Depth Of Anesthesia Research Articles

Automated Closed-Loop Propofol Anesthesia Versus Desflurane Inhalation Anesthesia in Obese Patients Undergoing Bariatric Surgery: A Comparative Randomized Analysis of Recovery Profile.

Precision general anesthesia (GA) techniques that minimize the presence of residual anesthetic and facilitate recovery, are desirable in patients with morbid obesity. Automated administration of propofol total intravenous anesthesia (TIVA), which facilitates precision propofol delivery by factoring in continuous patient input variable (bispectral index) to establish a closed feedback loop system, may help mitigate concerns related to propofol's lipid solubility and adverse accumulation kinetics in patients with morbid obesity. This randomized study evaluated the recovery of patients with morbid obesity undergoing bariatric surgery under propofol TIVA automated by a closed-loop anesthesia delivery system (CLADS) versus desflurane GA. Forty patients, randomly allocated to receive propofol TIVA (CLADS group) or desflurane GA (desflurane group), were evaluated for postoperative recovery (early and intermediate) (primary objective); they were evaluated for intraoperative hemodynamics, anesthesia depth consistency, anesthesia delivery performance characteristics, patient satisfaction, and incidence of adverse events (sedation, pain, postoperative nausea, and vomiting) (secondary objective). No difference was found for the time-to-eye-opening (CLADS group: 4.7 [3.0, 6.7] min vs. desflurane group: 5.6 [4.0, 6.9] min, P = 0.576), time-to-tracheal-extubation (CLADS group: 6.7 [4.7, 9.3] min vs. desflurane group: 7.0 [5.8, 9.2] min, P = 0.528), ability-to-shift score from operating room table to the transport bed (CLADS group: 3 [3.0, 3.5] vs. desflurane group: 3 [3.0, 4.0], P = 0.703), and time to achieve a modified Aldrete score 9/10 (CLADS group: 15 [15.0, 37.5] min vs. desflurane group: 15 [15.0, 43.7] min, P = 0.867). Automated propofol TIVA as administered by CLADS, which matched desflurane GA with respect to depth of anesthesia consistency and postanesthesia recovery profile, can be explored further as an alternative anesthesia technique in patients with morbid obesity.

Bispectral Index Monitor for Regulating Anesthetic Depth on Blood Glucose, Lactate Concentration and Intraoperative Stress Response in Patients Undergoing Craniocerebral Operation

Bispectral Index Monitor for Regulating Anesthetic Depth on Blood Glucose, Lactate Concentration and Intraoperative Stress Response in Patients Undergoing Craniocerebral Operation

Anesthesia and the Merry-go-round of Information in the Brain.

Anesthesia and the Merry-go-round of Information in the Brain.

Electroencephalographic spectrogram-guided total intravenous anesthesia using dexmedetomidine and propofol prevents unnecessary anesthetic dosing during craniotomy: a propensity score-matched analysis.

The bispectral index (BIS) may be unreliable to gauge anesthetic depth when dexmedetomidine is administered. By comparison, the electroencephalogram (EEG) spectrogram enables the visualization of the brain response during anesthesia and may prevent unnecessary anesthetic consumption. This retrospective study included 140 adult patients undergoing elective craniotomy who received total intravenous anesthesia using a combination of propofol and dexmedetomidine infusions. Patients were equally matched to the spectrogram group (maintaining the robust EEG alpha power during surgery) or the index group (maintaining the BIS score between 40 and 60 during surgery) based on the propensity score of age and surgical type. The primary outcome was the propofol dose. Secondary outcome was the postoperative neurological profile. Patients in the spectrogram group received significantly less propofol (1585 ± 581 vs. 2314 ± 810 mg, P < 0.001). Fewer patients in the spectrogram group exhibited delayed emergence (1.4% vs. 11.4%, P = 0.033). The postoperative delirium profile was similar between the groups (profile P = 0.227). Patients in the spectrogram group exhibited better in-hospital Barthel's index scores changes (admission state: 83.6 ± 27.6 vs. 91.6 ± 17.1; discharge state: 86.4 ± 24.3 vs. 85.1 ± 21.5; group-time interaction P = 0.008). However, the incidence of postoperative neurological complications was similar between the groups. EEG spectrogram-guided anesthesia prevents unnecessary anesthetic consumption during elective craniotomy. This may also prevent delayed emergence and improve postoperative Barthel index scores.

Comparative Evaluation Of The Effectiveness Of Dexamethasone And Adrenaline With 2% Lignocaine For Pterygomandibular Nerve Blocks: A Randomized Controlled Clinical Study

Background and Aim: Dexamethasone, a glucocorticoid, has been used in local anesthetics as an additive for various locoregional nerve blocks. Although, its use in the dental field has not been unexplored and concealed. The current study was conducted to evaluate and compare the calibre of anesthesia, their hemodynamic response, vasoconstrictive effects, and control of pain while administering pterygomandibular nerve blocks using 2% Lignocaine hydrochloride solution with Dexamethasone(4mg/ml) with that of the standard 2% Lignocaine hydrochloride solution and Adrenaline bitartrate (1:80000). Materials and Methods: This triple-blind randomized controlled study included 80 healthy subjects, aged between 18-45 years with an indication for surgical removal of impacted mandibular third molars. With the aid of a computer-generated sequence, the subjects were arbitrarily assigned into 2 groups (40/group)- Group 1: patients administered with 2% Lignocaine hydrochloride and Dexamethasone Sodium Phosphate (4mg/ml) solution, and Group 2: patients administered with 2% Lignocaine hydrochloride with Adrenaline bitartrate (Adr) 1: 80,000 (12.5 μgm/ml) solution. The variables were assessed based on their time of onset, depth (pain) and duration of anesthesia, systolic, diastolic, and mean arterial blood pressures, heart rate, and blood loss. Results: Statistically significant difference (P&lt;0.05) was noticed for the onset (shorter onset in Group 1) and duration of action (prolonged in group 1) and number of analgesics required (less in grp 1). Statistically non-significant difference between 2 groups (P&gt;0.05) for pain, blood loss, cardiovascular variables (systolic, diastolic and mean arterial blood pressures and heart rate) at various intervals was noted. Conclusion: Dexamethasone added to Lignocaine shortens onset, prolongs duration of action and yields better control of post-operative pain as compared to Lignocaine with Adr. Vasoconstrictive properties, hemodynamic variables and intra-op pain control were comparable. Bangladesh Journal of Medical Science Vol.22 (Special Issue) 2023 p.172-178

An Observational Study on the Intraoperative Awareness Following General Anesthetic Drugs

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

Anesthetic management of a patient with an electroencephalogram phenotype for a “vulnerable brain”: a case report

BackgroundLow frontal alpha power is an electroencephalogram phenotype suggesting vulnerability to anesthetics. This phenotype for a “vulnerable brain” carries risks for burst suppression at lower-than-expected anesthetic concentrations and therefore for postoperative delirium.Case presentationA 73-year-old man underwent a laparoscopic Miles’ operation. He was monitored with a bispectral index monitor. Before the skin incision, the fraction of age-adjusted minimum alveolar concentration of desflurane was 0.48, and a spectrogram showed slow-delta oscillation despite a bispectral index value of 38–48. Although the fraction of age-adjusted minimum alveolar concentration of desflurane decreased to 0.33, the EEG signature remained unchanged, along with a similar bispectral index value. No burst suppression patterns were observed throughout the whole procedure, and he did not experience postoperative delirium.ConclusionsThis case suggests that monitoring of electroencephalogram signatures is helpful for detecting patients with a “vulnerable brain” and for providing optimal anesthetic depth in such patients.

Effects of anesthetic depth on perioperative T lymphocyte subsets in patients undergoing laparoscopic colorectal cancer surgery: a prospective, parallel-controlled randomized trial

BackgroundDuring the perioperative period, the surgical stress response induced by surgical trauma tends to cause a decrease in peripheral lymphocytes. Anesthetics could reduce the stress response during surgery and prevent sympathetic nerve overexcitation. The goal of this study was to investigate how BIS-guided anesthetic depth affected peripheral T lymphocytes in patients undergoing laparoscopic colorectal cancer surgery.MethodsA total of 60 patients having elective laparoscopic colorectal cancer surgery were randomly assigned and analyzed (n = 30 for deep general anesthesia, BIS 35, n = 30 for light general anesthesia, BIS 55). Blood samples were collected immediately before anesthesia induction and immediately after operation, 24 h and 5 days postoperatively. The CD4+/CD8 + ratio, T lymphocyte subsets (including CD3 + T cells, CD4 + T cells, and CD8 + T cells), and natural killer (NK) cells were analyzed by flow cytometry. Serum interleukin-6 (IL-6), interferon -ɣ (IFN-ɣ), and vascular endothelial growth factor-α (VEGF-α) were also measured.ResultsThe CD4+/CD8 + ratio decreased 24 h after surgery in two groups, but the reduction did not differ between the two groups (P > 0.05). The concentration of IL-6 and the numerical rating scale (NRS) score in the BIS 55 group were significantly higher than that in the BIS 35 group 24 h after surgery (P = 0.001). There were no intergroup differences in CD3 + T cells, CD4 + T cells, CD8 + T cells, NK cells, VEGF-α, or the IFN-ɣ. Statistical analyses showed no differences between the two groups in the incidence of fever and surgical site infection during hospitalization.ConclusionsDespite the fact that patients in deep general anesthesia group had low levels of the IL-6 24 h after surgery, the deep general anesthesia was not associated to a positive effect on patients’ peripheral T lymphocytes during colorectal cancer surgery. We found no evidence that peripheral T lymphocyte subsets and natural killer cells were affected by the targeting a BIS of either 55 or 35 in patients undergoing laparoscopic colorectal cancer surgery in this trial.Trial registrationChiCTR2200056624 (www.chictr.org.cn).

Analysis of clinical series with the use of adjuvants to general anesthesia during elective caesarean section

Background. Caesarean section remains one of the most common surgical interventions in the world. The main disadvantages of the general anesthesia in caesarean section are a high risk of awareness during the operation and a pronounced hemodynamic reaction to the surgical trauma in a patient. The most dangerous period of intervention in terms of these complications is the period before the birth of a child. This article analyzes our own clinical cases of the general anesthesia during elective caesarean section with the addition of adjuvants and compares anesthetic management with world practices. In all cases from our own clinical practice, total intravenous anesthesia with artificial lung ventilation was performed. Intravenous forms of medical drugs were used as adjuvants: paracetamol (1000 mg) and clonidine (100 μg), 30 minutes before the elective surgical intervention. The newborns were examined with the Apgar scale and umbilical venous blood gas analysis was carried out. Preoperative, intraoperative, and postoperative management of patients was based on recommendations of the Enhanced Recovery After Caesarean Section and guidelines of the PROSPECT working group. Results. The analysis of our own clinical cases revealed the presence of a hemodynamic reaction of the patient’s body to the operative injury (in the period before the birth of a child), which does not exceed safe levels; absence of anesthetic complications and cases of accidental awareness during surgery; absence of a negative influence of adjuvants on newborns; sufficient depth of anesthesia and reduction of the intraoperative doses of opioids and intravenous anesthetics (“on patient’s request”). Conclusions. The analysis of clinical cases argues for the need to use “safe adjuvants” (acetaminophen, clonidine) to general anesthesia during elective caesarean section and the necessity for further research.

Comparison between patient state index, bispectral index, and clinical parameters for propofol induction in Indian patients: A prospective study.

Patient state index (PSI) and bispectral index (BIS) are depth of anesthesia monitors utilized for the dosage of propofol usage for induction. We compare PSI, BIS, and Observer's Assessment of Alertness/Sedation Scale (OAA/S) for propofol dose usage for induction. Seventy-four ASA I and II patients, aged 18-65 years scheduled for laparoscopic cholecystectomy were included and divided into groups to titrate the drug dosage of propofol needed for induction of anesthesia, monitored by PSI (Group A), BIS (Group B), or clinical OAA/S (Group C). The drug dosage needed for induction was based on a PSI value of 25 ± 2, BIS value of 48 ± 2, and OAA/S value of ≤2 as the endpoint of induction in respective groups. Intraoperative hemodynamic variables and any complications were compared. The mean doses of propofol needed for induction were 2.23 mg/kg (Group A), 2.05 mg/kg (Group B), and 2.11 mg/kg (Group C). A significantly decreased dose was needed to achieve the desired end in Group B compared to Group A (P = 0.01). The hemodynamic variables such as heart rate, systolic blood pressure, and diastolic blood pressure among the three groups were comparable. The clinical method of titrating the dose of propofol for induction and anesthetic depth by the loss of verbal response is comparable to both BIS and PSI monitoring.

Depth of anesthesia, temperature, and postoperative delirium in children and adolescents undergoing cardiac surgery

BackgroundAfter pediatric cardiosurgical interventions, postoperative delirium can occur, which can be associated with undesirable consequences during and after the hospital stay. It is therefore important to avoid any factors causing delirium as far as possible. Electroencephalogram (EEG) monitoring can be used during anesthesia to individually adjust dosages of hypnotically acting drugs. It is necessary to gain knowledge about the relationship between intraoperative EEG and postoperative delirium in children.MethodsIn a dataset comprising 89 children (53 male, 36 female; median age: 0.99 (interquartile range: 0.51, 4.89) years) undergoing cardiac surgery involving use of a heart–lung machine, relationships between depth of anesthesia as measured by EEG (EEG index: Narcotrend Index (NI)), sevoflurane dosage, and body temperature were analyzed. A Cornell Assessment of Pediatric Delirium (CAP-D) score ≥ 9 indicated delirium.ResultsThe EEG could be used in patients of all age groups for patient monitoring during anesthesia. In the context of induced hypothermia, EEG monitoring supported individually adjusted sevoflurane dosing. The NI was significantly correlated with the body temperature; decreasing temperature was accompanied by a decreasing NI.A CAP-D score ≥ 9 was documented in 61 patients (68.5%); 28 patients (31.5%) had a CAP-D < 9. Delirious patients with an intubation time ≤ 24 h showed a moderate negative correlation between minimum NI (NImin) and CAP-D (rho = -0.41, 95% CI: -0.70 – -0.01, p = 0.046), i.e., CAP-D decreased with increasing NImin. In the analysis of all patients’ data, NImin and CAP-D showed a weak negative correlation (rho = -0.21, 95% CI: -0.40 – 0.01, p = 0.064). On average, the youngest patients had the highest CAP-D scores (p = 0.002). Patients with burst suppression / suppression EEG had a longer median intubation time in the intensive care unit than patients without such EEG (p = 0.023).There was no relationship between minimum temperature and CAP-D score.ConclusionsThe EEG can be used to individually adjust sevoflurane dosing during hypothermia. Of the patients extubated within 24 h and classified as delirious, patients with deeper levels of anesthesia had more severe delirium symptoms than patients with lighter levels of anesthesia.

Intraoperative Neurophysiological Monitoring in Pediatric Patients

Because of technological advancements in preserving neurological function during surgery, intraoperative neurophysiological monitoring has become mandatory and increasingly common. Few studies have reported on the safety, feasibility, and reliability of intraoperative neurophysiological monitoring in children, especially infants. The maturation of nerve pathways is not fully achieved until 2 years of age. Moreover, it is often difficult to maintain stable anesthetic depth and hemodynamic status when operating on children. The interpretation of neurophysiological recordings in children is different from that in adults and requires further consideration.

Urethane provides an unparalleled anaesthetic model for natural sleep: Commentary on Mondino et al., 2022.

Urethane provides an unparalleled anaesthetic model for natural sleep: Commentary on Mondino et al., 2022.

The Relationship Between Esophageal Pressure and Diaphragm Thickening Fraction in Spontaneously Breathing Sedated Children: A Feasibility Study.

Diaphragm ultrasound is a novel alternative to esophageal pressure measurements in the evaluation of diaphragm function and activity, but data about its reliability in a pediatric setting are lacking. We aimed to compare the esophageal pressure swing (∆Pes, gold standard) with the diaphragmatic thickening fraction (DTF) as a measure of inspiratory effort in sedated children. Additionally, we studied the effect of positive end-expiratory pressure (PEEP) on the end-expiratory thickness of the diaphragm (DTee). Prospective open-label non-randomized interventional physiological cohort study. Operating room in tertiary academic hospital. Children 28 days to 13 years old scheduled for elective surgery with general anesthesia, spontaneously breathing through a laryngeal mask airway, were eligible for inclusion. Exclusion criteria were disorders or previous surgery of the diaphragm, anticipated difficult airway or acute cardiopulmonary disease. All measurements were performed prior to surgery. Patients were subjected to different levels of respiratory load, PEEP and anesthetic depth in a total of seven respiratory conditions. The esophageal pressure and diaphragm thickening fraction were simultaneously recorded for five breaths at each respiratory condition. The relation between ∆Pes and DTF was studied in a mixed model. We analyzed 407 breaths in 13 patients. Both DTF (p = 0.03) and ∆Pes (p = 0.002) could detect respiratory activity, and ∆Pes and DTF were associated across respiratory conditions (p < 0.001; R2 = 31%). With increasing inspiratory load, ∆Pes increased significantly, while DTF did not (p = 0.08). Additionally, DTee did not differ significantly between 10, 5, and 0 cm H2O PEEP (p = 0.08). In spontaneously breathing sedated children and across different respiratory conditions, DTF could differentiate minimal or no inspiratory effort from substantial inspiratory effort and was associated with ∆Pes. Increased efforts resulted in higher ∆Pes but not larger DTF.

Determination of the effective dose of dexmedetomidine to achieve loss of consciousness during anesthesia induction.

Dexmedetomidine (DEX) is a sedative with greater preservation of cognitive function, reduced respiratory depression, and improved patient arousability. This study was designed to investigate the performance of DEX during anesthesia induction and to establish an effective DEX induction strategy, which could be valuable for multiple clinical conditions. Patients undergoing abdominal surgery were involved in this dose-finding trial. Dixon's up-and-down sequential method was employed to determine the effective dose of DEX to achieve the state of "loss of consciousness", and an effective induction strategy was established with continuous infusion of DEX and remifentanil. The effects of DEX on hemodynamics, respiratory state, EEG, and anesthetic depth were monitored and analyzed. Through the strategy mentioned, the depth of surgical anesthesia was successfully achieved by DEX-led anesthesia induction. The ED50 and ED95 of the initial infusion rate of DEX were 0.115 and 0.200 μg/kg/min, respectively, and the mean induction time was 18.3 min. The ED50 and ED95 of DEX to achieve the state of "loss of consciousness" were 2.899 (95% CI: 2.703-3.115) and 5.001 (95% CI: 4.544-5.700) μg/kg, respectively. The mean PSI on the loss of consciousness was 42.8 among the patients. During anesthesia induction, the hemodynamics including BP and HR were stable, and the EEG monitor showed decreased α and β powers and increased θ and δ in the frontal and pre-frontal cortices of the brain. This study indicated that continuous infusion of combined DEX and remifentanil could be an effective strategy for anesthesia induction. The EEG during the induction was similar to the physiological sleep process.

Justification of the expediency of using harmless analgesia in bariatric surgery: prospective randomized study

BACKGROUND: The presence of various comorbid conditions in patients with obesity increases operational risk, and high sensitivity to sedatives and opioid drugs can contribute to their aggravation.&#x0D; OBJECTIVE: To compare and evaluate two methods of perioperative analgesia, namely, multimodal without opioid and non-opioid when performing longitudinal gastric resection for patients with morbid obesity using the enhanced recovery after surgery protocol.&#x0D; MATERIALS AND METHODS: A prospective randomized study of patients with morbid obesity was conducted. Depending on the type of analgesic component of anesthesia, the patients are divided into two groups. In both groups, low-flow desflurane inhalation was used; in group 1 (n=30), the technique of non-opioid analgesia was used, which included intraoperative infusion of ketamine, dexmedetomidine, lidocaine, and magnesium sulfate. In group 2 (n=30), traditional combined anesthesia using fentanyl was administered. In the postoperative period, the infusion of the above drugs continued for 10 h in group 1. Central and peripheral hemodynamic parameters, and the depth of anesthesia were studied, and TOF-monitoring was carried out. Postoperative rehabilitation was assessed based on the time of extubation, achievement of 13 points on the PARS scale, first getting up on ones feet, appearance of overstrain, and gas discharge. Postoperative analgesia was assessed on a 10-point visual analog scale, and anesthesia-related complications were recorded.&#x0D; RESULTS: Surgical intervention under low-flow inhalation anesthesia based on desflurane in combination with multimodal opioid-free analgesia reduced the need for opioid analgesics intraoperatively (in group 1, the fentanyl dose was 0.2 [01; 0.2] mg; in group 2 0.4 [0.3; 0.5] mg; p=0.002), provided less fluctuation of intraoperative hemodynamic parameters (AvBP: stage 1: group 1 102 [100; 103]; group 2 102 [98; 105], p=0.96; stage 2: group 1 93 [90; 95]; group 2 96 [93; 99], p=0.003; stage 3: group 1 95 [95; 97]; group 2 100 [96; 102], p 0.001; stage 4: group 1 95 [92; 97]; group 2 98 [98; 101], p 0.001; CI stage 1: group 1 492.2; group 2 49.52.2, p=0.39; stage 2: group 1 44.42; group 2 44.62.1, p=0.26; stage 3: group 1 45.52.11; group 2 50.62.8, p=0.001; stage 4: group 1 44.52.1; group 2 48.82.5 p 0.001), and contributed to a lower level of pain and faster rehabilitation. In addition, anesthesia-related complications such as postoperative nausea and vomiting, hypoxemia, and dysphoria were less frequently recorded.&#x0D; CONCLUSION: The use of multimodal non-opioid analgesia contributes to a lesser fluctuation in hemodynamic parameters, a low level of postoperative pain, early activation of patients and restoration of peristalsis, and a decrease in the number of postoperative complications in patients who underwent longitudinal gastric resection for morbid obesity.

BIS-monitoring as a tool for evaluation regional anesthesia in ophthalmology: pilot study

BACKGROUND: General anesthesia in vitreoretinal surgeries may be combined with ophthalmic blocks. Prolonged sub-tenon block (PSB) in extensive surgery ensures the continuous administration of a local anesthetic into the episcleral space; however, its effectiveness has not been evaluated.&#x0D; OBJECTIVE: To evaluate the effectiveness of sub-tenon block for vitreoretinal surgery in general anesthesia.&#x0D; MATERIALS AND METHODS: The pilot study included 24 patients. All patients underwent retinal detachment surgery under general anesthesia with sevoflurane for 90 min. Patients were randomized into two groups. In group 1, analgesia was induced with intravenous tramadol. In group 2, general anesthesia was combined with sub-tenon block, and 1% lidocaine was used continuously. Bispectral index (BIS) monitoring was employed for anesthesia depth assessment. The mean blood pressure and heart rates were estimated for the evaluation of the oculovisceral reflex block. The Student and WilcoxonBonferroni criterion was used for statistical analysis, and the statistical significance level was set at =0.05.&#x0D; RESULTS: The hemodynamic and consequently the degree of oculovisceral reflexes block had no statistically significant differences between the groups. The median BIS in groups 1 and 2 were 48.111.1 U and 42.68.2 U, respectively, and the difference between these values was statistically insignificant (p 0.05). However, in group 1, the BIS increased sharply during the laser phase. At this stage, the average BIS in groups 1 and 2 were 76.73.2 U and 40.46.9 U, respectively (p=0.001).&#x0D; CONCLUSION: BIS-monitoring can be used as an indicator of the effectiveness of ophthalmic regional blocks in further studies.

Comparison of Mean Insertion Time of Supraglottic Airway Device in Children Followed by Trapezius Squeeze Test Versus Jaw Thrust

Objective: To compare the assessment of the timing of insertion of supraglottic airway device in children by trapezius squeeze test versus jaw thrust as an indicator of the depth of anaesthesia. Study Design: Prospective comparative study. Place and Duration of Study: Combined Military Hospital, Quetta Pakistan, from Jan to Dec 2021. Methodology: Eighty children undergoing surgical interventions under Sevoflurane anaesthesia with supraglottic airway device having ASA physical status I or II were divided into two sets of 40 children. Both groups were labelled Group-A (trapezius squeeze test) and Group-B (jaw thrust). Supraglottic airway device iGel was inserted immediately after the negative trapezius squeeze test or jaw thrust. A negative test was defined as the absence of cough, reflex movements, breath-holding, gag reflex and laryngospasm. Insertion time and the number of attempts were carefully recorded. Results: The mean age of patients in the study was 4.8±2.028years, and the mean weight was 17.05±5.34. 47% of patients were in ASA-I, 52% in ASA-II in Group-A, 40 % were ASA-I and 60% in ASAII in Group-B. The mean insertion time was 143.42±5.56 seconds in Group-A and 117.525±7.15 seconds in Group-B with a p-value of 0.002. Conclusion: We concluded that the trapezius squeeze test provides better insertion conditions for supraglottic airway devices than jaw thrust during Sevoflurane anaesthesia in pediatric patients.

Effect of Use of Entropy Monitoring on Consumption of Sevoflurane Inhalational Agent in Patients Undergoing Off-Pump Coronary Artery Bypass Graft Surgery: A Randomized, Double Blinded, Controlled Study

Background: Monitoring the depth of Anesthesia using Entropy modality is essential and resourceful as it allows for more accurate hypnotic drug administration and decreased anesthetic drug consumption and shortens the recovery time. This study was performed to evaluate the effect of entropy monitoring on Sevoflurane consumption in patients undergoing Off Pump Coronary Artery Bypass Graft Surgery.&#x0D; Methods: A total of 60 patients of ages between 40 – 70 years and of either sex with American Society of Anesthesiologist (ASA) grade 2 and 3, planned for Off Pump Coronary Artery Bypass Graft Surgery were randomly allocated to two groups in this Randomized Controlled Trial. In the control group i.e. Group B, Sevoflurane was titrated according to changes in clinical parameters (Heart Rate (HR) and Blood Pressure (BP) changes within 20% of baseline values) and in the study group i.e. Group A, Sevoflurane was titrated to maintain State Entropy (SE) values between 40-60 accordingly. Response Entropy (RE) and State Entropy (SE) values were continuously recorded in both the groups but were displayed on the monitor only in the study group and were not displayed to the anesthesiologist in the control group. The entropy values, Sevoflurane Consumption and recovery times were compared amongst the two groups. Patients in both the groups were ventilated on Volume Control Mode of ventilator with 100% oxygen @ 2L/min.&#x0D; Results: There were no significant results in terms of age, sex, ASA Grade and NYHA Grade amongst the two groups. Sevoflurane consumption and time of recovery were significantly reduced in the study group i.e. Group A than the Control group i.e. Group B (p value &lt;0.001; Sevoflurane consumption: 7.03±0.67 ml/hr vs 12.42±0.68 ml/hr; Recovery Time 6.47±0.65 hr vs 12.05±1.11 hr). Response and State Entropy values were lower in the control group than the study group (p &lt; 0.001) during the maintenance phase of anesthesia. Systolic Blood Pressure values during skin incision, sternotomy and at the time of completion of all grafts were significantly lower in study group as compared to the control group.&#x0D; Conclusion: Monitoring the Depth of Anesthesia using Entropy Monitoring leads to significant reduction in Sevoflurane consumption and significant faster recovery rate from surgery.

Time-trend analysis of the center frequency of the intrinsic mode function from the Hilbert–Huang transform of electroencephalography during general anesthesia: a retrospective observational study

BackgroundAnesthesiologists are required to maintain an optimal depth of anesthesia during general anesthesia, and several electroencephalogram (EEG) processing methods have been developed and approved for clinical use to evaluate anesthesia depth. Recently, the Hilbert–Huang transform (HHT) was introduced to analyze nonlinear and nonstationary data. In this study, we assessed whether the changes in EEG characteristics during general anesthesia that are analyzed by the HHT are useful for monitoring the depth of anesthesia.MethodsThis retrospective observational study enrolled patients who underwent propofol anesthesia. Raw EEG signals were obtained from a monitor through a previously developed software application. We developed an HHT analyzer to decompose the EEG signal into six intrinsic mode functions (IMFs) and estimated the instantaneous frequencies (HHT_IF) for each IMF. Changes over time in the raw EEG waves and parameters such as HHT_IF, BIS, spectral edge frequency 95 (SEF95), and electromyogram parameter (EMGlow) were assessed, and a Gaussian process regression model was created to assess the association between BIS and HHT_IF.ResultsWe analyzed EEG signals from 30 patients. The beta oscillation frequency range (13–25 Hz) was detected in IMF1 and IMF2 during the awake state, then after loss of consciousness, the frequency decreased and alpha oscillation (8–12 Hz) was detected in IMF2. At the emergence phase, the frequency increased and beta oscillations were detected in IMF1, IMF2, and IMF3. BIS and EMGlow changed significantly during the induction and emergence phases, whereas SEF95 showed a wide variability and no significant changes during the induction phase. The root mean square error between the observed BIS values and the values predicted by a Gaussian process regression model ranged from 4.69 to 9.68.ConclusionsWe applied the HHT to EEG analyses during propofol anesthesia. The instantaneous frequency in IMF1 and IMF2 identified changes in EEG characteristics during induction and emergence from general anesthesia. Moreover, the HHT_IF in IMF2 showed strong associations with BIS and was suitable for depicting the alpha oscillation. Our study suggests that the HHT is useful for monitoring the depth of anesthesia.