TY - JOUR
T1 - Regional cerebral blood flow and glucose utilization during hypothermia in newborn dogs
AU - Palmer, C.
AU - Vannucci, R. C.
AU - Christensen, M. A.
AU - Brucklacher, R. M.
PY - 1989
Y1 - 1989
N2 - To ascertain the effect of profound hypothermia on brain function and metabolism, newborn dogs were subjected to surface cooling during which regional cerebral blood flow (rCBF) and glucose utilization (rCGU) were measured with iodo-[14C]-antipyrine and 2-deoxy-[14C]-glucose, respectively. Puppies were anesthetized with nitrous oxide, paralyzed, and their lungs artificially ventilated to maintain arterial normoxia (Pa(O2) > 60 mmHg) and normal acidbase balance (Pa(CO2) = 35-41 mmHg; pH(a) = 7.34-7.42). When rectal temperature was decreased from 37 to 20°C, mean arterial blood pressure (MABP) decreased from 75 to 47 mmHg (P < 0.001) and heart rate from 238 to 64 beats/min (P < 0.001). Arterial P(CO2) was reduced from 38 to 31 mmHg (P < 0.001) (corrected to 37°C),,whereas pH(a) was unchanged from control (7.40). The electroencephalogram slowed progressively and became isoelectric at 22-25° C. During normothermia (n = 6) blood flow to 16 component structures of brain varied from 17 (occipital white matter) to 65 (medulla) ml·100 g-1·min-1, whereas during hypothermia (n = 6) blood flow was lower in all regions (P < 0.001) at remarkably uniform levels (8.3-10.3 ml·100 g-1·min-1). Thus, the greatest reductions (range, 16-48% of control) in CBF occurred in those structures with the highest intrinsic flows during normothermia and were proportionately less in low flow structures. Regional CGU also decreased in all brain regions analyzed (P < 0.001). Normothermic CGU (n = 5) varied from 9 (occipital white matter) to 24 (cerebellum μmol·100 g-1·min-1, whereas during hypothermia rCGU (n = 5), like rCBF was within a narrow range (0.47-0.57 μmol·100 g-1·min-1). The percent reductions in rCGU (range 2.0-6.5% of control) were always greater than corresponding reductions in rCBF. The findings indicate that cerebral glucose utilization is globally depressed during profound hypothermia but that CBF remains more than adequate to support the energy needs of the immature brain.
AB - To ascertain the effect of profound hypothermia on brain function and metabolism, newborn dogs were subjected to surface cooling during which regional cerebral blood flow (rCBF) and glucose utilization (rCGU) were measured with iodo-[14C]-antipyrine and 2-deoxy-[14C]-glucose, respectively. Puppies were anesthetized with nitrous oxide, paralyzed, and their lungs artificially ventilated to maintain arterial normoxia (Pa(O2) > 60 mmHg) and normal acidbase balance (Pa(CO2) = 35-41 mmHg; pH(a) = 7.34-7.42). When rectal temperature was decreased from 37 to 20°C, mean arterial blood pressure (MABP) decreased from 75 to 47 mmHg (P < 0.001) and heart rate from 238 to 64 beats/min (P < 0.001). Arterial P(CO2) was reduced from 38 to 31 mmHg (P < 0.001) (corrected to 37°C),,whereas pH(a) was unchanged from control (7.40). The electroencephalogram slowed progressively and became isoelectric at 22-25° C. During normothermia (n = 6) blood flow to 16 component structures of brain varied from 17 (occipital white matter) to 65 (medulla) ml·100 g-1·min-1, whereas during hypothermia (n = 6) blood flow was lower in all regions (P < 0.001) at remarkably uniform levels (8.3-10.3 ml·100 g-1·min-1). Thus, the greatest reductions (range, 16-48% of control) in CBF occurred in those structures with the highest intrinsic flows during normothermia and were proportionately less in low flow structures. Regional CGU also decreased in all brain regions analyzed (P < 0.001). Normothermic CGU (n = 5) varied from 9 (occipital white matter) to 24 (cerebellum μmol·100 g-1·min-1, whereas during hypothermia rCGU (n = 5), like rCBF was within a narrow range (0.47-0.57 μmol·100 g-1·min-1). The percent reductions in rCGU (range 2.0-6.5% of control) were always greater than corresponding reductions in rCBF. The findings indicate that cerebral glucose utilization is globally depressed during profound hypothermia but that CBF remains more than adequate to support the energy needs of the immature brain.
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U2 - 10.1097/00000542-198911000-00017
DO - 10.1097/00000542-198911000-00017
M3 - Article
C2 - 2817467
AN - SCOPUS:0024397839
SN - 0003-3022
VL - 71
SP - 730
EP - 737
JO - Anesthesiology
JF - Anesthesiology
IS - 5
ER -