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Anxiolytics and sedatives are used in current anaesthetic practice for two main reasons: for anxiolysis before surgery and as adjuvants during anaesthesia. A wide choice of agents are available. Their safety profile is dependent on their pharmacokinetic and pharmacodynamic profiles, patient comorbidity and the experience of the clinician using them. All sedative drugs have the potential to cause severe respiratory depression, and hence they should only be used with standard physiological cardiorespiratory monitoring. This is especially true of procedural sedation administered by non-anaesthetists in remote locations. Drugs used for anaesthesia vary in their pharmacology, but have broadly similar clinical effects. The choice of drug is usually a matter of individual preference, although pharmacokinetic and pharmacodynamic parameters do influence the selection of anaesthetic agents, especially in day case surgery. Most intravenous agents are thought to alter consciousness by an effect at the γ-aminobutyric acid type A (GABAA) or N-methyl-D-aspartate (NMDA) receptors or both. Our understanding of the mechanisms of action of anaesthetic drugs is incomplete, not least because of a lack of understanding of consciousness. Several theories have been proposed over the last century, but none of them has managed to comprehensively elucidate the processes involved. There is now a sense of expectation that with the use of modern imaging techniques, anaesthetic drug action can be better understood, and that this may help in our understanding of consciousness and cognitive functions.

Objectives To describe the efficacy and safety of intranasal midazolam for sedation during essential dental treatment of geriatric patients with major neurocognitive disorder (MND) and care-resistant behaviour (CRB).Background Dental treatment is often impossible in geriatric MND patients with CRB. Intranasal midazolam may provide a non-invasive sedation method, but there is currently no information on its use in geriatric patients.Methods In this observational study, we included geriatric patients with severe MND and CRB needing urgent dental treatment. Each patient received 5 mg midazolam intranasally. Agitation/sedation levels, heart rate, respiration rate and oxygen saturation were recorded at 5-minute intervals.Results Thirty two patients were included. Mean age was 84 (+/- 7) years. Mean (SD) time to treatment start was 13 (+/- 5) minutes, and mean time to maximum sedation 17 (+/- 11) minutes. Sedation was sufficient to enable dental treatment to be completed in 31 (97%) patients. Anxiolysis/light sedation occurred in 16 (50%) patients, and moderate to deep sedation occurred in 16 (50%) patients. No patients suffered from apnoea, although 3 patients required a chin-lift manoeuvre. Hypoxaemia occurred in 1 of these patients and in 2 other patients without airway obstruction. All patients recovered uneventfully. In a regression model, age, weight and other sedative medication use were found not to be associated with maximum sedation depth.Conclusions Of 5 mg intranasal midazolam facilitates treatment of geriatric patients with MND in the comfort of their own environment. More information is needed to guide titration to balance the desired sedation level and patient safety.

For high-risk spinal surgeries, intraoperative neurophysiological monitoring (IONM) is used to detect and prevent intraoperative neurological injury. The motor tracts are monitored by recording and analyzing muscle transcranial electrical stimulation motor evoked potentials (mTc-MEPs). A mTc-MEP amplitude decrease of 50–80% is the most common warning criterion for possible neurological injury. However, these warning criteria often result in false positive warnings. False positives may be caused by inadequate depth of anesthesia and blood pressure on mTc-MEP amplitudes. The aim of this paper is to validate the study protocol in which the goal is to investigate the effects of depth of anesthesia (part 1) and blood pressure (part 2) on mTc-MEPs. Per part, 25 patients will be included. In order to investigate the effects of depth of anesthesia, a processed electroencephalogram (pEEG) monitor will be used. At pEEG values of 30, 40 and 50, mTc-MEP measurements will be performed. To examine the effect of blood pressure on mTc-MEPs the mean arterial pressure will be elevated from 60 to 100 mmHg during which mTc-MEP measurements will be performed. We hypothesize that by understanding the effects of depth of anesthesia and blood pressure on mTc-MEPs, the mTc-MEP monitoring can be interpreted more reliably. This may contribute to fewer false positive warnings. By performing this study after induction and prior to incision, this protocol provides a unique opportunity to study the effects of depths of anesthesia and blood pressure on mTc-MEPs alone with as little confounders as possible.Trial registration numberNL7772.

Supplemental Digital Content is available in the text., OBJECTIVES: Clinical trials evaluating the safety and effectiveness of sedative medication use in critically ill adults undergoing mechanical ventilation differ considerably in their methodological approach. This heterogeneity impedes the ability to compare results across studies. The Sedation Consortium on Endpoints and Procedures for Treatment, Education, and Research Recommendations convened a meeting of multidisciplinary experts to develop recommendations for key methodologic elements of sedation trials in the ICU to help guide academic and industry clinical investigators. DESIGN: A 2-day in-person meeting was held in Washington, DC, on March 28–29, 2019, followed by a three-round, online modified Delphi consensus process. PARTICIPANTS: Thirty-six participants from academia, industry, and the Food and Drug Administration with expertise in relevant content areas, including two former ICU patients attended the in-person meeting, and the majority completed an online follow-up survey and participated in the modified Delphi process. MEASUREMENTS AND MAIN RESULTS: The final recommendations were iteratively refined based on the survey results, participants’ reactions to those results, summaries written by panel moderators, and a review of the meeting transcripts made from audio recordings. Fifteen recommendations were developed for study design and conduct, subject enrollment, outcomes, and measurement instruments. Consensus recommendations included obtaining input from ICU survivors and/or their families, ensuring adequate training for personnel using validated instruments for assessments of sedation, pain, and delirium in the ICU environment, and the need for methodological standardization. CONCLUSIONS: These recommendations are intended to assist researchers in the design, conduct, selection of endpoints, and reporting of clinical trials involving sedative medications and/or sedation protocols for adult ICU patients who require mechanical ventilation. These recommendations should be viewed as a starting point to improve clinical trials and help reduce methodological heterogeneity in future clinical trials.

Dexmedetomidine can be used for sedation and analgesia and has been approved for this use by the European Medicines Agency since 2017. It causes an arousable state of sedation, which is beneficial during neurosurgical procedures that require the patient to cooperate with neurological tests (i.e. tumor surgery or implantation of deep brain stimulators). During procedures where monitoring of somatosensory evoked potentials and/or motor evoked potentials is required, dexmedetomidine can be used as an adjunct to general anesthesia with GABAergic drugs to decrease the dose of the latter when these drugs impair the monitoring signals. The use of dexmedetomidine has also been associated with neuroprotective effects and a decreased incidence of delirium, but studies confirming these effects in the peri-operative (neuro-) surgical setting are lacking. Although dexmedetomidine does not cause respiratory depression, its hemodynamic effects are complex and careful patient selection, choice of dose, and monitoring must be performed. (c) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

The clinical benefit of Deep Brain Stimulation (DBS) is associated with electrode positioning accuracy. Intraoperative assessment of clinical effect is therefore key. Evaluating this clinical effect in patients with dystonic head tremor, as opposed to limb tremor, is challenging because the head is fixed in a stereotactic frame. To clinically assess head tremor during surgery, surface electromyography (EMG) electrodes were bilaterally applied to the sternocleidomastoid and cervical paraspinal muscles. This case shows that intraoperative polymyography is an easy and useful tool to assess the clinical effect of DBS electrode positioning.

Patients undergoing coronary artery bypass grafting (CABG) are at risk of developing postoperative renal impairment, amongst others caused by renal ischemia and hypoxia. Intra-operative monitoring of renal region tissue oxygenation (SrtO2) might be a useful tool to detect renal hypoxia and predict postoperative renal impairment. Therefore, the aim of this study was to assess the ability of intra-operative SrtO2 to predict postoperative renal impairment, defined as an increase of serum creatinine concentrations of > 10% from individual baseline, and compare this with the predictive abilities of peripheral and cerebral tissue oxygenation (SptO2 and SctO2, respectively) and renal specific tissue deoxygenation. Forty-one patients undergoing elective CABG were included. Near-infrared spectroscopy (NIRS) was used to measure renal region, peripheral (thenar muscle) and cerebral tissue oxygenation during surgery. Renal region specific tissue deoxygenation was defined as a proportionally larger decrease in SrtO2 than SptO2. ROC analyses were used to compare predictive abilities. We did not observe an association between tissue oxygenation measured in the renal region and cerebral oxygenation and postoperative renal impairment in this small retrospective study. In contrast, SptO2 decrease > 10% from baseline was a reasonable predictor with an AUROC of 0.767 (95%CI 0.619 to 0.14; p = 0.010). Tissue oxygenation of the renal region, although non-invasively and continuously available, cannot be used in adults to predict postoperative renal impairment after CABG. Instead, peripheral tissue deoxygenation was able to predict postoperative renal impairment, suggesting that SptO2 provides a better indication of ‘general’ tissue oxygenation status.Registered at ClinicalTrials.gov: NCT01347827, first submitted April 27, 2011.

ObjectiveThis study aimed to explore the influence of coronary artery bypass grafting (CABG) on both postoperative cognitive dysfunction and quality of life (QoL) and the association between the two patient-related outcomes.MethodsIn a prospective, observational cohort study, patients with elective, isolated CABG were included. Cognitive function was assessed using the Cogstate computerised cognitive test battery preoperatively, 3 days and 6 months after surgery. QoL was measured preoperatively and at 6 months using the RAND-36 questionnaire including the Physical Component Score (PCS) and the Mental Component Score (MCS). Regression analysis, with adjustment for confounders, was used to evaluate the association between postoperative cognitive dysfunction and QoL.ResultsA total of 142 patients were included in the study. Evidence of persistent cognitive dysfunction was observed in 33% of patients after 6 months. At 6 months, the PCS had improved in 59% and decreased in 21% of patients, and the MCS increased in 49% and decreased in 29%. Postoperative cognitive changes were not associated with QoL scores.ConclusionsPostoperative cognitive dysfunction and decreased QoL are common 6 months after surgery, although cognitive function and QoL were found to have improved in many patients at 6 months of follow-up. Impaired cognitive function is not associated with impaired QoL at 6 months.Trial registration numberNCT03774342.

BACKGROUND: Anaesthetic induction occurs at higher plasma drug concentrations than emergence in animal studies. Some studies find evidence for such anaesthetic hysteresis in humans, whereas others do not. Traditional thinking attributes hysteresis to drug equilibration between plasma and the effect site. Indeed, a key difference between human studies showing anaesthetic hysteresis and those that do not is in how effect-site equilibration was modelled. However, the effect-site is a theoretical compartment in which drug concentration cannot be measured experimentally. Thus, it is not clear whether drug equilibration models with experimentally intractable compartments are sufficiently constrained to unequivocally establish evidence for the presence or absence of anaesthetic hysteresis. METHODS: We constructed several models. One lacked hysteresis beyond effect-site equilibration. In another, neuronal dynamics contributed to hysteresis. We attempted to distinguish between these two systems using drug equilibration models. RESULTS: Our modelling studies showed that one can always construct an effect-site equilibration model such that hysteresis collapses. So long as the concentration in the effect-site cannot be measured directly, the correct effect-site equilibration model and the one that erroneously collapses hysteresis are experimentally indistinguishable. We also found that hysteresis can naturally arise even in a simple network of neurones independently of drug equilibration. CONCLUSIONS: Effect-site equilibration models can readily collapse hysteresis. However, this does not imply that hysteresis is solely attributable to the kinetics of drug equilibration.

Target-controlled infusion systems are increasingly used to administer intravenous anaesthetic drugs to achieve a user-specified plasma or effect-site target concentration. While several studies have investigated the ability of the underlying pharmacokinetic-dynamic models to predict plasma concentrations, there are no data on their performance in predicting drug concentrations in the human brain. We assessed the predictive performance of the Marsh propofol model and Minto remifentanil model for plasma and brain tissue concentrations. Plasma samples were obtained during neurosurgery from 38 patients, and brain tissue samples from nine patients. Propofol and remifentanil concentrations were measured using gas chromatography mass spectrometry and liquid chromatography tandem mass spectrometry. Data were analysed from the nine patients in whom both plasma and brain samples were simultaneously obtained. For the Minto model (five patients), the median performance error was 72% for plasma and -14% for brain tissue concentration predictions. The model tended to underestimate plasma remifentanil concentrations, and to overestimate brain tissue remifentanil concentrations. For the Marsh model (five patients), the median prediction errors for plasma and brain tissue concentrations were 12% and 81%, respectively. However, when the data from all blood propofol assays (36 patients) were analysed, the median prediction error was 11%, with overprediction in 15 (42%) patients and underprediction in 21 (58%). These findings confirm earlier reports demonstrating inaccuracy for commonly used pharmacokinetic-dynamic models for plasma concentrations and extend these findings to the prediction of effect-site concentrations.

Total intravenous anesthesia (TIVA) using a mixture of propofol and remifentanil in the same syringe has become an accepted technique in Pediatric Anesthesia. A survey by a group of respected UK anesthetists demonstrated a low incidence of serious complications, related to the pharmacology and dose of the drugs. However, a current guideline for the safe use of TIVA recommends against this practice. Pharmaceutical concerns include the physical stability of the emulsion when remifentanil is mixed with propofol; changes in drug concentration over time; nonuniform mixing of propofol and remifentanil; the risk of bacterial contamination; and the potential for drug administration errors. Propofol and remifentanil have markedly different pharmacokinetic profiles. When remifentanil is mixed with propofol and delivered as a target-controlled infusion (TCI) of propofol, remifentanil delivery is not target-controlled but passively follows the variable infusion rates calculated by the syringe driver to deliver predicted plasma or effect-site concentrations of propofol. The pharmacokinetic consequences can be illustrated using pharmacokinetic modeling similar to that used in TCI pumps. The clinical consequences reflect the dose-dependent pharmacodynamics of remifentanil. Increasing the target propofol concentration produces a rapid increase and peak in remifentanil concentration that risks apnea, bradycardia, and hypotension, especially with higher concentrations of remifentanil. The faster decline in remifentanil concentration with falling propofol concentrations risks inadequate narcosis and unwanted responses to surgical stimuli. Remifentanil delivery is inflexible and dosing cannot be adjusted to the clinical need and responses of individual patients. The medicolegal considerations are stark. In UK and EU Law, mixing propofol and remifentanil creates a new, unlicensed drug and the person mixing takes on the responsibilities of manufacturer. If a patient receiving anesthesia in the form of a mixed propofol-remifentanil infusion suffered a critical incident or actual harm, the clinician's practice may come under scrutiny and criticism, potentially involving a legal challenge and the Medical Regulator.

Background: Target-controlled infusion (TCI) systems use pharmacokinetic (PK) models to predict the drug infusion rates necessary to achieve a desired target plasma or effect-site concentration. As new PK models are developed and implemented in TCI systems, there can be uncertainty as to which target concentrations are appropriate. Existing dose recommendations can serve as a point of reference to identify target concentrations suitable for clinical applications. Methods: Simulations of remifentanil TCI were performed using three PK models (Minto, Eleveld, and Kim). We sought to identify models and target concentrations for remifentanil administration in children, adult, older people, and severely obese individuals, consistent with the remifentanil product label. In a typical adult this is an induction dose of 0.5–1 μg kg−1 and starting maintenance infusion rate of 0.25 μg kg−1 min−1. Results: For the Minto, Eleveld, and Kim remifentanil models, a plasma target concentration of ∼ 4 ng ml−1 achieves drug administration consistent with product label recommended initial doses for all groups with minor exceptions. With effect-site targeting in older individuals, a target concentration of ∼2 ng ml−1 is required for induction and ∼4 ng ml−1 for starting maintenance to achieve drug dosages close to product label recommendations. Conclusions: We identified remifentanil TCI target concentrations that resulted in drug administration similar to product label dosing recommendations. This approach did not necessarily identify target concentrations that achieve desired clinical effect, only those that are consistent with the product label recommended doses. We estimate that plasma target concentrations of 3.1–5.3 ng ml−1 are suitable for initial dosing.

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.RECENT FINDINGS: General purpose PKPD models for propofol and remifentanil designed to apply to a broader population, including children, the elderly and the obese, reduce the need for population-specific models. PKPD models for drugs such as dexmedetomidine and antimicrobial agents may be useful for procedural sedation or in the ICU. Technological advances such as Bayesian model adjustment based on point-of-care plasma concentration measurements, closed-loop drug delivery and artificial intelligence may improve the ease of use of the anaesthetic drugs and increase the accuracy of titration.SUMMARY: Newer and more complex modelling techniques and technological advancements can help to deliver anaesthetic drugs, sedatives and other drugs in a more stable and thereby safer way.

BACKGROUND: Accurate prognostic biomarkers would substantially improve surgical planning and decisions making yet no studies have been reported exploring the inflammatory response in surgically treated older patients with cancer. The aim of this study was to explore inflammatory biomarkers as potential prognostic factors for postoperative complications within 30 days in older patients with cancer.METHOD: Patients 65 years and older undergoing surgery for removal of a solid malignant tumour were included in an observational cohort study. All complications occurring up to 30 days postoperatively were documented prospectively. Inflammatory markers were measured in plasma samples pre- and postoperatively: C-reactive protein (CRP), Interleukin-1 beta (IL-1β), IL-6, IL-10, IL-12, and Tumour necrosis factor-alpha (TNF-α). Associations between inflammatory markers and postoperative complications were explored using logistic regression analysis.RESULTS: Between July 2010 and April 2014, plasma samples of 224 patients were collected. Median age was 72 (65-89) years and 116 (51.8%) patients were female. Approximately half of the patients developed postoperative complications (49.6%) of whom 62 patients (55.9%) developed >1 complication. An independent prognostic effect was observed for the inflammatory biomarkers IL-6 and IL-10 for the occurrence of postoperative complications.CONCLUSION: The perioperative inflammatory response is associated with complications, independently from patient and surgical factors which are also associated with outcome. Research is warranted towards further exploration of the perioperative inflammatory response with the aim to improve perioperative care and outcome, and might help to improve surgical planning and decision making for older patients with cancer.

Purpose Little is known about the reliability and value of intraoperative neurophysiological monitoring (IONM) in patients with Duchenne muscular dystrophy (DMD) undergoing scoliosis correction surgery. The aim of this study was to investigate the feasibility of IONM and the cortical excitability in these patients. Methods Fifteen patients with DMD and scoliosis and 15 patients with adolescent idiopathic scoliosis (AIS) underwent scoliosis correction surgery with the use of IONM. IONM consisted of transcranial electrical stimulation motor evoked potential (Tc-MEP) and somatosensory evoked potential (SSEP) monitoring. The highest Tc-MEP amplitudes were collected to test the feasibility. Preoperative compound muscle action potentials (CMAPs) and transcranial magnetic stimulation (TMS)-MEPs were recorded to test the cortical excitability. SSEPs were scored as elicitable or not elicitable. Results Tc-MEP amplitudes were significantly lower in the DMD group for both the gastrocnemius and tibialis anterior muscles. However, the abductor hallucis muscle had similar amplitudes in both the DMD as the AIS group. TMS/CMAP and Tc-MEP/CMAP ratios were similar in the DMD and AIS group (P = 0.126 and P = 0.792 respectively). Conclusions Tc-MEP and SSEP monitoring is feasible, particularly when Tc-MEPs are recorded from the abductor hallucis muscle in patients with DMD. Similar TMS/CMAP and Tc-MEP/CMAP ratios show that there were no differences observed in cortical excitability between the groups. IONM seems a feasible and valuable neurophysiological tool to signal possible surgically induced damage to the spinal cord during scoliosis correction surgery in patients with DMD.

Summary The multidisciplinary International Committee for the Advancement of Procedural Sedation presents the first fasting and aspiration prevention recommendations specific to procedural sedation, based on an extensive review of the literature. These were developed using Delphi methodology and assessment of the robustness of the available evidence. The literature evidence is clear that fasting, as currently practiced, often substantially exceeds recommended time thresholds and has known adverse consequences, for example, irritability, dehydration and hypoglycaemia. Fasting does not guarantee an empty stomach, and there is no observed association between aspiration and compliance with common fasting guidelines. The probability of clinically important aspiration during procedural sedation is negligible. In the post‐1984 literature there are no published reports of aspiration‐associated mortality in children, no reports of death in healthy adults (ASA physical status 1 or 2) and just nine reported deaths in adults of ASA physical status 3 or above. Current concerns about aspiration are out of proportion to the actual risk. Given the lower observed frequency of aspiration and mortality than during general anaesthesia, and the theoretical basis for assuming a lesser risk, fasting strategies in procedural sedation can reasonably be less restrictive. We present a consensus‐derived algorithm in which each patient is first risk‐stratified during their pre‐sedation assessment, using evidence‐based factors relating to patient characteristics, comorbidities, the nature of the procedure and the nature of the anticipated sedation technique. Graded fasting precautions for liquids and solids are then recommended for elective procedures based upon this categorisation of negligible, mild or moderate aspiration risk. This consensus statement can serve as a resource to practitioners and policymakers who perform and oversee procedural sedation in patients of all ages, worldwide.

Background: The proposed underlying mechanisms of anxiety and depression, and of postoperative neurocognitive disorder (NCD), each include immune system involvement. Therefore, the aims of this study were to investigate the incidence of postoperative NCD 3 months after surgery among oncological patients undergoing surgery and to evaluate the role of preoperative anxiety and depression. Method: A consecutive series of patients (age ≥ 18 years) undergoing surgery for the removal of solid tumors were included (n = 218). Cognitive performance was assessed preoperatively and at 3 months postoperatively. Preoperative anxiety and depression were evaluated using the Hospital Anxiety and Depression Scale. Results: NCD affected 12.3% of elderly patients (age ≥ 70 years, n = 57) at 3 months after surgery, with executive function mostly affected. By contrast, 8.4% of younger patients (age < 70 years, n = 107) were affected, with information processing speed mostly affected. Low educational attainment was a risk factor (OR, 6.0; 95% CI, 1.9–19.0) of overall NCD, whereas preoperative anxiety was associated with decline in the domain of executive function. Conclusion: Postoperative NCD is a complication of oncological surgery for all adults instead of the elderly only. Preoperative anxiety was associated with an increased risk of executive function decline, and low educational attainment was a key factor for overall NCD.

Funder: Università degli Studi di Brescia, BACKGROUND: The use of processed electroencephalography (pEEG) for depth of sedation (DOS) monitoring is increasing in anesthesia; however, how to use of this type of monitoring for critical care adult patients within the intensive care unit (ICU) remains unclear. METHODS: A multidisciplinary panel of international experts consisting of 21 clinicians involved in monitoring DOS in ICU patients was carefully selected on the basis of their expertise in neurocritical care and neuroanesthesiology. Panelists were assigned four domains (techniques for electroencephalography [EEG] monitoring, patient selection, use of the EEG monitors, competency, and training the principles of pEEG monitoring) from which a list of questions and statements was created to be addressed. A Delphi method based on iterative approach was used to produce the final statements. Statements were classified as highly appropriate or highly inappropriate (median rating ≥ 8), appropriate (median rating ≥ 7 but < 8), or uncertain (median rating < 7) and with a strong disagreement index (DI) (DI < 0.5) or weak DI (DI ≥ 0.5 but < 1) consensus. RESULTS: According to the statements evaluated by the panel, frontal pEEG (which includes a continuous colored density spectrogram) has been considered adequate to monitor the level of sedation (strong consensus), and it is recommended by the panel that all sedated patients (paralyzed or nonparalyzed) unfit for clinical evaluation would benefit from DOS monitoring (strong consensus) after a specific training program has been performed by the ICU staff. To cover the gap between knowledge/rational and routine application, some barriers must be broken, including lack of knowledge, validation for prolonged sedation, standardization between monitors based on different EEG analysis algorithms, and economic issues. CONCLUSIONS: Evidence on using DOS monitors in ICU is still scarce, and further research is required to better define the benefits of using pEEG. This consensus highlights that some critically ill patients may benefit from this type of neuromonitoring.

Background: Deep brain stimulation (DBS) is an accepted treatment for patients with medication-resistant Tourette syndrome (TS). Sedation is commonly required during electrode implantation to attenuate anxiety, pain, and severe tics. Anesthetic agents potentially impair the quality of microelectrode recordings (MER). Little is known about the effect of these anesthetics on MER in patients with TS. We describe our experience with different sedative regimens on MER and tic severity in patients with TS. Methods: The clinical records of all TS patients who underwent DBS surgery between 2010 and 2018 were reviewed. Demographic data, stimulation targets, anesthetic agents, perioperative complications, and MER from each hemisphere were collected and analyzed. Single-unit activity was identified by filtering spiking activity from broadband MER data and principal component analysis with K-means clustering. Vocal and motor tics which caused artifacts in the MER data were manually selected using visual and auditory inspection. Results: Six patients underwent bilateral DBS electrode implantation. In all patients, the target was the anterior internal globus pallidus. Patient comfort and hemodynamic and respiratory stability were maintained with conscious sedation with one or more of the following anesthetic drugs: propofol, midazolam, remifentanil, clonidine, and dexmedetomidine. Good quality MER and clinical testing were obtained in 9 hemispheres of 6 patients. In 3 patients, MER quality was poor on one side. Conclusion: Cautiously applied sedative drugs can provide patient comfort, hemodynamic and respiratory stability, and suppress severe tics, with minimal interference with MER.

BackgroundThe literature related to the use of processed EEG (pEEG) for depth of sedation (DOS) monitoring is increasing, however it is unclear how to use this type of monitoring for critical care patients within the intensive care unit (ICU).MethodsWe performed a systematic review of the literature according to the Grade of Recommendation assessment, Development, and Evaluation (GRADE) approach. The modified Delphi method was utilised by a team of experts to produce statements and recommendations derived from study questions. Three separate online rounds discussing 89 statements categorized into four domains were formulated. The panelists rated the appropriateness of each statement and were able to suggest modifications or addition of statements. An analysis of anonymised ratings of the statements by part of the panel followed each Delphi round and previously validated criteria were used to define appropriateness and consensus.ResultsLevel of evidence regarding the four domains was very low. Fourteen panelists participated in the Delphi rounds and consensus was reached for 28 out of 89 statements, from which the reccomendations were created. The main findings were that DOS monitoring should be performed in critically ill patients whenever clinical evaluation is not possible, it should be performed by continuous pEEG techniques and the resulting data depicted with graphical tools to facilitate detection of excessive sedation, a potential cause of burst-suppression, and finally, structured training is suggested to achieve a basic pEEG competency.ConclusionsAlthough evidence on using DOS monitors in ICU is scarce and further research is required in order to better define the benefits of using pEEG, the results of this consensus highlight the general agreement that critically-ill patients would benefit from this type of neuromonitoring.

The results of the PErioperAtive CHildhood ObesitY (PEACHY) study showed an alarmingly high incidence of obesity amongst children presenting for surgical procedures under general anaesthesia in the UK. The study was performed by the Paediatric Anaesthesia Trainee Research Network (PATRN), a network of trainee anaesthetists seeking to quantify important clinical problems. Networks and consortia that facilitate collaboration amongst clinicians and academics working in a wide range of types of hospitals are particularly important in the current era, as they have the potential to gather data rapidly on important clinical problems, and by their size improve the power to identify factors associated with rare complications. Collaboration amongst clinicians within networks instead of competition between clinicians can have wide-ranging benefits that extend beyond research, and can include improvements in training, rapid dissemination of protocols, and knowledge concerning new problems, ultimately improving general standards of care.

This prospective study evaluates haemodynamic and electroencephalographic effects observed when administering four combinations of effect-site concentrations of propofol (CePROP) and remifentanil (CeREMI), all yielding a single predicted probability of tolerance of laryngoscopy of 90% (PTOL = 90%) according to the Bouillon interaction model. We aimed to identify combinations of CePROP and CeREMI along a single isobole of PTOL that result in favourable hypnotic and haemodynamic conditions. This knowledge could be of advantage in the development of drug advisory monitoring technology. 80 patients (18–90 years of age, ASA I–III) were randomized into four groups and titrated towards CePROP (Schnider model, ug⋅ml−1) and CeREMI (Minto model, ng⋅ml−1) of respectively 8.6 and 1, 5.9 and 2, 3.6 and 4 and 2.0 and 8. After eleven minutes of equilibration, baseline measurements of haemodynamic endpoints and bispectral index were compared with three minutes of responsiveness measurements after laryngoscopy. Before laryngoscopy, bispectral index differed significantly (p PROP. Heart rate decreased with increasing CeREMI (p = 0.001). The haemodynamic and arousal responses evoked by laryngoscopy were not significantly different between groups, but CePROP = 3.6 μg⋅ml−1 and CeREMI = 4 ng⋅ml−1 evoked the lowest median value for ∆HR and ∆SAP after laryngoscopy. This study provides clinical insight on the haemodynamic and hypnotic consequences, when a model based predicted PTOL is used as a target for combined effect-site controlled target- controlled infusion of propofol and remifentanil. Heart rate and bispectral index were significantly different between groups despite a theoretical equipotency for PTOL, suggesting that each component of the anaesthetic state (immobility, analgesia, and hypnotic drug effect) should be considered as independent neurophysiological and pharmacological phenomena. However, claims of (in)accuracy of the predicted PTOL must be considered preliminary because larger numbers of observations are required for that goal.

Introduction: Crewmembers of the “Royal Netherlands Sea Rescue Institution” (KNRM) lifeboats must wear heavy survival suits with integrated lifejackets. This and the challenging environment onboard (boat movements, limited space) might influence Basic Life Support (BLS) performance. The primary objective of this study was to assess the impact of the protective gear on single-rescuer BLS-quality.Material and Methods: Sixty-five active KNRM crewmembers who had recently undergone a BLS-refresher course were randomized to wear either their protective gear (n = 32) or their civilian clothes (n = 33; control group) and performed five 2-min sessions of single rescuer BLS on a mannequin on dry land. BLS-quality was assessed according to Dutch and European Resuscitation guidelines. A between group analysis (Mann-Whitney U) and a repeated within group analysis of both groups (Friedman test) were performed.Results: There were no major demographic differences between the groups. The protective gear did not significant impair BLS-quality. It was also not associated with a significant increase in the perceived exertion of BLS (Borg's Rating scale). Compression depth, compression frequency, the percentage of correct compression depth and of not leaning on the thorax, and ventilation volumes in both groups were suboptimal when evaluated according to the BLS-guidelines.Conclusions: The protective gear worn by KNRM lifeboat-crewmembers does not have a significant influence on BLS-quality under controlled study conditions. The impact and significance on outcome in real life situations needs to be studied further. This study provides valuable input for optimizing the BLS-skills of lifeboat crewmembers.

Background Absence of interlobar collateral ventilation is key to successful endobronchial valve treatment in patients with severe emphysema and can be functionally assessed by using the Chartis measurement. This system has been validated during spontaneous breathing, undergoing procedural sedation (PS), but can also be performed under general anesthesia. Performing the Chartis measurement under PS is often challenging because of coughing, mucus secretion, and difficulties in maintaining an adequate level of sedation. The objective of this study was to investigate whether there is a difference in Chartis measurement outcomes between PS and general anesthesia. Methods In this prospective study, patients underwent Chartis measurements under both PS and general anesthesia. Study outcomes were Chartis measurement duration, number of measurements, feasibility, and success rate. Results The study included 30 patients with severe emphysema (mean age, 62 years; median FEV1, 29% of predicted). Chartis measurement duration was significantly longer under PS than under general anesthesia (mean, 20.3 ± 4.2 min vs 15.1 ± 4.4 min; P Conclusions This study found that Chartis measurement under general anesthesia is faster and more feasible to perform compared with performance with PS, without affecting measurement outcomes. Trial Registration Clinicaltrials.gov; No. NCT03205826 ; URL: www.clinicaltrials.gov .

Stroke is a major global health issue, contributing to an age-standardised global death rate for cerebrovascular diseases of 86.5 per 100 000. For many years intravenous thrombolytic agents were the main treatment option for acute ischaemic strokes. In recent years, strong evidence has emerged that the use of intra-arterial thrombectomy in addition to standard care improves outcome after acute ischaemic strokes because of large vessel occlusions. The challenge for anaesthetists is to determine how they can assist the interventionists to optimise the treatment and improve clinical outcomes for patients undergoing intra-arterial thrombectomy. At present there are insufficient data upon which to guide anaesthetic management during intra-arterial thrombectomy because previous studies showed conflicting results and there is a lack of standardised reporting of relevant haemodynamic, respiratory, and anaesthetic parameters. We encourage anaesthetists working in thrombectomy capable centres to get actively involved in their neuro-interventional team. Their involvement can make an important contribution in investigating and implementing optimal management strategies for patients with acute ischaemic strokes requiring intra-arterial thrombectomy.

This cross-sectional study aimed to investigate the effect of premenopausal risk reducing salpingo-oophorectomy (RRSO) on the cholesterol profile of women at increased ovarian cancer risk and to assess possible effects of age at and time since RRSO. We included 207 women who underwent RRSO before menopausal age (52 years) attending the family cancer clinic of an academic hospital and 828 age-matched women from a general population cohort (PREVEND). Participants filled out a questionnaire on socio-demographic characteristics, lifestyle and medical history, had anthropometric measurements and provided blood samples for assessment of serum levels of total cholesterol, HDL-cholesterol and non-HDL-cholesterol. The correlation between RRSO and cholesterol profile was assessed with logistic regression. Furthermore, subgroup analyses were performed to explore a possible effect of age at and time since RRSO. At a median time of 5.9 years (range 2.3–25.2) after surgery, RRSO was associated with low (

Propofol is an intravenous hypnotic drug that is used for induction and maintenance of sedation and general anaesthesia. It exerts its effects through potentiation of the inhibitory neurotransmitter -aminobutyric acid (GABA) at the GABA(A) receptor, and has gained widespread use due to its favourable drug effect profile. The main adverse effects are disturbances in cardiopulmonary physiology. Due to its narrow therapeutic margin, propofol should only be administered by practitioners trained and experienced in providing general anaesthesia. Many pharmacokinetic (PK) and pharmacodynamic (PD) models for propofol exist. Some are used to inform drug dosing guidelines, and some are also implemented in so-called target-controlled infusion devices, to calculate the infusion rates required for user-defined target plasma or effect-site concentrations. Most of the models were designed for use in a specific and well-defined patient category. However, models applicable in a more general population have recently been developed and published. The most recent example is the general purpose propofol model developed by Eleveld and colleagues. Retrospective predictive performance evaluations show that this model performs as well as, or even better than, PK models developed for specific populations, such as adults, children or the obese; however, prospective evaluation of the model is still required. Propofol undergoes extensive PK and PD interactions with both other hypnotic drugs and opioids. PD interactions are the most clinically significant, and, with other hypnotics, tend to be additive, whereas interactions with opioids tend to be highly synergistic. Response surface modelling provides a tool to gain understanding and explore these complex interactions. Visual displays illustrating the effect of these interactions in real time can aid clinicians in optimal drug dosing while minimizing adverse effects. In this review, we provide an overview of the PK and PD of propofol in order to refresh readers' knowledge of its clinical applications, while discussing the main avenues of research where significant recent advances have been made.

Purpose of review Ambulatory procedural sedation is used to relieve anxiety, pain and discomfort in a broad spectrum of patients during many types of diagnostic or therapeutic procedures. This review focuses on recent comparative studies of commonly used and new drugs for adult ambulatory sedation. Recent findings Midazolam and propofol are commonly used for ambulatory sedation. Their pharmacological properties offer many advantages and there is much experience with their use. Ketamine can be a useful addition to hypnotic drugs but the advantage of the use of ketofol (a mixture of propofol and ketamine) is, although often practiced, difficult to assess. Dexmedetomidine is a relatively new sedative drug and many studies suggest advantages. New findings about its effects, however, show that the hemodynamic consequences of the use of dexmedetomidine may last for several hours. New sedative drugs for procedural sedation are still being developed: remimazolam has many properties that would make it an ideal sedative and has been studied in a phase 3 study. The properties that would constitute the ideal sedative have yet to be combined in one drug. The selection of the drugs used for ambulatory sedation depends on many factors such as procedure type, patient characteristics and the expectations of patients and the healthcare provider. Because of this, the literature cannot yet provide a definitive answer to the question which drug is best selected in a specific situation.

Simple SummaryOlder patients can have an increased expression of inflammatory cytokines due to ageing of the immune system. It is likely that older cancer patients with a low-grade inflammatory state are more at risk for an exaggerated inflammatory response to surgery and for poor outcome after surgery. The aim of this study was to examine whether preoperative inflammatory markers could be a predictor of overall survival in older patients undergoing oncologic surgery. In this prospective cohort study, a plasma level of C-reactive protein (CRP) >= 10 mg/L was a predictor of inferior three-year overall survival after oncologic surgery in older cancer patients, and also for the specific group of older patients with a colorectal tumor. Measuring preoperative plasma level of CRP might be useful in risk stratification for poor outcome after surgery in older cancer patients.Oncologic surgery results in substantially higher morbidity and mortality rates in older patients compared to younger patients, yet little is known about the relation between the preoperative inflammatory state and postoperative outcome in the specific group of older cancer patients. The aim of this study was to examine whether preoperative inflammatory markers could be a predictor of overall survival in older patients undergoing elective surgery for a solid malignant tumor. Patients 65 years and older undergoing surgery for a solid malignant tumor were included in a prospective cohort study. Inflammatory markers C-reactive protein (CRP), interleukin-1 beta (IL-1 beta), IL-6, IL10, IL-12 and tumor necrosis factor-alpha (TNF-alpha) were measured in plasma samples preoperatively. The main outcome was overall survival three years after surgery. Between 2010 and 2016, 328 patients with a median age of 71.5 years (range 65-89) were included. A significantly higher mortality rate three years after surgery, was found in patients with high preoperative plasma levels of CRP and IL-6 (p = 0.013 and p = 0.046, respectively). In multivariate analysis, corrected for variables such as age, disease stage, frailty, comorbidities, type of surgery and complications, a preoperative plasma level of CRP >= 10 mg/L was an independent prognostic factor for inferior overall survival three years after surgery (multivariate hazard ratio 1.50, 95% confidence interval 1.04-2.16, p = 0.031). Also, for the specific group of patients with colorectal cancer, a preoperative plasma level of CRP >= 10 mg/L was a prognostic factor for inferior survival three years after surgery (multivariate hazard ratio 2.40, 95% confidence interval 1.20-4.81, p = 0.014). Preoperative elevated plasma level of CRP is an independent unfavorable prognostic factor for overall survival three years after oncologic surgery. This gives more insight into the relationship between inflammation and survival in older cancer patients, and might contribute to risk stratification for poor outcome after surgery in older cancer patients.

BACKGROUND: Subthalamic nucleus (STN) deep brain stimulation (DBS) has become a routine treatment of advanced Parkinson's disease (PD). DBS surgery is commonly performed under local anesthesia (LA) to obtain reliable microelectrode recordings. However, procedural sedation and/or analgesia (PSA) is often desirable to improve patient comfort. The impact of PSA in addition to LA on outcome is largely unknown. Therefore, we performed an observational study to assess the effect of PSA compared to LA alone during STN DBS surgery on outcome in PD patients.METHODS: Seventy PD patients (22 under LA, 48 under LA + PSA) scheduled for STN DBS implantation were included. Dexmedetomidine, clonidine or remifentanil were used for PSA. The primary outcome was the change in Movement Disorders Society Unified Parkinson's Disease Rating Score III (MDS-UPDRS III) and levodopa equivalent daily dosage (LEDD) between baseline, one month before surgery, and twelve months postoperatively. Secondary outcome measures were motor function during activities of daily living (MDS-UPDRS II), cognitive alterations and surgical adverse events. Postoperative assessment was conducted in "on" stimulation and "on" medication conditions.RESULTS: At twelve months follow-up, UPDRS III and UPDRS II scores in "on" medication conditions were similar between the LA and PSA groups. The two groups showed a similar LEDD reduction and an equivalent decline in executive function measured by the Stroop Color-Word Test, Trail Making Test-B, and verbal fluency. The incidence of perioperative and postoperative adverse events was similar between groups.CONCLUSION: This study demonstrates that PSA during STN DBS implantation surgery in PD patients was not associated with differences in motor and non-motor outcome after twelve months compared with LA only.

Background: The pathophysiology of numerous central nervous system disorders remains poorly understood. Biomarker research using cerebrospinal fluid (CSF) is a promising way to illuminate the neurobiology of neuropsychiatric disorders. CSF biomarker studies performed so far generally included patients with neurodegenerative diseases without an adequate control group. The Anaesthetic Biobank of Cerebrospinal fluid (ABC) was established to address this. The aims are to (I) provide healthy-control reference values for CSF-based biomarkers, and (II) to investigate associations between CSF-based candidate biomarkers and neuropsychiatric symptoms.& nbsp; & nbsp;Methods: In this cross-sectional study, we collect and store CSF and blood from adult patients undergoing spinal anaesthesia for elective surgery. Blood (20.5 mL) is collected during intravenous cannulation and CSF (10 mL) is aspirated prior to intrathecal local anaesthetic injection. A portion of the blood and CSF is sent for routine laboratory analyses, the remaining material is stored at & minus;80 ?. Relevant clinical, surgical and anaesthetic data are registered. A neurological examination and Montreal Cognitive Assessment (MoCA) are performed pre-operatively and a subset of patients fill in questionnaires on somatic and mental health (depression, anxiety and stress).& nbsp; Results: Four-hundred-fifty patients (58% male; median age: 56 years) have been enrolled in the ABC. The planned spinal anaesthetic procedure was not attempted for various reasons in eleven patients, in fourteen patients the spinal puncture failed and in twelve patients CSF aspiration was unsuccessful. A mean of 9.3 mL CSF was obtained in the remaining 413 of patients. Most patients had a minor medical history and 60% scored in the normal range on the MoCA (median score: 26).& nbsp; Conclusions: The ABC is an ongoing biobanking project that can contribute to CSF-based biomarker research. The large sample size with constant sampling methods and extensive patient phenotyping provide excellent conditions for future neuroscientific research.

A decline in cognitive function is a frequent complication of major surgery. Postoperative cognitive impairments have generally been divided into short- (postoperative delirium) and long-term disturbances (postoperative cognitive dysfunction [POCD]). Long-term impairments are often subtle and overlooked. They need to be objectively assessed using neuropsychological tests to be diagnosed. Although POCD has been the subject of considerable research over the past decades, it remains uncertain why some patients do not return to preoperative levels of cognitive function. Surgery and anesthesia have both been implicated to play a role in POCD development, and certain patient-related factors, such as advanced age and low preoperative baseline cognitive function, have consistently been found to predict postoperative cognitive decline. This article will present an overview of POCD and its etiology and provide advice on possible strategies on its prevention.

BACKGROUND: Target-controlled infusion (TCI) systems incorporating pharmacokinetic (PK) or PK-pharmacodynamic (PK-PD) models can be used to facilitate drug administration. Existing models were developed using data from select populations, the use of which is, strictly speaking, limited to these populations. Recently a propofol PK-PD model was developed for a broad population range. The aim of the study was to prospectively validate this model in children, adults, older subjects, and obese adults undergoing general anaesthesia.METHODS: The 25 subjects included in each of four groups were stratified by age and weight. Subjects received propofol through TCI with the Eleveld model, titrated to a bispectral index (BIS) of 40-60. Arterial blood samples were collected at 5, 10, 20, 30, 40, and 60 min after the start of propofol infusion, and every 30 min thereafter, to a maximum of 10 samples. BIS was recorded continuously. Predictive performance was assessed using the Varvel criteria.RESULTS: For PK, the Eleveld model showed a bias < ±20% in children, adults, and obese adults, but a greater bias (-27%) in older subjects. Precision was CONCLUSIONS: The Eleveld propofol PK-PD model showed predictive precision

Lumbar puncture (LP) procedures are commonly performed for diagnostic purposes by neurologists and emergency physicians, and for intrathecal local anesthesthetic administration for spinal anesthesia by anesthesiologists. Complications include post-dural puncture headache, meningitis, epidural hematoma and neurological injury. A recent article by Ertas et al in the Journal of Clinical Neurology and Neurosurgery highlights the risks of intervertebral disc injury during LP. Disc injury, has been shown to initiate degenerative chances in animal models. During an LP the degree of damage to the intervertebral disc is probably determined by the force applied, and nature and diameter of the needle. It is perhaps time to reprise the evidence concerning needle choice and the incidence of complications. A range of traumatic (cutting) and atraumatic (pencil point) LP needles have been developed in a variety of sizes. At present there is no evidence that atraumatic needles reduce the incidence of back pain. A large body of evidence shows that atraumatic needles are easy to use and are associated with a lower incidence of post-dural puncture headache, and do not increase the rates of failure or neurological injury. As a result, the use of atraumatic needles for spinal anesthesia is almost universal. Adoption of atraumatic needles in neurology practice has been slow and patchy. We challenge our neurological colleagues to follow the recommendations of several international guidelines, including those of the American Academy of Neurology, and incorporate the use of narrower gauge atraumatic needles for the benefit of their patients.

Backgroundγ-Aminobutyric acid type A (GABAA) receptor agonists are known to cause involuntary muscle movements. The mechanism of these movements is not known, and its relationship to depth of anesthesia monitoring is unclear. We have explored the effect of involuntary muscle movement on the pharmacokinetic-pharmacodynamic model for the GABAA receptor agonist ABP-700 and its effects on the Bispectral Index (BIS) as well as the Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) scores.MethodsObservations from 350 individuals (220 men, 130 women) were analyzed, comprising 6,312 ABP-700 concentrations, 5,658 ABP-700 metabolite (CPM-acid) concentrations, 25,745 filtered BIS values, and 6,249 MOAA/S scores, and a recirculatory model developed. Various subject covariates and pretreatment with an opioid or a benzodiazepine were explored as covariates. Relationships between BIS and MOAA/S models and involuntary muscle movements were examined.ResultsThe final model shows that the pharmacokinetics of ABP-700 are characterized by small compartmental volumes and rapid clearance. The BIS model incorporates an effect-site for BIS suppression and a secondary excitatory/disinhibitory effect-site associated with a risk of involuntary muscle movements. The secondary effect-site has a threshold that decreases with age. The MOAA/S model did not show excitatory effects.ConclusionsThe GABAA receptor agonist ABP-700 shows the expected suppressive effects for BIS and MOAA/S, but also disinhibitory effects for BIS associated with involuntary muscle movements and reduced by pretreatment. Our model provides information about involuntary muscle movements that may be useful to improve depth of anesthesia monitoring for GABAA receptor agonists.Editor’s PerspectiveWhat We Already Know about This TopicWhat This Article Tells Us That Is New

Physical inactivity and a sedentary lifestyle are associated with a chronic low-level inflammatory state which has been implicated in the pathogenesis of cardiovascular disease. There is growing interest in exercise programs as part of surgical ‘prehabilitation’. We therefore studied preoperative physical activity levels of patients undergoing elective Coronary Artery Bypass Graft (CABG) surgery, and performed an exploratory analysis of the influence of physical activity on postoperative outcome. The Short Questionnaire to Assess Health (SQUASH) was used to assess physical activity among 100 patients, of mean (SD) age 65.4 (7.6) years. Additionally, handgrip strength was measured, and the get-up-and-go test was conducted. Anxiety, depression, and quality of life were assessed, and a computerised cognitive test battery was used to assess cognitive performance preoperatively, and three months after surgery. Preoperatively, 76% of patients met the recommended national guidelines for physical activity. The incidence of pre-existing medical conditions, and other pre-operative patient features were similar in active and inactive patients. Preoperative physical activity was significantly inversely related to the logistic EuroSCORE. The level of physical activity was also significantly inversely related with preoperative C-reactive protein (CRP) and peak postoperative CRP, but physical activity did not appear to be associated with any adverse postoperative outcomes or extended length of hospital stay. The incidence of postoperative neurocognitive disorder (PNCD) at 3 months postoperatively was 26%. Cognitive performance was not related with physical activity levels. In summary, this was the first study to assess activity levels of cardiac surgical patients with the SQUASH questionnaire. The majority of patients were physically active. Although physical activity was associated with lower levels of inflammation in this pilot study, it was not associated with an improved clinical or cognitive postoperative outcome.

Although drugs have been used to administer general anaesthesia for more than a century and a half, relatively little was known until recently about the molecular and cellular effects of the anaesthetic agents and the neurobiology of anaesthesia. Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) studies have played a valuable role in improving this knowledge. PET studies using 11C-flumazenil binding have been used to demonstrate that the molecular action of some, but not all, of the current anaesthetic agents is mediated via the GABAA receptor. Using different tracers labelled with 18F, 11C and 15O, PET studies have shown the patterns of changes in cerebral metabolism and blood flow associated with different intravenous and volatile anaesthetic agents. Within classes of volatile agents, there are minor variations in patterns. More profound differences are found between classes of agents. Interestingly all agents cause alterations in the blood flow and metabolism of the thalamus, providing strong support for the hypothesis that the anaesthetic agents interfere with consciousness by interfering with thalamocortical communication.

Background: Target-controlled infusion (TCI) systems are used to facilitate anesthetic drug administration. Current systems use pharmacokinetic models developed for specific patient groups. Their use in patients with different characteristics to that of the development population is therefore discouraged. Recently, Eleveld et al1 developed a propofol PK-PD model for broad application. The aim of the current study was to validate it in a broad range of patients, from children to the elderly, and in obese adults. Methods: The medical ethics committee of the University Medical Center Groningen (reference METc2018/216) approved the study. Four groups of 25 patients undergoing an elective surgical procedure were included. Eligibility criteria for the four groups were: children (age ≥ 3 years and

BACKGROUND: In the University Medical Center Groningen in Groningen, the Netherlands, moderate-to-deep sedation is provided by nursing staff trained and supervised by the anesthesia department using protocol-based target-controlled infusions (TCIs) of propofol and remifentanil. The aim of this retrospective cohort study was to investigate the incidence of events with potential adverse health consequences within this service model and the risk factors for the occurrence of these events. METHODS: We retrospectively interrogated a database containing the computerized anesthetic records of 2937 procedures where moderate-to-deep sedation was provided using TCI administration of propofol and remifentanil between May 2014 and October 2017. The primary outcome measures were the incidence of sedation-related events with potential adverse health consequences and risk factors for the occurrence of such events. The events under investigation were unplanned intensive care unit (ICU) admission, need for cardiopulmonary resuscitation (CPR), death on the day of the procedure due to sedation-related events, cardiovascular events (arrhythmias, hypertension, and hypotension), pulmonary events (aspiration, desaturation, unplanned tracheal intubation), anaphylactic or allergic reactions, and the termination of the procedure due to sedation-related events. Cardiovascular and pulmonary events were classified as severe, significant, or moderate. Events were identified by using computer algorithms to search the computerized records from all included procedures. RESULTS: Data from 2937 procedures were analyzed. No patients suffered catastrophic events (death, need for CPR, or unplanned ICU admission). Thirty-two severe sedation-related events occurred in 32 procedures. Severe desaturation (0.6%; 95% confidence interval [CI], 0.4-0.9) and severe hypertension (0.2%; 95% CI, 0.04-0.37) were the most common severe events. Significant hypotension (8.8%; 95% CI, 7.73-9.77) and significant desaturation (1.6%; 95% CI, 1.12-2.02) were found to be the most common events with potential adverse health consequences. No patient suffered lasting health consequences. Average mean and maximum targeted effect-site concentrations (Cet) for propofol were 2.6 ± 0.83 and 3.3 ± 1.09 µg·mL-1, respectively, and for remifentanil 0.84 ± 0.18 and 0.99 ± 0.22 ng·mL-1, respectively. Maximum Cets of propofol were lower among patients with higher body mass index (BMI) and were higher among patients of younger age. Higher BMI was a risk factor for desaturation. Increased age and lower BMI were risk factors for hypotension. Longer procedure time was a risk factor for both desaturation and hypotension. CONCLUSIONS: Moderate-to-deep sedation by propofol and remifentanil TCI has a low incidence of catastrophic and severe events.

This article corrects the Guidelines by Green SM, Leroy PL, Roback MG, Irwin MG, Andolfatto G, Babl FE, Barbi E, Costa LR, Absalom A, Carlson DW, Krauss BS, Roelofse J, Yuen VM, Alcaino E, Costa PS, Mason KP on behalf of the International Committee for the Advancement of Procedural Sedation, ‘An international multidisciplinary consensus statement on fasting before procedural sedation in adults and children’ [1]. The authors thank a careful reader who identified that a study from this table by Rajasekaran et al should have been excluded, as it included fewer than 5000 patients. The corrected table without this study is shown below, and this change does not alter our other findings and conclusions. An author and corresponding affiliation were omitted and is now revised as follows: 1 Table Literature estimates of aspiration risk during procedural sedation* (Table presented.) * To include just the largest studies we display those with 5,000 or more patients. We also exclude studies which report duplicate sub-sets of patients.