Closed loop anaesthesia

Artificial intelligence (AI) is making giant strides in the medical domain, and the field of anaesthesia is not untouched. Enhancement in technology, especially AI, in many fields, including medicine, has proven to be far superior, safer and less erratic than human decision-making. The intersection of anaesthesia and AI holds the potential for augmenting constructive advances in anaesthesia care. AI can improve anaesthesiologists' efficiency, reduce costs and improve patient outcomes. Anaesthesiologists are well placed to harness the advantages of AI in various areas like perioperative monitoring, anaesthesia care, drug delivery, post-anaesthesia care unit, pain management and intensive care unit...

This single blinded randomized controlled trial aims to assess whether the application of a Bayesian-adjusted CePROP (effect-site of propofol) advisory tool leads towards a more stringent control of the cerebral drug effect during anaesthesia, using qCON as control variable. 100 patients scheduled for elective surgery were included and randomized into a control or intervention group (1:1 ratio). In the intervention group the advisory screen was made available to the clinician, whereas it was blinded in the control group...

Current guidelines support the use of continuous glucose monitoring devices and insulin pumps in minor surgical procedures for pediatric patients with type 1 diabetes mellitus. However, there are few reported cases of using hybrid closed loop technology in the perioperative period. This retrospective case series presents seven pediatric patients with type 1 diabetes who underwent eight surgical procedures with maintenance of hybrid closed loop systems. This paper also provides considerations for future use of hybrid closed loop systems perioperatively...

BACKGROUND: Conscious states are typically inferred through responses to auditory tasks and noxious stimulation. We report the use of a stimulus-free behavioural paradigm to track state transitions in responsiveness during dexmedetomidine sedation. We hypothesised that estimated dexmedetomidine effect-site (Ce) concentrations would be higher at loss of responsiveness (LOR) compared with return of responsiveness (ROR), and both would be lower than comparable studies that used stimulus-based assessments...

In neurological and neuropsychiatric disorders neuronal oscillatory activity between basal ganglia and cortical circuits are altered, which may be useful as biomarker for adaptive deep brain stimulation. We investigated whether changes in the spectral power of oscillatory activity in the motor cortex (MCtx) and the sensorimotor cortex (SMCtx) of rats after injection of the dopamine (DA) receptor antagonist haloperidol (HALO) would be similar to those observed in Parkinson disease. Thereafter, we tested whether a convolutional neural network (CNN) model would identify brain signal alterations in this acute model of parkinsonism...

BACKGROUND: Laparoscopic removal of cryptorchid testes has been routinely reported through enlarged paramedian incisions in dorsally recumbent horses. Outcomes following removal through an extended umbilical incision has not been previously reported. OBJECTIVE: To describe the surgical technique of removing cryptorchid testicles in dorsally recumbent horses through an enlarged umbilical portal after laparoscopic intra-abdominal castration. STUDY DESIGN: Retrospective case series...

BACKGROUND: Epilepsy is a common neurological disorder affecting over 60 million people globally, approximately a third of whom are refractory to pharmacotherapy. Surgical resection of the epileptogenic zone is frequently unsuitable or ineffective, particularly for individuals with focal neocortical or mesial temporal lobe epilepsy. Therefore, there is a need to develop animal models for elucidating the mechanisms of focal epilepsies and evaluating novel treatment strategies. NEW METHOD: We present two adapted in vivo seizure models, the neocortical and hippocampal epileptic afterdischarge models, that enable stereotyped seizures to be induced on demand by electrical stimulation in anaesthetised, neurologically intact rats...

PURPOSE OF REVIEW: Growing concerns about the environmental effects of volatile anaesthetics are likely to lead to increased use of intravenous anaesthetic drugs. Pharmacokinetic/pharmacodynamic (PKPD) models can increase the accuracy of intravenous drug titration, especially in populations that differ from the 'average.' However, with a growing number of PKPD models, and other technology available to date, it can be hard to see the wood for the trees. This review attempts to guide the reader through the PKPD jungle...

The Analgesia Nociception Index (ANI), derived from heart rate variability is a proposed guide to obtain an adequate control of the analgesic component during anaesthesia. This single blind observational study was designed to evaluate the relationship between intraoperative ANI values and length of stay in Day Surgery Units (DSU) in patients undergoing varicose vein intervention. 131 patients (ASA I-II) scheduled for elective varicose vein surgery were studied. A propofol closed-loop TCI was used to maintain a specific level of BIS...

BACKGROUND AND OBJECTIVE: The main aim of this work is to present an optimal and robust controller design in order to improve the drug infusion to the automatic control of mean arterial blood pressure in conditions like critically-ill or post-operative or anaesthesia administration. The physiological systems also have uncertainty issues such as parameter variations with time or external disturbances and noise. Therefore, a controlled drug administration is necessary to regulate the mean arterial blood pressure of a person during surgery/observation...

INTRODUCTION: This systematic review investigates the effect of closed-loop anaesthesia delivery on the maintenance of cardiovascular parameters. The specific challenges arise from the fact that many physiological variables used for the control of anaesthetic delivery and maintenance of haemodynamic stability are regulated by the autonomic nervous system, which is subject to high inter-individual variability. EVIDENCE ACQUISITION: A systematic database search (MEDLINE, EMBASE and Web of Science) was conducted following the PRISMA guidelines and the principles of the Cochrane Handbook for Systematic Reviews of Interventions...

BACKGROUND: Trigger-free anaesthesia is required for patients who are susceptible to malignant hyperthermia. Therefore, all trace of volatile anaesthetics should be removed from anaesthetic machines before induction of anaesthesia. Because the washout procedure is time consuming, activated charcoal filters have been introduced, but never tested under minimal flow conditions. OBJECTIVE: To investigate performance of activated charcoal filters during long duration (24 h) simulated ventilation...

BACKGROUND: Trigger-free anaesthesia is required for patients who are susceptible to malignant hyperthermia. Therefore, all trace of volatile anaesthetics should be removed from anaesthetic machines before induction of anaesthesia. Because the washout procedure is time consuming, activated charcoal filters (ACFs) have been introduced, but never tested under minimal flow conditions. OBJECTIVE(S): The current study aims to investigate performance of ACFs during long duration (24 h) simulated ventilation...

Peripheral nerve stimulators have widespread among anaesthesiologists and remain a popular technique. However, in commercial devices, the user has to manually adjust stimulus intensity. Thus, the aim of this study is to propose a method that allows automating the current intensity control. An earlier nerve stimulator prototype was modified to add an accelerometer and an sEMG module. The choice of these two sensors is aimed at the possibility of observing the mechanical and electrical responses of the muscle contraction evoked by the stimulation...

BACKGROUND: Volatile anaesthetics are a potential hazard during occupational exposure, pregnancy or in individuals with existing disposition to malignant hyperthermia. Anaesthetic waste gas concentration in postanaesthesia care units (PACU) has rarely been investigated. OBJECTIVE(S): The current study aims to assess concentrations of volatile anaesthetics in relation to room size, number of patients and ventilator settings in different PACUs. DESIGN: A prospective observational study...

BACKGROUND: Hypnosis has a positive effect on peri-operative anxiety and pain. OBJECTIVE: The objective of this study was to assess the impact of a formal deep hypnosis session on the consumption of propofol for anaesthetic induction using automated administration of propofol guided by the bispectral index (BIS) in a closed loop. DESIGN: A 1 : 1 randomised, usual-care-controlled, single-centre trial. SETTING: Tertiary care centre in France from April 2014 to December 2015...

OBJECTIVES: To compare the efficacy of anaesthetic depth control using Closed Loop Anaesthesia Delivery System (CLADS) and Target Controlled Infusion (TCI) in patients with moderate to severe left ventricular dysfunction (LVSD). DESIGN: Randomized control trial. PATIENTS: Forty ASA III/IV adult patients with moderate to severe LVSD scheduled for open heart surgery. INTERVENTIONS: Propofol was administered using CLADS or TCI for maintaining BIS of 50...

OBJECTIVE: Determine the influence of general anaesthesia with closed-loop systems in the results of outpatient varicose vein surgery. PATIENTS AND METHODS: Retrospective observational study including data from 270 outpatients between 2014 and 2015. The patients were divided into 2 groups according to the type of general anaesthesia used. The CL Group included patients who received propofol in closed-loop guided by BIS and remifentanil using TCI, and the C Group received non-closed-loop anaesthesia...

BACKGROUND: Automated titration of propofol and remifentanil guided by the bispectral index (BIS) has been used for numerous surgical procedures. Orthotopic liver transplantation (OLT) uniquely combines major changes in circulating volume, an anhepatic phase, and ischaemia-reperfusion syndrome. We assessed the behaviour of this automated controller during OLT. METHODS: Adult patients undergoing OLT were included in this pilot study. Consumption of propofol and remifentanil was calculated for each surgery period (dissection, anhepatic, and liver reperfusion phases)...

PURPOSE OF REVIEW: Drug administration might be optimized by incorporating pharmacokinetic-dynamic (PK/PD) principles and control engineering theories. This review gives an update of the actual status of target-controlled infusion (TCI) and closed-loop computer-controlled drug administration and the ongoing research in the field. RECENT FINDINGS: TCI is becoming mature technology clinically used in many countries nowadays with proven safety. Nevertheless, changing populations might require adapting the established PK/PD models...