfusion strategy randomly assigned. A cranial window was created over the parietal cortex for visualization of the cerebral vessels with intravital microscopy. Rhodamine-stained leukocytes were observed in cerebral postcapillary venules for adhesion and rolling. Microdialysis analysis was used for determination of brain metabolism. RESULTS: Brain concentration of lactate was significantly higher in the alpha-stat group at 45 minutes of SCP, and at 15- and 45-minute rewarming intervals (p = 0.03; p = 0.003; and p = 0.05; respectively), reaching borderline statistical significance when assessed throughout the experiment (p = 0.06 for differences between groups). Further, at the end of cooling, the oxygen delivery tended to be higher in the pH-stat group (p = 0.07), whereas at the 30-minute rewarming interval, the oxygen extraction tended to be higher in the alpha-stat group (p = 0.06). There were no statistically significant differences between the groups in leukocyte-endothelial interaction, arterial diameter, or tissue oxygenation. CONCLUSIONS: The higher concentration of brain lactate and the tendency to higher oxygen extraction levels during rewarming with alpha-stat strategy suggests anaerobic metabolism occurred during SCP. No major differences between pH management strategies in cerebral microcirculation could be shown during SCP.},
  author       = {Dahlbacka, S. and Alaoja, H. and Makela, J. and Niemela, E. and Laurila, P. and Kiviluoma, K. and Honkanen, Anna and Ohtonen, P. and Anttila, V. and Juvonen, T.},
  issn         = {1552-6259},
  keyword      = {Animals,Brain/metabolism,Cardiopulmonary Bypass,Cell Communication,Cerebrovascular Circulation,Dogs,Endothelial Cells/physiology,Female,Hydrogen-Ion Concentration,Lactic Acid/metabolism,Leukocyte Count,Leukocytes/physiology,Microdialysis,Oxygen/metabolism,Perfusion/methods},
  language     = {eng},
  pages        = {847--855},
  publisher    = {Elsevier},
  series       = {Annals of Thoracic Surgery},
  title        = {Effects of pH management during selective antegrade cerebral perfusion on cerebral microcirculation and metabolism: alpha-stat versus pH-stat},
  url          = {http://dx.doi.org/10.1016/j.athoracsur.2007.03.065},
  volume       = {84},
  year         = {2007},
}