title: The hemodynamic effects of ephedrine on the onset time of rocuronium in pigs.
abstract: Several studies have found a correlation between the onset time of muscle relaxants, cardiac index, and muscle blood flow. Ephedrine increases these hemodynamic variables and shortens onset time of rocuronium in humans. Our aim in this animal study was to determine the effect of ephedrine on the onset time of rocuronium, cardiac index, and muscle blood flow after administration of thiopental. At predefined measuring points, mean arterial blood pressure and cardiac index were measured invasively and onset time was determined mechanomyographically. Twenty-four pigs were randomly assigned to three groups. Group I received etomidate and subsequently rocuronium (2 x 95% effective dose). Instead of etomidate, Group II received thiopental. In Group III, ephedrine 100 mug/kg was given before thiopental; additionally, muscle blood flow was measured (fluorescent microspheres). Although there were differences in hemodynamics between Groups I and II, this was not reflected in different onset times of rocuronium. In Group III, ephedrine compensated the thiopental-induced decrease of mean arterial blood pressure, cardiac index, and muscle blood flow, but no significant shortening of onset time (Group I: 74 +/- 21 s; Group II: 71 +/- 24; Group III: 69 +/- 22 s) was found. Our results demonstrated that ephedrine-related increases in cardiac index and blood flow did not shorten onset time of rocuronium in healthy pigs.
authors.affiliation: *Department of Anesthesiology, †2nd Medical Clinic, and ‡Institute for Neurosurgical Pathophysiology, Johannes Gutenberg-University, Mainz, Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Herweling
authors.forename: Federico
authors.initials: F
authors.lastname: Latorre
authors.forename: Andreas
authors.initials: A
authors.lastname: Herwig
authors.forename: Georg
authors.initials: G
authors.lastname: Horstick
authors.forename: Oliver
authors.initials: O
authors.lastname: Kempski
authors.forename: Hendrik W
authors.initials: HW
authors.lastname: Gervais
mesh_terms: D000732:Androstanols / Q000493:pharmacokinetics / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D004809:Ephedrine / Q000494:pharmacology*; D005045:Etomidate / Q000494:pharmacology; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006993:Hypnotics and Sedatives; D008297:Male; D008475:Median Nerve / Q000187:drug effects; D018482:Muscle, Skeletal / Q000098:blood supply / Q000294:innervation; D009213:Myography; D003473:Neuromuscular Nondepolarizing Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D012039:Regional Blood Flow / Q000187:drug effects; D000077123:Rocuronium; D013552:Swine; D013874:Thiopental / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
chemical_list: D000732:Androstanols; D006993:Hypnotics and Sedatives; D003473:Neuromuscular Nondepolarizing Agents; D014662:Vasoconstrictor Agents; D004809:Ephedrine; D013874:Thiopental; D000077123:Rocuronium; D005045:Etomidate