Background: The A-Line Autoregressive Index (AAI), which is derived from auditory evoked potentials, has been used for determining anesthetic depth. This study verified the correlation between AAI values and the corresponding end-tidal concentrations of sevoflurane during general anesthesia induction. Methods: Thirty young male adults undergoing elective minor orthopedic surgery were sequentially allocated to receive inspiratory 3%, 5%, or 6% sevoflurane for mask induction, followed by mechanical ventilation after tracheal intubation. The inspiratory, end-tidal and estimated jugular bulb concentrations of sevoflurane were recorded at three target AAI values: below 20, below 10, and at the start of burst suppression. Results: The mean time to loss of consciousness in the 6% sevoflurane group was shorter than that in the 5% and 3% groups; however, the groups had comparable AAI values (range: 16–45). The 6% group had a higher end-tidal concentration (4.5% ± 0.2% vs. 3.8% ± 0.2%, p < 0.05) than did the 5% group, despite having the same target anesthetic levels by AAI score ≤10, whereas the estimated jugular bulb concentrations were comparable (1.9% vs. 1.9%) in both groups. Conclusions: Following mechanical ventilation with inspiratory 3%, 5%, or 6% sevoflurane, the end-tidal concentrations were discrepant at the same end points of AAI levels, despite similar estimated jugular bulb concentrations of sevoflurane. Thus, conventional alveolar concentration may overestimate anesthesia depth during rapid wash-in of sevoflurane.

Traditional Chinese herbal medicine has widespread use in Taiwan. This cross-sectional questionnaire survey investigates the preoperative use and discontinuation of Chinese herbal medicine and dietary supplements among Taiwanese patients. We obtained the types, frequency, and sources of Chinese herbal remedies and supplements used. Among 1428 presurgical patients, 727 (50.9%) and 977 (68.4%) reported the use of traditional Chinese herbal medicine and supplements in the past one month, respectively. Only 17.5% of the 727 patients stated discontinuation of herbal remedies 4.7 ± 5.1 (1–24) days before the surgery, and 36.2% took traditional Chinese herbal medicine with concomitant physician-prescribed Western medicine for their underlying diseases. The most commonly used Chinese herbs are goji berry (Lycium barbarum) (62.9%) and Si-Shen-Tang (48.1%) in single and compound forms, respectively. The presurgical use of traditional Chinese herbal medicine was common in patients undergoing gynecologic (68.6%) surgery or diagnosed with asthma (60.8%). Women and those with a high household income had a greater tendency to use herbal remedies. This study demonstrates the high proportion of the presurgical use of Chinese herbal remedies and supplements along with physician-prescribed Western medicine in Taiwan. Surgeons and anesthesiologists should be aware of the potential adverse effects of drug–herb interaction for Chinese patients.