Optimal blood flow for cooled brain at 20 degrees C.
Ann Thorac Surg
; 68(3): 864-9, 1999 Sep.
Article
en En
| MEDLINE
| ID: mdl-10509975
ABSTRACT
BACKGROUND:
Optimal conditions for deep hypothermic perfusion and protective brain blood flow remain unclear.METHODS:
Dogs (n = 52) underwent 120 minutes of cardiopulmonary bypass at 20 degrees C with perfusion flow rates of 2.5, 5, 10, 20, 40, and 100 mL x kg(-1) x min(-1). We examined the effect of the various flow rates and different perfusion pressures on brain blood flow, metabolism, and intracellular pH.RESULTS:
The brain was ischemic and acidotic when the perfusion flow rate was less than 5 mL kg(-1) x min(-1) and pressure was less than 10 mm Hg. When perfusion pressure was higher than 10 mm Hg, cerebral cortex blood flow was more than 9 mL x 100 g(-1) x min(-1) and intracellular pH, higher than 6.95. The cerebral metabolic rate for oxygen decreased at a flow rate of 2.5 mL x kg(-1) min(-1). The cerebral metabolic ratio of glucose to oxygen and the cerebral vascular resistance were lowest when perfusion pressure was 10 to 30 mm Hg. Full-flow (100 mL x kg(-1) x min(-1)) perfusion caused paradoxical brain acidosis; a flow of 40 mL x kg(-1) x min(-1) provided the best results.CONCLUSIONS:
Both extremely low-flow perfusion and excessive perfusion cause brain acidosis. Low-flow perfusion at a pressure of 20 mm Hg provides cerebral vasorelaxation and aerobic metabolism during operations at 20 degrees C.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Puente Cardiopulmonar
/
Circulación Cerebrovascular
/
Hipotermia Inducida
Límite:
Animals
Idioma:
En
Revista:
Ann Thorac Surg
Año:
1999
Tipo del documento:
Article
País de afiliación:
Japón