Effect of neuromuscular blockade reversal by pyridostigmine on spectral entropy values during recovery from desflurane anesthesia: a prospective, randomized, double-blind, controlled trial.
BACKGROUND
According to several studies investigating the relationship between muscle activity and electroencephalogram results, reversal of neuromuscular blockade (NMB) may affect depth of anesthesia indices. Therefore, we investigated the effect of pyridostigmine on these indices via spectral entropy.


METHODS
Fifty-six patients scheduled for thyroidectomy or parotidectomy were included in this study and randomized into two groups. At the start of skin suturing, the desflurane concentration was adjusted to 4.2 vol% in both groups. Following this, the pyridostigmine group (group P, n = 28) was administered pyridostigmine 0.2 mg/kg mixed with glycopyrrolate 0.04 mg/kg, while the control group (group C, n = 28) received normal saline. Entropy values (response entropy [RE] and state entropy [SE]), train of four (TOF) ratio, and end-tidal desflurane concentration were recorded from point of drug administration to 15 minutes post-drug administration.


RESULTS
Mean RE values at 15 minutes, when the maximum effect of pyridostigmine was anticipated, showed a statistically significant difference between groups (53.8 ± 10.5 in group P and 48.0 ± 8.8 in group C; P = 0.030). However, mean SE at 15 minutes showed no significant difference between the two groups (P = 0.066). At 15 minutes, there were significant differences in the TOF ratio between the two groups (P < 0.001).


CONCLUSIONS
NMB reversal by pyridostigmine significantly increased RE values but not SE values. This finding suggests that spectral entropy may be a useful alternative tool for monitoring anesthetic depth during recovery from anesthesia in the presence of electromyogram activity.
Department of Anesthesiology and Pain Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea.
Eugene
0000-0002-1926-4191
E
Kim
Department of Anesthesiology and Pain Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea.
Jae Hun
JH
Ryu
Department of Anesthesiology and Pain Medicine, Catholic University of Daegu School of Medicine, Daegu, Korea.
Sung Hye
0000-0002-9287-5087
SH
Byun
Electromyography; Entropy; Pyridostigmine bromide