title: Comparative vascular effects of midazolam and lorazepam administered during cardiopulmonary bypass.
abstract: We studied the comparative vascular effects of midazolam and lorazepam in 52 patients undergoing elective cardiac surgery procedures. After administration of fentanyl, 100 micrograms/kg intravenously, the patients were randomized to receive either midazolam 0.1 mg/kg (M high), midazolam 0.05 mg/kg (M low), lorazepam 0.1 mg/kg (L high), lorazepam 0.05 mg/kg (L low), or placebo during cardiopulmonary bypass (CPB). Compared to the placebo and L-low groups, the high-dose midazolam group had more effect on systemic vascular resistance (SVR) starting at 5 min after study drug administration (P < 0.02). M high and L high required increased quantities of phenylephrine administered to maintain the mean arterial pressure (MAP) at > 50 mm Hg after rewarming and removal of the aortic cross-clamp (P < 0.03). In the first 12 h of the postoperative period, the M-high group required phenylephrine (PHE) infusion for hypotension associated with decreased SVR more often than placebo (8/10 vs 1/11 patients, P < 0.008, chi 2). In conclusion, midazolam more effectively attenuated the increase in SVR that occurred during CPB than patients receiving either placebo or lorazepam. The hemodynamic effects from a single dose of 0.1 mg/kg midazolam administered at the start of CPB may persist into the postoperative period.
authors.affiliation: Department of Anesthesiology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107-5092.
authors.forename: S E
authors.initials: SE
authors.lastname: McNulty
authors.forename: D
authors.initials: D
authors.lastname: Gratch
authors.forename: J Y
authors.initials: JY
authors.lastname: Kim
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D000758:Anesthesia; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage; D006350:Heart Valve Prosthesis; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008140:Lorazepam / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008874:Midazolam / Q000008:administration & dosage / Q000494:pharmacology*; D008875:Middle Aged; D014655:Vascular Resistance / Q000187:drug effects*
chemical_list: D008140:Lorazepam; D008874:Midazolam; D005283:Fentanyl