Anesthetic Dose Research Articles

DIGITAL BLOCK APPLICATIONS; A DETAILED SURVEY BETWEEN SURGICAL BRANCH SPECIALIST AND SPECIALIST STUDENTS

Purpose: The purpose of this study was to investigate the digital block application methods of specialists and assistants working in the Departments of Orthopedics and Traumatology, Emergency Medicine, Anesthesia and Reanimation, and Plastic and Reconstructive Surgery in Turkey and the accuracy of the information on which these methods are based, through a survey, and to interpret the survey results.Study plan: In the survey consisting of a total of eighteen questions, the personal information of the physicians, their preferred digital block application methods, local anesthetic agent selection and application doses, and the source of the information on which these preferences are based were questioned in a digital environment. The responses were interpreted and analyzed.Findings: A total of 110 physicians, 16 specialists and 94 assistants, participated in our survey. In the responses given to the multiple-choice question asked to the participants about the cases you encounter most frequently in your clinic, we saw that the most common ones were fractures at the finger and toe level, skin and subcutaneous lacerations at the finger level, and tendon injuries. In the responses we received to the question of the most preferred type of anesthesia in such injuries, we saw that 51.9% preferred digital block and 42.6% preferred regional anesthesia. In the responses we received to other questions regarding the application method, dosage and different usage patterns in our survey, it was seen that traditional and personal experiences were effective in digital block applications.Conclusion: It was determined that the digital nerve block applications preferred by specialists and specialist students were not compatible with the literature. The results of the study are warning signs for the revision of digital block applications. Experience-based applications and personal teachings should be replaced by evidence-based applications in digital block applications.

Digital twin for the formal analysis of a depth of anesthesia controller

Effective management of depth of anesthesia (DoA) is crucial for patient safety in healthcare. Anesthesiologists typically adjust anesthetic dosages to maintain desired sedation, analgesia (pain relief), and muscle relaxation states. In this paper, we present a digital twin (DT) architecture for the formal modeling and verification of an infusion pump controller for DoA management. The DT incorporates a virtual patient model, an autonomous DoA controller adjusting the infusion rate of the anesthetic agent, i.e., propofol, a test-case manager, and a runtime verification monitor. Data exchange occurs via Ethernet frames. Challenges arise from noise in the Bispectral Index monitoring system readings and infusion rate measurements in clinical scenarios. To mitigate noise impact, we design a feedback controller that is robust against noise. We reason about DT performance by evaluating control specifications using a temporal-logic language within the context of our runtime verification tool.

Case Report: Ultrasound-Guided Neuroaxial Anesthesia in Pregnant Patient with Opioid-Allergic Achondroplasia

Achondroplasia is a low prevalence genetic disorder characterized by disproportionate short stature and skeletal dysplasia, caused primarily by mutations in the fibroblast growth factor receptor 3 (FGFR3) gene associated with disturbances in bone growth. It is the most common form of dwarfism characterized by rhizomelic shortening of the limbs, macrocephaly with frontal bossing and spinal alterations, which presents significant challenges in the anesthetic management of pregnant women due to anatomical and physiological alterations, such as predictors of difficult airway, thoracic restriction due to bone dysplasias, spinal deformities and the multiple physiological changes characteristic of pregnancy. Achondroplasia has an increased incidence of menstrual disorders, infertility, amenorrhea, so conception is rare. We report the case of a 29-year-old female patient diagnosed with achondroplasia and 37 weeks of pregnancy with cephalopelvic disproportion, with a history of opioid allergy documented by provocation test, who underwent elective cesarean section. After a detailed evaluation that included a careful spinal assessment with ultrasound to ensure the feasibility of the neuroaxial block, given the frequent technical difficulties associated, an ultrasound-guided neuroaxial block was chosen as the primary anesthetic technique due to the predictors of difficult airway and opioid allergy, which was performed with adjusted doses of local anesthetics, in addition to the preoperative use of intravenous non-opioid drugs to optimize intraoperative and postoperative pain control. The procedure passed without complications, and the multidisciplinary management allowed a satisfactory maternal-fetal evolution.

Numerical investigation on the differential injection angle effects of intrathecal anesthetic drug delivery

In lumbar anesthesia surgery, the accurate determination of key parameters such as injection angle and dosage is facilitated by the real-time observation of intrathecal drug distribution. In this study, a non-invasive and visual computational fluid dynamics method was used to simulate drug injections in the “cloverleaf” lumbar thoracic segment with a multiphase mixture model, clarifying the intrathecal unsteady flow behaviors and the drug transport mechanisms. The transport properties of three clinically significant injection angles — [Formula: see text], [Formula: see text] and [Formula: see text]— were compared, determining the fastest and slowest block onset angles based on drug concentration levels in the thoracic vertebral plane. The calculation results are aligned with clinical practice trends, and it is found that significantly different drug amounts are required for different injection angles, with higher doses necessitated for ultrasound-assisted anesthesia. During anesthesia, a trend of increasing and then decreasing local anesthetic concentrations in each vertebral plane was observed, with the presence of a minimum effective dose of local anesthetic at the target block site. Injecting at the “concave” part of the cloverleaf ([Formula: see text] and [Formula: see text]) results in greater drug pulsation, faster diffusion and more efficient mixing than injecting at the positive “convex” part of the cloverleaf cross-section ([Formula: see text]). At the L2 vertebral plane, the flow rate and mixing ratios during injection for angles of [Formula: see text], [Formula: see text] and [Formula: see text] were approximately 1:4:2. Compared with orthostatic [Formula: see text] injections, [Formula: see text] and [Formula: see text] oblique injections resulted in higher drug concentrations in the T12-10 vertebral plane during the pre-transport period, with [Formula: see text] injections being the fastest. However, over a longer period of time, [Formula: see text] injections resulted in the lowest drug concentrations in the target block plane (T10), necessitating a higher dose. A faster anesthetic response was produced by [Formula: see text] injections at the same dose. Valuable insights for the application of appropriate drug dosages in clinical anesthesia practice are offered by the calculations.

Approaches for difficult-to-induce-seizures electroconvulsive therapy cases (DEC): a Japanese expert consensus

BackgroundSeizure threshold increases with age and the frequency of electroconvulsive therapy (ECT). Therefore, therapeutic seizures can be difficult to induce, even at maximum stimulus charge with available ECT devices. Such cases are known as difficult-to-induce-seizures electroconvulsive therapy cases (DECs). However, no clinical guidelines exist for DECs; thus, clinicians often face difficulties determining treatment strategies. This study aimed to obtain a consensus among clinical experts regarding the treatment of DECs.MethodsWe asked Japanese ECT experts to rate 14 approaches under six conditions of DECs on a 9-point Likert scale (1 = “disagree” to 9 = “agree”). Based on responses from 195 experts, the approaches were classified as first-line (95% confidence interval mean ≥ 6.5), second-line (mean, 3.5–6.5), or third-line strategies (mean < 3.5). Approaches rated 9 points by at least 50% of the respondents were considered “treatments of choice.”ResultsTo avoid difficult seizure induction, dose reduction of benzodiazepine receptor agonist (BZRA) (8.33 ± 1.25), dose reduction or discontinuation of antiepileptic drugs (AEDs) or other drugs that may make seizure induction difficult (8.16 ± 1.18), and ensure hyperventilation (7.95 ± 1.47) were classified as treatments of choice. First-line treatment strategies were BRZA discontinuation (7.89 ± 1.45), stimulation timing adjustment (7.00 ± 2.00), and anesthetic dose reduction (6.93 ± 1.94). Dose reduction or discontinuation of AEDs or other drugs that might make seizure induction difficult and ensure hyperventilation were the treatments of choice across all patient conditions. The results of rating approaches for patients with mood disorders and schizophrenia were similar, with differences observed among the approaches for patients with catatonia, high risk of cognitive impairment, and cardiovascular events.ConclusionsECT expert recommendations are useful and can assist in clinical decision-making. Our results suggest that while some strategies are applicable across all conditions, others should be tailored to meet the specific needs of patients. These recommendations should be further evaluated in future clinical studies.

Anaesthetics disrupt complex I-linked respiration and reverse the ATP synthase

The mechanism of volatile general anaesthetics has long been a mystery. Anaesthetics have no structural motifs in common, beyond lipid solubility, yet all exert a similar effect. The fact that the inert gas xenon is an anaesthetic suggests their common mechanism might relate to physical rather than chemical properties. Electron transfer through chiral proteins can induce spin polarization. Recent work suggests that anaesthetics dissipate spin polarization during electron transfer to oxygen, slowing respiration. Here we show that the volatile anaesthetics isoflurane and sevoflurane specifically disrupt complex I-linked respiration in the thoraces of Drosophila melanogaster, with less effect on maximal respiration. Suppression of complex I-linked respiration was greatest with isoflurane. Using high-resolution tissue fluorespirometry, we show that these anaesthetics simultaneously increase mitochondrial membrane potential, implying reversal of the ATP synthase. Inhibition of ATP synthase with oligomycin prevented respiration and increased membrane potential back to the maximal (LEAK state) potential. Magnesium-green fluorescence predicted a collapse in ATP availability following a single anaesthetic dose, consistent with ATP hydrolysis through reversal of the ATP synthase. Raised membrane potential corresponded to a rise in ROS flux, especially with isoflurane. Anaesthetic doses causing respiratory suppression were in the same range as those that induce anaesthesia, although we could not establish tissue concentrations. Our findings show that anaesthetics suppress complex I-linked respiration with concerted downstream effects. But we cannot explain why only mutations in complex I, and not elsewhere in the electron-transfer system, confer hypersensitivity to anaesthetics.

Local anesthetic systemic toxicity after brachial plexus block with ropivacaine: a case report

The aim of this article is presentation of clinical case of local anesthetic systemic toxicity (LAST). Local anesthetic systemic toxicity is a rare but life-threatening complication. Ropivacaine is widely used for the regional blocks and rarely leads to the development of LAST. LAST may develop due to intravascular injection or high dose of ropivacaine. We present the case of 48-year-old-female (ASA I, 56 kg, and 165 cm), who underwent surgery on the right shoulder under brachial plexus block. Brachial plexus nerve block was performed by interscalene access with introduction of 40 ml of 0.75% ropivacaine (300 mg). Twenty minutes after the injection, complete sensory/motor block was achieved. Twenty-five minutes after the injection, the patient complained of numbness in the tongue, tinnitus and dizziness. During this time, her blood pressure was 132/83 mmHg, heart rate 82 beats/min. oxygen saturation 97%. No changes were observed on the ECG. Suspecting ropivacaine-induced toxicity, 50 mg of thiopental sodium followed by 2 mg of midazolam were administered for seizure prophylaxis, and supplemental oxygen was given via face mask. Patient’s state improved in 10 minutes. Ten minutes later 20% intralipid emulsion bolus during 2-3 min was administered followed by continuous infusion at a dose of0.25 ml/kg/min. Against clinical stablility and consciousness of the patient, decision was made to proceed with surgery, which was uneventful. Implementation of preventive measures can decrease the possibility for development of complication and emergency treatment can safe patient’s health and life. Preventive measures should include implementation of ultrasound nerve location guidance, individual calculation of local anesthetic dose, taking into account sex, weight, and physical status of a patient.

Electroencephalogram monitoring during anesthesia and critical care: a guide for the clinician.

Perioperative anesthetic, surgicaland critical careinterventions can affect brain physiology and overall brain health. The clinical utility of electroencephalogram (EEG) monitoring in anesthesia and intensive care settings is multifaceted, offering critical insights into the level of consciousness and depth of anesthesia, facilitating the titration of anesthetic doses, and enabling the detection of ischemic events and epileptic activity. Additionally, EEG monitoring can aid in predicting perioperative neurocognitive disorders, assessing the impact of systemic insults on cerebral function, and informing neuroprognostication. This review provides acomprehensive overview of the fundamental principles of electroencephalography, including the foundations of processed and quantitative electroencephalography. It further explores the characteristic EEG signatures associated wtih anesthetic drugs, the interpretation of the EEG data during anesthesia, and the broader clinical benefitsand applications of EEG monitoring in both anesthetic practice and intensive care environments.

The anesthetic and recovery profiles of low-dose hypobaric mepivacaine and bupivacaine for spinal anesthesia in total hip and knee arthroplasty: a prospective observational study.

Same-day mobilization and early hospital discharge is increasingly emphasized following hip and knee arthroplasty. One challenge of spinal anesthesia in this setting is achieving adequate block height while avoiding excessively large local anesthetic doses and prolonged motor and sensory blockade. Using a hypobaric local anesthetic solution is one potential strategy, as its intrathecal distribution can be reliably manipulated by patient positioning to achieve adequate block height independent of dose. We conducted a prospective observational study to determine the clinical characteristics of spinal anesthesia with low-dose hypobaric mepivacaine and bupivacaine in patients undergoing hip and knee arthroplasty. Thirty patients scheduled for same-day discharge received 51mg of hypobaric 1.5% mepivacaine and 30 patients scheduled for inpatient stay received 10mg of hypobaric 0.33% bupivacaine. The mean (standard deviation) time to achieve sensory blockade at or above L1 and T10 in the operative limb was 5.7 (1.8) and 7.3 (3.3) min with mepivacaine and 6.2 (2.6) and 8.1 (4.8) min with bupivacaine, respectively. Anesthesia was adequate for surgical commencement in all patients regardless of spinal injection level. Four patients required anesthetic supplementation for surgical completion. Sensory block duration at or above T10 and L1 in the operative limb was 97 (27) and 115 (37) min with mepivacaine and 127 (32) and 161 (34) min with bupivacaine, respectively. Motor function returned by 145 (37) and 217 (43) min in mepivacaine and bupivacaine groups, respectively. The anesthetic profiles of low-dosehypobaric mepivacaine and bupivacaine were favorable for fast-track hip and knee arthroplasty with short and predictable operating times.

Regional anesthesia in the obese patient

Regional anesthesia in obese patients presents significant challenges due to the high prevalence of comorbidities such as hypertension, diabetes, and obstructive sleep apnea (OSA), which increase the risk of perioperative complications. Additionally, the excess adipose tissue complicates the administration of anesthesia, making it necessary to adjust the technique and dosage of anesthetics to improve safety and surgical outcomes. Obesity, considered a multisystem disease, imposes additional requirements in the management of ventilation, venous access, and effective analgesia.

The clinical value of ultrasound-guided sacral anesthesia in Intracavitary and/or interstitial brachytherapy for cervical Cancer

ObjectiveTo explore the effectiveness and safety of ultrasound-guided sacral anesthesia in intracavitary and/or interstitial brachytherapy for cervical cancer patients. MethodA retrospective analysis was conducted on a total of 1039 intracavitary and/or interstitial brachytherapy involving 220 patients in our department from December 7, 2020 to March 21, 2024. The study assessed the satisfaction with anesthesia, changes in vital signs, onset time of anesthesia, dosage of anesthetic drugs, duration of anesthesia, and incidence of adverse reactions. ResultThe rate of satisfaction with anesthesia was 73.8 %. There were no significant differences in patients' heart rate (HR), mean arterial pressure (MAP), systolic blood pressure (SBP), or oxygen saturation (SaO2) before and after anesthesia (P > 0.05). The onset time of anesthesia ranged from 20 to 35 min, the average dosage of anesthetic was 20 ml, and the duration of anesthesia lasted from 30 to 120 min. Serious adverse reactions included 2 cases of post-anesthesia syncope (associated with sacral cysts). The incidence of nausea was 2.2 %, and the total incidence of other adverse reactions, such as vomiting, urinary retention, bradycardia, anal discomfort, and dizziness, was less than 1 %. ConclusionUltrasound guided sacral anesthesia demonstrates significant advantages, including effective anesthesia, minimal impact on vital signs, rapid onset, prolonged maintenance, and a low incidence of adverse reactions. It is recommended for widespread application in intracavitary and/or interstitial brachytherapy for cervical cancer patients.

Comparison of postoperative awakening between ciprofol and propofol in elderly patients undergoing hip replacement surgery: a single-blind, randomized, controlled trial.

The aim of this paper was to compare the impact of continuous infusion of ciprofol versus propofol on postoperative awakening in elderly patients following hip replacement surgery. Patients were randomized into two groups (N.=45 each): the ciprofol group and the propofol group. The ciprofol group received ciprofol for anesthesia induction and maintenance, while the propofol group underwent anesthesia induction and maintenance using propofol. The primary outcome was awakening time. Secondary outcomes included spontaneous breathing recovery time, extubation time, time to modified Aldrete Score ≥9, modified observer's assessment of alertness/sedation (MOAA/S) scores, anesthetic dosage, volume of fluid replacement, urine output and administration of vasoactive drugs. The Ciprofol group exhibited a significantly prolonged awakening time (11.0±6.4 min vs. 7.4±4.3 min, P=0.003), spontaneous breathing recovery time (9.9±6.3 min vs. 5.9±4.3 min, P=0.001), and extubation time (12.0 [8.0-16.0] min vs. 8.5 [6.0-11.0] min, P=0.005), and reduced requirement for intraoperative fluid replacement (728.9±254.2 mL vs. 908.3±287.5 mL, P=0.003), increased urine output (235.1±102.1 mL vs. 173.5±106.2 mL, P=0.007), decreased likelihood of vasoactive drug administration (15/30 vs. 28/14, P=0.002). No significant differences were observed between the two groups in terms of reaching a modified Aldrete Score ≥9, MOAA/S scores at 0, 5, 15, or 30 minutes post-extubation, or occurrence of adverse reactions (P>0.05). The dosage of remifentanil was significantly higher in the ciprofol group [5.4 (2.7-7.4) μg·kg-1·h-1 vs. 3.4 (1.9-4.3) μg·kg-1·h-1, P=0.004], with a mean maintenance dose of ciprofol at 0.8 mg·kg-1·h-1 (range: 0.5 to 1.2 mg·kg-1·h-1). Compared to propofol, the administration of ciprofol in elderly patients following hip replacement surgery is associated with prolonged awakening time, spontaneous breathing recovery time, and extubation. The average intravenous maintenance dosage of ciprofol in geriatric patients under general anesthesia was 0.8 mg·kg-1·h-1.

Impact of Spinal Anesthesia Dosage in Elective Cesarean Section on the Duration of Stay in Post-Anesthesia Care Unit at the Women's Health Hospital, National Guard Health Affairs.

In the field of obstetrics, cesarean sections have now become the most prominent procedure for the delivery of newborns. Cesarean sections may be handled with a variety of different anesthetic approaches, of which most focus seems to be on that of spinal forms, due to their rapid and effective action. Dosages of spinal anesthesia formulations differ depending on multiple variables, such as depth of anesthesia, level of analgesia, and desired duration of effects. Furthermore, length of stay in the hospital is also a crucial variable to take into account when using spinal anesthesia due to its implications for patient comfort, quality of care, and return to daily life. Hyperbaric bupivacaine is a mainstay agent in regard to cesarean section anesthesia, with the most commonly used dosages being 1.8 mL and 2.0 mL. This study aims to assess the difference in duration of stay in the post-anesthesia care unit between patients receiving 1.8 mL and 2.0 mL of 0.5% hyperbaric bupivacaine. Of the 306 patients who underwent elective cesarean sections, 63 patients received 2.0 mL of 0.5% hyperbaric bupivacaine and 243 patients received 1.8 mL of 0.5% hyperbaric bupivacaine.

Genetic Differences Modify Anesthetic Preconditioning of Traumatic Brain Injury in Drosophila.

Pre-clinical vertebrate models of traumatic brain injury (TBI) routinely use anesthetics for animal welfare; however, humans experience TBI without anesthetics. Therefore, translation of findings from vertebrate models to humans hinges on understanding how anesthetics influence cellular and molecular events that lead to secondary injuries following TBI. To investigate the effects of anesthetics on TBI outcomes, we used an invertebrate Drosophila melanogaster model to compare outcomes between animals exposed or not exposed to anesthetics prior to the same primary injury. Using a common laboratory fly line, w1118, we found that exposure to the volatile anesthetics isoflurane or sevoflurane, but not ether, prior to TBI produced a dose-dependent reduction in mortality within 24 h following TBI. Thus, isoflurane and sevoflurane precondition w1118 flies to deleterious effects of TBI. To examine the effects of genetic differences on anesthetic preconditioning of TBI, we repeated the experiment with the Drosophila Genetic Reference Panel (DGRP) collection of genetically diverse, inbred fly lines. Pre-exposure to either isoflurane or sevoflurane revealed a wide range of preconditioning levels among 171 and 144 DGRP lines, respectively, suggesting a genetic component for variation in anesthetic preconditioning of mortality following TBI. Finally, genome-wide association study analyses identified single-nucleotide polymorphisms in genes associated with isoflurane or sevoflurane preconditioning of TBI. Several of the genes, including the fly ortholog of mammalian Calcium Voltage-Gated Subunit Alpha1 D (CACNA1D), are highly expressed in neurons and are functionally linked to both anesthetics and TBI. These data indicate that anesthetic dose and genetic background should be considered when investigating effects of anesthetics in vertebrate TBI models, and they support use of the fly model for elucidating the mechanisms underlying anesthetic preconditioning of TBI.

Impact of intravenous infusion of lidocaine on intrapulmonary shunt and postoperative cognitive function in patients undergoing one-lung ventilation.

Intravenous infusion of lidocaine as an anesthesia adjuvant can improve patient outcomes, but its impact on intrapulmonary shunt during one-lung ventilation (OLV) has not been clarified. To determine the effect of intravenous lidocaine infusion on intrapulmonary shunt during OLV and postoperative cognitive function in video-assisted thoracoscopic surgery (VATS). Sixty patients who underwent OLV for thoracic surgery were randomized to receive intravenous infusion of lidocaine (lidocaine group, n = 30) or normal saline (control group, n = 30) for anesthesia induction. Arterial and venous blood gases were measured during two-lung ventilation and at 15 and 30 min after OLV (OLV + 15 and OLV + 30). The Mini-Mental State Examination was administered before the surgery and at postoperative 12 months to assess patient cognitive function. No significant difference was found in intrapulmonary shunt fraction (Qs/Qt) between the lidocaine group and the control group at OLV + 15 (p = 0.493) and OLV + 30 (p = 0.754). The lidocaine group used significantly lower doses of propofol and remifentanil compared to the control group (both p < 0.001). Furthermore, no significant difference was observed in the incidence of postoperative cognitive dysfunction between the lidocaine group and the control group at 1 year post-operation (3.3% vs 6.7%, p = 0.554). Intravenous lidocaine administered in VATS had no significant impact on intrapulmonary shunt during OLV or postoperative cognitive function. However, it significantly reduced the doses of anesthetics used during the surgery.

Ultrasound guided pediatric caudal dose: a two-center randomized controlled trial

BackgroundThe drug volume to be used in caudal in pediatric patients has remained an unmet issue since long. We determined the minimum drug volume required to reach T10 level in pediatric patients using ultrasonography and compared it with the already established volume by Armitage formula.AimTo determine the minimum effective caudal local anesthetic dose using ultrasound guidance.MethodsStudy was performed at two centres and at each centre, 50 pediatric patients (Total 100 patients), aged 1 to 3 years, undergoing below umbilical surgeries were included and randomised into two groups of 25 each (Total 50) to receive ultrasound guided drug volume vs. Armitage formula based volume. The volume required to reach T10 level was assessed with ultrasound in one group. Also, maximum height achieved, cutaneous level achieved after 15 min, FLACC scores 30 min post extubation and parental satisfaction scores were noted.ResultsThe mean drug volume required to reach T10 level in Group U was 0.755 ± 0.053 ml/kg with a P value < 0.001. (Compared to the drug volume of 1 ml/kg using one sample t test). The highest level achieved in both groups were calculated as the mode value of T8 and T7 in Group U and Group A respectively. The highest cutaneous level achieved after 15 min was also calculated as the mode value of T4 in both groups. FLACC scores at 30 min were also comparable. Satisfaction scores were comparable in both groups.ConclusionA volume of 0.7 ml/kg of local anaesthetic in pediatric caudal block is sufficient to achieve a target of T10 level for infraumblical surgeries.

Risk of postoperative delirium in older adults under balanced general anesthesia

Anesthetic depth can influence the incidence of postoperative delirium (POD). This depth is related to the potency of the volatile anesthetics used to maintain balanced general anesthesia. This potency is measured by means of the minimum alveolar concentration (MAC). In older adults, it is unknown which MAC is associated with the risk of POD. To estimate the risk of POD associated with minimum alveolar concentration (MAC) levels of volatile anesthetics in older adults who received balanced general anesthesia. A prospective cohort study was carried out with 119 patients, aged ≥ 60 years, with 0 points in the 4 "As" test (4AT), without neurological or psychiatric diseases. During the intraoperative period, the CAM provided was recorded, and in the postoperative period, the presence of emergency with delirium and/or POD was evaluated at 2 and 24 hours, considering a score ≥ 4. A longer hospital stay was found in the group that received a MAC ≥0.9. The incidence of POD was 29.4%. Those who received a MAC ≥ 0.9 had an RR of 2.22 (95%CI: 1.2-4.2) of presenting POD. An adjusted logistic regression model was performed with the variables female sex (OR: 4, 95%CI: 1.5-10.4), ASA physical status 3-4 (OR: 3.7, 95%CI: 1.5-9) and MAC ≥ 0.9 (OR: 3.1 95%CI: 1.2-8) with an R2: 0.26 and a constant of 3.005. MAC ≥ 0.9 represents a risk factor for DPO, so individualized dosing of volatile anesthetics should be used.

The Utility of Electroencephalograhy in Guiding General Anesthesia in Children.

Traditional pediatric anesthetic dosing using pharmacokinetic estimates based on age and weight is often imprecise, frequently leading to oversedation. Intraoperative electroencephalography (EEG) allows visualization of the brain's response to anesthetic agents in real time, facilitating precise titration of anesthetic drug doses optimized for the individual child. The goal of EEG-guided anesthesia management is to maintain an optimal state of hypnosis during various stages of the procedure while minimizing hemodynamic instability and other adverse effects of anesthesia. This is especially important in children with less predictable anesthetic requirements, such as children with atypical neurodevelopment, altered levels of consciousness before anesthesia, or those receiving total intravenous anesthesia, neuromuscular blockers, or a combination of anesthetic agents with different mechanisms of actions. Children with limited cardiorespiratory reserves and those undergoing high-risk procedures such as cardiopulmonary bypass also benefit from EEG guidance as they have a narrower therapeutic window for optimal anesthetic dosing. Various processed EEG (pEEG) monitors are available for intraoperative monitoring in children. These monitors display a pEEG index based on the manufacturer's algorithm, purportedly indicating the patient's hypnotic state. Due to differences in developmental neurophysiology and EEG dynamics in children, pEEG indices may not always reliably indicate the hypnotic state, especially in neonates and infants. Learning to interpret nonproprietary EEG parameters including the raw EEG, spectral-edge frequency 95% (SEF95), and density spectral array can prevent overreliance on pEEG indices. This review provides an overview of the advantages of EEG guidance during clinical anesthesia, including potential reduction in anesthetic dosage, prevention of EEG suppression, and reduction in peri-operative adverse events. We describe the use of nonproprietary EEG parameters in guiding anesthesia in children for various clinical end points including laryngoscopy, surgical incision, and maintenance of anesthesia, as well as sedation. We illustrate these principles with various case examples commonly encountered during pediatric anesthesia. Lastly, we discuss strategies to expand intraoperative EEG monitoring in children through education and training programs, as well as advocate for further research to assess clinical outcomes associated with EEG guidance to support its routine use in clinical care.

General anesthesia activates a central anxiolytic center in the BNST

Low doses of general anesthetics like ketamine and dexmedetomidine have anxiolytic properties independent of their sedative effects, but the underlying mechanisms remain unclear. We discovered a population of GABAergic neurons in the oval division of the bed nucleus of the stria terminalis that are activated by multiple anesthetics and the anxiolytic drug diazepam (ovBNSTGA). The majority of ovBNSTGA neurons express neurotensin receptor 1 (Ntsr1) and form circuits with brain regions known to regulate anxiety and stress responses. Optogenetic activation of ovBNSTGA or ovBNSTNtsr1 neurons significantly attenuated anxiety-like behaviors in both naive animals and mice with inflammatory pain, while inhibition of these cells elevated anxiety. Activation of these neurons decreased heart rate and increased heart rate variability, suggesting that they reduce anxiety by modulating autonomic responses. Our study identifies ovBNSTGA/ovBNSTNtsr1 neurons as a common neural substrate mediating the anxiolytic effect of low-dose anesthetics and a potential therapeutic target for treating anxiety-related disorders.

A Comparative Study between Ultrasound-guided Concomitant Infraclavicular Plus Distal Median, Radial, and Ulnar Nerve Blockade Versus Infraclavicular Block Alone

Abstract Background: Peripheral nerve blocks can be used alone as the sole “surgical” anesthetic technique as the initial step in providing prolonged postoperative analgesia. There are studies, where accurate deposition of local anesthetic perineurally has the potential to improve the success rate and reduce the incidence of complications of the infraclavicular block. We hypothesized whether a combined block of the infraclavicular brachial plexus and distal median, radial, and ulnar nerves would accelerate upper extremity anesthesia compared with an infraclavicular block alone. Materials and Methods: This study was a prospective randomized control study conducted among 60 patients undergoing elective and emergency wrist and hand surgeries. A group of 30 patients received an infraclavicular block with 30 mL of a local anesthetic mixture containing 1% lignocaine with adrenaline and 0.25% bupivacaine from Group A. Group B received an infraclavicular block with 15 mL of local anesthetic mixture containing 1% lignocaine with adrenaline and 0.25% bupivacaine along with distal median, radial, and ulnar nerve blockade with 5 mL each of local anesthetic mixture containing 1% lignocaine with adrenaline and 0.25% bupivacaine. Pain score, assessment of sensory and motor functions, block performance time, and surgical anesthesia were observed. Results: The mean block performance time of Group A was 10.9 ± 1.1 min and Group B was 14.7 ± 0.5 min. The difference between the two groups’ block performance minutes was statistically significant (P &lt; 0.001). The difference in the onset of the sensory block between the two groups was statistically significant (P &lt; 0.001). The mean onset of motor blockade between the two groups was statistically very highly significant (P &lt; 0.001). The mean of Group A was 5.0 ± 0.2 and Group B was 2.1 ± 0.4. Conclusion: From this study, we conclude that using an approximately equivalent dose of local anesthetics, combining ultrasound-guided infraclavicular block with distal median, radial, and ulnar nerve blockade shortens the onset time of sensory and motor block with improved block consistency compared to infraclavicular block alone.