Benefício da anestesia geral com monitoração do índice bispectral em comparação com o monitoramento guiado apenas por parâmetros clínicos. Revisão sistemática e metanálise

Machine learning with clinical and intraoperative biosignal data for predicting postoperative delirium after cardiac surgery

Early identification of patients at high risk of delirium is crucial for its prevention. Our study aimed to develop machine learning models to predict delirium after cardiac surgery using intraoperative biosignals and clinical data. We introduced a novel approach to extract relevant features from continuously measured intraoperative biosignals. These features reflect the patient's overall or baseline status, the extent of unfavorable conditions encountered intraoperatively, and beat-to-beat variability within the data. We developed a soft voting ensemble machine learning model using retrospective data from 1,912 patients. The model was then prospectively validated with data from 202 additional patients, achieving a high performance with an area under the receiver operating characteristic curve of 0.887 and an accuracy of 0.881. According to the SHapley Additive exPlanation method, several intraoperative biosignal features had high feature importance, suggesting that intraoperative patient management plays a crucial role in preventing delirium after cardiac surgery.

Perioperative Concerns in the Patient with History of Alcohol Use

Alcohol use is common in patients presenting for surgery and can result in significant physiologic changes and postoperative complications. Anesthesia providers must be aware of the potential risks associated with alcohol consumption and take steps to minimize them. Perioperative management includes assessing patients for alcohol use, providing alcohol cessation interventions, adjusting the anesthetic plan according to the patient's alcohol use history, providing appropriate pain management strategies, and closely monitoring patients during and after surgery for signs of alcohol withdrawal.

Effect of sugammadex on processed EEG parameters in patients undergoing robot-assisted radical prostatectomy

BACKGROUND

Sugammadex has been associated with increases in the bispectral index (BIS). We evaluated the effects of sugammadex administration on quantitative electroencephalographic (EEG) and electromyographic (EMG) measures.

METHODS

We performed a prospective observational study of adult male patients undergoing robot-assisted radical prostatectomy. All patients received a sevoflurane-based general anaesthetic and a continuous infusion of rocuronium, which was reversed with 2 mg kg-1 of sugammadex i.v. BIS, EEG, and EMG measures were captured with the BIS Vista™ monitor.

RESULTS

Twenty-five patients were included in this study. Compared with baseline, BIS increased at 4-6 min (β coefficient: 3.63; 95% confidence interval [CI]: 2.22-5.04; P<0.001), spectral edge frequency 95 (SEF95) increased at 2-4 min (β coefficient: 0.29; 95% CI: 0.05-0.52; P=0.016) and 4-6 min (β coefficient: 0.71; 95% CI: 0.47-0.94; P<0.001), and EMG increased at 4-6 min (β coefficient: 1.91; 95% CI: 1.00-2.81; P<0.001) after sugammadex administration. Compared with baseline, increased beta power was observed at 2-4 min (β coefficient: 93; 95% CI: 1-185; P=0.046) and 4-6 min (β coefficient: 208; 95% CI: 116-300; P<0.001), and decreased delta power was observed at 4-6 min (β coefficient: -526.72; 95% CI: -778 to -276; P<0.001) after sugammadex administration. Neither SEF95 nor frequency band data analysis adjusted for EMG showed substantial differences. None of the patients showed clinical signs of awakening.

CONCLUSIONS

After neuromuscular block reversal with 2 mg kg-1 sugammadex, BIS, SEF95, EMG, and beta power showed small but statistically significant increases over time, while delta power decreased.

The Impact of Rocuronium and Sugammadex on Length of Stay in Patients Undergoing Open Spine Surgery: A Propensity Score-Matched Analysis

Enhanced Recovery After Surgery (ERAS), an all-encompassing perioperative care approach, has been demonstrated to enhance surgical results, mitigate postoperative issues, and decrease the length of hospital stay (LOS) in diverse surgical specialties. In this retrospective study, our objective was to examine the influence of muscle relaxant selection on LOS and perioperative results in adult patients undergoing open spine surgery. Specifically, we compared 201 patients who received cisatracurium and neostigmine with 201 patients who received rocuronium and sugammadex, after 1:1 propensity score matching. The utilization of the rocuronium and sugammadex combination in anesthesia for open spinal surgery did not lead to a reduction in the LOS but was associated with a decreased incidence of postoperative chest radiographic abnormalities, including infiltration, consolidation, atelectasis, or pneumonia (p = 0.027). In our secondary analysis, multivariate analysis revealed multiple determinants influencing the prolonged LOS (>7 days) during open spine surgery. Bispectral index-guided anesthesia emerged as a protective factor, while variables such as excessive intraoperative blood loss and fluid administration as well as postoperative chest radiographic abnormalities independently contributed to prolonged LOS.

Efficacy analysis of enhanced recovery after surgery in laparoscopic-assisted radical resection of type I choledochal cyst

Objective

The objective of this study was to investigate the feasibility and effectiveness of laparoscopic-assisted radical resection of type I choledochal cyst (CC) guided by the principles of enhanced recovery after surgery (ERAS).

Methods

A retrospective cohort study of type I CC admitted to our hospital between May 2020 and December 2021 were analyzed, a total of 41 patients with choledochal cyst underwent surgery during this period and 30 cases were selected based on inclusion and exclusion criteria. Patients (n = 15) who received the traditional treatment from May 2020 to March 2021 were included in the traditional group. Patients (n = 15) who received ERAS from April 2021 to December 2021 were included in the ERAS group. Both groups underwent surgery performed by the same surgical team. Preoperative data of the two groups were recorded, and relevant data were statistically analyzed and compared.

Results

There was a statistically significant difference in the dose of opioids. Significant differences were observed between the ERAS and traditional groups in the results of the FLACC pain assessment scale on the 1st and 2nd day after surgery, time of gastric tube, urinary catheter and abdominal drainage tube removal, time of first defecation after operation, time of first eating after operation, time to reach full food intake, results of CRP, ALB, and ALT on the 3rd and 7th postoperative day, postoperative hospital stay, and total treatment cost. No significant differences were observed between the two groups in terms of gender, age, body weight, cyst size, preoperative CRP, ALB, ALT, intraoperative blood loss, operation time, and the number of cases converted to laparotomy. Neither the FLACC pain assessment scale on the 3rd day after surgery, the incidence of postoperative complications, nor the rate of readmission within 30 days showed significant differences.

Conclusions

Laparoscopic-assisted radical resection of type I CC guided by the principles of ERAS is safe and effective for children. The ERAS concept demonstrated advantages over traditional laparoscopic surgery, including reduced opioid use, shorter time to first postoperative defecation, earlier resumption of postoperative feeding, shorter time to reach full feeding, shorter postoperative hospital stay, and lower total treatment cost.

Evaluating efficacy and safety of sub-anesthetic dose esketamine as an adjuvant to propofol/remifentanil analgosedation and spontaneous respiration for children flexible fibreoptic bronchoscopy: a prospective, double-blinded, randomized, and placebo-controlled clinical trial

Background: Flexible fiberoptic bronchoscopy (FFB) for children is widely performed under sedation. Currently, the optimal sedation regimen remains unclear. Esketamine is an N-methyl-D-aspartic acid (NMDA) receptor antagonist, which has stronger sedative and analgesic effects and exerts less cardiorespiratory depression than other sedatives. The purpose of this study was to evaluate whether a subanesthetic dose of esketamine as an adjuvant to propofol/remifentanil and spontaneous ventilation compared with control reduces the procedural and anesthesia-related complications of FFB in children. Materials and methods: Seventy-two children ≤ 12 years of age who were scheduled for FFB were randomly assigned, in a 1:1 ratio, to the esketamine-propofol/remifentanil (Group S, n = 36) or to the propofol/remifentanil group (Group C, n = 36). All children were retained spontaneous ventilation. The primary outcome was the incidence of oxygen desaturation (respiratory depression). Perioperative hemodynamic variables, blood oxygen saturation (SPO₂), end-tidal partial pressure of carbon dioxide (PetCO₂), respiratory rate (R), and the Bispectral index (BIS), induction time, procedural time, recovery time, the time to the ward from the recovery room, consumption of propofol and remifentanil during the procedure and the appearance of adverse events, including paradoxical agitation following midazolam administration, injection pain, laryngospasm, bronchospasm, PONV, vertigo, and hallucination were also compared. Results: The incidence of oxygen desaturation was significantly lower in Group S (8.3%) compared to Group C (36.1%, p = 0.005). The perioperative hemodynamic profile including SBP, DBP, and HR were more stable in Group S than that in Group C (p < 0.05). Consumption of propofol and remifentanil was lower in Group S than in Group C (p < 0.05). Furthermore, PAED scores, cough scores and injection pain were lower in the Group S than in Group C (p < 0.05). The recovery time of Group S was slightly longer than that of Group C (p < 0.05). Nobody happened paradoxical agitation following midazolam administration, PONV, vertigo, and hallucinations in both groups (p > 0.05). Conclusion: Our findings indicate that a subanesthetic dose of esketamine as an adjuvant to propofol/remifentanil and spontaneous respiration is an effective regimen for children undergoing FFB. Our findings will provide a reference for clinical sedation practice during these procedures in children. Clinical Trail Registration: Chinese clinicaltrials.gov registry (identifier: ChiCTR2100053302).

Effect of mini-dose dexmedetomidine supplemented intravenous analgesia on sleep structure in older patients after major noncardiac surgery: A randomized trial

STUDY OBJECTIVES

In previous studies, low-dose dexmedetomidine supplemented opioid analgesia improved sleep architecture but increased sedation level. Herein we tested the hypothesis that mini-dose dexmedetomidine supplemented analgesia improves sleep structure without increasing sedation.

METHODS

In this randomized trial, 118 older patients (≥65 years) following major noncardiac surgery were randomized to receive patient-controlled intravenous analgesia supplemented with either placebo or dexmedetomidine (median 0.02 μg kg^-1 h^-1) for up to 3 days. Polysomnogram was monitored from 9:00 p.m. on the day of surgery until 6:00 a.m. on the first day after surgery. Our primary outcome was the percentage of non-rapid eye movement stage 2 (N2) sleep. Secondary outcomes included other sleep structure parameters during the night of surgery and the sedation score during the first five postoperative days.

RESULTS

All 118 patients completed the study; of these, 85 were included in sleep structure analysis. Dexmedetomidine supplemented analgesia increased the percentage of N2 sleep (median difference, 10%; 95% CI, 1%-20%; P = 0.03). It also prolonged total sleep time (median difference, 78 min; 95% CI, 21 to 143; P = 0.01), increased sleep efficiency (median difference, 14%; 95% CI, 4%-26%; P = 0.01), decreased percentage of N1 sleep (median difference, -10%; 95% CI, -20% to -1%; P = 0.04), and lowered sleep fragmentation index (median difference, -1.6 times⋅h^-1; 95% CI, -3.7 to 0.1; P = 0.04). Sedation score within 5 days did not differ between the two groups.

CONCLUSIONS

Supplementing intravenous analgesia with mini-dose dexmedetomidine improved sleep structure without increasing sedation in older patients recovering from major surgery.

CLINICAL TRIALS

www.

CLINICALTRIALS

gov (NCT03117790), registered 2 April 2017.

ED50 and ED95 of Propofol Combined with Different Doses of Intravenous Lidocaine for First-Trimester Uterine Aspiration: A Prospective Dose-Finding Study Using Up-and-Down Sequential Allocation Method

Purpose

This study aimed to test the effect of different doses of intravenous lidocaine on the median effective dose (ED50) and 95% effective dose (ED95) of propofol-induction dose and identify the optimal dose.

Patients and Methods

Patients undergoing first-trimester uterine aspiration were screened and randomly enrolled into the following groups: saline (L₀), 0.5 mg/kg lidocaine (L_0.5), 1.0 mg/kg lidocaine (L_1.0), and 1.5 mg/kg lidocaine (L_1.5). Anesthesia was induced with 1.0 µg/kg fentanyl. Prepared lidocaine or saline solution was injected later according to allocation, followed by propofol. The dose of propofol for each patient was determined using the up-and-down sequential study design. The primary end point was the ED50 and ED95 of the propofol-induction dose. The total propofol doses, awakening time, and adverse events were recorded.

Results

The ED50 (95% confidence interval) of propofol was significantly lower in groups L_1.0 and L_1.5 than group L₀ (1.6 [1.5–1.7] mg/kg and 1.8 [1.6–1.9] mg/kg, versus 2.4 [2.3–2.5] mg/kg, respectively; p<0.001). There was no significant difference in ED50 between groups L_1.0 and L_1.5 (p>0.05). However, surprisingly, the ED50 was significantly higher in group L_0.5 than L₀ (2.8 [2.6–3.0] mg/kg vs 2.4 [2.3–2.5] mg/kg; p<0.05). The total doses of propofol in groups L_1.0 and L_1.5 were lower than those in groups L₀ and L_0.5 (p<0.05). The systolic blood pressure (SBP) decline after anesthesia induction in group L_0.5 was greater than that in group L₀ (p<0.01). The incidence of respiratory depression in group L_0.5 was greater than that in groups L₀ and L_1.0 (p<0.05).

Conclusion

In patients who underwent first-trimester uterine aspiration, intravenous lidocaine 1.0 mg/kg prior to propofol injection significantly reduced the ED50 of propofol induction dose without severe side effects, equivalent to the effect of 1.5 mg/kg dose. We recommend 1.0 mg/kg as the optimal dose.

Spectral edge frequency during general anaesthesia: A narrative literature review

Previous studies have attempted to determine the depth of anaesthesia with different anaesthetic agents using electroencephalogram (EEG) measurements with variable success. Measuring depth of anaesthesia is confounded by the complexity of the EEG and the fact that different agents create different pattens. A narrative review was undertaken to examine the available research evidence on the effect and reliability of spectral edge frequency (SEF) for assessing the depth of anaesthesia in adult patients under general anaesthesia. A systematic search of the PubMed®, Scopus®, CINAHL and Cochrane databases identified six randomized controlled trials and five observational studies. The findings of these studies suggest that SEF varies according to the anaesthetic drugs used. Remifentanil and age are two factors that can affect SEF, while other opioids and benzodiazepine (administered separately) seem to have no effect. No patients experienced intraoperative awareness. However, this does not indicate that SEF can provide full protection against it and the number of articles in which intraoperative awareness was studied was too small to afford any certainty. None of the studies demonstrated a reliable SEF interval associated with adequate general anaesthesia. SEF must be adapted to the anaesthetic drug used, the patient’s age and state while under general anaesthesia.

Usefulness of bispectral index and patient state index during sevoflurane anesthesia in children: A prospective observational study

Cortical electroencephalography-based devices are used to monitor the depth of anesthesia. In this study, we evaluated the values of bispectral index (BIS) and patient state index (PSI) during sevoflurane anesthesia in children. The ability/accuracy of BIS and PSI to predict the maintenance and recovery state of anesthesia was evaluated based on prediction probability (Pk) values and the secondary outcomes were agreement and correlation of 2 monitors. Fifty children (3-12 years old) were enrolled and the patients received sevoflurane anesthesia with remifentanil followed by propofol administration. Before the induction of anesthesia, BIS and PSI sensors were simultaneously placed on the forehead, and data were collected until the end of anesthesia. Maintenance state was defined as the period following intubation until the cessation of sevoflurane, while recovery state was defined as the period following the cessation of sevoflurane until awake. Pk, agreement or correlation of BIS and PSI in different anesthesia state were calculated. Anesthesia reduced mean BIS and PSI values. Pk of BIS (95% confidential interval [CI]: 0.78-0.91) and PSI (95% CI: 0.82-0.91) for anesthesia were 0.85 and 0.87, respectively. Agreement was 0.79 for recovery state and 0.73 for maintenance state. Pk values were comparable for BIS and PSI. Agreement between BIS and PSI measurements in the same state was relatively good. Therefore, these monitors are appropriate for monitoring for different state of anesthesia in pediatric population.

Comparing propofol anaesthesia guided by Bispectral Index monitoring and frontal EEG wave analysis with standard monitoring in laparoscopic surgery: protocol for the 'EEG in General Anaesthesia - More Than Only a Bispectral Index' Trial, a multicentre, double-blind, randomised controlled trial

INTRODUCTION

The use of Bispectral Index (BIS) monitors for assessing depth of sedation has led to a reduction in both the incidence of awareness and anaesthetic consumption in total intravenous anaesthesia. However, these monitors are vulnerable to artefacts. In addition to the processed number, the raw frontal electroencephalogram (EEG) can be displayed as a curve on the same monitor. Anaesthesia practitioners can learn to interpret the EEG in a short tutorial and may be quicker and more accurate thanBIS in assessing anaesthesia depth by recognising EEG patterns. We hypothesise that quality of recovery (QoR) in patients undergoing laparoscopic surgery is better, if propofol is titrated by anaesthesia practitioners able to interpret the EEG.

METHODS AND ANALYSIS

This is a multicentre, double-blind (patients and outcome assessors) randomised controlled trial taking place in four Swiss hospitals. Patients aged 18 years or older undergoing laparoscopic procedures with general anaesthesia using propofol and anaesthesia practitioners with more than 2 years experience will be eligible. The primary study outcome is the difference in QoR 24 hours after surgery. Secondary outcomes are propofol consumption, incidence of postoperative nausea and vomiting (PONV) and postoperative delirium.QoR and propofol consumption are compared between both groups using a two-sample t-test. Fisher's exact test is used to compare the incidences of PONV and delirium. A total of 200 anaesthesia practitioners (and 200 patients) are required to have an 80% chance of detecting the minimum relevant difference for the QoR-15 as significant at the 5% level assuming a SD of 20.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from all responsible ethics committees (lead committee: Ethikkommission Nordwest- und Zentralschweiz, 16 January 2021). The findings of the trial will be published in a peer-reviewed journal, presented at international conferences, and may lead to a change in titrating propofol in clinical practice.

TRIAL REGISTRATION NUMBER

www.

CLINICALTRIALS

gov:NCT04105660.

Evaluation of the impact of deep neuromuscular blockade on surgical conditions for laryngeal microsurgery with High Frequency Jet Ventilation. A comparison with no block during intravenous general anesthesia with topical lidocaine

OBJECTIVE

Laryngeal transoral surgery classically requires a neuromuscular block (NMB) to facilitate tracheal intubation and to improve surgical conditions. However, the short duration of most procedures and the potential complications of residual NMB lead to consider a no block approach. The hypothesis that intravenous anesthesia (remifentanil and propofol infusions) without NMB but including glottis topical lidocaine anesthesia would allow clinically acceptable laryngeal exposure and good surgical conditions was tested in the specific context of procedures undergone with High Frequency Jet Ventilation (HFJV).

STUDY DESIGN

A prospective randomized clinical comparison.

METHODS

66 consenting patients were planned to receive 0.6 mg·kg^-1 rocuronium or saline at random. The outcome measurements included the time and conditions to complete suspended laryngoscopy, and the surgical conditions rated by the surgeon. Any vocal cord movement or coughing was recorded. Data were compared using a Wilcoxon rank-sum test for numerical variables and chi-square test for categorical ones. Treatment failure was defined as an impossible laryngoscopy or a grade 4 surgical field occurring at any time during surgery and was compared to its null theoretical value by a general z-test. An interim analysis after completion of 50% patients was performed using Pocock boundaries at 0.0294 significance levels.

RESULTS

A significant failure rate occurred in the non paralysed group (27%, p < 0.001). No coughing and no vocal cords movement occurred in the NMB group. Poorer surgical conditions were obtained without NMB (p = 0.011).

CONCLUSION

Inducing a deep NMB ensured improved conditions during direct laryngeal microsurgery with HFJV.

Airway management in general anesthesia for endovascular treatment of cerebral arteriovenous malformation: a retrospective observational study

Background and objective

This retrospective and observational study aimed to retrospectively evaluate the use of the endotracheal tube (ETT) and the Laryngeal Mask Airway (LMA) for the airway management with respect to airway safety, hemodynamic stability, adverse respiratory events, and recovery characteristics in patients who underwent endovascular treatment (EVT) for cerebrovascular arteriovenous malformation under general anesthesia between 2011 and 2018.

Methods

The study included data from the patient's electronic medical records and anesthesia files. The primary outcome measure was the incidence of hemodynamic disturbances and respiratory adverse events during airway management. The secondary outcome measure was the comparison of recovery characteristics.

Results

The airway was secured using ETT in 41 patients and LMA in 39 patients. Airway safety was established in all patients without a complication throughout the procedure. Mean arterial blood pressure and heart rate were increased to > 20% of baseline levels at intubation and extubation periods in more patients in the ETT group than the LMA group (27 vs. 3; p = 0.07, and 11 vs. 2; p = 0.021). Respiratory adverse events including straining and coughing were observed in ten patients in the ETT group but only in one patient in the LMA group (p = 0.013). Time to extubation, to neurological assessment, and to discharge from the angiography unit were similar (p > 0.05).

Conclusion

It was concluded that LMA provided sufficient airway safety as with ETT and may be used as an alternative to ETT for EVTs under general anesthesia.

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.

Cerebral Macro- and Microcirculation during Ephedrine versus Phenylephrine Treatment in Anesthetized Brain Tumor Patients: A Randomized Clinical Trial Using Magnetic Resonance Imaging

BACKGROUND

This study compared ephedrine versus phenylephrine treatment on cerebral macro- and microcirculation, measured by cerebral blood flow, and capillary transit time heterogeneity, in anesthetized brain tumor patients. The hypothesis was that capillary transit time heterogeneity in selected brain regions is greater during phenylephrine than during ephedrine, thus reducing cerebral oxygen tension.

METHODS

In this single-center, double-blinded, randomized clinical trial, 24 anesthetized brain tumor patients were randomly assigned to ephedrine or phenylephrine. Magnetic resonance imaging of peritumoral and contralateral hemispheres was performed before and during vasopressor infusion. The primary endpoint was between-group difference in capillary transit time heterogeneity. Secondary endpoints included changes in cerebral blood flow, estimated oxygen extraction fraction, and brain tissue oxygen tension.

RESULTS

Data from 20 patients showed that mean (± SD) capillary transit time heterogeneity in the contralateral hemisphere increased during phenylephrine from 3.0 ± 0.5 to 3.2 ± 0.7 s and decreased during ephedrine from 3.1 ± 0.8 to 2.7 ± 0.7 s (difference phenylephrine versus difference ephedrine [95% CI], -0.6 [-0.9 to -0.2] s; P = 0.004). In the peritumoral region, the mean capillary transit time heterogeneity increased during phenylephrine from 4.1 ± 0.7 to 4.3 ± 0.8 s and decreased during ephedrine from 3.5 ± 0.9 to 3.3 ± 0.9 s (difference phenylephrine versus difference ephedrine [95%CI], -0.4[-0.9 to 0.1] s; P = 0.130). Cerebral blood flow (contralateral hemisphere ratio difference [95% CI], 0.3 [0.06 to 0.54]; P = 0.018; and peritumoral ratio difference [95% CI], 0.3 [0.06 to 0.54; P = 0.018) and estimated brain tissue oxygen tension (contralateral hemisphere ratio difference [95% CI], 0.34 [0.09 to 0.59]; P = 0.001; and peritumoral ratio difference [95% CI], 0.33 [0.09 to 0.57]; P = 0.010) were greater during ephedrine than phenylephrine in both regions.

CONCLUSIONS

Phenylephrine caused microcirculation in contralateral tissue, measured by the change in capillary transit time heterogeneity, to deteriorate compared with ephedrine, despite reaching similar mean arterial pressure endpoints. Ephedrine improved cerebral blood flow and tissue oxygenation in both brain regions and may be superior to phenylephrine in improving cerebral macro- and microscopic hemodynamics and oxygenation.

EDITOR’S PERSPECTIVE

Applications and Limitations of Neuro-Monitoring in Paediatric Anaesthesia and Intravenous Anaesthesia: A Narrative Review

Safe management of anaesthesia in children has been one of the top areas of research over the last decade. After the large volume of articles which focused on the putative neurotoxic effect of anaesthetic agents on the developing brain, the attention and research efforts shifted toward prevention and treatment of critical events and the importance of peri-anaesthetic haemodynamic stability to prevent negative neurological outcomes. Safetots.org is an international initiative aiming at raising the attention on the relevance of a high-quality anaesthesia in children undergoing surgical and non-surgical procedures to guarantee a favourable outcome. Children might experience hemodynamic instability for many reasons, and how the range of normality within brain autoregulation is maintained is still unknown. Neuro-monitoring can guide anaesthesia providers in delivering optimal anaesthetic drugs dosages and also correcting underling conditions that can negatively affect the neurological outcome. In particular, it is referred to EEG-based monitoring and monitoring for brain oxygenation.

[Inhalational anesthetics]

Inhalational anesthetics have been used for induction and maintenance of general anesthesia for more than 150 years. All of the currently used inhalational anesthetics are chlorinated and fluorinated derivatives of ether. Dosing is carried out using the minimal alveolar concentration (MAC) concept. The pharmacokinetic properties of the various inhalational anesthetics are governed by the specific distribution coefficients. Mechanisms of action include specific modulations of various receptors of the central nervous system as well as an unspecific interaction with the cell membrane. Organ toxicity of modern inhalational anesthetics is considered to be minimal. The role of inhalational anesthetics in the context of postoperative nausea and vomiting (PONV) has been reassessed in recent years. The superiority of inhalational anesthetics over intravenous hypnotics with respect to intraoperative awareness is undisputed. The organ protective mechanism of preconditioning is an exclusive property of inhalational anesthetics among all the currently available hypnotics.

Postoperative recovery of patients with differential requirements for sevoflurane after abdominal surgery: A prospective observational clinical study

An association between animals and volatile anaesthetic requirements has been shown; however, evidence related to the postoperative outcome of human patients is lacking. Our aim was to investigate whether there is a difference in the requirement for sevoflurane among people undergoing gastrointestinal surgery.We observed 390 adult patients who underwent gastrointestinal surgery with an American Society of Anesthesiologists physical status of I or II with an expected surgery duration of > 2 hours. We used the bispectral index (BIS) to guide the regulation of end-tidal sevoflurane concentration (ETsevo). The mean ETsevo from 20 minutes after endotracheal intubation to 2 hours after the start of surgery was calculated for all patients. Differential sevoflurane requirements were identified according to ETsevo. The BIS, ETsevo, heart rate, mean arterial pressure, dose of sufentanil and cisatracurium, tracheal extubation time, incidence of intraoperative awareness, and incidence of postoperative nausea and vomiting were compared between patients with a low requirement for sevoflurane (group L) and patients with a high requirement for sevoflurane (group H).The mean ETsevo of the 390 patients was 1.55% ± 0.26%. Based on our definition, patients with an ETsevo of < 1.29% were allocated to the low requirement group (group L; n = 69), while patients with an ETsevo of > 1.81% were allocated to the high requirement group (group H; n = 78). The ETsevo of group L was significantly lower than the ETsevo of group H (1.29% ± 0.014% vs 1.82% ± 0.017%, P < .001). There was no significant difference in the ETsevo, BIS, heart rate, mean arterial pressure, dose of sufentanil and cisatracurium, tracheal extubation time, incidence of intraoperative awareness, and incidence of postoperative nausea and vomiting. The tracheal extubation time in the L group was significantly shorter than that in the H group. No intraoperative awareness occurred.There was a significant difference in the requirement for sevoflurane in adult patients. The tracheal extubation time in group L was significantly shorter than that in group H.

Comparative study of analgesia nociception index (ANI) vs. standard pharmacokinetic pattern for guiding intraoperative fentanyl administration among mastectomy patients

Background

The Analgesia Nociception Index (ANI) has been suggested as a non-invasive guide for analgesia. Our objective was to compare the efficacy of ANI vs. standard pharmacokinetic pattern for guiding intraoperative fentanyl administration.

Methods

This was a prospective, randomized, controlled study of adult female patients undergoing elective mastectomy under general anesthesia. The patients were randomized to the ANI-guided group receiving a loading dose of 75 μg of fentanyl followed by 25 μg when the ANI score was under 50. The Control group received the same loading dose followed by 25 μg every 30 min with additional doses when there were signs of inadequate analgesia (viz., tachycardia or hypertension).

Results

Sixty patients—30 in each group—were recruited. Although the actual mean ANI score was higher in the ANI-guided than in the Control group (mean difference 2.2; 95% CI: 0.3 to 4.0, P = 0.022), there was no difference in the primary outcome—i.e., intraoperative fentanyl consumption (mean difference − 4.2 μg; 95% CI: − 24.7 to 16.4, P = 0.686 and − 0.14 μg·kg^− 1·h^− 1; 95% CI: − 0.31 to 0.03, P = 0.105). No difference between groups was shown for either intraoperative blood pressure and heart rate, or for postoperative outcomes (i.e., pain scores, morphine consumption, or sedation scores) in the postanesthesia care unit.

Conclusions

Intraoperative fentanyl administration guided by ANI was equivalent to that guided by a modified pharmacologic pattern. In a surgical model of mastectomy, the ANI-guided intraoperative administration of fentanyl had no impact on clinical outcomes.

Trial registration

The study was registered with ClinicalTrials.gov (NCT03716453) on 21/10/2018.

The Effects of Bispectral Index-Guided Anesthesia on Postoperative Delirium in Elderly Patients: A Systematic Review and Meta-Analysis

OBJECTIVE

Postoperative delirium (POD) is a form of delirium that affects patients who have undergone surgical procedures and anesthesia, usually peaking between 1 and 3 days after their operation. The aim of this meta-analysis was to determine whether monitoring of depth of anesthesia may influence the incidence of POD.

METHODS

A systematic literature search was conducted on studies that reported POD in elderly patients (>60 years old) who underwent surgery. This meta-analysis was carried out using random-effects model.

RESULTS

Compared with control group, intraoperative bispectral index (BIS) monitoring reduced POD (odds ratio 1.32, 95% confidence interval 1.11-1.57, P = 0.001, I² = 51%). In the mixed-surgery group, compared with the control group, BIS monitoring decreased the incidence of POD (odds ratio 1.24, 95% confidence interval 1.07-1.44, P = 0.004, I² = 61%). There was also no significant difference in the incidence of POD among patients who underwent cardiac, colon, and orthopedic surgeries.

CONCLUSIONS

BIS monitoring during surgery can reduce the incidence of POD in elderly patients. Whether BIS monitoring may reduce the incidence of POD in a single type of surgery needs further study.

Ephedrine versus Phenylephrine Effect on Cerebral Blood Flow and Oxygen Consumption in Anesthetized Brain Tumor Patients: A Randomized Clinical Trial

BACKGROUND

Studies in anesthetized patients suggest that phenylephrine reduces regional cerebral oxygen saturation compared with ephedrine. The present study aimed to quantify the effects of phenylephrine and ephedrine on cerebral blood flow and cerebral metabolic rate of oxygen in brain tumor patients. The authors hypothesized that phenylephrine reduces cerebral metabolic rate of oxygen in selected brain regions compared with ephedrine.

METHODS

In this double-blinded, randomized clinical trial, 24 anesthetized patients with brain tumors were randomly assigned to ephedrine or phenylephrine treatment. Positron emission tomography measurements of cerebral blood flow and cerebral metabolic rate of oxygen in peritumoral and normal contralateral regions were performed before and during vasopressor infusion. The primary endpoint was between-group difference in cerebral metabolic rate of oxygen. Secondary endpoints included changes in cerebral blood flow, oxygen extraction fraction, and regional cerebral oxygen saturation.

RESULTS

Peritumoral mean ± SD cerebral metabolic rate of oxygen values before and after vasopressor (ephedrine, 67.0 ± 11.3 and 67.8 ± 25.7 μmol · 100 g · min; phenylephrine, 68.2 ± 15.2 and 67.6 ± 18.0 μmol · 100 g · min) showed no intergroup difference (difference [95% CI], 1.5 [-13.3 to 16.3] μmol · 100 g · min [P = 0.839]). Corresponding contralateral hemisphere cerebral metabolic rate of oxygen values (ephedrine, 90.8 ± 15.9 and 94.6 ± 16.9 μmol · 100 g · min; phenylephrine, 100.8 ± 20.7 and 96.4 ± 17.7 μmol · 100 g · min) showed no intergroup difference (difference [95% CI], 8.2 [-2.0 to 18.5] μmol · 100 g · min [P = 0.118]). Ephedrine significantly increased cerebral blood flow (difference [95% CI], 3.9 [0.7 to 7.0] ml · 100 g · min [P = 0.019]) and regional cerebral oxygen saturation (difference [95% CI], 4 [1 to 8]% [P = 0.024]) in the contralateral hemisphere compared to phenylephrine. The change in oxygen extraction fraction in both regions (peritumoral difference [95% CI], -0.6 [-14.7 to 13.6]% [P = 0.934]; contralateral hemisphere difference [95% CI], -0.1 [- 12.1 to 12.0]% [P = 0.989]) were comparable between groups.

CONCLUSIONS

The cerebral metabolic rate of oxygen changes in peritumoral and normal contralateral regions were similar between ephedrine- and phenylephrine-treated patients. In the normal contralateral region, ephedrine was associated with an increase in cerebral blood flow and regional cerebral oxygen saturation compared with phenylephrine.

Essential elements of anaesthesia practice in ERAS programs

PURPOSE

Enhanced recovery pathways vary amongst institutions but include key components for anesthesiologists, such as haemodynamic optimization, use of short-acting drugs (and monitoring), postoperative nausea and vomiting (PONV) prophylaxis, protective ventilation, and opioid-sparing multimodal analgesia.

METHODS

After critical appraisal of the literature, studies were selected with particular attention being paid to meta-analyses, randomized controlled trials, and large prospective cohort studies. For each item of the perioperative treatment pathway, available English literature was examined and reviewed.

RESULTS

Patients should be permitted to drink clear fluids up to 2 h before anaesthesia and surgery. Oral carbohydrate loading should be used routinely. All patients may have an individualized plan for fluid and haemodynamic management that matches the monitoring needs with patient and surgical risk. Minimizing the side effects of anaesthetics and analgesics using short-acting drugs with careful perioperative monitoring should be encouraged. Protective ventilation with alveolar recruitment maneuvers is required. Preventive use of a combination with 2-3 antiemetics in addition to propofol-based total intravenous anaesthesia (TIVA) is most likely to reduce PONV. While the ideal analgesia regimen remains to be determined, it is clear that a multimodal opioid-sparing analgesic strategy has significant benefits.

CONCLUSION

Careful evaluation of single patient and planning of the anesthetic care are mandatory to join the ERAS philosophy. Optimal fluid management, use of short-acting drugs, prevention of PONV, protective ventilation, and multimodal analgesia are the cornerstones of the anaesthesia management within ERAS protocols.

Effect of depth of anesthesia on the phase lag entropy in patients undergoing general anesthesia by propofol: A STROBE-compliant study

The PLEM100 (Inbody Co., Ltd., Seoul, Korea) is a device for measuring phase lag entropy (PLE), a recently developed index for the quantification of consciousness during sedation and general anesthesia. In the present study, we assessed changes in PLE along with the level of consciousness during the induction of general anesthesia using propofol. PLE was compared with the bispectral index (BIS), which is currently the most commonly used index of consciousness.After obtaining Institutional Review Board approval and written informed consent, we enrolled 15 patients (8 men, 7 women; mean age: 37 ± 9 years; mean height: 168 ± 8 cm; mean weight; 68 ± 11 kg) undergoing nasal bone reduction. PLE and BIS sensors were attached simultaneously, and general anesthesia was induced via target-controlled infusion (TCI) of propofol. PLE and BIS scores were recorded when the calculated effect site concentration shown on the TCI pump was equal to the target concentrations of 1.5, 2.0, 2.5, 2.8, 3.0, 3.2, 3.4, and 3.5 μg/mL (and at each 0.1 μg/mL increase, thereafter). Observer's Assessment of Alertness/Sedation (OAA/S) scores were also recorded until unconsciousness was achieved. Throughout the anesthesia period, all pairs of PLE and BIS data were collected using data acquisition software.The partial correlation coefficients between OAA/S scores and PLE, and between OAA/S scores and BIS were 0.778 (P < .001) and 0.846 (P < .001), respectively. Throughout the period of anesthesia, PLE and BIS exhibited a significant positive correlation. The partial correlation coefficient prior to the loss of consciousness was 0.838 (P < .001), and 0.669 (P < .001) following the loss of consciousness. Intra-class correlation between the 2 indices was 0.889 (P < .001) and 0.791 (P < .001) prior and following the loss of consciousness, respectively.PLE exhibited a strong and predictable correlation with both BIS and OAA/S scores. These results suggest that PLE is reliable for assessing the level of consciousness during sedation and general anesthesia.

Neuroanesthesia Guidelines for Optimizing Transcranial Motor Evoked Potential Neuromonitoring During Deformity and Complex Spinal Surgery: A Delphi Consensus Study

STUDY DESIGN

Expert opinion-modified Delphi study.

OBJECTIVE

We used a modified Delphi approach to obtain consensus among leading spinal deformity surgeons and their neuroanesthesiology teams regarding optimal practices for obtaining reliable motor evoked potential (MEP) signals.

SUMMARY OF BACKGROUND DATA

Intraoperative neurophysiological monitoring of transcranial MEPs provides the best method for assessing spinal cord integrity during complex spinal surgeries. MEPs are affected by pharmacological and physiological parameters. It is the responsibility of the spine surgeon and neuroanesthesia team to understand how they can best maintain high-quality MEP signals throughout surgery. Nevertheless, varying approaches to neuroanesthesia are seen in clinical practice.

METHODS

We identified 19 international expert spinal deformity treatment teams. A modified Delphi process with two rounds of surveying was performed. Greater than 50% agreement on the final statements was considered "agreement"; >75% agreement was considered "consensus."

RESULTS

Anesthesia regimens and protocols were obtained from the expert centers. There was a large amount of variability among centers. Two rounds of consensus surveying were performed, and all centers participated in both rounds of surveying. Consensus was obtained for 12 of 15 statements, and majority agreement was obtained for two of the remaining statements. Total intravenous anesthesia was identified as the preferred method of maintenance, with few centers allowing for low mean alveolar concentration of inhaled anesthetic. Most centers advocated for <150 μg/kg/min of propofol with titration to the lowest dose that maintains appropriate anesthesia depth based on awareness monitoring. Use of adjuvant intravenous anesthetics, including ketamine, low-dose dexmedetomidine, and lidocaine, may help to reduce propofol requirements without negatively effecting MEP signals.

CONCLUSION

Spine surgeons and neuroanesthesia teams should be familiar with methods for optimizing MEPs during deformity and complex spinal cases. Although variability in practices exists, there is consensus among international spinal deformity treatment centers regarding best practices.

LEVEL OF EVIDENCE

5.

Comparison of the Level of Free Hexafluoro-isopropanol in Adults' Blood and the Incidence of Emergence Agitation After Anesthesia With Different Concentrations of Sevoflurane in Laparoscopic Gastrointestinal Surgery: A Randomized Controlled Clinical Trial

PURPOSE

The aim of the study is to compare the free hexafluoro-isopropanol (HFIP) concentration in adults' blood and the incidence of emergence agitation (EA) after inhaled different concentrations of sevoflurane.

METHODS

Sixty adult patients planning to undergo laparoscopic gastrointestinal surgery were randomly assigned to 3 groups. Each group received sevoflurane as the volatile anesthetic at different concentrations: 0.5 minimum alveolar concentration (MAC), 1.0 MAC, and 1.5 MAC. The use of sevoflurane was continued until the end of surgery. Venous blood samples were obtained at 30, 60, 120, and 180 minutes after starting the use of sevoflurane and subsequently at 60, 180, and 300 minutes after discontinuation of volatile anesthetic administration. Blood concentrations of sevoflurane and free HFIP were determined using gas chromatography. The recovery time and the incidence of EA at different time points were evaluated among the 3 groups.

FINDINGS

Changes in the blood concentrations of sevoflurane and free HFIP during and after the use of sevoflurane were similar in all 3 groups. The peak blood concentration of free HFIP occurred 60 minutes after onset of sevoflurane anesthesia in all 3 groups (P < 0.05). The lowest level of free HFIP and the longest recovery time were found in the 1.5-MAC group (P < 0.05). No significant difference was found in the incidence of EA or moderate pain among the 3 groups during recovery.

IMPLICATIONS

The generation of HFIP would be inhibited when the inhaled sevoflurane concentration increased to 1.5 MAC. However, the incidence of EA during recovery had nothing to do with the inhaled different sevoflurane concentrations (within 1.5 MAC) in adults. ChicCTR.org identifier: ChiCTR-IPD-17011558.

Bispectral index for improving intraoperative awareness and early postoperative recovery in adults

BACKGROUND

The use of clinical signs, or end-tidal anaesthetic gas (ETAG), may not be reliable in measuring the hypnotic component of anaesthesia and may lead to either overdosage or underdosage resulting in adverse effects because of too deep or too light anaesthesia. Intraoperative awareness, whilst uncommon, may lead to serious psychological disturbance, and alternative methods to monitor the depth of anaesthesia may reduce the incidence of serious events. Bispectral index (BIS) is a numerical scale based on electrical activity in the brain. Using a BIS monitor to guide the dose of anaesthetic may have advantages over clinical signs or ETAG. This is an update of a review last published in 2014.

OBJECTIVES

To assess the effectiveness of BIS to reduce the risk of intraoperative awareness and early recovery times from general anaesthesia in adults undergoing surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and Web of Science on 26 March 2019. We searched clinical trial registers and grey literature, and handsearched reference lists of included studies and related reviews.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and quasi-RCTs in which BIS was used to guide anaesthesia compared with standard practice which was either clinical signs or end-tidal anaesthetic gas (ETAG) to guide the anaesthetic dose. We included adult participants undergoing any type of surgery under general anaesthesia regardless of whether included participants had a high risk of intraoperative awareness. We included only studies in which investigators aimed to evaluate the effectiveness of BIS for its role in monitoring intraoperative depth of anaesthesia or potential improvements in early recovery times from anaesthesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We assessed the certainty of evidence with GRADE.

MAIN RESULTS

We included 52 studies with 41,331 participants; two studies were quasi-randomized and the remaining studies were RCTs. All studies included participants undergoing surgery under general anaesthesia. Three studies recruited only participants who were at high risk of intraoperative awareness, whilst two studies specifically recruited an unselected participant group. We analysed the data according to two comparison groups: BIS versus clinical signs; and BIS versus ETAG. Forty-eight studies used clinical signs as a comparison method, which included titration of anaesthesia according to criteria such as blood pressure or heart rate and, six studies used ETAG to guide anaesthesia. Whilst BIS target values differed between studies, all were within a range of values between 40 to 60.BIS versus clinical signsWe found low-certainty evidence that BIS-guided anaesthesia may reduce the risk of intraoperative awareness in a surgical population that were unselected or at high risk of awareness (Peto odds ratio (OR) 0.36, 95% CI 0.21 to 0.60; I2 = 61%; 27 studies; 9765 participants). However, events were rare with only five of 27 studies with reported incidences; we found that incidences of intraoperative awareness when BIS was used were three per 1000 (95% CI 2 to 6 per 1000) compared to nine per 1000 when anaesthesia was guided by clinical signs. Of the five studies with event data, one included participants at high risk of awareness and one included unselected participants, four used a structured questionnaire for assessment, and two used an adjudication process to identify confirmed or definite awareness.Early recovery times were also improved when BIS was used. We found low-certainty evidence that BIS may reduce the time to eye opening by mean difference (MD) 1.78 minutes (95% CI -2.53 to -1.03 minutes; 22 studies; 1494 participants), the time to orientation by MD 3.18 minutes (95% CI -4.03 to -2.33 minutes; 6 studies; 273 participants), and the time to discharge from the postanaesthesia care unit (PACU) by MD 6.86 minutes (95% CI -11.72 to -2 minutes; 13 studies; 930 participants).BIS versus ETAGAgain, events of intraoperative awareness were extremely rare, and we found no evidence of a difference in incidences of intraoperative awareness according to whether anaesthesia was guided by BIS or by ETAG in a surgical population at unselected or at high risk of awareness (Peto OR 1.13, 95% CI 0.56 to 2.26; I2 = 37%; 5 studies; 26,572 participants; low-certainty evidence). Incidences of intraoperative awareness were one per 1000 in both groups. Only three of five studies reported events, two included participants at high risk of awareness and one included unselected participants, all used a structured questionnaire for assessment and an adjudication process to identify confirmed or definite awareness.One large study (9376 participants) reported a reduced time to discharge from the PACU by a median of three minutes less, and we judged the certainty of this evidence to be low. No studies measured or reported the time to eye opening and the time to orientation.Certainty of the evidenceWe used GRADE to downgrade the evidence for all outcomes to low certainty. The incidence of intraoperative awareness is so infrequent such that, despite the inclusion of some large multi-centre studies in analyses, we believed that the effect estimates were imprecise. In addition, analyses included studies that we judged to have limitations owing to some assessments of high or unclear bias and in all studies, it was not possible to blind anaesthetists to the different methods of monitoring depth of anaesthesia.Studies often did not report a clear definition of intraoperative awareness. Time points of measurement differed, and methods used to identify intraoperative awareness also differed and we expected that some assessment tools were more comprehensive than others.

AUTHORS' CONCLUSIONS

Intraoperative awareness is infrequent and, despite identifying a large number of eligible studies, evidence for the effectiveness of using BIS to guide anaesthetic depth is imprecise. We found that BIS-guided anaesthesia compared to clinical signs may reduce the risk of intraoperative awareness and improve early recovery times in people undergoing surgery under general anaesthesia but we found no evidence of a difference between BIS-guided anaesthesia and ETAG-guided anaesthesia. We found six studies awaiting classification and two ongoing studies; inclusion of these studies in future updates may increase the certainty of the evidence.

Comparative Evaluation of IV Paracetamol Versus IV Dexmedetomidine in Inpatient Oral and Maxillofacial Surgery: A Double-Blinded Randomized Controlled Study

Purpose

Reconstructive surgeries following fractures in the maxillofacial region often involve considerable bone manipulation, and paracetamol is a commonly used analgesic medication in both intraoperative and postoperative periods. Dexmedetomidine, an alpha-2 adrenoceptor agonist, has both sedative and analgesic properties with minimal cardiorespiratory effects and has been used primarily for its sedative properties in oral and maxillofacial surgery.

Aims and Objectives

To compare the intraoperative analgesic requirements among patients undergoing oral and maxillofacial surgery who receive IV paracetamol versus IV dexmedetomidine. The time to requirement for the first postoperative analgesic dose and safety and adverse events of both medications were also assessed.

Patients and Methods

In total, 64 patients needing primary reconstructive surgery for facial fractures were recruited and divided into two groups for this double-blinded study. Patients were randomized to receive a preinduction dose of either IV paracetamol 1 g (Group P) or IV dexmedetomidine 1 µg/kg (Group D). Sedation scores (Ramsay sedation scale), maximal interincisal distance and pain scores at maximal mouth opening (visual analogue scale) were assessed in both groups just prior to and after the administration of the study drugs. After induction, Group P and Group D received a maintenance dose of normal saline and dexmedetomidine (0.5 µg/kg/h) during the intraoperative period, respectively. Standard noninvasive cardiorespiratory monitoring was done for the entire duration of surgery. Following extubation, postoperative pain scores and the time to request for first analgesic dose in either group were recorded.

Results

The time taken to perform the surgery was comparable in both groups. There was a significant difference between the groups in visual analogue scores and interincisal distance after the bolus dose (p < 0.05). Systolic and diastolic blood pressure was significantly lower in Group D at around 150 and 175 min of surgery. While the intraoperative fentanyl consumption was comparable in both groups, the time to request for the first analgesic dose in the postoperative period was significantly delayed in Group P (p < 0.05). No adverse cardiopulmonary events were observed in either group.

Conclusion

The intraoperative anesthetic and analgesic requirements and hemodynamic stability were comparable in IV paracetamol and dexmedetomidine groups. Dexmedetomidine did not confer any enhanced analgesia effect in the postoperative period. More research examining the role of dexmedetomidine for longer duration inpatient oral and maxillofacial surgery is needed.

Clinical Trial Number

http://ClinicalTrials.gov (No. CTRI/2017/08/009468).

Anesthetics influence concussive head injury induced blood-brain barrier breakdown, brain edema formation, cerebral blood flow, serotonin levels, brain pathology and functional outcome

Several lines of evidences show that anesthetics influence neurotoxicity and neuroprotection. The possibility that different anesthetic agents potentially influence the pathophysiological and functional outcome following neurotrauma was examined in a rat model of concussive head injury (CHI). The CHI was produced by an impact of 0.224N on the right parietal bone by dropping a weight of 114.6g from a 20cm height under different anesthetic agents, e.g., inhaled ether anesthesia or intraperitoneally administered ketamine, pentobarbital, equithesin or urethane anesthesia. Five hour CHI resulted in profound volume swelling and brain edema formation in both hemispheres showing disruption of the blood-brain barrier (BBB) to Evans blue and radioiodine. A marked decrease in the cortical CBF and a profound increase in plasma or brain serotonin levels were seen at this time. Neuronal damages were present in several parts of the brain. These pathological changes were most marked in CHI under ether anesthesia followed by ketamine (35mg/kg, i.p.), pentobarbital (50mg/kg, i.p.), equithesin (3mL/kg, i.p.) and urethane (1g/kg, i.p.). The functional outcome on Rota Rod performances or grid walking tests was also most adversely affected after CHI under ether anesthesia followed by pentobarbital, equithesin and ketamine. Interestingly, the plasma and brain serotonin levels strongly correlated with the development of brain edema in head injured animals in relation to different anesthetic agents used. These observations suggest that anesthetic agents are detrimental to functional and pathological outcomes in CHI probably through influencing the circulating plasma and brain serotonin levels, not reported earlier. Whether anesthetics could also affect the efficacy of different neuroprotective agents in CNS injuries is a new subject that is currently being examined in our laboratory.

Precise anesthesia in thoracoscopic operations

Purpose of review

The current review focuses on precise anesthesia for video-assisted thoracoscopic surgery (VATS) with the goal of enhanced recovery.

Recent findings

VATS has become an established and widely used minimally invasive approach with broad implementation on a variety of thoracic operations. In the current environment of enhanced recovery protocols and cost containment, minimally invasive VATS operations suggest adoption of individualized tailored, precise anesthesia. In addition to a perfect lung collapse for surgical interventions with adequate oxygenation during one lung ventilation, anesthesia goals include a rapid, complete recovery with adequate postoperative analgesia leading to early discharge and minimized costs related to postoperative inpatient services. The components and decisions related to precise anesthesia are reviewed and discussed including: letting patients remain awake versus general anesthesia, whether the patient should be intubated or not, operating with or without muscle relaxation, whether to use different separation devises, operating with different local and regional blocks and monitors.

Conclusion

The determining factors in designing a precise anesthesic for VATS operations involve consensus on patients’ tolerance of the associated side effects, the best practice or techniques for surgery and anesthesia, the required postoperative support, and the care team's experience.

Safety and efficacy of propofol anesthesia for pediatric target-controlled infusion in children below 3 years of age: a retrospective observational study

BACKGROUND

Although the requirement of propofol in children is increasing, propofol for induction and maintenance of anesthesia below 3 years old has not been approved in Korea. This study can provide a clinical evidence to increase the range of approval.

RESEARCH DESIGN AND METHODS

We reviewed the medical records of patients below 3 years of age who underwent surgery between September 2013 and December 2016. Safety was evaluated on the basis of vital signs, and laboratory findings and efficacy were evaluated on the basis of the bispectral index (BIS). Adverse events were examined.

RESULTS

A total of 109 patients anesthetized with propofol (propofol group) were compared with 109 patients with volatile anesthetics (volatile group) after propensity score matching. There was a difference in the proportion of patients showing decreased systolic pressure (P < 0.001) and heart rate (P = 0.03), but there was no difference in diastolic pressure (P = 0.238), mean arterial pressure (P = 0.175) during surgery. After surgery, there was no difference in all vital signs and the proportion patients who experienced adverse events of two groups.

CONCLUSIONS

Propofol anesthesia by target-controlled infusion was effective and didn't show serious propofol-related perioperative adverse events.

Early postoperative recovery in operating room after desflurane anesthesia combined with Bispectral index (BIS) monitoring and warming in lengthy abdominal surgery: a randomized controlled study

BACKGROUND

This study aimed to determine whether the use of desflurane (DES) anesthesia combined with bispectral index (BIS) monitoring and warming is effective in reducing anesthesia-controlled operating room time (ACT) in patients undergoing lengthy abdominal surgery.

METHODS

Seventy patients, 40 years of age or older, undergoing abdominal surgery expected to last three to five hours were randomly assigned to the DES group (n = 35) or the control group (n = 35). Patients in the DES group were maintained with desflurane anesthesia and received BIS monitoring and warming. Patients in the control group were given non-desflurane anesthesia for maintenance, and the usage of BIS monitoring and warming were not mandatory and determined by anesthesia care providers. Early postoperative recovery times were recorded.

RESULTS

The times to extubation (8.8 ± 8.5 vs 14.7 ± 13.7 min, P = 0.035), eye opening (8.4 ± 8.6 vs 14.4 ± 13.4 min, P = 0.028), responds on command (8.2 ± 8.5 vs 14.4 ± 13.0 min, P = 0.022), and the ACT (23.8 ± 11.4 vs 32.7 ± 15.4 min, P = 0.009) were significantly less in the DES group than that in the control group. The postanesthesia care unit (PACU) length of stay, incidence of prolonged extubation, and surgeon and anesthesiologist satisfaction were similar in two groups. Also, the result of multivariable linear regressions showed that patients who were younger, female, lower BMI and non-DES anesthesia regimen resulted in prolonged extubation.

CONCLUSIONS

Desflurane anesthesia combined with BIS monitoring and warming is associated with early postoperative recovery in lengthy abdominal surgery.

TRIAL REGISTRATION

ChiCTR-INR-17013333 . Date of registration: November 11, 2017.

Effect of creatine phosphate sodium on bispectral index and recovery quality during the general anaesthesia emergence period in elderly patients: A randomized, double-blind, placebo-controlled trial

Objective

To evaluate the effect of creatine phosphate sodium on bispectral index (BIS) and recovery quality during the general anaesthesia emergence period in elderly patients.

Methods

This randomized, double-blind, placebo-controlled study enrolled patients undergoing transabdominal cholecystectomy under general anaesthesia. Patients were randomly assigned to receive either creatine phosphate sodium (1.0 g/100 ml 0.9% saline; group P) or 100 ml 0.9% saline (group C) over 30 minutes during surgical incision. The BIS values were recorded at anaesthesia induction (T₀), skin incision (T₁), cutting the gallbladder (T₂), suturing the peritoneum (T₃), skin closure (T₄), sputum suction (T₅), extubation (T₆) and 1 min (T₇), 5 min (T₈), 10 min (T₉), and 15 min (T₁₀) after extubation. The anaesthesia duration, operation time, waking time, extubation time, consciousness recovery time, time in the postanaesthesia care unit (PACU), and the Steward recovery scores at T₇, T₈, T₉ and T₁₀ were recorded.

Results

A total of 120 elderly patients were randomized equally to the two groups. Compared with group C, the BIS values were significantly higher in group P at T₅, T₆, T₇ and T₈; and the Steward recovery scores at T₇ and T₈ were significantly higher in group P. The waking time, extubation time, consciousness recovery time and time in the PACU were significantly shorter in group P compared with group C.

Conclusion

Creatine phosphate sodium administered during transabdominal cholecystectomy can improve BIS values and recovery following general anaesthesia in elderly patients.

Effect of bispectral index-guided anesthesia on consumption of anesthetics and early postoperative cognitive dysfunction after liver transplantation: An observational study

The objective of this study was to summarize the incidence of postoperative cognitive dysfunction (POCD) after 7days following liver transplantation (LT), and to evaluate the effectiveness of bispectral index (BIS) guided anesthetic intervention in reducing POCD. Additional serum concentrations of S100β and neuron-specific enolase (NSE) were detected during surgery to determine whether they were reliable predictors of POCD.Patients who underwent LT at Beijing YouAn Hospital Affiliated to Capital University of Medical Science from January 2014 to December 2015 were enrolled. BIS monitor was needed during surgery. Patients who underwent LT without BIS monitoring during August 2012 to December 2014 served as historical controls. A battery of 5 neuropsychological tests were performed and scored preoperatively and 7days after surgery. POCD was diagnosed by the method of one standard deviation (SD). The blood samples of BIS group were collected at 5 time points: just before induction of general anesthesia (T0), 60 minutes after skin incision (T1), 30 minutes after the start of the anhepatic phase (T2), 15 minutes after reperfusion of the new liver (T3), and at 24 hours after surgery (T4).A total of 33 patients were included in BIS group, and 27 in the control group. Mean arterial pressure was different between 2 groups at 30 minutes after the start of the anhepatic phase (P = .032). The dose of propofol using at anhepatic phase 30 min and new liver 15 min was lower in the BIS group than control group (0.042 ± 0.021 vs. 0.069 ± 0.030, P < .001; 0.053 ± 0.022 vs. 0.072 ± 0.020, P = .001). Five patients were diagnosed as having POCD after 7 days in the BIS group and the incidence of POCD was 15.15%. In the control group, 9 patients had POCD and the incidence of POCD was 33.33%. The incidence of POCD between 2 groups had no statistical difference (P = .089). S100β increased at stage of anhepatic 30 minutes (T2) and new liver 15 minutes (T3) compared with the stage of before anesthesia (T0) (1.49 ± 0.66 vs. 0.72 ± 0.53, P < .001; 1.92 ± 0.78 vs. 0.72 ± 0.53, P < .001). NSE increased at stage of anhepatic 30 minutes (T2) and new liver 15 minutes (T3) compared with the stage of before anesthesia (T0) (5.80 ± 3.03 vs. 3.58 ± 3.24, P = .001; 10.04 ± 5.65 vs. 3.58 ± 3.24, P < .001). At 24 hours after surgery, S100β had no difference compared to one before anesthesia (1.0 ± 0.62 vs. 0.72 ± 0.53, P = .075), but NSE still remained high (5.19 ± 3.64 vs. 3.58 ± 3.24, P = .043). There were no significant differences in the serum concentrations of S100β between patients with and without POCD at 5 time points of operation (P > .05). But at 24 hours after surgery, NSE concentrations were still high of patients with POCD (8.14 ± 3.25 vs. 4.81 ± 3.50, P = .035).BIS-guided anesthesia can reduce consumption of propofol during anhepatic and new liver phase. Patients in BIS group seem to have a mild lower incidence of POCD compared to controls, but no statistical significant. The influence of BIS-guided anesthesia on POCD needs to be further confirmed by large-scale clinical study. S100β protein and NSE are well correlative with neural injury, but NSE is more suitable for assessment of incidence of postoperative cognitive deficits after surgery.