[Effects of magnesium on the onset time of rocuronium in patients for cesarean delivery].
BACKGROUND
Although magnesium can potentially shorten onset time of a muscle relaxant, it is unclear whether it does shorten the onset time of rocuronium for patients in cesarean delivery (CD). Thus the purpose of this study is to compare the onset time of rocuronium in patients with or without preoperative magnesium treatment.


METHODS
In 9 CD patients without magnesium (CD group) and 8 CD patients with magnesium (CD-Mg group), neuromuscular function was continuously assessed with acceleromyography immediately after induction of general anesthesia with intravenous injection of thiopental (4-5 mg x kg(-1)) and rocuronium (0.6 mg x kg(-1)). Onset time of muscle relaxation, defined by the time from rocuronium bolus injection until complete absence of twitch height, was measured.


RESULTS
The onset time of both groups did not significantly differ (50 +/- 10 seconds vs. 51 +/- 11 seconds; P = 0.93, unpaired t-test). Median magnesium concentration, 5.2 mg x dl(-1) (3.8-6.3), and the onset time of CD-Mg group did not correlate magnesium concentrations (P = 0.23, Pearson's correlation coefficient test).


CONCLUSIONS
Magnesium did not shorten the onset time of rocuronium 0.6 mg x kg(-1) in CD patients.
Yasuyoshi
Y
Sakurai
Michiko
M
Uchida
Junko
J
Aiba
Fumiaki
F
Mimura
Midori
M
Yamaguchi
Masaya
M
Kakumoto
D000328:Adult; D000732:Androstanols / Q000008:administration & dosage / Q000494:pharmacology*; D000768:Anesthesia, General; D000773:Anesthesia, Obstetrical; D002585:Cesarean Section; D004347:Drug Interactions; D005260:Female; D006801:Humans; D017616:Magnesium Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D008875:Middle Aged; D009126:Muscle Relaxation / Q000187:drug effects*; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage / Q000494:pharmacology*; D011247:Pregnancy; D011300:Preoperative Care; D000077123:Rocuronium; D013997:Time Factors
D000732:Androstanols; D017616:Magnesium Compounds; D003473:Neuromuscular Nondepolarizing Agents; D000077123:Rocuronium