Mean arterial pressure about 40 mmHg during CPB is associated with cerebral ischemia in piglets.
OBJECTIVE
To investigate if a mean arterial pressure below 50 mmHg during CPB may lead to cerebral ischemia.


METHODS
Piglets with low mean arterial pressure by nitroprusside (LP-group) (n=6) were compared with piglets given norepinephrine to obtain high pressure (HP-group) (n=6) during normothermic and hypothermic CPB. Intracranial pressure, flow and markers of cerebral energy metabolism (microdialysis) were recorded.


RESULTS
Mean arterial pressure differed significantly between the groups and stabilized about 40-45 mmHg in the LP-group. Cerebral perfusion pressure decreased to 21.3 (7.7) mmHg in the LP-group and increased to 51.8 (11.2) mmHg in the HP-group at 150 min of CPB (P<0.001, between groups). During bypass the intracerebral glucose concentration decreased significantly in the LP-group. In this group the lactate/pyruvate ratio increased from 15.5 (5.3) to 64.5 (87.6) at 90 min and 45.0 (36.5) at 150 min (P<0.05) with no such changes in the HP-group. Similarly the cerebral glycerol concentration increased significantly in the LP-group, whereas glycerol remained stable in the HP-group.


CONCLUSIONS
Mean arterial pressure about 40 mmHg during CPB is associated with cerebral ischemia.
Haugen
Oddbjorn
O
Department of Surgical Sciences, Section for Anesthesiology and Intensive care, University of Bergen, Haukeland University Hospital, N-5021, Bergen, Norway.
Farstad
Marit
M
Lise Kvalheim
Venny
V
Rynning
Stein-Erik
SE
Hammersborg
Stig
S
Mongstad
Arve
A
Husby
Paul
P
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000098:blood supply / Q000378:metabolism; D002545:Brain Ischemia / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D002315:Cardiopulmonary Bypass; D002560:Cerebrovascular Circulation; D005947:Glucose / Q000378:metabolism; D007022:Hypotension / Q000150:complications; D019344:Lactic Acid / Q000378:metabolism; D017551:Microdialysis; D009599:Nitroprusside / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D019289:Pyruvic Acid / Q000378:metabolism; D013552:Swine; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D019344:Lactic Acid; D019289:Pyruvic Acid; D005947:Glucose; D009638:Norepinephrine