In this retrospective study, data of 2,435 patients who received fentanyl and ropivacaine-based patient-controlled epidural analgesia (PCEA) for pain relief after elective surgery under general or spinal anesthesia were reviewed. Differences in postoperative pain, incidence of patient-controlled analgesia (PCA)-related adverse effects, and risk factors for the need for rescue analgesics for 48 hours postsurgery in young (age 20–39 years) and elderly (age ≥70 years) patients were evaluated. Although there were no significant differences in postoperative pain intensity between the two groups until 6 hours postsurgery, younger patients experienced greater postoperative pain intensity compared with older patients 6–48 hours postsurgery. While younger patients exhibited greater incidence of numbness, motor weakness, and discontinuation of PCA postsurgery, elderly patients exhibited greater incidence of hypotension, nausea/vomiting, rescue analgesia, and antiemetic administration. Upon multivariate analysis, low fentanyl dosage and history of smoking were found to be associated with an increased need for rescue analgesia among younger patients, while physical status classification III/IV and thoracic surgery were associated with a decreased need for rescue analgesia among the elderly. Discontinuation of PCA was more frequent among younger patients than the elderly (18.5% vs 13.5%, P=0.001). Reasons for discontinuation of PCA among young and elderly patients, respectively, were nausea and vomiting (6.8% vs 26.6%), numbness or motor weakness (67.8% vs 11.5%), urinary retention (7.4% vs 8.7%), dizziness (2.2% vs 5.2%), and hypotension (3.1% vs 20.3%). In conclusion, PCEA was more frequently associated with numbness, motor weakness, and discontinuation of PCA in younger patients and with hypotension, nausea/vomiting, and a greater need for rescue analgesics/antiemetics among elderly patients. Therefore, in order to minimize the adverse effects of PCEA and enhance pain relief, different PCEA regimens and administration/prevention strategies should be considered for young and elderly patients.

BACKGROUND: The changes in hypnotic indicators in remimazolam sedation remain unclear. We investigated the correlation of the electroencephalogram (EEG) parameters with the effect-site remimazolam concentration and the depth of sedation in patients receiving a target-controlled infusion of remimazolam. METHODS: This prospective observational study enrolled 35 patients (32 analyzed) who underwent lower extremity varicose vein surgery or lower extremity orthopedic surgery under spinal anesthesia. We administered remimazolam by target-controlled infusion using the pharmacokinetic model introduced by Schüttler et al. The EEG data were continuously recorded, including the bispectral index (BIS), patient state index (PSI), spectral edge frequency (SEF), and raw EEG signals. The relative beta ratio (RBR), defined as log (spectral power [30–47 Hz]/spectral power [11–20 Hz]), was obtained by analyzing raw EEG. The level of sedation corresponding to each effect-site remimazolam concentration was assessed using the Modified Observer’s Assessment of Alertness/Sedation (MOAA/S). The prediction probability (Pk) and Spearman’s correlation coefficients (R) were calculated between effect-site remimazolam concentration, MOAA/S, and EEG parameters. RESULTS: BIS and PSI showed significantly higher Pk for effect-site remimazolam concentration (Pk = 0.76 [0.72–0.79], P < .001 for BIS; Pk = 0.76 [0.73–0.79], P < .001 for PSI) compared to RBR (Pk = 0.71 [0.68–0.74], P < .001) and SEF (Pk = 0.58 [0.53–0.63], P = .002). BIS, PSI, and RBR showed significantly higher correlation coefficients for effect-site remimazolam concentration (R = −0.70 [−0.78 to −0.63], P < .001 for BIS; R = −0.72 [−0.79 to −0.66], P < .001 for PSI; R = −0.61 [−0.69 to −0.54], P < .001 for RBR) compared to SEF (R = −0.22 [−0.36 to −0.08], P = .002). BIS and PSI also had significantly higher Pk and correlation coefficients for MOAA/S (Pk = 0.81 [0.79–0.83], P < .001; R = 0.84 [0.81–0.88], P < .001 for BIS) (Pk = 0.80 [0.78–0.83], P < .001; R = 0.82 [0.78–0.87], P < .001 for PSI) compared to RBR (Pk = 0.74 [0.72–0.77], P < .001; R = 0.72 [0.65–0.78], P < .001) and SEF (Pk = 0.55 [0.50–0.59], P = .041; R = 0.13 [−0.01 to 0.27], P = .067). CONCLUSIONS: BIS, PSI, and RBR showed an acceptable correlation with the effect-site remimazolam concentration and depth of sedation in this study, suggesting that these EEG-derived parameters are potentially reliable hypnotic indicators during remimazolam sedation. BIS and PSI showed superior performance as hypnotic indicators to RBR and SEF in patients receiving target-controlled infusion of remimazolam.

Summary: Stimulation of the sympathetic nervous system associated with tracheal intubation causes corrected QT (QTc) interval prolongation. We postulated that the use of remifentanil during induction of anaesthesia might prevent this. Sixty unpremedicated, ASA grade 1 patients were selected and randomly allocated to receive either saline (group S), remifentanil 0.5 μg.kg ⁻¹ (group R 0.5) or remifentanil 1.0 μg.kg ⁻¹ (group R1.0) 1 min before laryngoscopy. The QTc interval was significantly prolonged immediately following intubation in group S and group R0.5, but it remained stable in group R1.0, compared with the QTc interval just before laryngoscopy. It is concluded that the administration of remifentanil 1.0 μg.kg ⁻¹ before intubation can prevent the prolongation of the QTc interval associated with tracheal intubation during induction of anaesthesia with sevoflurane.