title: Cerebral blood flow does not change following sodium nitroprusside infusion during hypothermic cardiopulmonary bypass.
abstract: Changes in cerebral blood flow (CBF) associated with decreases in mean arterial pressure (MAP) produced by sodium nitroprusside (SNP) infusion were measured by intra-aortic injection of 133Xe in 17 patients during hypothermic cardiopulmonary bypass (CPB). In each patient, CBF was determined at baseline and then again following SNP-induced reduction of MAP. Two groups were studied. In Group I (n = 9), PaCO2 was maintained near 42 mm Hg uncorrected for nasopharyngeal temperature (NPT). In Group II (n = 8), PaCO2 was maintained near 60 mm Hg, uncorrected for NPT. Nasopharyngeal temperature, MAP, pump oxygenator flow, PaO2, and hematocrit were maintained within a narrow range in each patient during both studies. Since the baseline CBF determinations were conducted at the higher MAP in all subjects, we corrected post-SNP CBF data for the spontaneous decline that occurs over time during CPB. In Group I, a reduction in MAP from 76 +/- 9 mm Hg (mean +/- SD) to 50 +/- 6 mm Hg was associated with a reduction in CBF from 17 +/- 5 to 13 +/- 3 ml.100 g.min-1 (P less than 0.01), a decrease that became statistically insignificant once the time correction factor had been applied (16 +/- 4 ml.100 g-1.min-1). In Group II, MAP declined from 75 +/- 5 mm Hg to 54 +/- 5 mm Hg, and CBF declined from 25 +/- 10 to 17 +/- 7 ml.100 g.min-1 (P less than 0.01), but, again, after time correction, the CBF decline was statistically insignificant (22 +/- 8 ml.100 g-1.min-1).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesia, Bowman Gray School of Medicine of Wake Forest University, Winston-Salem, NC 27103.
authors.forename: A T
authors.initials: AT
authors.lastname: Rogers
authors.forename: D S
authors.initials: DS
authors.lastname: Prough
authors.forename: D A
authors.initials: DA
authors.lastname: Stump
authors.forename: G P
authors.initials: GP
authors.lastname: Gravlee
authors.forename: K C
authors.initials: KC
authors.lastname: Angert
authors.forename: R C
authors.initials: RC
authors.lastname: Roy
authors.forename: S A
authors.initials: SA
authors.lastname: Mills
authors.forename: L
authors.initials: L
authors.lastname: Hinshelwood
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D002315:Cardiopulmonary Bypass; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D005260:Female; D005292:Ferricyanides / Q000494:pharmacology*; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D008875:Middle Aged; D009599:Nitroprusside / Q000494:pharmacology*
chemical_list: D005292:Ferricyanides; D002245:Carbon Dioxide; D009599:Nitroprusside