Anesthesia Monitoring Research Articles

The Current Situation of Anaesthesia for Hysteroscopy in Mainland China: A National Survey.

Purpose: The need for anaesthesia or analgesia for performing hysteroscopy remains debatable. This study aimed to conduct an overview of the situation of anaesthesia for hysteroscopy in mainland China. Methods: Two questionnaires were separately designed for anaesthesiologists and gynaecologists and distributed to every medical institution that performed hysteroscopic procedures on patients with infertility in mainland China. Electronic questionnaires were distributed via WeChat, and data on anaesthesia regimen, monitoring parameters, procedure number, and other information were collected. Results: Reproductive technology is conducted by 536 institutions in mainland China. The survey received 491 responses from anaesthetists (91.6%) and 436 from gynaecologists (81.3%). In 2021, 552,225 hysteroscopies were conducted in 268 medical centres. The average percentage of hysteroscopy under anaesthesia is 63.8% in 2021, wherein 47.3% of institutions have an anaesthesia percentage of >75%. Propofol and opioid analgesics, such as fentanyl and sufentanil, were the most commonly used intravenous anaesthetics. All sedations were performed by anaesthesiologists. Monitoring parameters included pulse oxygen saturation (98.9%), electrocardiogram (91.6%) and noninvasive blood pressure (91.3%). An anaesthesiologist-to-operating room ratio of <1 was observed in 31.3% of medical institutions. Surprisingly, 52.4% of medical institutions performing hysteroscopy had no postanaesthesia care unit (PACU). Most institutions with PACU were equipped with independent oxygen sources, suction and monitors. Both rigid and flexible hysteroscopes (rigid hysteroscope, 45.1%; flexible hysteroscope, 4.5%; both types, 50.4%) were used, and the hysteroscopic diameter was ≤5 mm in 60.3% of medical centres. Conclusions: China performs a large number of hysteroscopies, and sedation is the most frequently used anesthesia regimen. However, issues such as inadequate emergency support devices, insufficient personnel and weak resuscitation management after anaesthesia, have been observed.

Intraoperative application of regional cerebral oxygen saturation monitoring for geriatric patients in China: a survey.

Regional cerebral oxygen saturation (rSO2) monitoring is a real-time and non-invasive technique for estimating the balance of regional cerebral oxygen supply and consumption. Despite the growing popularity of this monitoring technique, data regarding outcome benefits remain sparse and contradictory. This study was conducted to explore the popularity and understanding of cerebral oxygen saturation monitoring during anesthesia in geriatric patients. An online self-report questionnaire was distributed in March 2021 to various hospitals in China for dissemination to anesthesiologists. Questions surveyed cerebral oximetry equipment and utilization, demographics, and clinical practice of participants. In total, 447 anesthesiologists responded. Of these, 301 (67.3%) respondents reported that their hospitals were equipped with cerebral oximetry, which 274 anesthesiologists use during anesthesia. A high percentage of anesthesiologists chose to monitor rSO2 during cardiac surgery (77.4%, n = 212) and neurosurgery (40.5%, n = 111). Most anesthesiologists agreed that a 30% reduction from the rSO2 baseline requires intervention to avoid cerebral ischemia, mainly via elevating arterial pressure and fraction of inspired oxygen (FiO2). Of those without cerebral oximetry, 138 of 146 (94.5%) anesthesiologists were willing to monitor rSO2. In addition, 291 respondents believed that cerebral oxygen monitoring would help prevent postoperative cognitive dysfunction. Our survey indicated that the prevalence of cerebral oximetry remains relatively low, while almost all anesthesiologists expressed their willingness to use rSO2 monitoring in geriatric anesthesia. Heterogeneity in clinical practice was identified, indicating relevant knowledge gaps that should encourage further clinical research to optimize treatment.

Clinical Outcomes and Quality of Life after Patent Foramen Ovale (PFO) Closure in Patients with Stroke/Transient Ischemic Attack of Undetermined Cause and Other PFO-Associated Clinical Conditions: A Single-Center Experience.

The aim of this study was to assess clinical outcomes and quality of life after PFO closure in patients with previous stroke/TIA of undetermined cause and in patients with other complex PFO-associated clinical conditions. Between July 2009 and December 2019 at our University Cardiology Department, 118 consecutive patients underwent a thorough diagnostic work-up including standardized history taking, clinical evaluation, full neurological examination, screening for thrombophilia, brain magnetic resonance imaging (MRI), ultrasound-Doppler sonography of supra-aortic vessels and 24 h ECG Holter monitoring. Anatomo-morphological evaluation using 2D transthoracic/transesophageal echocardiography (TTE/TEE) color Doppler and functional assessment using contrast TTE (cTTE) in the apical four-chamber view and contrast transcranial Doppler (cTCD) using power M-mode modality were performed to verify the presence, location and amount of right-to-left shunting via PFO or other extracardiac source. Completed questionnaires based on the Quality-of-Life Short Form-36 (QoL SF-36) and Migraine Disability Assessment (MIDAS) were obtained from the patients before PFO closure and after 12 months. Contrast TTE/TEE and cTCD were performed at dismission, 1, 6 and 12 months and yearly thereafter. Brain MRI was performed at 1-year follow-up in 54 patients. Transcatheter PFO closure was performed in 106 selected symptomatic patients (mean age 41.7 ± 10.7 years, range 16-63, 65% women) with the following conditions: ischemic stroke (n = 23), transient ischemic attack (n = 22), peripheral and coronary embolism (n = 2), MRI lesions without cerebrovascular clinical events (n = 53), platypnea-orthodeoxia (n = 1), decompression sickness (n = 1) and refractory migraine without ischemic cerebral lesions (n = 4). The implanted devices were Occlutech Figulla Flex I/II PFO (n = 99), Occlutech UNI (n = 3), Amplatzer PFO (n = 3) and CeraFlex PFO occluders (n = 1). Procedures were performed under local anesthesia and rotational intracardiac monitoring (Ultra ICE) alone. The devices were correctly implanted in all patients. The mean fluoroscopy time was 15 ± 5 min (range = 10-45 min) and the mean procedural time was 55 ± 20 min (range = 35-90 min). The total occlusion rate at follow-up (mean 50 months, range 3-100) was 98.1%. No recurrent neurological events were observed in the long-term follow-up. The data collected in this study demonstrate that percutaneous PFO closure is a safe and effective procedure, showing long-term prevention of recurrent cerebrovascular events, significant reduction in migraine symptoms and substantial improvement in quality of life.

DoseFormer: Dynamic Graph Transformer for Postoperative Pain Prediction

Many patients suffer from postoperative pain after surgery, which causes discomfort and influences recovery after the operation. During surgery, the anesthetists usually rely on their own experience when anesthetizing, which is not stable for avoiding postoperative pain. Hence, it is essential to predict postoperative pain and give proper doses accordingly. Recently, the relevance of various clinical parameters and nociception has been investigated in many works, and several indices have been proposed for measuring the level of nociception. However, expensive advanced equipment is required when applying advanced medical technologies, which is not accessible to most institutions. In our work, we propose a deep learning model based on a dynamic graph transformer framework named DoseFormer to predict postoperative pain in a short period after an operation utilizing dynamic patient data recorded in existing widely utilized equipment (e.g., anesthesia monitor). DoseFormer consists of two modules: (i) We design a temporal model utilizing a long short-term memory (LSTM) model with an attention mechanism to capture dynamic intraoperative data of the patient and output a hybrid semantic embedding representing the patient information. (ii) We design a graph transformer network (GTN) to infer the postoperative pain level utilizing the relations across the patient embeddings. We evaluate the DoseFormer system with the medical records of over 999 patients undergoing cardiothoracic surgery in the Fourth Affiliated Hospital of Zhejiang University School of Medicine. The experimental results show that our model achieves 92.16% accuracy for postoperative pain prediction and has a better comprehensive performance compared with baselines.

Pro-Con Debate: Should All General Anesthesia Be Done Using Target-Controlled Propofol Infusion Guided by Objective Monitoring of Depth of Anesthesia?

In this Pro-Con commentary article, we discuss whether all general anesthesia should be done using target-controlled propofol anesthesia guided by monitoring of depth of anesthesia. This is an ongoing debate since more than 25 years, representing a scientific, cultural as well as geographical divide in the anesthesia community. The Pro side argues that total intravenous anesthesia causes less postoperative nausea and higher patient satisfaction than anesthesia using volatile anesthetics. Target-controlled infusion (TCI) of anesthetic agents allows for better titration of intravenous anesthesia using pharmacokinetic models. Processed EEG monitors, such as bispectral index monitoring, allows for better assessing the effect of TCI anesthesia than solely assessment of clinical parameters, such as ECG or blood pressure. The combination of TCI propofol and objective depth of anesthesia monitoring allows creating a pharmacokinetic-pharmacodynamic profile for each patient. Finally, anesthesia using volatile anesthetics poses health risks for healthcare professionals and contributes to greenhouse effect. The Con side argues that for procedures accompanied with ischemia and reperfusion injury of an organ or tissue and for patients suffering from a severe inflammation' the use of volatile anesthetics might well have its advantages above propofol. In times of sudden shortage of drugs, volatile anesthetics can overcome the restriction in the operating theater or even on the intensive care unit, which is another advantage. Volatile anesthetics can be used for induction of anesthesia when IV access is impossible, end-tidal measurements of volatile anesthetic concentration allows confirmation that patients receive anesthetics. Taking environmental considerations into account, both propofol and volatile anesthetics bear certain harm to the environment, be it as waste product or as greenhouse gases. The authors therefore suggest to carefully considering advantages and disadvantages for each patient in its according environment. A well-balanced choice based on the available literature is recommended. The authors recommend careful consideration of advantages and disadvantages of each technique when tailoring an anesthetic to meet patient needs. Where appropriate, anesthesia providers are encouraged to account for unique features of anesthetic drug behavior, patient-reported and observed postoperative outcomes, and economic and environmental considerations when choosing any of the 2 described techniques.

Etomidate Versus Propofol for Monitored Anesthesia Care During Endoscopic Retrograde Cholangiopancreatography: A Prospective Randomized Controlled Trial.

Background and objectives Propofol-based sedation is one of the most commonly used methods for endoscopic retrograde cholangiopancreatography (ERCP). The commonest complications during ERCP are in the form of adverse cardiopulmonary events as a result of sedation. Etomidate has a more stable cardiovascular and respiratory profile than propofol and has been used forsedation in simple gastrointestinal endoscopy but has not been studied for procedural sedation in ERCP. The objective of the present study was to compare the safety and feasibility of etomidate and propofol for sedation during ERCP procedures. Methods This single-center, randomized trial included 100 American Society of Anesthesiologists (ASA) physical status class I to II patients who were scheduled for ERCP. All patients received midazolam 0.02 mg/kg, lignocaine (2%) 1 mg/kg, and fentanyl 1 µg/kg intravenously, followed by etomidate or propofol according to the group allocation. The primary outcome was to compare the mean arterial pressure (MAP) at various timepoints between the two groups and secondary outcomes were to compare oxygen saturation, induction and recovery times, and adverse events. Transient hypotension was defined as any decrease in MAPbelow 60 mmHg or 20% below the baseline. Transient hypoxia was defined as desaturation (saturation of peripheral oxygen (SpO2) <92%) lasting for more than 10 seconds requiring airway intervention. Results Fifty patients were enrolled in each group (Group E: etomidate and Group P: propofol). Transient hypotension occurred in eight (16%) patients in Group P, and two (4%) patients in Group E (P= 0.045). Baseline MAP was comparable between the two groups but was significantly lower in Group P at three timepoints during the study. Nine (18 %) patients in Group P had a transient hypoxic episode, compared to none in Group E (p= 0.006). The induction and recovery times were similar in the two groups. Conclusions Etomidate offers better hemodynamic and respiratory stability than propofol and can be recommended for use during ERCP in ASA I/II patients.

Perioperative Management and Anesthesia in Patients with Hemifacial Spasm Undergoing Microvascular Decompression: A Case Report

Introduction: Microvascular decompression (MVD) is an operation performed to treat a symptom of hemifacial spasm. Hemifacial spasm is described as a disorder of neuromuscular movement characterized by repeated to persistent involuntary contractions affecting the muscles innervated by the facial nerve.&#x0D; Case presentation: A 33-year-old woman came to consciousness with complaints of twitching on the right side of her face since 1 year ago. Initially, the complaint was felt for the first time 3 years ago, only on the upper right eyelid, but it has been getting worse over the past year. Magnetic resonance imaging (MRI) was obtained vascular loop on the right anterior inferior cerebellar artery (AICA) in level cerebellar pontine angle (CPA). MVD is a unilateral neurosurgical procedure in the axial section of the posterior fossa. Positions that can be used are supine and modified lateral decubitus or park bench. The management of anesthesia-related to posterior fossa surgery includes, first, the effect of the drug on the ability of the lungs to hold air from entering the venous circulation. Intravenous administration of anesthetics, for example, fentanyl, can maintain a higher threshold for retaining air bubbles in the pulmonary circulation compared with inhalational anesthetics.&#x0D; Conclusion: Optimal hemodynamic monitoring, good analgesia, and adequate muscle relaxation are the principles of anesthesia monitoring that aim to facilitate the operator in finding access to the disturbed nerve complex.

Anesthesia in Renal Transplant

Background: Transplantation provides near-normal life and excellent rehabilitation compared to dialysis and is the preferred method of treating end-stage renal disease (ESRD) patients. Methods: We conducted a retrospective analysis of anesthesia management from 20 cases of live renal transplants carried out between August 2017 and April 2019 at Dr. Sardjito Central General Hospital, Yogyakarta. The subjects ' preoperative patient status, anesthesia management, and postoperative care were assessed. Results: Most patients had preoperative anemia, normal serum potassium, serum creatinine, and average ejection fraction. Anesthesia management began 24 hours before surgery, in which the patients were hospitalized, had peripheral IV access and fluid maintenance, and hemodialysis, followed by premedication 1 hour before surgery. Before surgery, anesthesia induction and intubation were done, followed by maintenance of anesthesia and intraoperative monitoring. Postoperative care consisted of the administration of analgesia and management of complications. Conclusion: Optimization of preoperative status, proper anesthesia management, and good postoperative care are keys to a successful renal transplant program.

Efficacy of intravenous dexmedetomidine-lignocaine infusion compared to morphine for intraoperative haemodynamic stability in modified radical mastectomy: A randomised controlled trial.

In recent times, non-opioid analgesic-based anaesthesia has been gaining popularity as it can achieve the goals of hypnosis, amnesia, and haemodynamic stability while avoiding opioid side effects. Our study compares the efficacy of opioid-free anaesthesia and opioid-based general anaesthesia regarding intraoperative haemodynamic stability, anaesthetic requirements, awareness, and recovery profile. After receiving ethical approval and registering the trial, we conducted this randomised, single-blinded study on American Society of Anesthesiologists (ASA) physical status I and II patients who were aged 18-65 and were scheduled for modified radical mastectomy under general anaesthesia. Patients were randomised into two groups of 60 each. Group DL received IV dexmedetomidine 1 μg/kg loading over 10 min, 10 min before induction and 0.5 μg/kg/h infusion after that along with IV lignocaine 1.5 mg/kg at bolus followed by 1.5 mg/kg/h infusion. Group MN received IV morphine 0.15 mg/kg. Standard monitoring and general anaesthesia protocol were followed. Intraoperative haemodynamics, anaesthetic requirement, extubation time, and recovery profile were monitored. Data were analysed using Stata version 14 software, and statistical tests (Chi-squared test for qualitative variables, unpaired t-test and Mann-Whitney U test for quantitative variables) were performed. Both groups had comparable haemodynamic stability (P > 0.05). Group DL had a significantly lower propofol requirement for induction and maintenance (P < 0.001). Ramsay sedation score (P = 0.002) and extubation time (P = 0.029) were significantly higher in Group MN. The recovery profile was favourable in Group DL, with there being lower postoperative complications. Dexmedetomidine and lignocaine IV infusion demonstrated stable intraoperative haemodynamic stability, lower anaesthetic requirement, and better recovery profile than morphine without significant complications.

Differences in the EEG Power Spectrum and Cross-Frequency Coupling Patterns between Young and Elderly Patients during Sevoflurane Anesthesia.

Electroencephalography (EEG) is widely used for monitoring the depth of anesthesia in surgical patients. Distinguishing age-related EEG features under general anesthesia will help to optimize anesthetic depth monitoring during surgery for elderly patients. This retrospective cohort study included 41 patients aged from 18 to 79 years undergoing noncardiac surgery under general anesthesia. We compared the power spectral signatures and phase-amplitude coupling patterns of the young and elderly groups under baseline and surgical anesthetic depth. General anesthesia by sevoflurane significantly increased the spectral power of delta, theta, alpha, and beta bands and strengthened the cross-frequency coupling both in young and elderly patients. However, the variation in EEG power spectral density and the modulation of alpha amplitudes on delta phases was relatively weaker in elderly patients. In conclusion, the EEG under general anesthesia using sevoflurane exhibited similar dynamic features between young and elderly patients, and the weakened alteration of spectral power and cross-frequency coupling patterns could be utilized to precisely quantify the depth of anesthesia in elderly patients.

CO2 Stunning in Pigs: Physiological Deviations at Onset of Excitatory Behaviour.

Stunning by carbon dioxide (CO2) inhalation is controversial because it is associated with vigorous movements and behaviours which may or may not be conscious reactions. Furthermore, it is unknown whether some behaviours might indicate the transition into unconsciousness. Our study objective was to investigate the loss of consciousness during CO2 stunning by linking physiological variables (in particular pH, PaO2 and PaCO2) to the onset of observed behaviours. A total of 11 cross-bred pigs were studied. A tracheostomy tube, venous and arterial cannulae were placed under sevoflurane anaesthesia. After recovery from this, and a "wash out" period of at least 30 min, arterial blood samples were taken (and baseline values established) before 90-95% CO2 in medical air was administered through the tracheostomy tube. Subsequent behaviours were video-recorded and key physiological variables were evaluated using an anaesthetic monitor and the frequent sampling of arterial blood (albeit with inconsistent inter-sample intervals). After the study, behaviours were classified in an ethogram. At the onset of behaviours categorised as "vigorous movement extremities", "opisthotonos" and "agonal gasping" pH values (range) were: 6.74-7.34; 6.66-6.96 and 6.65-6.87, while PaCO2 (kPa) was 4.6-42.2, 24.4-51.4 and 29.1-47.6. Based upon these values, we conclude that the pigs were probably unconscious at the onset of "opisthotonos" and "agonal gasping", but some were probably conscious at the onset of "vigorous movements".

Electroencephalographic monitoring of anesthesia during surgical procedures in mice using a modified clinical monitoring system

Monitoring brain activity and associated physiology during the administration of general anesthesia (GA) in mice is pivotal to guarantee postanesthetic health. Clinically, electroencephalogram (EEG) monitoring is a well-established method to guide GA. There are no established methods available for monitoring EEG in mice (Mus musculus) during surgery. In this study, a minimally invasive rodent intraoperative EEG monitoring system was implemented using subdermal needle electrodes and a modified EEG-based commercial patient monitor. EEG recordings were acquired at three different isoflurane concentrations revealing that surgical concentrations of isoflurane anesthesia predominantly contained burst suppression patterns in mice. EEG suppression ratios and suppression durations showed strong positive correlations with the isoflurane concentrations. The electroencephalographic indices provided by the monitor did not support online monitoring of the anesthetic status. The online available suppression duration in the raw EEG signals during isoflurane anesthesia is a straight forward and reliable marker to assure safe, adequate and reproducible anesthesia protocols.

The preparedness of preoperative anesthesia equipment's and monitors for pediatric patients.

This study aimed to determine the practice of preoperative anaesthesia equipment and monitor preparation for paediatric patients. A cross-sectional study was employed among 150 consecutively selected paediatrics from April to June 2020. Data were collected by semi-structured questionnaire. Data entry and analysis were done using Epi Data and Stata version 14.0. Descriptive statistics were employed. A total of 150 patients who undergo surgery under anaesthesia were observed in surgical and ophthalmic operation rooms. From those procedures, only stethoscope and small-sized syringes achieved 100% of the standards. But paediatric stylet, paediatric defibrillator and paediatric folly catheter had achieved 0%. The remaining were between 10 and 97% according to standards. Even though some paediatric anaesthesia equipments and monitoring preparation have fulfilled the standards, this study showed practice gaps in majority of cases in the preparation of appropriately sized paediatric equipments and monitors.

Meta-analysis of the effect of entropy-assisted general anesthesia on the quality of postoperative recovery.

To evaluate the effect of the quality of postoperative anesthetic resuscitation in patients with entropy index monitoring assisted general anesthesia versus standard clinical practice. The randomized controlled trials on the application of entropy index monitoring in general anesthesia were searched in PubMed, Web of Science, Embase, The Cochrane Library, CNKI, Wanfang, VIP, and other databases by computer. The data were collected from inception to January 2022. Two researchers independently screened the retrieved literature according to the inclusion and exclusion criteria and used Cochrane's risk-of-bias assessment criteria to evaluate the quality of the literature. The evaluation indicators included respiratory recovery time, extubation time, consciousness recovery time, emergence agitation, postoperative nausea and vomiting (PONV), and intraoperative awareness. The RevMan 5.4.1 software was used for the meta-analysis of the data. A total of 860 patients from 10 eligible randomized controlled trials were included in this study. The results showed that compared with the control group, the respiratory recovery time (MD = -3.37, 95% CI: -5.09 to -1.85, P < .0001), extubation time (MD = -4.57, 95% CI: -6.08 to -3.95, P < .00001), and consciousness recovery time (MD = -4.95, 95% CI: -7.21 to -2.70, P < .00001) in the entropy index group were significantly shortened. The incidence of emergence agitation in the entropy index group (RR = 0.23, 95% CI: 0.11-0.47, P < .0001) decreased significantly. The incidence of PONV (RR = 0.46, 95% CI: 0.27-0.79, P = .004) was significantly reduced. However, the incidence of intraoperative awareness (RR = 0.33, 95% CI: 0.04-3.16, P = .34) wasn't significantly different. The application of the entropy index can improve the recovery quality of patients under general anesthesia, not only shortening the postoperative recovery time but also reducing the occurrence of agitation and PONV. It does not affect the incidence of intraoperative awareness.

Repurposing electroencephalogram monitoring of general anaesthesia for building biomarkers of brain ageing: an exploratory study

BackgroundElectroencephalography (EEG) is increasingly used for monitoring the depth of general anaesthesia, but EEG data from general anaesthesia monitoring are rarely reused for research. Here, we explored repurposing EEG monitoring from general anaesthesia for brain-age modelling using machine learning. We hypothesised that brain age estimated from EEG during general anaesthesia is associated with perioperative risk. MethodsWe reanalysed four-electrode EEGs of 323 patients under stable propofol or sevoflurane anaesthesia to study four EEG signatures (95% of EEG power <8–13 Hz) for age prediction: total power, alpha-band power (8–13 Hz), power spectrum, and spatial patterns in frequency bands. We constructed age-prediction models from EEGs of a healthy reference group (ASA 1 or 2) during propofol anaesthesia. Although all signatures were informative, state-of-the-art age-prediction performance was unlocked by parsing spatial patterns across electrodes along the entire power spectrum (mean absolute error=8.2 yr; R2=0.65). ResultsClinical exploration in ASA 1 or 2 patients revealed that brain age was positively correlated with intraoperative burst suppression, a risk factor for general anaesthesia complications. Surprisingly, brain age was negatively correlated with burst suppression in patients with higher ASA scores, suggesting hidden confounders. Secondary analyses revealed that age-related EEG signatures were specific to propofol anaesthesia, reflected by limited model generalisation to anaesthesia maintained with sevoflurane. ConclusionsAlthough EEG from general anaesthesia may enable state-of-the-art age prediction, differences between anaesthetic drugs can impact the effectiveness and validity of brain-age models. To unleash the dormant potential of EEG monitoring for clinical research, larger datasets from heterogeneous populations with precisely documented drug dosage will be essential.

Permutation entropy is not an age-independent parameter for EEG-based anesthesia monitoring.

An optimized anesthesia monitoring using electroencephalographic (EEG) information in the elderly could help to reduce the incidence of postoperative complications. Processed EEG information that is available to the anesthesiologist is affected by the age-induced changes of the raw EEG. While most of these methods indicate a "more awake" patient with age, the permutation entropy (PeEn) has been proposed as an age-independent measure. In this article, we show that PeEn is also influenced by age, independent of parameter settings. We retrospectively analyzed the EEG of more than 300 patients, recorded during steady state anesthesia without stimulation, and calculated the PeEn for different embedding dimensions m that was applied to the EEG filtered to a wide variety of frequency ranges. We constructed linear models to evaluate the relationship between age and PeEn. To compare our results to published studies, we also performed a stepwise dichotomization and used non-parametric tests and effect sizes for pairwise comparisons. We found a significant influence of age on PeEn for all settings except for narrow band EEG activity. The analysis of the dichotomized data also revealed significant differences between old and young patients for the PeEn settings used in published studies. Based on our findings, we could show the influence of age on PeEn. This result was independent of parameter, sample rate, and filter settings. Hence, age should be taken into consideration when using PeEn to monitor patient EEG.

Use of transcutaneous CO2 monitoring in adult anaesthesia

Use of transcutaneous CO2 monitoring in adult anaesthesia

P.099 A novel electrophysiologic reflex in neurovascular compression syndromes serving as a marker of pain resolution

Background: Radiofrequency rhizotomy is a commonly used percutaneous technique for treatment of trigeminal neuralgia especially in cases not eligible for microvascular decompression. This technique is usually performed with the patient under conscious sedation. We devised a method for performance of this technique under general anesthetic with neurophysiology monitoring. Methods: The patient is put under general anaesthetic and EMG monitoring is set up. Needles are placed in temporalis muscle, masseter and mylohyoid or anterior belly of digastric. Resting activityis monitored. Rhizotomy is then performed under fluoroscopic guidance, with monitoring of EMG potentials pre- and post-lesioning, with specific attention paid to presence of an abnormal electrophysiologic reflex. Results: A total of 38 procedures were performed in 23 patients. Of these, 15 were revision procedures. Patients had improvement from BNI pain scale 3.8 ±0.8 to 1.3 ±1.5, and had a reduction in number of medications from 1.9 ±1.0 to 0.8 ±0.9. Survey results indicate greater practitioner satisfaction with this technique. Conclusions: Radiofrequency rhizotomy can be performed under GA with IONM guidance with good results. We present a novel method for EMG-based monitoring. Further study is required to validate this technique.

A novel recognition of artificial intelligence in regional anaesthesia

Mechanised analysis of algorithms for problem solving, object recognition and decision-making assistance defines the general concept underlining artificial intelligence (AI).[1] The former presents notable applications in perioperative medicine across diverse situations like depth of anaesthesia monitoring, closed-loop anaesthesia delivery, risk-predictive models, pain-management through objective analgo-scoring, operating-room planning logistics and, guidance of perioperative ultrasonography. The recent Food and Drug Administration (FDA) approval[2] of the Scan Nav™ Anatomy Peripheral Nerve Block (PNB) system (Intelligent Ultrasound Group, Cardiff, United Kingdom)[3] only emerges as a novel recognition of the potential of AI in regional anaesthesia. Worthwhile to mention, Hemmerling et al.[4] described an encouraging seminal use of the robotic ultrasound-guided nerve block system or the Magellan system, almost a decade ago. Employing the same system, Morse et al.[5] went on to compare the performance parameters (learning curve and success rates) and subjective performance variability of manual versus robot-assisted ultrasonographic nerve blocks in a phantom model. The authors found that assistance of nerve blocks, enabled significant faster needle guidance (1.8 [1.6] seconds vs. 0.3 [0.3] seconds; P = 0.007), than for manual blocks. Inter-subject performance variability was also found to be considerably attenuated. Specific to the context of the recently FDA approved software medical device, ScanNav™ Anatomy PNB system uses deep-learning AI technology. During performance of a peripheral nerve block the ScanNav™ system identifies and grades a live ultrasound image using this technology. A distinctive colour overlay of the key sono-anatomical structures during a live ultrasound scan is a characteristic valuable attribute of the system.[3] This enhances standardisation and accuracy of the ultrasound image interpretation. This device colour highlights anatomy of 10 vital regions relevant to ultrasound-guided regional anaesthesia namely Interscalene, Supraclavicular, Axillary and Superior Trunk Brachial plexus of the upper limb; Erector Spinae Plane, Rectus Sheath and Supra-inguinal Fascia Iliaca sheath of truncal structures; and Femoral Nerve, Adductor canal and Popliteal nerve sheath of the lower limb. Furthermore, a 3-dimension inbuilt reference material provides a review of the relevant anatomy, probe-positioning technique; and demonstrates a virtual scan of the selected anatomical region. The system enables adjustments in the intensity of coloured highlighting according to user preference and allows for viewing the unmodified and highlighted images side-by-side for better comprehension of the sono-anatomy. The use of ScanNav™ system thereby facilitates as a labelling device alongside real-time anatomy visualisation during regional anaesthesia. The system also has inbuilt virtual scans that assist the clinician functioning as a 3D reference material of the relevant PNB anatomy scanned. Notably so, the software is compatible with the general-purpose ultrasound systems in addition to being a stand-alone device. Talking of the literature relevant to the ScanNav™ Anatomy PNB system, Bowness et al.[6] compared 240 ultrasound scans performed across 15 expert versus non-expert regional anaesthesia providers on evaluating its' role in promoting the uptake and generalisability of ultrasound-guided regional anaesthesia. The authors outlined that non-experts were more likely to submit positive feedback and less likely to submit negative reviews than the experts (P = 0.001). Positive feedbacks were obtained on the role of the device in training (37/60, 61.7%) and utility for teaching (30/60, 50.0%). Meanwhile the non-experts appreciated the anatomic structure identification and learning, as the contextual benefits, some nonexperts and experts thought the device could decrease the scanning confidence. Additionally, expert providers reported a potentially increased, yet insignificant, risk in 12/254 (4.7%) vs. 8/254 (3.1%, P = 0.362) scans for needle trauma to “safety” structures. The discussion elaborates the tremendous opportunity AI has to offer in guiding regional anaesthesia, awaiting prospective validation outside the core 10 block areas. The utility of this device can be further extended to sympathetic blocks like the stellate-ganglion, celiac-plexus and other blocks for treatment of chronic pain syndromes like complex regional pain syndrome. The times might not be distant when perioperative physicians have routine access to ultrasound machines integrated with AI-assisted colour reframing for anatomical landmark “coding” side by side with the present B-mode, M-mode and colour/pulse Doppler profiling.

Implementation of CLOSE protocol for pulmonary vein isolation in paroxysmal atrial fibrillation by young electrophysiologists in real world clinical practice

Abstract Funding Acknowledgements Type of funding sources: None. Background Paroxysmal atrial fibrillation (AF) is widely treated by radiofrequency (RF) catheter ablation. The CLOSE protocol has been proposed and accepted to guide a successful, safe and durable pulmonary vein isolation in patients with paroxysmal AF. However, the reproducibility of the protocol in real clinical practice and on less experienced hands is less established. Objective To assess the acute effectiveness, safety and reproducibility of RF catheter ablation based on the CLOSE protocol for pulmonary vein isolation in paroxysmal AF patients, performed by young electrophysiologists with less than 5 years of experience. Methods Fifty consecutive patients (25 men, aged 61±11 years) with symptomatic paroxysmal AF were enrolled during the period 2020- 2021. RF catheter ablation based on the CLOSE protocol, using a conventional contact force sensing catheter (Thermocool SmartTouch ST D/F) and a circumferential multipolar catheter (Lasso) after double transseptal puncture (2 SL0 long sheaths), under general anesthesia and oesophageal temperature monitoring was performed in all patients. Results Pulmonary vein isolation demonstrated by entrance and exit block was achieved in all patients. Total procedure time was 147 ± 29 minutes, exposure X-ray time was 5.36 ± 4.46 minutes and exposure dose was 922 ± 1616 cGy*cm2. Left pulmonary veins (LPVs) first pass isolation (94%) was numerically higher than the right pulmonary veins (RPVs) first pass isolation (82%). There were not safety issues. In comparison with the results reported by the authors of the CLOSE protocol, the procedure time was similar (p= 0.84), however, the exposure X-ray time and the exposure dose were significantly lower in our study (p&amp;lt;0.0001 and p=0.01, respectively). The rates of first pass isolation of left and right pulmonary veins did not differ when compared to the respective rates reported by the CLOSE protocol authors (82% vs CLOSE 100% for RPVs and 94% vs CLOSE 97% for LPVs, p&amp;gt; 0.05 for both). Conclusions RF catheter ablation in paroxysmal AF patients using the CLOSE protocol is highly effective, safe and reproducible not only by experienced but also by young electrophysiologists. Adaptation of an ablation strategy for pulmonary vein isolation based on the CLOSE protocol may improve the workflow of the procedure and the training curve of young electrophysiologists without compromising the efficacy and safety.