Anesth. Res., Volume 3, Issue 2 (June 2026) – 5 articles

Background/Objectives: Opioids are widely used for perioperative analgesia in small animal practice; however, their administration is associated with dose-dependent adverse effects, regulatory restrictions, and increasing stewardship concerns. Evidence supporting opioid-free anesthesia protocols in cats remains limited. The aim of this study was to evaluate the analgesic efficacy of a dexmedetomidine constant rate infusion as part of an opioid-free anesthetic protocol in cats undergoing ovariectomy, as well as to determine its effect on intraoperative opioid requirements. Methods: This prospective, randomized clinical trial included forty healthy female cats (mean age 1.9 ± 0.7 years; mean body weight 3.5 ± 0.6 kg; body condition score 5 [range 4–5]/9) undergoing elective ovariectomy. Cats were randomly assigned to receive either a dexmedetomidine constant rate infusion (CRI) at 1 mcg kg⁻¹ h⁻¹ (GR-E) or a control protocol without dexmedetomidine CRI (GR-C). Anesthesia was induced and maintained using standardized protocols in both groups. Intraoperative fentanyl (5 mcg kg⁻¹ IV) was administered as rescue analgesia when two of three physiological parameters (heart rate, respiratory rate, mean arterial pressure) increased by ≥20% compared to the previous recorded value. Cardiovascular and respiratory variables, rescue opioid requirements, and recovery quality were recorded. Results: The requirement for rescue analgesia was significantly lower in GR-E (4/20; 20%) compared to GR-C (13/20; 65%) (p = 0.0097). Cats receiving dexmedetomidine showed greater intraoperative cardiovascular stability during ovarian pedicle manipulation. No clinically relevant adverse effects were observed. Recovery was smooth in all cats, and all resumed feeding within eight hours postoperatively. Conclusions: A low-dose dexmedetomidine CRI effectively reduced intraoperative opioid requirements during feline ovariectomy while maintaining physiological stability and satisfactory recovery. This opioid-free anesthetic protocol represents a safe and clinically applicable alternative in settings where opioid use is restricted or limited. Full article

Introduction: Propofol is one of the most commonly used intravenous anesthetics worldwide and is considered safe for all age groups. However, there have been reports that propofol can induce severe atrioventricular block in humans, and several studies have shown that propofol hinders or prevents the inducibility of arrhythmias during electrophysiological studies (EPS) and radiofrequency (RF) ablation. Objectives: To compare arrhythmia inducibility during electrophysiological study and radiofrequency ablation in pediatric patients with Wolff–Parkinson–White syndrome undergoing propofol-based sedation versus sevoflurane-based general anesthesia. Methods: We conducted a retrospective observational cohort study including 45 pediatric patients aged 0–18 years. Patients were identified through a review and analysis of a database of individuals with Wolff–Parkinson–White syndrome who were referred for electrophysiological study and/or radiofrequency ablation at the Electrophysiology Laboratory of the Institute of Cardiology (IC/FUC) in Porto Alegre over the past five years (2019–2024). Patients with prior ablation, structural heart disease, or ongoing antiarrhythmic therapy were excluded. The patients were divided into two groups and designated as group S (who received sedation) or group G (who received general anesthesia). Sedation (group S) was performed with midazolam (0.08–0.2 mg/kg), fentanyl (0.1–0.2 μcg/kg), and propofol 50–60 µg/kg/min in continuous infusion. General anesthesia (group G), in turn, was performed with sevoflurane at an average dose of 2% (1 MAC according to age). Results: From 4874 invasive electrophysiology procedures performed during the study period, 45 involved pediatric patients with WPW. The sedation group (n = 29) had significantly older patients (14.6 ± 2.5 vs. 10.3 ± 2.8 years, p < 0.001) with higher weight (65.9 ± 16.3 vs. 41.2 ± 7.8 kg, p < 0.001) compared to the general anesthesia group (n = 16). Arrhythmia was successfully induced in 15/29 (51.7%) patients in the sedation group compared to 13/16 (81.2%) in the general anesthesia group (p = 0.062, Fisher’s exact test). Although this difference did not reach statistical significance, it represents a clinically relevant 29.5% lower induction rate in the sedation group. Post hoc power analysis revealed the study was underpowered (49.8%), suggesting a possible Type II error. Analysis of the “procedure room time” revealed a longer duration in the general anesthesia group (97.8 ± 36.7 vs. 67.8 ± 24.4 min), and this difference was statistically significant (p = 0.002). Conclusions: This study compared propofol-based sedation with sevoflurane-based general anesthesia in pediatric WPW patients. While sedation with propofol did not show a statistically significant reduction in arrhythmia inducibility, there was a concerning trend toward lower induction rates (29.5% difference) that may be clinically relevant. The study’s limited statistical power (49.8%) suggests these findings should be interpreted cautiously, and larger prospective studies are needed to definitively establish whether propofol affects arrhythmia inducibility in this population. Propofol remains a viable option for these procedures, but clinicians should be aware of the potential for reduced inducibility, particularly in cases where arrhythmia induction is critical for diagnosis and treatment. Full article

Background: While providing enough sedatives to avoid pain and trauma during surgery is important, studies show a link between the received sedatives and the development of postoperative delirium (POD). Therefore, predicting POD from clinical or physiological data before or during surgery is highly advantageous. This capability enables healthcare providers to proactively implement necessary measures, thereby mitigating or preventing potential complications. Methods: In this study, we focus on patients with Parkinson’s disease undergoing deep brain stimulation surgery who are particularly susceptible to POD. We investigate what aspects of EEG’s power, functional connectivity and complexity during the course of the surgery are influenced by the amount of sedative. Furthermore, we aim to determine whether and to what extent the recorded brain activity during surgery can serve as a reliable means for the prediction of POD in this group of patients. Results and Conclusions: Our results show significant correlations between various power, connectivity and complexity features of EEG and the amount of sedatives. Even though single EEG features are not significantly different between the two groups who either developed or did not develop POD, we show that a classifier based on support vector machines using the selected EEG features could predict POD. Furthermore, our results provide evidence that a classifier trained only on the amount of sedatives is unable to predict POD. Accompanying this paper, our code is published as an open-source toolbox for the analysis of the EEG signal recorded with the four-channel SEDLine Root system, which is among the widely used EEG systems in operation rooms and its recorded data come with challenges that are addressed in our toolbox. Full article

Background: Access to reliable medicines information is essential to support safe medicine use during pregnancy and breastfeeding, where concerns regarding fetal and neonatal safety complicate clinical decision-making. Analgesics are widely used during these periods, yet uncertainty regarding safety persists due to evolving evidence, regulatory changes, and inconsistent information sources. Obstetric medicines information services play a critical role in addressing these information needs. This study aimed to evaluate patterns of analgesic-related enquiries to a pharmacist-led specialist obstetric medicines information service over a 20-year period. Methods: A retrospective observational study was conducted using enquiry data from the King Edward Memorial Hospital Obstetric Medicines Information Service (KEMH OMIS), Western Australia. All enquiries recorded between 1 January 2001 and 31 December 2020 were extracted from the Microsoft Access^® database. Records with incomplete data were excluded. Data were standardised, coded, and analysed using Microsoft Excel^® and SPSS^® Version 25. Descriptive statistics were used to summarise enquiry characteristics, caller type, the timing of exposure, and analgesic medicines involved. Trends over time were analysed. Results: A total of 48,458 enquiries were analysed, of which 4,978 (10.3%) related to analgesics, making this the third most common medicine class. Most enquiries related to breastfeeding (62.1%), followed by pregnancy (32.7%). The public accounted for 60.9% of calls, while health professionals contributed 39.1%. The highest frequency of breastfeeding enquiries occurred within the first four weeks postpartum, and pregnancy enquiries were most common in the second trimester. Paracetamol was the most frequently enquired analgesic (24.5%), followed by codeine (19.8%), ibuprofen (14.4%), diclofenac (7.2%), and tramadol (9.3%). Analgesic-related enquiries declined significantly over time (p < 0.001), particularly codeine-related enquiries following regulatory safety warnings. Conclusions: Analgesics represent a substantial proportion of medicines information enquiries in pregnancy and breastfeeding, reflecting widespread use and ongoing safety concerns. Pharmacist-led medicines information services play a critical role in supporting safe analgesic use. Full article

Introduction: In adult patients undergoing deceased donor kidney transplantation, anesthesia management impacts graft function and survival and is influenced by various donor and recipient clinical factors. The aim of this study was to describe the perioperative factors and to evaluate their association with delayed graft function (DGF) during the first seven days after transplantation. Materials and Methods: This cross-sectional study of adult patients who underwent deceased donor kidney transplantation at a tertiary care hospital from 2022–2023 was performed to evaluate pre-, trans- and postoperative patient’s characteristics. Comparisons or association tests were implemented between patient characteristics grouped by the absence or presence of DGF. In the case of the variables with clinical relevance, univariate and multivariate logistic models were constructed to evaluate the predictive capacity of these variables to predict delayed graft function. Crude and adjusted odds ratio (ORs) with 95% confidence intervals were calculated for each variable. Results: DGF was present in 25/69 (36.23%) patients. The anesthesia time was significantly longer (310.28 vs. 273.55 min; p = 0.043) and the post-transplantation stay was significantly longer (11.04 vs. 8.11 days; p < 0.001) in patients with delayed graft function. In univariable analyses, male sex (p = 0.018), platelet count (p = 0.025), and surgical time (p = 0.062) showed significant or borderline associations with DGF. In the multivariable model, male sex remained independently associated with DGF (adjusted OR 10.64; 95% CI 1.23–92.1; p = 0.031). Platelet count (per 50 × 10³ µL increase) demonstrated a borderline inverse association (adjusted OR 0.57; 95% CI 0.32–1.02; p = 0.057). Conclusions: Our results suggest that male sex was independently associated with delayed graft function after deceased donor kidney transplantation, while platelet count showed a borderline association. Full article