title: Cardiopulmonary bypass impairs vascular endothelial relaxation: effects of gaseous microemboli in dogs.
abstract: Gaseous microemboli during hypothermic cardiopulmonary bypass (CPB) may injure the vascular endothelium and interfere with intrinsic vasomotion. We tested whether gaseous microemboli reduced the vasodilator response to acetylcholine (ACh, 10(-9)-10(-6) M) and potentiated the vasoconstrictor response to norepinephrine (NE, 3 x 10(-8)-10(-4) M). Arteries from 18 dogs were excised before and after 120 min 28 degrees C CPB using membrane (n = 9) and bubble (n = 9) oxygenators to produce microemboli, which were quantitated by Doppler. Five nonbypassed dogs were controls. In isolated vessel rings, the 50% effective dose (ED50) values for ACh (10(-8) M) and NE (10(-7) M) responses were calculated. Mean microemboli count per minute was 0 +/- 0 in the control group, 1.0 +/- 0.4 in the membrane group (P < 0.05 vs. controls), and 46.9 +/- 8.4 in the bubble group (P < 0.05 vs. control and membrane groups). ACh ED50 values did not change in controls but increased in the membrane group from 4.01 +/- 1.52 to 5.66 +/- 1.39 (P < 0.05) and in the bubble group from 2.32 +/- 0.56 to 7.21 +/- 1.90 (P < 0.05). The change in ED50 was greater for bubble than for membrane animals (P < 0.05) but did not correlate with microemboli number (bubble: r = 0.392, P = 0.297; membrane: r = 0.058, P = 0.802). NE responses were similar in all groups. Hypothermic CPB reduces ACh-induced dilation of the canine femoral artery independent of the incidence of gaseous microemboli.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesiology, University of Texas Medical Branch, Galveston 77755-0591.
authors.forename: A E
authors.initials: AE
authors.lastname: Feerick
authors.forename: W E
authors.initials: WE
authors.lastname: Johnston
authors.forename: O
authors.initials: O
authors.lastname: Steinsland
authors.forename: C
authors.initials: C
authors.lastname: Lin
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: T
authors.initials: T
authors.lastname: Uchida
authors.forename: D S
authors.initials: DS
authors.lastname: Prough
mesh_terms: D000818:Animals; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D005263:Femoral Artery / Q000187:drug effects / Q000503:physiopathology; D005740:Gases; D006439:Hemodynamics; D008297:Male; D008863:Microspheres; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D005740:Gases; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents