Changes in onset time of rocuronium in patients pretreated with ephedrine and esmolol - the role of cardiac output

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 µg kg−1), Es (500 µg 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