title: Changes in onset time of rocuronium in patients pretreated with ephedrine and esmolol--the role of cardiac output.
abstract: BACKGROUND
  We investigated the hypothesis that manipulation of cardiac output (CO) with esmolol (Es) or ephedrine (E) affects the onset time of rocuronium.
  
  
  METHODS
  Following anesthesia induction, 33 patients received E (70 micro g kg-1), Es (500 micro g kg-1) or placebo (P) 30 s before rocuronium (0.6 mg kg-1) administration. Cardiac output was measured non-invasively after intubation every 3 min. The interval from the end of rocuronium administration to the disappearance of all twitches was considered to be the onset time.
  
  
  RESULTS
  Onset time was shorter after E (52.2 +/- 16.5 s) and longer after Es (114.3 +/- 11.1 s) compared with P (87.4 +/- 7.3 s) (P < 0.0001). Cardiac output increased (P < 0.05) in group E for 15 min after rocuronium. In group Es, CO decreased (P < 0.05) at 3 and 6 min. Cardiac output was higher in group E vs. group Es, 3-6 min post administration of rocuronium (P=0.015).
  
  
  CONCLUSIONS
  Pretreatment with E or Es appears to affect the onset time of rocuronium by altering CO as measured with the NICO (Non-Invasive Cardiac Output) monitor (Novametrix Medical Systems Inc., Willingford, CO).
authors.affiliation: Department of Anesthesia Wolfson Medical Center, Holon, affiliated to the Sackler School of Medicine, Tel Aviv, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Ezri
authors.forename: P
authors.initials: P
authors.lastname: Szmuk
authors.forename: R D
authors.initials: RD
authors.lastname: Warters
authors.forename: R E
authors.initials: RE
authors.lastname: Gebhard
authors.forename: E G
authors.initials: EG
authors.lastname: Pivalizza
authors.forename: J
authors.initials: J
authors.lastname: Katz
mesh_terms: D000293:Adolescent; D000328:Adult; D000732:Androstanols / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000494:pharmacology; D002245:Carbon Dioxide / Q000032:analysis; D002302:Cardiac Output / Q000187:drug effects*; D004311:Double-Blind Method; D004809:Ephedrine / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D011412:Propanolamines / Q000494:pharmacology*; D011446:Prospective Studies; D000077123:Rocuronium; D013997:Time Factors
chemical_list: D000732:Androstanols; D018685:Anesthetics, Inhalation; D003473:Neuromuscular Nondepolarizing Agents; D011412:Propanolamines; D002245:Carbon Dioxide; D004809:Ephedrine; C036604:esmolol; D000077123:Rocuronium