End-tidal concentration of sevoflurane for preventing rocuronium-induced withdrawal of the arm in pediatric patients.
BACKGROUND
During induction of general anesthesia, the intravenous injection of rocuronium is often associated with withdrawal movement of the arm due to pain, and this abrupt withdrawal may result in dislodgement of the venous catheter, injury, or inadequate injection of rocuronium. We performed this study to evaluate the 50 and 95% effective end-tidal concentrations of sevoflurane (ETsev) for preventing rocuronium-induced withdrawal of the arm.


METHODS
We conducted a prospective double-blind study in 31 pediatric patients. After free flow of lactated Ringer's IV fluid was confirmed, anesthesia was induced in the patients by using 2.5% thiopental sodium (4 mg/kg) and sevoflurane (4 vol%) with 6 L/min of oxygen. When the target ETsev was reached, preservative-free 1% lidocaine (1.5 mg/kg) was intravenously injected during manual venous occlusion and rocuronium (0.6 mg/kg) was injected after lidocaine injection under free-flow intravenous fluid. A nurse who was an investigator and was blinded to the ETsev injected the rocuronium. The nurse evaluated the response.


RESULTS
Non-withdrawal movement was observed in 5 out of 11 patients with ETsev 3.0 vol% and in 5 out of 6 patients with ETsev 3.5 vol%. By Dixon's up-and-down method, the 50% effective concentration (EC50) of sevoflurane for non-withdrawal movement at rocuronium injection was 3.1 ± 0.4 vol%. A logistic regression curve of the probability of non-withdrawal movements showed that the 50% effective ETsev for abolishing withdrawal movement at rocuronium injection was 2.9 vol% (95% confidence interval [CI] 2.4-3.8 vol%) and the 95% effective ETsev was 4.3 vol% (95% CI 3.6-9.8 vol%).


CONCLUSIONS
This study showed that the 50 and 95% effective ETsev that prevent withdrawal movement at rocuronium injection are 2.9 and 4.3 vol%, respectively.
Department of Anesthesiology and Pain Medicine, Hanyang University Guri Hospital, Guri, Korea.
Jong Hoon
JH
Yeom
Department of Anesthesiology and Pain Medicine, Hanyang University Guri Hospital, Guri, Korea.
Yong Oh
YO
Kim
Department of Anesthesiology and Pain Medicine, Hanyang University Guri Hospital, Guri, Korea.
Jae Min
JM
Lee
Department of Anesthesiology and Pain Medicine, Hanyang University Guri Hospital, Guri, Korea.
Woo Jae
WJ
Jeon
Pain; Rocuronium; Sevoflurane; Withdrawal