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 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).
Ezri
T
T
Department of Anesthesia Wolfson Medical Center, Holon, affiliated to the Sackler School of Medicine, Tel Aviv, Israel.
Szmuk
P
P
Warters
R D
RD
Gebhard
R E
RE
Pivalizza
E G
EG
Katz
J
J
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
D000732:Androstanols; D018685:Anesthetics, Inhalation; D003473:Neuromuscular Nondepolarizing Agents; D011412:Propanolamines; D002245:Carbon Dioxide; D004809:Ephedrine; C036604:esmolol; D000077123:Rocuronium