title: Diazepam's effect on systemic vascular resistance during cardiopulmonary bypass is not caused by its vehicle (alcohol-propylene glycol).
abstract: Control of hemodynamic parameters during cardiopulmonary bypass (CPB) is a desirable goal of the anesthesiologist. Diazepam is known to reduce systemic vascular resistance (SVR) during CPB. This study tested the hypothesis that diazepam reduces SVR during CPB through the action of its vehicle, alcohol-propylene glycol (APG). The study protocol was approved by the Institution's Human Experimentation Review Board and all patients gave informed consent. Premedication, induction, and maintenance of anesthesia were standardized. Thirty consecutive patients undergoing nonemergent cardiac surgical procedures were randomized to receive a standardized amount of diazepam, diazemuls, or alcohol-propylene glycol during stable CPB. SVR in the diazepam group decreased significantly (1,242 to 968 dyne.s.cm-5, P < 0.05) compared to baseline; whereas there was no significant change in SVR in the diazemul group, and a statistically significant increase in SVR (1,217 to 1,537 dyne.s.cm-5, P < 0.05) in the APG group. It is concluded that diazepam reduces SVR during CPB. Diazepam's vehicle does not reduce SVR during CPB, and is in fact associated with an increase in SVR.
authors.affiliation: Queen's University, Kingston General Hospital, Ontario, Canada.
authors.forename: M J
authors.initials: MJ
authors.lastname: Jacka
authors.forename: G D
authors.initials: GD
authors.lastname: Johnson
authors.forename: B
authors.initials: B
authors.lastname: Milne
mesh_terms: D000368:Aged; D000438:Alcohols / Q000494:pharmacology*; D000771:Anesthesia, Intravenous; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D003975:Diazepam / Q000494:pharmacology*; D005260:Female; D006351:Heart Valves / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D014677:Pharmaceutical Vehicles; D011409:Propylene Glycols / Q000494:pharmacology*; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects*
chemical_list: D000438:Alcohols; D014677:Pharmaceutical Vehicles; D011409:Propylene Glycols; C079685:alcohol-propylene glycol; D003975:Diazepam