Explore the vast range of titles available.

Within biomedical engineering, there has been significant collaboration among clinicians, control engineers, and researchers to tailor treatments to individual patients. Anesthesia is integral to numerous medical procedures, necessitating precise management of hypnosis, analgesia, neuromuscular blockade, and hemodynamic variables. Recent attention has focused on computer-controlled anesthesia and hemodynamic stabilization. This research proposes the integration of a decentralized control strategy for the induction phase with a decoupled control approach for the maintenance phase, aimed at mitigating interactions within the multivariable human system. The proposed strategy is based on fractional-order controllers. The solution is validated using an open-source patient simulator featuring data from 24 virtual patients, demonstrating the efficiency of the proposed approach with respect to decentralized control.

IntroductionProlonged infusion of anaesthetics is associated with delayed emergence (DE) from general anaesthesia due to residual drug effects. Remimazolam besylate, a novel ultrashort-acting benzodiazepine, exhibits minimal accumulation, and its sedative effects can be reversed with flumazenil. This study aimed to evaluate the incidence of DE from anaesthesia using remimazolam–flumazenil or propofol in patients undergoing major spine surgery.Methods and analysisThis multicentre, randomised controlled trial will be conducted in five hospitals in Hunan Province, China. Approximately 164 patients undergoing major spine surgery lasting >3 hours will be randomly assigned to two groups in a 1:1 ratio. In the remimazolam–flumazenil group, remimazolam will be administered for anaesthesia induction and maintenance, followed by flumazenil for reversal after surgery, whereas propofol will be administered in the propofol group. The primary outcome is the incidence of DE from anaesthesia. The secondary outcomes include the time to obey verbal command, time to bispectral index over 80, time to extubation, length of stay in the post-anaesthesia care unit (PACU), Richmond Agitation–Sedation Scale scores and Modified Aldrete scores on arrival at PACU, at 30 and 60 min, as well as adverse events throughout recovery. All statistical tests will be conducted using SPSS version 27.0 (IBM Corp., Armonk, NY, USA). A P-value<0.05 will be considered significant.Ethics and disseminationThis randomised controlled trial protocol has received ethical approval from the Second Xiangya Hospital, Central South University (Approval number: LYEC2024-0357). All participants will be required to provide written informed consent before study enrolment. The findings will be disseminated at academic conferences and published in a peer-reviewed journal.Trial registration numberChiCTR2400092451

[This corrects the article DOI: 10.3389/fphar.2026.1741851.].

Fractional calculus has been opening new doors in terms of better modeling and control of several phenomena and processes. Biomedical engineering has seen a lot of combined attention from clinicians, control engineers and researchers in their attempt to offer individualized treatment. A large number of medical procedures require anesthesia, which in turn requires a closely monitored and controlled level of hypnosis, analgesia and neuromuscular blockade, as well maintenance of hemodynamic variables in a safe range. Computer-controlled anesthesia has been given a tremendous amount of attention lately. Hemodynamic stabilization via computer-based control is also a hot topic. However, very few studies on automatic control of combined anesthesia–hemodynamic systems exist despite the fact that hemodynamics is strongly influenced by hypnotic drugs, while the depth of hypnosis is affected by drugs used in hemodynamic control. The very first multivariable fractional-order controller is developed in this paper for the combined anesthesia–hemodynamic system. Simulation studies on 24 patients show the effectiveness of the proposed approach.

Background In low-flow anesthesia, automated monitoring of end-tidal oxygen (etO 2 ) and end-tidal anesthetic agents (etAA) has been favored to reduce clinicians’ cognitive workload during anesthesia maintenance. This systematic review, therefore, aimed to determine the comparative efficacy and safety of automated end-tidal controlled anesthesia (etCA) versus manually controlled anesthesia (MCA). Methods An electronic search was conducted across four databases: PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and Scopus. The retrieved references were then analyzed against the studies’ screening and eligibility criteria before the full articles were included in the study. The Review Manager (RevMan 5.4.1) was then used to conduct the statistical analysis of the reported outcomes. Results The electronic search retrieved 965 articles, among which 10 were included in this review. The studies included a pooled sample size of 1269 who underwent surgical procedures under low-flow anesthesia. The analyzed evidence suggests with low certainty that the type of anesthesia control may not have any significant effect on both the anesthesia duration (SMD − 0.00 min; 95% CI [-0.34, 0.34] p  = 0.99) and the procedural duration MCA (SMD 0.04 min; 95% CI; 95% CI [-0.26, 0.33] p  = 0.80). Moreover, we found with low certainty in the evidence that the amount of sevoflurane consumed may not be significantly different between etCA and MCA (SMD − 0.32 mLs; 95% CI [-0.94, 0.29] p  = 0.31). Our narrative synthesis indicated that etCA can potentially improve anesthesia delivery by reducing the required anesthetist interventions and ensuring stable and accurately administered anesthetics. Conclusion This review found very low-quality evidence suggesting that the type of anesthesia control may not significantly affect anesthesia delivery parameters, such as the amount of anesthesia consumed and procedural and anesthesia duration. The analyses, however, had significant heterogeneity, making the estimates highly unreliable. On the other hand, some studies indicate potential advantages of using etCA, such as reducing the number of interventions required during anesthesia; however, the evidence remains limited, preventing a full exploration of these advantages.

Background Postoperative residual curarization (PORC) may be a potential risk factor of postoperative pulmonary complications (PPCs), and both of them will lead to adverse consequences on surgical patient recovery. The train-of-four ratio (TOFr) which is detected by acceleromyography of the adductor pollicis is thought as the gold standard for the measurement of PORC. However, diaphragm function recovery may differ from that of the peripheral muscles. Recent studies suggested that diaphragm ultrasonography may be useful to reveal the diaphragm function recovery, and similarly, lung ultrasound was reported for the assessment of PPCs in recent years as well. Sugammadex reversal of neuromuscular blockade is rapid and complete, and there appear to be fewer postoperative complications than with neostigmine. This study aims to compare the effects of neostigmine and sugammadex, on PORC and PPCs employing diaphragm and lung ultrasonography, respectively. Methods/design In this prospective, double-blind, randomized controlled trial, patients of the American Society of Anesthesiologists Physical Status I–III, aged over 60, will be enrolled. They will be scheduled to undergo arthroplasty under general anesthesia. All patients will be allocated randomly into two groups, group NEO (neostigmine) and group SUG (sugammadex), using these two drugs for reversing rocuronium. The primary outcome of the study is the incidence of PPCs in the NEO and SUG groups. The secondary outcomes are the evaluation of diaphragm ultrasonography and lung ultrasound, performed by an independent sonographer before anesthesia, and at 10 min and 30 min after extubation in the post-anesthesia care unit, respectively. Discussion Elimination of PORC is a priority at the emergence of anesthesia, and it may be associated with reducing postoperative complications like PPCs. Sugammadex was reported to be superior to reverse neuromuscular blockade than neostigmine. Theoretically, complete recovery of neuromuscular function should be indicated by TOFr > 0.9. However, the diaphragm function recovery may not be the same matter, which probably harms pulmonary function. The hypothesis will be proposed that sugammadex is more beneficial than neostigmine to reduce the incidence of PPCs and strongly favorable for the recovery of diaphragm function in our study setting. Trial registration ClinicalTrials.gov NCT05040490 . Registered on 3 September 2021

In the field of individualized anesthesia, pharmacokinetic-pharmacodynamic (PKPD) models are crucial as they assist in determining the appropriate dosage for various patient groups. This research reviews the development of primary PKPD anesthetic models proposed in the literature from 1987 to 2024. The results from 33 studies are combined, offering a range of concepts from the earliest contributions, such as the “pharmacokinetic mass” concept of Shibutani et al. for fentanyl in obese patients, to the most recent developments in multi-input control strategies for managing anesthesia depth with propofol and remifentanil. Recent advancements are also discussed, including the propofol model proposed by Braathen et al. for severe obesity, which employs innovative scaling techniques to enhance dose accuracy. This study examines physiologically based modeling approaches, reviews traditional compartmental models, and highlights the use of nonlinear mixed-effects modeling. The review concludes by outlining future research aimed at creating more individualized, closed-loop anesthetic delivery systems, emphasizing significant developments in PKPD modeling and identifying limitations in the existing techniques.

This paper investigates the performance achievable with a fractional-order PID regulator controlling the Depth of Hypnosis (measured via the Bispectral Index Scale) through the administration of propofol during the maintenance phase of total intravenous anesthesia. In particular, two different methodologies were applied to tune the controller: in the first case, genetic algorithms (GAs) were used to minimize the integrated absolute error, while in the second case, the isodamping approach—a method that targets phase margin invariance with respect to the process dc gain—was employed. In both cases, the performance was extensively analyzed and compared with that of a standard PID controller by simulating multiple patients through a Monte Carlo method. The results demonstrate that a fractional-order PID controller can be effectively used to control the Depth of Hypnosis, but the improvement with respect to a standard PID controller is marginal.

Modeling and control of drug dosing regimes are particularly well-suited for applications of control design and analysis techniques. These problems frequently incorporate the use of mathematical models, lending themselves to a large range of model-based control methods. There has been ongoing research aimed at the development of closed-loop drug dosing and delivery regimens in a number of specific medical domains for more than five decades. In this paper, we discuss the development of modeling and control methods aimed at closed-loop delivery of pharmaceutical agents. We focus most of this discussion on the problem of controlling sedation levels during surgical procedures; results from the application of linear parameter varying and robust L1-adaptive modeling and control approaches are presented in some detail.

Background Quantitative neuromuscular monitoring is the gold standard to detect postoperative residual curarization (PORC). Many anesthesiologists, however, use insensitive, qualitative neuromuscular monitoring or unreliable, clinical tests. Goal of this multicentre, prospective, double-blinded, assessor controlled study was to develop an algorithm of muscle function tests to identify PORC. Methods After extubation a blinded anesthetist performed eight clinical tests in 165 patients. Test results were correlated to calibrated electromyography train-of-four (TOF) ratio and to a postoperatively applied uncalibrated acceleromyography. A classification and regression tree (CART) was calculated developing the algorithm to identify PORC. This was validated against uncalibrated acceleromyography and tactile judgement of TOF fading in separate 100 patients. Results After eliminating three tests with poor correlation, a model with four tests ( r  = 0.844) and uncalibrated acceleromyography ( r  = 0.873) were correlated to electromyographical TOF-values without losing quality of prediction. CART analysis showed that three consecutively performed tests (arm lift, head lift and swallowing or eye opening) can predict electromyographical TOF. Prediction coefficients reveal an advantage of the uncalibrated acceleromyography in terms of specificity to identify the EMG measured train-of-four ratio < 0.7 (100% vs. 42.9%) and <0.9 (89.7% vs. 34.5%) compared to the algorithm. However, due to the high sensitivity of the algorithm (100% vs. 94.4%), the risk to overlook an awake patient with a train-of-four ratio < 0.7 was minimal. Tactile judgement of TOF fading showed poorest sensitivity and specifity at train of four ratio < 0.9 (33.7%, 0%) and <0.7 (18.8%, 16.7%). Conclusions Residual neuromuscular blockade can be detected by uncalibrated acceleromyography and if not available by a pathway of four clinical muscle function tests in awake patients. The algorithm has a discriminative power comparable to uncalibrated AMG within TOF-values >0.7 and <0.3. Trial registration Clinical Trials.gov (principal investigator’s name: CU, and identifier: NCT03219138) on July 8, 2017.