Feasibility of intraoperative neuromonitoring during thyroid surgery after administration of nondepolarizing neuromuscular blocking agents.
BACKGROUND
A short-acting depolarizing neuromuscular blocking agent (NMBA), succinylcholine, has been utilized for thyroid operations with intraoperative neuromonitoring (IONM). Because of its potential to cause serious side effects, this prospective study tried to determine the feasibility of IONM after administration of a nondepolarizing NMBA during thyroid operations.


METHODS
Complete IONM data for 179 patients who had normal cord mobility were investigated: 90 patients received an induction dose of rocuronium (group R) and 89 received atracurium (group A). Electromyography signals were obtained from the vagus nerve before and after resection of the thyroid lobe and were defined as V(1) and V(2) signals, respectively. Accelerometry (percent twitch) was used to monitor the quantitative degree of neuromuscular blockade.


RESULTS
V(1) and V(2) signals were obtained successfully in all patients. The percent twitch at the V(1) signal was significantly lower than that at the V(2) signal in both groups (39% +/- 20% vs. 69% +/- 26% in group R; 35% +/- 28% vs. 56% +/- 35 % in group A; both p < 0.01). However, the magnitude of the V(1) and V(2) signals did not differ significantly in either in group (473.8 +/- 290.8 microV vs. 528 +/- 316.2 microV in group R; 584.8 +/- 394.3 microV vs. 637.8 +/- 458.2 microV in group A; both p > 0.05).


CONCLUSIONS
A single dose of either rocuronium or atracurium was feasible for IONM during thyroid surgery and provided adequate muscle relaxation for tracheal intubation.
Department of Anesthesiology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
Koung-Shing
KS
Chu
Sheng-Hua
SH
Wu
I-Cheng
IC
Lu
Cheng-Jing
CJ
Tsai
Che-Wei
CW
Wu
Wen-Rei
WR
Kuo
Ka-Wo
KW
Lee
Feng-Yu
FY
Chiang
D000328:Adult; D000368:Aged; D000732:Androstanols / Q000494:pharmacology*; D001279:Atracurium / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004576:Electromyography / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009126:Muscle Relaxation / Q000187:drug effects*; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D011336:Probability; D011446:Prospective Studies; D012307:Risk Factors; D000077123:Rocuronium; D013965:Thyroidectomy / Q000009:adverse effects / Q000379:methods*; D055815:Young Adult
D000732:Androstanols; D003473:Neuromuscular Nondepolarizing Agents; D001279:Atracurium; D000077123:Rocuronium