Depth Of General Anesthesia Research Articles

The role of depth of general anesthesia in serum CGRP and SP level in diabetes patients.

Diabetes, which is associated with cardiovascular disease and related microvascular complications, affects life expectancy and decrease quality of life. A trial reports that the risk of patients with diabetes having cardiovascular disease is 2-4 times compared with that in patients without diabetes. This study aims to investigate the relationship between depth of general anesthesia in patients with diabetes mellitus. This clinical study totally includes 40 patients with diabetes mellitus, and these patients are divided into following two groups: diabetes mellitus deep anesthesia group and diabetes mellitus light anesthesia group, and then these patients receive general anesthesia combined with laparoscopic surgery. Preoperative patient general data and intraoperative patient general data are collected and analyzed. Calcitonin gene-related peptide (CGRP) and substance P (SP) level are determined by Enzyme-linked immunosorbent assay (ELISA). This study included a total of 40 patients. There were no significant differences in demographic and preoperative patient general data between the two groups. Measurements were taken for operative time, anesthesia time, recovery time after drug withdrawal, dwell time in the recovery room, intraoperative fluid volume, intraoperative blood loss, and intraoperative urine output between the two groups. Significant differences were observed in the recovery time after drug withdrawal between the two groups. CGRP and SP level in diabetes mellitus deep anesthesia group are evidently more than those in diabetes mellitus light anesthesia group. CGRP and SP level are involved in the diabetes mellitus and up-regulated CGRP and SP can prevent the development of diabetes mellitus. Our study extends the existing literature by addressing a gap in knowledge regarding the impact of anesthesia depth on neuropeptide levels in diabetes mellitus patients. By delineating this relationship, we aim to contribute to the advancement of perioperative care practices and ultimately improve outcomes for individuals with diabetes undergoing surgical procedures. Our study's findings provide valuable insights into the complex interactions between anesthesia, neuropeptides, and diabetes mellitus, offering the potential for personalized perioperative care, enhanced pain management, and improved surgical outcomes. These implications highlight the clinical relevance of our research and its potential to inform future advancements in perioperative care for diabetic patients undergoing surgery.

The effect of propofol-midazolam versus sevoflurane on bispectral index and eye position in pediatric cataract surgery: A randomized controlled study

ABSTRACT Background Cataract surgery is one of the infrequent ocular surgeries. The adequate ocular position with central alignment is the main prerequisite for good surgical technique. Propofol and sevoflurane are the common anesthetics drugs used during pediatric anesthesia. BIS monitor is one of the common intraoperative awareness monitors used. Aim To assess the efficacy of the bispectral index monitor in quantifying the depth of anesthesia and its correlation with ocular alignment during juvenile cataract surgery. Specifically, we will compare the use of sevoflurane anaesthesia with total intravenous anesthesia using a midazolam bolus and propofol infusion. Methods This study included 100 children scheduled for cataract surgery. The children were divided into two groups: group (S) included 50 children who were anesthetized using sevoflurane maintenance only and group (P) included 50 children who were anesthetized using continuous intravenous anesthesia (midazolam bolus plus propofol infusion) as maintenance after induction with sevoflurane anesthesia 8%. The bispectral index was recorded immediately after induction and after intubation and every 5 min later on until end of surgery. Results The eye position showed statistically significant central position among the propofol group with p value 0.02. An eye position-BIS value association was found statistically significant negative correlation in sevoflurane group while no statistically significant link was found in the propofol group. Conclusion Use of BIS monitor for making correlation between depth of anesthesia for prediction of ocular alignment was significant in sevoflurane group, but not in propofol group in pediatric patients and even with adequate depth of general anesthesia.

Evaluating the Accuracy of Patient State Index for Measuring Anaesthetic Depth in Patients Undergoing Propofol-Sevoflurane Anaesthesia

Abstract Processed electroencephalographic indices such as the Patient State Index (PSi) have been proposed as a method of monitoring the depth of general anaesthesia. However, in order to establish the validity of PSi, it is necessary to compare its accuracy to other techniques, such as the isolated forearm technique (IFT). 30 ASA (American Society of Anaesthesiologists classification) I–III patients were administered standard propofol-sevoflurane anaesthesia with PSi monitoring. Before each dose of muscle relaxant, the forearm contralateral to the intravenous cannula was isolated for 30 minutes. PSi, hand movements, and exhaled sevoflurane concentrations were recorded during the induction of anaesthesia, intubation, throughout the surgical procedure, prior to extubation, and patients’ responses to commands were classified as positive or negative. The Brice questionnaire was used to assess intraoperative awareness after the patient regained consciousness. All patients completed the study without memory of the surgery or IFT commands, 53.3% of patients showed a response to IFT commands during intubation. PSi values ranged around 26 (23.5; 30) in IFT non-responders and 33.5 (26; 42) in responders (p = 0.15). The best cut-off value for PSi to predict IFT response was 55, with a sensitivity of 60% and specificity of 85.2%, which led to the conclusion that PSi is not a fully reliable tool for monitoring the depth of anaesthesia.

The Adequacy of Anesthesia Guidance for Vitreoretinal Surgeries with Preemptive Paracetamol/Metamizole.

Despite the possibility of postoperative pain occurrence, in some patients, vitreoretinal surgeries (VRSs) require performance of general anesthesia (GA). The administration of intraoperative intravenous rescue opioid analgesics (IROA) during GA constitutes a risk of perioperative adverse events. The Adequacy of Anesthesia (AoA) concept consists of an entropy electroencephalogram to guide the depth of GA and surgical pleth index (SPI) to optimize the titration of IROA. Preemptive analgesia (PA) using cyclooxygenase-3 (COX-3) inhibitors is added to GA to minimize the demand for IROA and reduce postoperative pain. The current analysis evaluated the advantage of PA using COX-3 inhibitors added to GA with AoA-guided administration of IROA on the rate of postoperative pain and hemodynamic stability in patients undergoing VRS. A total of 165 patients undergoing VRS were randomly allocated to receive either GA with AoA-guided IROA administration with intravenous paracetamol/metamizole or with preemptive paracetamol or metamizole. Preemptive paracetamol resulted in a reduction in the IROA requirement; both preemptive metamizole/paracetamol resulted in a reduced rate of postoperative pain as compared to metamizole alone. We recommend using intraoperative AOA-guided IROA administration during VRS to ensure hemodynamic stability alongside PA using both paracetamol/metamizole to reduce postoperative pain.

Effect of BIS-guided anesthesia on emergence delirium following general anesthesia in children: A prospective randomized controlled trial

ObjectiveEmergence delirium (ED) is a postoperative complication in pediatric anesthesia characterized by a perception and psychomotor disorder, with a negative impact on postoperative recovery. As the use of inhalation anesthesia is associated with a higher incidence of ED, we investigated whether titrating the depth of general anesthesia with BIS monitor can reduce the incidence of ED. DesignRandomized, prospective, and double-blind. SettingPatients undergoing endoscopic adenoidectomy under general anesthesia according to a uniform protocol. PatientsA total of 163 patients of both sexes aged 3–8 years were enrolled over 18 months. InterventionsImmediately after the induction of general anesthesia, a bispectral index (BIS) electrode was placed on the patient’s forehead. In the study group, the depth of general anesthesia was monitored with the aim of achieving BIS values of 40–60. In the control group, the dose of sevoflurane was determined by the anaesthesiologist based on MAC (minimum alveolar concentration) and the end-tidal concentration. MeasurementsThe primary objective was to compare the occurrence of ED during the PACU (post-anesthesia care unit) stay in both arms of the study. The secondary objective was to determine the PAED score at 10 and 30 min in the PACU and the need for rescue treatment of ED. Main results86 children were randomized in the intervention group and 77 children in the control group. During the entire PACU stay, 23.3% (38/163) of patients developed ED with PAED score >10: 35.1% (27/77) in the control group and 12.8% (11/86) in the intervention group (p = 0.001). Lower PAED scores were also found in the intervention group at 10 (p < 0.001) and 30 (p < 0.001) minutes compared to the control group. The need for rescue treatment did not differ between groups (p = 0.067). ConclusionIndividualization of the depth of general anesthesia with BIS monitoring is an effective method of preventing ED in children. Clinical trial registrationNCT04466579.

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.

Using the TI.VA algorithm to titrate the depth of general anaesthesia: a first-in-humans study

BackgroundThe dose of anaesthetic and opioid drugs must be continuously adjusted after the induction of general anaesthesia to maintain an adequate depth of anaesthesia. The TI.VA algorithm is a multiple-input/multiple-output algorithm designed to optimise the balance between anaesthetic and opioid concentrations during general anaesthesia. It applies vector analysis to a two-dimensional matrix to quantify any inadequacy of the depth of anaesthesia at any given moment and determine any drug dose adjustments required to achieve an adequate depth of anaesthesia. This study aimed to capture preliminary data on the performance and safety of the TI.VA algorithm during total i.v. anaesthesia in patients. MethodsThis prospective study enrolled nine patients with breast cancer scheduled to undergo surgery. General anaesthesia was induced under manual control using propofol and remifentanil. Anaesthesia was guided using the TI.VA algorithm from skin incision until surgical resection was completed. The quality of anaesthesia was assessed through an analysis of performance errors. A bispectral index global score (GSBIS) <50 was considered an acceptable target for algorithm performance. ResultsAll nine procedures were completed without any adverse events and none of the patients recalled any intraoperative event. Overall, we analysed 3417 monitoring points corresponding to 285 min of surgery. All patients presented a GSBIS below the cut-off value of 50. ConclusionsThe TI.VA algorithm provides adequate control of clinical anaesthesia. A more sophisticated prototype needs to be developed before the trial is expanded to include larger patient populations. Clinical trial registrationNCT05199883.

An Observational Study on the Intraoperative Awareness Following General Anesthetic Drugs

Objective To determine intraoperative awareness and estimate the factors associated with intraoperative awareness. Methods An observational cross-sectional study was carried out after approval from the institutional ethical committee. The duration of the study is 2 months. After completion of the surgical procedure, anesthesia was reversed, and there was an adequate return of consciousness. The patients were interviewed about their surgery using the modified form of the Brice questionnaire. After the questionnaire was completed, it was analyzed, and patients were categorized into either having definite awareness, possible awareness, or no awareness. Results It was observed that out of 90 patients operated on under general anesthesia, eight reported having remembered something under general anesthesia. Out of eight patients, two were found to have definite awareness, and the occurrence of definite awareness was calculated to be 2.22%. Six patients were categorized under possible awareness, and the occurrence of possible awareness was estimated to be 6.6% in our study. Conclusion The occurrence of intraoperative awareness was estimated to be 8.8%, including definite and possible awareness under general anesthesia. Finally, we conclude that intraoperative awareness might be due to the inadequate depth of general anesthesia given to the patients. The dose of general anesthetic drugs was not maintained based on its minimum alveolar concentration (MAC).

Nonintubated bronchoscopic interventions with high-flow nasal oxygen: A retrospective observational study.

To determine the feasibility on maintaining oxygenation of high-flow nasal oxygenation (HFNO) with bispectral index-guided intravenous anesthesia for nonintubated interventional bronchoscopy (NIIB). If desaturation happens, the factors influencing intraprocedural desaturation were also analyzed.This is a single-center retrospective study on patients receiving NIIB with HFNO and intravenous anesthesia guided by bispectral index levels to the depth of general anesthesia, which were between 40 and 60. Intraprocedural desaturation (SPO2 < 90%) and complications (bleeding, delayed discharge, unexpected admission) were collected. Factors affecting desaturation and complications were analyzed including patients’ factors (age, American Society of Anesthesiologists classification, body mass index [BMI]), procedural factors (procedural time, with or without use of cryoprobe), and setting (outpatient or hospitalized).Records of 223 patients receiving NIIB were collected. The NIIB procedures time was 56.1 ± 26.8 minute. Sixty patients (26.9%) presented desaturation events. Higher BMI, but not procedure time or setting, was significantly associated with desaturation. The desaturation were resolved after relieving upper airway obstruction but 1 patient required bag–valve–mask ventilation to restore oxygenation. Accidental massive bleeding and intraprocedural desaturation during tracheal and bronchial recannulation with cryoprobes happened in 2 patients and 1 of them was admitted to intensive care unit.HFNO is feasible to maintain oxygenation during NIIB only if there is effective upper airway management especially for patients with higher BMI. Longer procedural time and different setting did not affect the desaturation rate. Complications and unexpected admission were associated with the use of cryoprobes.

JUSTIFICATION FOR THE COMBINED USE OF PROPOFOL AND DEXMEDETOMIDINE IN ELECTIVE PROCEDURAL SEDATION

Procedural sedation (PS) is the technique of administering sedatives with or without analgesics to induce a condition in which the patient can tolerate unpleasant procedures while maintaining cardio-respiratory function. Planned PSs are performed with procedures of various invasiveness, painfulness and duration, but by definition, they do not reach the depth of general anesthesia and do not require the use of respiratory support or controlled mechanical ventilation, and even more – muscle relaxants. For effective PS, it is extremely important to establish verbal contact with the patient and achieve a stable emotional state of the patient and carefully explain to him the details of the PS. When choosing the depth of PS, it’s necessary to reach a compromise between the degree of anesthesia and amnesia, on the one hand, and the effectiveness of spontaneous breathing, as well as the possibility of an early recovery of consciousness, on the other. If possible, the problem of pain (when consciousness is partially preserved) or nociceptive stimuli (when the level of consciousness is reduced or absent) is solved separately through the use of local or regional anesthesia. In addition, non-steroidal anti-inflammatory drugs (NSAIDs) and some other drugs with analgesic properties are often used, and opioid analgesics are avoided or used in small or minimal doses. Unlike anesthesia, even deep sedation cannot and should not completely prevent the patient from moving during intense pain / nociceptive stimuli. If necessary, the problem of patient movements is solved not only and not so much by further deepening sedation, but precisely by improving analgesia and/or fixing the patient for the duration of short-term painful manipulations. To achieve these goals, PS is most often used propofol, or its dexmedetomidine or midazolam. This publication focuses on the advantages of using a multimodal approach for prolonged PS, which allows for a significant reduction in the dose of corresponding drugs and rate of complications in comparison with sedation with a single anaesthetic at significantly higher doses.

Monitoring of Anesthesia by Bispectral Analysis of EEG Signals.

Background In intensive care, monitoring the depth of anesthesia during surgical procedures is a key element in the success of the medical operation and postoperative recovery. However, despite the development of anesthesia thanks to technological and pharmacological advances, its side effects such as underdose or overdose of hypnotics remain a major problem. Observation and monitoring must combine clinical observations (loss of consciousness and reactivity) with tools for real-time measurement of changes in the depth of anesthesia. Methodology. In this work, we will develop a noninvasive method for calculating, monitoring, and controlling the depth of general anesthesia during surgery. The objective is to reduce the effects of pharmacological usage of hypnotics and to ensure better quality recovery. Thanks to the overall activity of sets of neurons in the brain, we have developed a BIS technique based on bispectral analysis of the electroencephalographic signal EEG. Discussion. By collecting the electrical voltages from the brain, we distinguish light sleep from deep sleep according to the values of the BIS indicator (ranging from 0 : sleep to 100 : wake) and also control it by acting on the dosage of propofol and sevoflurane. We showed that the BIS value must be maintained during the operation and the anesthesia at a value greater than 60. Conclusion This study showed that the BIS technology led to an optimization of the anesthetic management, the adequacy of the hypnotic dosage, and a better postoperative recovery.

Correlation Between Monitoring Practices During Anesthesia and Patient Recovery

Anesthesia is used by healthcare professionals to induce loss of sensation in the body of the patient so that the surgical process of treatment is carried out effectively. Anesthesia doses that are given to patients have been classified into three types which are general anesthesia, sedation anesthesia, and regional or local anesthesia. These medications are given to patients as per the severity of the injury and treatment process. The provision of anesthesia includes monitoring processes such as Electrocardiography (ECG), Noninvasive Blood Pressure (NIBP), pulse oximetry, and others so that patient safety is ensured at all the levels of treatment. It also includes Depth of General Anesthesia (DGA) is an advanced monitoring process of anesthesia through which accurate drug administration in the individual patient is executed. The study introduces current prospects of anesthesia monitoring and mentions details about important methods and technologies in use and their both advantages and disadvantages. It also provides details about DGA and other latest upcoming methods for anesthesia monitoring.

Polyspikes and Rhythmic Polyspikes During Volatile Induction of General Anesthesia With Sevoflurane Result in Bispectral Index Variations.

Although electroencephalography (EEG)-based indices may show artifactual values, raw EEG signal is seldom used to monitor the depth of volatile induction of general anesthesia (VIGA). The current analysis aimed to identify whether bispectral index (BIS) variations reliably reflect the actual depth of general anesthesia during presence of different types of epileptiform patterns (EPs) in EEGs during induction of general anesthesia. Sixty patients receiving either VIGA with sevoflurane using increasing concentrations (group VIMA) or vital capacity (group VCRII) technique or intravenous single dose of propofol (group PROP) were included. Monitoring included facial electromyography (fEMG), fraction of inspired sevoflurane (FiAA), fraction of expired sevoflurane (FeAA), minimal alveolar concentration (MAC) of sevoflurane, BIS, standard EEG, and hemodynamic parameters. In the PROP group no EPs were observed. During different stages of VIGA with sevoflurane in the VIMA and VCRII groups, presence of polyspikes and rhythmic polyspikes in patients' EEGs resulted in artifactual BIS values indicating a false awareness/wakefulness from anesthesia, despite no concomitant change of FiAA, FeAA, and MAC of sevoflurane. Periodic epileptiform discharges did not result in aberrant BIS values. Our results suggest that raw EEG correlate it with values of BIS, FiAA, FeAA, and MAC of sevoflurane during VIGA. It seems that because artifactual BIS values indicating false awareness/wakefulness as a result of presence of polyspikes and rhythmic polyspikes in patients' EEGs may be misleading to an anesthesiologist, leading to unintentional administration of toxic concentration of sevoflurane in ventilation gas.

Magnesium Sulfate and Clonidine; Effects on Hemodynamic Factors and Depth of General Anesthesia in Cesarean Section.

BackgroundMaking stable hemodynamic and also durable unawareness is a daily challenge in the setting of general anesthesia in women who undergo surgical delivery of neonate and have limitations to receive opioids derivatives.ObjectivesWe aimed to evaluate the effects of magnesium sulfate and clonidine on hemodynamic changes and depth of anesthesia and in mentioned mothers and also in neonatal APGAR index.MethodsCurrent randomized, double-blind controlled trial study was conducted among a total of 360 pregnant females (38 - 41 weeks of gestation) who underwent elective cesarean section. Participants were randomly divided into three drug-receiving groups (equal 120 members): magnesium sulfate (30 mg/kg), clonidine (3 µg/kg), and placebo (0.9% NaCl). Patients’ blood pressure, heart rate, cerebral state index (CSI) in specific time zones, and also late 24-hour recall were recorded. The CSI is an electroencephalographic monitoring method helping to assess the depth of anesthesia. Neonatal parameters, including APGAR score and umbilical venous blood sampling, were measured.ResultsMean patients’ age was 28 ± 4.5. A significant decreasing and stabilizing effect of magnesium sulfate and clonidine on hemodynamic parameters (blood pressure and heart rate) was revealed (P < 0.001). Evidence implied on deeper anesthesia (lower CSI) among drug receivers comparing to placebo (P < 0.001). None of the participants experienced a late 24-hour recall postoperatively. All neonates were healthy, and no decrease was reported in APGAR score at minutes 1 and 5. Umbilical blood gas analysis showed no signs of acidosis and/or hypoxemia.ConclusionsAdjuvant administration of either magnesium sulfate or clonidine is associated with hemodynamic stability and favorable unawareness in the setting of elective surgical delivery.

Variations in Values of State, Response Entropy and Haemodynamic Parameters Associated with Development of Different Epileptiform Patterns during Volatile Induction of General Anaesthesia with Two Different Anaesthetic Regimens Using Sevoflurane in Comparison with Intravenous Induct: A Comparative Study.

Background and Objectives: Raw electroencephalographic (EEG) signals are rarely used to monitor the depth of volatile induction of general anaesthesia (VIGA) with sevoflurane, even though EEG-based indices may show aberrant values. We aimed to identify whether response (RE) and state entropy (SE) variations reliably reflect the actual depth of general anaesthesia in the presence of different types of epileptiform patterns (EPs) in EEGs during induction of general anaesthesia. Materials and Methods: A randomized, prospective clinical study was performed with 60 patients receiving VIGA using sevoflurane with the increasing concentrations (group VIMA) or the vital capacity (group VCRII) technique or an intravenous single dose of propofol (group PROP). Facial electromyography (fEMG), fraction of inspired sevoflurane (FiAA), fraction of expired sevoflurane (FeAA), minimal alveolar concentration (MAC) of sevoflurane, RE and SE, and standard electroencephalographic evaluations were performed in these patients. Results: In contrast to periodic epileptiform discharges, erroneous SE and RE values in the patients’ EEGs were associated with the presence of polyspikes (PS) and rhythmic polyspikes (PSR), which were more likely to indicate toxic depth rather than false emergence from anaesthesia with no changes in the FiAA, FeAA, and MAC of sevoflurane. Conclusion: Calculated RE and SE values may be misleading during VIGA when EPs are present in patients’ EEGs. During VIGA with sevoflurane, we recommend monitoring raw EEG data in scientific studies to correlate it with potentially erroneous RE and SE values and the end-tidal concentration of sevoflurane in everyday clinical practice, when monitoring raw EEG is not available, because they can mislead anaesthesiologists to reduce sevoflurane levels in the ventilation gas and result in unintentional true emergence from anaesthesia. Further studies are required to investigate the behaviour of EEG-based indices during rapid changes in sevoflurane concentrations at different stages of VIGA and the influence of polyspikes and rhythmic polyspikes on the transformation of EEG signals into a digital form.

Antinociceptive Effect of Intravenous Regional Analgesia in Horses Underwent Selected Short-Time Distal Limb Surgeries

The aim of the present study was to establish appropriate doses for both lidocaine hydrochloride (Hcl) and mepivacaine in intravenous regional analgesia (IVRA) and to assess their intraoperative and postoperative analgesic effects in horses with distal limb surgeries. A total of 55 draft horses were included in the present study. Six clinically healthy horses were selected randomly for establishing the doses of lidocaine Hcl and mepivacaine in IVRA in horse limbs. After selection, 32 horses suffered from various distal limb surgical affections were randomly allocated into three groups: thiopental group (n = 6), animals were operated under general anesthesia using thiopental sodium; IVRA-LID group (n = 12), animals were operated under both general anesthesia and IVRA using lidocaine Hcl; and IVRA-MEP group (n = 14), horses were operated under both general anesthesia and IVRA using mepivacaine. Postoperative pain was measured using both Horse Grimace Pain Scale and multifactorial numerical rating composite pain. The results showed that conjunction of IVRA along with thiopental general anesthesia using either lidocaine or mepivacaine significantly decreased the total required doses of thiopental sodium during the operations and significantly increased the duration of postoperative analgesia to 60 and 150 minutes using lidocaine and mepivacaine, respectively. In conclusion, the uses of local IVRA before distal limb surgery improve the depth of general anesthesia and reduced postoperative pain, despite thiopental anesthesia alone. Mepivacaine is superior to lidocaine in IVRA, with a longer duration of action.

The Unbearableness of Being Light.

The Unbearableness of Being Light.

Practical Training of Anesthesia Clinicians in Electroencephalogram-Based Determination of Hypnotic Depth of General Anesthesia.

Electroencephalographic (EEG) brain monitoring during general anesthesia provides information on hypnotic depth. We hypothesized that anesthesia clinicians could be trained rapidly to recognize typical EEG waveforms occurring with volatile-based general anesthesia. This was a substudy of a trial testing the hypothesis that EEG-guided anesthesia prevents postoperative delirium. The intervention was a 35-minute training session, summarizing typical EEG changes with volatile-based anesthesia. Participants completed a preeducational test, underwent training, and completed a posteducational test. For each question, participants indicated whether the EEG was consistent with (1) wakefulness, (2) non-slow-wave anesthesia, (3) slow-wave anesthesia, or (4) burst suppression. They also indicated whether the processed EEG (pEEG) index was discordant with the EEG waveforms. Four clinicians, experienced in intraoperative EEG interpretation, independently evaluated the EEG waveforms, resolved disagreements, and provided reference answers. Ten questions were assessed in the preeducational test and 9 in the posteducational test. There were 71 participants; 13 had previous anesthetic-associated EEG interpretation training. After training, the 58 participants without prior training improved at identifying dominant EEG waveforms (median 60% with interquartile range [IQR], 50%-70% vs 78% with IQR, 67%-89%; difference: 18%; 95% confidence interval [CI], 8-27; P < .001). In contrast, there was no significant improvement following the training for the 13 participants who reported previous training (median 70% with IQR, 60%-80% vs 67% with IQR, 67%-78%; difference: -3%; 95% CI, -18 to 11; P = .88). The difference in the change between the pre- and posteducational session for the previously untrained versus previously trained was statistically significant (difference in medians: 21%; 95% CI, 2-28; P = .005). Clinicians without prior training also improved in identifying discordance between the pEEG index and the EEG waveform (median 60% with IQR, 40%-60% vs median 100% with IQR, 75%-100%; difference: 40%; 95% CI, 30-50; P < .001). Clinicians with prior training showed no significant improvement (median 60% with IQR, 60%-80% vs 75% with IQR, 75%-100%; difference: 15%; 95% CI, -16 to 46; P = .16). Regarding the identification of discordance, the difference in the change between the pre- and posteducational session for the previously untrained versus previously trained was statistically significant (difference in medians: 25%; 95% CI, 5-45; P = .012). A brief training session was associated with improvements in clinicians without prior EEG training in (1) identifying EEG waveforms corresponding to different hypnotic depths and (2) recognizing when the hypnotic depth suggested by the EEG was discordant with the pEEG index.

Comparison of efficacy and safety of dexmedetomidine versus propofol infusion for maintaining depth of general anesthesia when muscle relaxants are not used

Background: In surgeries where direct nerve stimulation is required intraoperatively, the use of long-acting muscle relaxants should be avoided. The study aimed to assess the efficacy of dexmedetomidine versus propofol infusion in providing an adequate depth of general anesthesia where long-acting muscle relaxants were not used intraoperatively and to compare hemodynamics in both the groups. Patients and Methods: It was a prospective randomized controlled study done in forty patients undergoing total parotidectomy or brachial plexus surgeries. Group D received an intravenous (IV) bolus of dexmedetomidine 1 mcg/kg body weight before induction, followed by infusion at 0.7 mcg/kg/h intraoperatively. In Group B, the infusion of propofol was started at a rate of 1.5 mg/kg/h to a maximum of 100 mg/h after intubation. In both the groups, if the patient moved, bucked on the endotracheal tube, or if there were signs of inadequate depth of anesthesia, a bolus of propofol 0.5 mg/kg IV was given and repeated as required. Statistical analysis was performed using Mann–Whitney U-test and Fisher's exact test. Results: The number of times propofol bolus was required intraoperatively did not show any significant difference between groups. The mean heart rate was significantly lower in Group D before induction. At any other time points, the mean systolic blood pressure and mean arterial blood pressure were comparable in both the groups. Conclusion: Both dexmedetomidine and propofol infusions are equally effective and safe in providing an adequate depth of general anesthesia as reflected by patient immobility during surgeries where long-acting muscle relaxants were not used.

Effectiveness of deep general anesthesia compared to the standard depth of general anesthesia for acute postoperative pain and patient safety: a systematic review protocol.

The objective of this systematic review is to synthesize the best available evidence related to the effectiveness of deep general anesthesia on acute postoperative pain and patient safety in adult patients. Acute postoperative pain is a common physiological side effect of surgery that should be alleviated as soon as possible to reduce suffering and other detrimental effects. Given the adverse effects related to the use of opioids for pain management, and in the current opioid epidemic, evidence-based clinical practice recommendations are needed to reduce the use of opioids in the treatment of acute postoperative pain. This review will include studies of adult patients that incorporate the intervention of deep general anesthesia (bispectral index values of 45 or less), compared to the provision of a standard depth of general anesthesia (bispectral index values 45-60). Included studies will report acute postoperative pain (within the first 48 hours after surgery) as a primary outcome variable. Secondary outcomes of interest include opioid consumption and any reported adverse outcomes. A three-step search strategy will be used to locate studies published in English from 1992 (advent of electroencephalography index monitoring technology) in Ovid MEDLINE, Embase and CINAHL databases. Two independent reviewers will assess retrieved studies against inclusion criteria, complete critical appraisal for methodological quality and extract data using a standardized tool. Data will be synthesized using statistical meta-analysis, where possible.