Minimum Alveolar Concentration Research Articles

Infant Perioperative Risk Factors and Adverse Brain Findings Following Long-Gap Esophageal Atresia Repair

Recent findings implicate brain vulnerability following long-gap esophageal atresia (LGEA) repair. We explored the relationship between easily quantifiable clinical measures and previously reported brain findings in a pilot cohort of infants following LGEA repair. MRI measures (number of qualitative brain findings; normalized brain and corpus callosum volumes) were previously reported in term-born and early-to-late premature infants (n = 13/group) <1 year following LGEA repair with the Foker process. The severity of underlying disease was classified by an (1) American Society of Anesthesiologist (ASA) physical status and (2) Pediatric Risk Assessment (PRAm) scores. Additional clinical end-point measures included: anesthesia exposure (number of events; cumulative minimal alveolar concentration (MAC) exposure in hours), length (in days) of postoperative intubated sedation, paralysis, antibiotic, steroid, and total parenteral nutrition (TPN) treatment. Associations between clinical end-point measures and brain MRI data were tested using Spearman rho and multivariable linear regression. Premature infants were more critically ill per ASA scores, which showed a positive association with the number of cranial MRI findings. Clinical end-point measures together significantly predicted the number of cranial MRI findings for both term-born and premature infant groups, but none of the individual clinical measures did on their own. Listed easily quantifiable clinical end-point measures could be used together as indirect markers in assessing the risk of brain abnormalities following LGEA repair.

Comparative Study Between Desflurane and Sevoflurane Regarding Haemodynamics and Recovery Profiles in Obese Patients Undergoing Laparoscopic Sleeve Gastrectomy

ABSTRACT Background Enhanced recovery after bariatric surgeries and resumption of complicated physiological functions are properties of ideal anaesthetic. The goal of the current study was to compare the effects of desflurane and sevoflurane on intra-operative haemodynamics and recovery profiles in obese individuals undergoing laparoscopic sleeve gastrectomy. Settings and Design Prospective randomized controlled trial. Methods After Local Ethical Committee approval, 50 obese patients, between ages 20 and 40, undergoing elective LSG were randomly assigned to receive desflurane (group D) or sevoflurane (group S). Entropy value was maintained between 40 and 60. Haemodynamic parameters including cardiac index (CI) were recorded. Minimum alveolar concentration that maintained target entropy (MACEN) values were calculated immediately after intubation and every 30 minutes until the end of procedure. After weaning from anaesthesia, time to fully awake entropy values and immediate recovery parameters were recorded. In post anaesthesia care unit (PACU), intermediate recovery was assessed using Modified Aldrete’s Score (MAS) and Digit Symbol Substitution Test (DSST).The duration of PACU stay was documented. Results Intra-operative haemodynamic parameters were comparable between two groups. The mean MACEN values for D group were significantly higher than S group immediately after intubation; however, they were significantly less than S group during the whole intra-operative period. Post-operatively, time to reach fully awake entropy values and immediate recovery parameters were shorter in group D than in group S. Desflurane anaesthetized patients had higher MAS than sevoflurane patients upon arrival at PACU and after 5 minutes. DSST restored to baseline values more quickly after desflurane anaesthesia. In comparison to group S, group D’s PACU stay was shorter. Conclusions Desflurane and sevoflurane both had similar haemodynamic parameters; however, the recovery profiles were significantly quicker after desflurane anaesthesia enabling fast-tracking and patients to be early discharged.

Accidental intrathecal injection of tranexamic acid: a case report

BackgroundTranexamic acid is a well-known antifibrinolytic medication frequently prescribed to individuals with bleeding disorders. Following accidental intrathecal injection of tranexamic acid, major morbidities and fatalities have been documented. The aim of this case report is to present a novel method for management of intrathecal injection of tranexamic acid.Case presentationIn this case report, a 400 mg intrathecal injection of tranexamic acid resulted in significant back and gluteal pain, myoclonus of the lower limbs, agitation, and widespread convulsions in a 31-year-old Egyptian male with history of left arm and right leg fracture. Immediate intravenous sedation with midazolam (5 mg) and fentanyl (50 μg) was delivered with no response in seizure termination. A 1000 mg phenytoin intravenous infusion and subsequently, induction of general anesthesia was performed by thiopental sodium (250 mg) and atracurium (50 mg) infusion, and the trachea of the patient was intubated. Maintenance of anesthesia was achieved by isoflurane 1.2 minimum alveolar concentration and atracurium 10 mg every 20 minutes, and subsequent doses of thiopental sodium (100 mg) to control seizures. The patient developed focal seizures in the hand and leg, so cerebrospinal fluid lavage was done by inserting two spinal 22-gauge Quincke tip needles, one on level L2–L3 (drainage) and the other on L4–L5. Intrathecal normal saline infusion (150 ml) was done over an hour by passive flow. After cerebrospinal fluid lavage and the patient’s stabilization was obtained, he was transferred to the intensive care unit.ConclusionsEarly and continuous intrathecal lavage with normal saline, with the airway, breathing, and circulation protocol is highly recommended to decrease morbidity and mortality. The selection of the inhalational drug as a sedative and for brain protection in the intensive care unit provided possible benefits in management of this event with medication errors.

Effect of oral administration of gabapentin on the minimum alveolar concentration of isoflurane in cats.

To determine if oral gabapentin decreases the minimum alveolar concentration (MAC) of isoflurane in cats. Prospective, randomized, blinded, crossover, and experimental study. A total of six healthy adult cats (three male, three female) aged 18-42 months, weighing 3.31 ± 0.26 kg. Cats were randomly given oral gabapentin (100 mg cat-1) or placebo 2 h before starting MAC determination, with the crossover treatment given at least 7 days apart. Anesthesia was induced and maintained with isoflurane in oxygen. Isoflurane MAC was determined in duplicate using an iterative bracketing technique and tail clamp method. Hemodynamic and other vital variables were recorded at each stable isoflurane concentration and were compared between gabapentin and placebo treatments at lowest end-tidal isoflurane concentration when cats did not respond to tail clamping. A paired t-test was used to compare normally distributed data, and a Wilcoxon signed-rank test was applied for non-normally distributed data. Significance was set at p < 0.05. Data are mean ± standard deviation. Isoflurane MAC in the gabapentin treatment was 1.02 ± 0.11%, which was significantly lower than that in the placebo treatment (1.49 ± 0.12%; p < 0.001), decreasing by 31.58 ± 6.94%. No significant differences were found in cardiovascular and other vital variables between treatments. Oral administration of gabapentin 2 h before starting MAC determination had a significant isoflurane MAC-sparing effect in cats with no observed hemodynamic benefit.

Nebulized dexmedetomidine for preventing postoperative sore throat after tracheal intubation: a randomized, double‐blind clinical trial

Background and Objective: Endotracheal intubation is part of general anesthesia, and probably the most commonly performed airway related procedure in operating rooms as well as intensive care units. It may be a causative factor in about 74% of patients who experience postoperative sore throat (POST) due to airway mucosal injury. This double-blind randomized clinical trial assessed the effectiveness of nebulized dexmedetomidine in preventing POST by comparing with a control group.&#x0D; Methodology: In this randomized, double‐blind clinical trial, we enrolled 56 patients, who were to undergo general anesthesia with endotracheal intubation. Patients were randomly divided into two groups of 28 each. Group A received dexmedetomidine nebulization, and Group B had normal saline nebulization, both for 15 min before induction. POST was assessed at 1, 2, 4, 6, 12, and 24 h after extubation using a POST scale. Data were collected and statistically analyzed&#x0D; Results: The overall incidence of POST was 60.3%: Control group experienced POST by 28 (96.6%) patients, compared to 7 (24,1%) patients in dexmedetomidine group (P = 0.0001). Differences were significant at recording times post-operatively. The dexmedetomidine group had milder sore throats, less coughing, and lower heart rates/blood pressures compared to the control group.&#x0D; Conclusion: Patients who were nebulized with dexmedetomidine, experienced lower rates and intensity of postoperative sore throat compared to the control group. Administering dexmedetomidine via nebulization before intubation can be considered a safe and effective method for reducing postoperative sore throat, with less postintubation hemodynamic derangement.&#x0D; Abbreviations: ETT: Endotracheal Tube; GA: General Anesthesia; IL: Interleukin; MAC: Minimum Alveolar Concentration; N2O: Nitic Oxide; PACU: Post Anesthesia Care Unit; PONV- Postoperative Nausea and Vomiting; POST- Postoperative Sore Throat; TNF: Tumor Necrosis Factor&#x0D; Key words: Dexmedetomidine; Endotracheal Intubation; Anaesthesia, General; Nebulization; Postoperative sore throat&#x0D; Citation: Pradian E, Kestriani SS ND, Ritonga DZ. Nebulized dexmedetomidine for preventing postoperative sore throat after tracheal intubation: a randomized, double‐blind clinical trial. Anaesth. pain intensive care 2023;27(6):737−744. DOI: 10.35975/apic.v27i6.2348&#x0D; Received: Aug 28, 2023; Revised: Oct 21, 2023; Accepted: Oct 21, 2023

γ-Aminobutyric Acid-Ergic Development Contributes to the Enhancement of Electroencephalogram Slow-Delta Oscillations Under Volatile Anesthesia in Neonatal Rats.

General anesthetics (eg, propofol and volatile anesthetics) enhance the slow-delta oscillations of the cortical electroencephalogram (EEG), which partly results from the enhancement of (γ-aminobutyric acid [GABA]) γ-aminobutyric acid-ergic (GABAergic) transmission. There is a GABAergic excitatory-inhibitory shift during postnatal development. Whether general anesthetics can enhance slow-delta oscillations in the immature brain has not yet been unequivocally determined. Perforated patch-clamp recording was used to confirm the reversal potential of GABAergic currents throughout GABAergic development in acute brain slices of neonatal rats. The power density of the electrocorticogram and the minimum alveolar concentrations (MAC) of isoflurane and/or sevoflurane were measured in P4-P21 rats. Then, the effects of bumetanide, an inhibitor of the Na+-K+-2Cl- cotransporter (NKCC1) and K+-Cl- cotransporter (KCC2) knockdown on the potency of volatile anesthetics and the power density of the EEG were determined in vivo. Reversal potential of GABAergic currents were gradually hyperpolarized from P4 to P21 in cortical pyramidal neurons. Bumetanide enhanced the hypnotic effects of volatile anesthetics at P5 (for MACLORR, isoflurane: 0.63% ± 0.07% vs 0.81% ± 0.05%, 95% confidence interval [CI], -0.257 to -0.103, P < .001; sevoflurane: 1.46% ± 0.12% vs 1.66% ± 0.09%, 95% CI, -0.319 to -0.081, P < .001); while knockdown of KCC2 weakened their hypnotic effects at P21 in rats (for MACLORR, isoflurane: 0.58% ± 0.05% to 0.77% ± 0.20%, 95% CI, 0.013-0.357, P = .003; sevoflurane: 1.17% ± 0.04% to 1.33% ± 0.04%, 95% CI, 0.078-0.244, P < .001). For cortical EEG, slow-delta oscillations were the predominant components of the EEG spectrum in neonatal rats. Isoflurane and/or sevoflurane suppressed the power density of slow-delta oscillations rather than enhancement of it until GABAergic maturity. Enhancement of slow-delta oscillations under volatile anesthetics was simulated by preinjection of bumetanide at P5 (isoflurane: slow-delta changed ratio from -0.31 ± 0.22 to 1.57 ± 1.15, 95% CI, 0.67-3.08, P = .007; sevoflurane: slow-delta changed ratio from -0.46 ± 0.25 to 0.95 ± 0.97, 95% CI, 0.38-2.45, P = .014); and suppressed by KCC2-siRNA at P21 (isoflurane: slow-delta changed ratio from 16.13 ± 5.69 to 3.98 ± 2.35, 95% CI, -18.50 to -5.80, P = .002; sevoflurane: slow-delta changed ratio from 0.13 ± 2.82 to 3.23 ± 2.49, 95% CI, 3.02-10.79, P = .003). Enhancement of cortical EEG slow-delta oscillations by volatile anesthetics may require mature GABAergic inhibitory transmission during neonatal development.

Effect on physiological parameters and anaesthetic dose requirement of isoflurane when tramadol given as a continuous rate infusion vs a single intravenous bolus injection during ovariohysterectomy in dogs.

Tramadol produces a significant reduction in both sevoflurane and isoflurane minimum alveolar concentrations in dogs under experimental conditions. This study aims to compare the effects of tramadol administered as a constant rate infusion (CRI) with those of tramadol administered as a single intravenous bolus on physiological parameters and isoflurane requirements in dogs undergoing ovariohysterectomy. In this study, forty female dogs undergoing ovariohysterectomy were enrolled. The bitches were anesthetized with 5 mg/kg of tiletamine/zolazepam combined with 0.05 mg/kg of acepromazine intravenously. Anesthesia was maintained with isoflurane delivered in 100% oxygen. The group A (n = 20) received tramadol 4 mg/kg in a single intravenous bolus, whereas the group B (n = 20) received tramadol 1.5 mg/kg in an intravenous bolus followed by tramadol 2.6 mg/kg/h as a CRI. The following parameters were recorded: heart rate, respiratory rate, non-invasive blood pressure, body temperature, EtCO2, SpO2 and inspired and expired concentrations of isoflurane. Parameter measurements were performed from pre-preedication (baseline) to skin suturing. The dogs were healthy subjects that demonstrated no abnormalities on laboratory investigations. Significant tachycardia was recorded after administration of tiletamine/zolazepam combined with acepromazine in both groups. Heart rate decreased after intubation but remained significantly higher compared to baseline values in both groups. Systolic blood pressure significantly decreased in both groups but the recorded values were within the physiological range. Mild reduction in body temperature was recorded in both groups. SpO2 and EtCO2 remained within the physiological range. Isoflurane requirement was significantly lower in the group B compared to the group A. Transient twitching was recorded in two dogs belonging to the group A after tramadol administration. Compared to tramadol given as a single intravenous bolus injection during ovariohysterectomy in dogs, tramadol administered as a CRI reduces isoflurane requirements in dogs anesthetized with tiletamine/zolazepam combined with acepromazine. Both tramadol given as a CRI and a single intravenous bolus injection, induce decrease in heart rate, respiratory rate and in body temperature but the values of these parameters remain within physiological range in dogs undergoing ovariohysterectomy.

SARS-CoV-2 parainfection associated Landry -Guillain- Barre Syndrome (LGBS) in a term pregnant women: A clinical conundrum.

Sir Guillain-Barre Syndrome (GBS) is a rare neurological disease that is characterized by progressive weakness in legs and arms, areflexia, or decreased tendon reflexes in weak limbs.[1] Evidence of GBS cases associated with SARS-CoV-2 infection has recently been reported.[2] Though GBS is considered mostly a post-infectious, immune-mediated disease, it might also occur during the infectious phase in some cases. Herein, we report first case of SARS-CoV-2 parainfection associated GBS in a term pregnant patient. A 22 year primigravida at 36 weeks of gestation, presented with acute onset of quadriparesis since 3 days and cough since 2 days. Patient c/o weakness in all four limbs, sudden onset, started distally in both lower limbs which progressed to involve upper limbs. On examination, she was tachypneic with respiratory rate of 32-34 breaths/min. She maintained saturation of 97% on ventimask at 0.4 fraction of inspired oxygen. On motor examination, in lower limb she had power of 2/5 at both ankle and knee joints. At hip joint, she had power of 1/5. In upper limb, she had power of 3/5 at both the shoulders and 4/5 at both the elbow joints. Deep tendon reflexes were absent. Her blood investigations were normal except for total serum bilirubin which was 3.2 mg/dl. She also tested SARS CoV-2 reverse transcriptase positive. Since she had no prior history of any gastrointestinal infection, she was diagnosed as SARS-CoV-2 parainfection associated Landry -Guillain- Barre Syndrome (LGBS) with respiratory involvement. In view of the worsening motor weakness and decline in respiratory functions, she was planned for urgent caesarean section. After preoxygenation, rapid sequence induction was done using thiopentone sodium and rocuronium and intubated with oral cuffed endotracheal tube with 7.0 mm internal diameter. She was ventilated using controlled mode with peak inspiratory pressure of 22 cm water, positive end expiratory pressure 5 and maintained on sevoflurane + oxygen at minimum alveolar concentration of 0.7-1. After delivery of baby, oxytocine infusion was started at 5 IU/h and injection fentanyl 50 μg was administered. Post-surgery she was shifted unreversed to COVID-19 intensive care unit (ICU). In ICU, she was administered intravenous immunoglobulins gram once a day (OD) for 4 days, low molecular weight heparin 0.6 ml OD, injection dexamethasone 6 mg twice a day, and Tablet Gabapentin 300 mg at night. Her CSF analysis showed total protein of 31.5 mg/dl and glucose levels of 68.9 mg/dL. During her ICU stay, she developed collapse and consolidation of left lung lower lobe with left sided pleural effusion, which resolved over next few days after she was tracheostomized. After 10 days of her ICU stay, she tested SARS-CoV-2 reverse transcriptase negative. Thereafter, she was shifted to non-COVID-19 ICU where she was gradually weaned from ventilatory support. Her nerve conduction study was performed which reported complete absence of compound muscle action potential (CAMP) with normal sensory nerve action potential (SNAP) suggestive of Acute Motor Axonal Polyneuropathy (AMAN) [Table 1]. She was shifted to medical ward for rehabilitative care. She was discharged from the hospital and was mobilized using wheel chair. There was complete return of motor power in upper limbs.Table 1: Nerve conduction study parameters of the patientTo the best of our knowledge, this is the first reported case of SARS-CoV-2 parainfection associated LGBS in term pregnant patient. She presented with short history of acute onset of muscle weakness accompanied by cough which gradually worsened and required assisted ventilation. As patient had already reached term, emergent caesarean section followed by management according to SARS-CoV-2 protocols was done. Guillain barre syndrome (GBS) worsens in postpartum period due to restoration of cellular immunity, with increase in delayed type of hypersensitivity which was adaptively depressed during pregnancy.[3] In an observational multicentre study, thirty GBS cases associated with COVID-19, stated COVID-19-associated GBS as being predominantly demyelinating and more severe than non-COVID-19 GBS.[4] Tekin et al.[5] have reported occurrence of LGBS in pregnant patient who had preceding SARS-CoV-2 infection. The patient developed muscle weakness in postpartum period, which recovered after receiving intravenous immunoglobulins. The prognosis of SARS-CoV-2 parainfection associated LGBS in term pregnant patient is still unclear and requires early recognition of danger signs for timely management and favorable outcome. Thus, clinical course of SARS-CoV-2 parainfection associated LGBS during pregnancy is highly complicated, due to presence of non-specific signs and symptoms and carries high risk of maternal morbidity. Early identification and multidisciplinary involvement are essential for diagnosis and good outcome. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Effects of dexmedetomidine on evoked potentials in spinal surgery under combined intravenous inhalation anesthesia: a randomized controlled trial

ObjectiveWe aimed to investigate the effects of different doses of dexmedetomidine (Dex) on evoked potentials in adult patients undergoing spinal surgery under intravenous anesthesia with low-concentration desflurane.MethodsNinety patients were divided into three groups at random. To maintain anesthesia in the control group (group C), desflurane 0.3 MAC (minimal alveolar concentration), propofol, and remifentanil were administered. Dex (0.5 μg·kg−1) was injected for 10 min as a loading dose in the low-dose Dex group (group DL), then adjusted to 0.2 μg·kg−1·h−1 until the operation was completed. Dex (1 μg·kg−1) was injected for 10 min as a loading dose in the high-dose Dex group (group DH), then adjusted to 0.7 μg·kg−1·h−1 until the operation was completed. The additional medications were similar to those given to group C. The perioperative hemodynamics, body temperature, intraoperative drug dosages, fluid volume, urine volume, blood loss, the latency and amplitude of somatosensory evoked potentials (SEPs) at four different time points, the incidence of positive cases of SEPs and transcranial motor evoked potentials (tcMEPs), and perioperative adverse reactions were all recorded.ResultsData from 79 patients were analyzed. The MAP measured at points T2-T4 in group DH was higher than at corresponding points in group C (P < 0.05). The MAP at point T4 in group DL was higher than at corresponding points in group C (P < 0.05). The remifentanil dosage in group DH was significantly lower than in group C (P = 0.015). The fluid volume in group DL was significantly lower than in group C (P = 0.009). There were no significant differences among the three groups in the amplitude and latency of SEP at different time points, nor in the incidence of warning SEP signals. The incidence of positive tcMEP signals did not differ significantly between groups C and DL (P > 0.05), but was significantly higher in group DH than in groups DL (P < 0.05) or C (P < 0.05). The incidence of intraoperative hypertension was significantly higher in group DH than in group C (P = 0.017).ConclusionsLow-dose Dex has no effect on the SEPs and tcMEPs monitoring during spinal surgery. High-dose Dex has no effect on SEPs monitoring, but it may increase the rate of false positive tcMEPs signals and the incidence of intraoperative hypertension.Trial registrationThis study has completed the registration of the Chinese Clinical Trial Center at 11/09/2020 with the registration number ChiCTR2000038154.

Effect of atracurium and rocuronium on the state and response entropy during isoflurane anesthesia: randomized prospective study

BackgroundSeveral researches have examined the impact of inhalation anesthetics, intravenous anesthetics, and muscle relaxants on spectral entropy, but many did not evaluate the extent of neuromuscular block. Besides, they did not inspect the impact of distinct degrees of neuromuscular blockade on spectral entropy under dissimilar saturations of isoflurane inhalation. Hence, this study has evaluated variant degrees of minimum alveolar concentration (MAC) to estimate the isoflurane concentration, along with various levels of neuromuscular blockade.This study aims to evaluate the effect of muscle relaxants (atracurium and rocuronium) on entropy readings (state, response entropy, and response-state difference) during isoflurane anesthesia.This is a prospective randomized study, as forty patients have been included and divided into two study groups: patients in group A received atracurium, while patients in group R received rocuronium. Under 50% and 100% neuromuscular blockage, state and response entropy were observed at MACs of 0.8% and 1%, respectively.ResultsThere was a positive correlation between state (SE) and response entropy (RE) at baseline, different MACs, and different trains of four (TOF) for both atracurium and rocuronium. State and response entropy decreased with increasing MAC of isoflurane (P < 0.001), while atracurium and rocuronium at TOF 50% and 100% showed no effect on SE, RE, or RE-SE (P > 0.05).ConclusionsState and response entropy can be used effectively to evaluate the depth of anesthesia at different isoflurane MAC and atracurium or rocuronium doses.Registration numberClinicalTrials.gov identifier: NCT 05097508, Registered October 5, 2021 (prospectively registered), http://www.ClinicalTrial.gov

A randomized crossover study of the effect of butorphanol-lidocaine and tramadol-lidocaine on sevoflurane's minimum alveolar concentration in dogs.

Inhalational anesthesia is routinely used in small animal surgery. Selecting a suitable drug combination is vital since it may negatively affect the patient's physiological condition. We conducted this study to examine the sparing effect of butorphanol-lidocaine (BUT-LID) and tramadol-lidocaine (TRM-LID) on sevoflurane's minimum alveolar concentration (MAC) in 10 healthy mongrel dogs aged 1-2 years and weighing 11.5 ± 0.8 kg (mean ± SD). Sevoflurane's MAC was measured on three separate occasions. The three dog treatment groups were control (CONT) anesthetized only with sevoflurane, TRM-LID (TRM, i.v. 1.5 mg kg-1, then 1.3 mg kg-1 h-1 and LID, i.v. 2 mg kg-1, then 3 mg kg-1 h-1) or BUT-LID treatment (BUT, i.v. 0.1 mg kg-1 then 0.2 mg kg-1 h-1 and LID, i.v. 2 mg kg-1, then 3 mg kg-1 h-1). We hypothesized that both TRM-LID and BUT-LID would result in a significant MAC sparing effect in healthy dogs. The TRM-LID treatment resulted in a non-significant MAC reduction. MAC was lowered significantly in the BUT-LID group (p = 0.009). The sevoflurane MAC-sparing effects of TRM-LID and BUT-LID treatments were 7.05 ± 22.20 and 19.90 ± 5.91%, respectively, a difference that was not statistically significant (p = 0.13). Bradycardia was observed in the TRM-LID (p < 0.001) treatment. The esophageal temperature was significantly higher for the TRM-LID treatment than the CONT (p < 0.001) treatment. No statistically significant changes were detected between the three groups in f R, Pe'CO2, and MABP. In conclusion, there was a significant sparing effect after adding BUT-LID co-infusion than the control group. No sparing effect was noticed when adding TRM-LID co-infusion. However, no difference in the MAC sparing percentages between the TRM-LID and BUT-LID treatments. The BUT-LID co-infusion resulted in a sevoflurane MAC reduction superior to TRM-LID in addition to minimal cardiorespiratory changes. Both BUT-LID and TRM-LID may be clinically beneficial to dogs during anesthesia. However, BUT-LID produced higher sparing effect and reduction of sevoflurane MAC value.

Impact of Dexmedetomidine Infusion during Functional Endoscopic Sinus Surgery: A Randomised Controlled Trial

Introduction: Functional Endoscopic Sinus Surgery (FESS) requires a surgical field with minimal bleeding, and numerous pharmacological agents have been used to achieve this. Dexmedetomidine has been widely used as a sedative, analgesic, and as a supplement to general anaesthesia. It has been found to decrease norepinephrine release, thereby decreasing heart rate (HR) and blood pressure. These properties, along with its opioid-sparing analgesic effects, make it an attractive drug to use during FESS. Aim: The aim of this study was to determine if dexmedetomidine infusion during FESS improves the visibility of the surgical field, provides stable haemodynamics, and alters the consumption of sevoflurane and other anaesthetic agents. Materials and Methods: This randomised, double-blinded controlled trial was conducted at the Otorhinolaryngology Operation Theatre, BYL Nair Charitable Hospital, Mumbai, India, from July 2018 to December 2019. The study included 100 patients of either sex, with American Society of Anaesthesiologists (ASA) I and II classification, aged 18-55 years, who were randomly divided into two groups. Group D received a dexmedetomidine infusion (0.5 mcg/kg/hour), while group C (control group) received a saline infusion. Haemodynamic parameters, Minimum Alveolar Concentration (MAC) of sevoflurane, surgeon’s grading of the operative field, and the requirement of additional hypotensive agents were compared. Statistical analysis was performed using Student’s unpaired t-test to evaluate the significance of normally distributed variables, Mann-Whitney U test and Chi-square test for ordinal data and categorical variables. Results: The groups were comparable with respect to age, weight, gender, and ASA grade. The average mean MAC of sevoflurane at various time intervals was 1.135±0.664635 in group D and 1.9675±0.438 in group C, which was statistically significant. The surgeon’s grading of the surgical field using the Fromme and Boezaart scale was significantly better in group D (1.53±0.45625 versus 2.907±0.5835 in the control group). Although not statistically significant, more number of patients in group C needed additional drugs to lower HR and blood pressure. Conclusion: Dexmedetomidine infusion during FESS is effective in maintaining stable haemodynamics with a lesser need for additional agents to lower HR and Mean Arterial Pressure (MAP). It improves the visibility of the surgical field and decreases the MAC of sevoflurane required to maintain anaesthesia.

Comparison of Recovery Profile and Cost-effectiveness of Sevoflurane and Desflurane using Low Flow Anaesthesia in Adults: A Randomised Clinical Study

Introduction: Newer inhalational agents, like sevoflurane and desflurane, offer advantages of rapid induction and early recovery due to their low blood gas solubility. However, cost remains a major drawback of these agents, despite the reduction in agent consumption achieved through low flow anaesthesia. Aim: To evaluate the recovery profile and cost-effectiveness of sevoflurane and desflurane using low flow anaesthesia in adults. Materials and Methods: A randomised clinical study was conducted at, Department of Anaesthesia, Bharati Vidyapeeth Medical College, Pune, Maharashtra, India, during October 2019 to August 2021, with 60 patients classified as American Society of Anaesthesiologists (ASA) I or II, aged 18-65 years, undergoing elective surgeries lasting 1-4 hours under general anaesthesia with the low flow technique. Group S received sevoflurane, while group D received desflurane. Anaesthesia was maintained using a 50/50 mixture of oxygen/air and either sevoflurane or desflurane, depending on the group. The inhalational agents were titrated intraoperatively to achieve a Minimum Alveolar Concentration (MAC) of approximately one. The amount of inhalational agent consumed was calculated, and recovery profiles were studied. The means of continuous variables were compared using an Independent sample t-test, with p-values &lt;0.05 considered significant. Results: In Groups S and D, the mean ages were 39.17 years and 41.5 years, and the percentages of males were 30% and 50%, respectively. The mean times to swallowing, spontaneous eye opening, limb movements, establishing spontaneous regular breathing, responding to verbal commands, extubation, stating a name on command, and achieving a modified Aldrete score ≥9 in minutes were 6.13, 4.87, 5.07, 4.57, 7.40, 8.97, 10.40, and 11.50, respectively. These values were significantly lower in group D. The mean cost per hour and average volume consumption were significantly higher in group D. Conclusion: The study concludes that desflurane provides faster and better recovery from anaesthesia. Although the total cost of desflurane was higher compared to sevoflurane, its use can be beneficial for faster emergence, early transfer from the Post Anaesthesia Care Unit (PACU), and earlier discharge from the hospital.

Comparison between the effect of bispectral index and minimum alveolar concentration monitoring on recovery after general anesthesia: a prospective, randomized, clinical study

Comparison between the effect of bispectral index and minimum alveolar concentration monitoring on recovery after general anesthesia: a prospective, randomized, clinical study

COMPARISON BETWEEN TOTAL INTRAVENOUS ANESTHESIA (TIVA) WITH PROPOFOL – FENTANYL AND BALANCED ANESTHESIA WITH SEVOFLURANE – FENTANYL IN TERMS OF HEMODYNAMIC CHANGES AND RECOVERY PROFILES DURING LAPAROSCOPIC CHOLECYSTECTOMY

Background: Sevoflurane and propofol are considered to be the agents of choice in laparoscopic surgery due to their smooth induction of anesthesia, hemodynamic stability, better recovery profile and less postoperative complications. The aim of study is to compare hemodynamic changes and recovery profile of propofol with sevoflurane-based anesthesia in laparoscopic cholecystectomy. Methods: Single blind comparative study was conducted among 132 patients aged 18-65 years, ASA-PS I &amp; II undergoing laparoscopic cholecystectomy, randomized by computer generated random number table into two groups, 66 patients each- Group A patients induced with propofol 1.5-2.5 mg/kg IV and maintained with propofol 100-200 mcg/kg/min IV and Group B induced with sevoflurane and maintained with sevoflurane at minimum alveolar concentration of 0.7-1.3. Primary outcome were hemodynamic parameters (heart rate, systolic and diastolic blood pressure, mean arterial pressure) and recovery profile. Results: Intraoperative heart rate and diastolic blood pressure were comparable between two groups at all times while there was a significantly lower systolic blood pressure only at 3 and 5 minutes after intubation in group B compared to group A (p &lt; 0.05). Recovery profiles assessed in terms of time of eye opening (657.89 ± 172.30 s vs 453.58 ± 157.49 s), obeying command (696.79 ± 192.44s vs 481.06±164.96s), and time of extubation (706.41±166.27s vs 483.38±160.62s) were significantly faster in group B (p value &lt; 0.001). Conclusions: Hemodynamic changes were comparable between propofol group and sevoflurane group while sevoflurane group had faster recovery.

ОЦЕНКА АДЕКВАТНОСТИ ГЛУБИНЫ АНЕСТЕЗИИ ПРИ ИСПОЛЬЗОВАНИИ БИСПЕКТРАЛЬНОГО ИНДЕКСА

Purpose of the study: based on the analysis of the bispectral index (BIS-index), to assess the adequacy of the depth of anesthesia in patients with oncological profile. Material and methods. An analysis of BIS-monitoring was carried out during 77 surgical interventions in patients of the oncosurgical profile of the Grodno University Clinic. Results. 30 minutes after the start of surgery, a decrease in the concentration of Sevorane in the inhaled mixture to 0.8-0.6 vol% lead to a significant decrease in the minimum alveolar concentration (MAC) of the anesthetic. However, at the same time, the BIS-index during the operation did not go beyond the limits of acceptable values. There was a decrease in the BIS-index (p&lt;0.05) only during induction anesthesia and during the formation of anesthesia in the first minutes of surgery (57.87 and 47.65 units). Conclusions. With a decrease in the concentration of inhalation anesthetic in the inhaled air to 0.8-0.6 vol% and, consequently, MAC to 0.6-0.7, no statistically significant differences were found in the increase in the BIS-index and in the decrease in the depth of anesthesia.

The effect of remifentanil infusion on sevoflurane minimum alveolar concentration–no movement (MACNM) and bispectral index in dogs

ObjectiveTo determine the effect of remifentanil infusion on the minimum alveolar concentration of sevoflurane preventing movement (SEVOMACNM) and bispectral index (BIS) in dogs. Study designProspective, unmasked study. AnimalsA total of 10 adult Beagle dogs weighing 9.0 ± 1.1 kg. MethodsDogs were anesthetized with sevoflurane and baseline SEVOMACNM was determined. Remifentanil was infused at 5, 10 and 20 μg kg–1 hour–1, in sequence, with 20 minutes washout between infusions. Variables monitored throughout anesthesia included heart rate (HR), oscillometric blood pressure, end-tidal partial pressure of carbon dioxide, end-tidal sevoflurane concentration (Fe′Sevo) and BIS. SEVOMACNM after remifentanil infusion (SEVOMACNM-REMI) determination started 20 minutes after the start of each infusion. Venous blood samples were collected for plasma remifentanil concentration determination at baseline, SEVOMACNM-REMI determination time points, and 20 minutes after each infusion was stopped. A mixed model analysis was used to determine the effect of remifentanil infusion on response variables. The relationships between BIS and Fe′Sevo, plasma remifentanil concentrations and the percentage decrease in baseline SEVOMACNM were evaluated (p < 0.05). ResultsThe overall SEVOMACNM at baseline was 2.47 ± 0.11%. Addition of remifentanil at all infusion rates significantly decreased SEVOMACNM, but the medium and high doses resulted in significantly greater decreases in SEVOMACNM than the lower dose. There was no difference in SEVOMACNM percentage change between infusions 10 and 20 μg kg–1 hour–1. Plasma remifentanil concentrations were significantly different in all infusion rates. Baseline BIS value was 70 ± 1 and was lower than the BIS values recorded during all remifentanil infusions. BIS values were not significantly different among infusion rates. HR was lower and mean arterial pressure was higher during remifentanil infusions than at baseline. Conclusions and clinical relevanceAll remifentanil infusions decreased SEVOMACNM in dogs. Remifentanil infusion at any rate studied did not reduce BIS values.

Developments in buffalo anaesthesia with special reference to diaphragmatic herniorrhaphy

Ruminants are poor subject for general anaesthesia. Diaphragmatic hernia (DH) is a common digestive disorder in buffaloes requiring balanced general anaesthesia for surgical repair. For premedication, initially, a combination of phenothiazine/chloralhydrate was used which was later replaced by alpha2 agonist like xylazine. Anticholinergics like atropine or glycopyrrolate were included in balanced anaesthetic protocols to reduce cardiac depression by alpha2 agonists. Thiobarbiturates historically were used for induction and maintenance but late recovery and cardiorepiratory depression lead to switch over to propofol. Maintenance of anaesthesia by top-up or continuous rate infusion (CRI) of propofol was not economical. The inclusion of opioids like butorphanol improved the analgesia as well as has dose sparing effect on induction and maintenance agent. The introduction of inhalants for maintenance significantly improved outcomes with the ease of change of depth of anaesthesia. It has also been observed that adrenocortical suppression by etomidate and mechanical intermittent positive pressure ventilation (IPPV) resulted in poor outcomes whereas maintaining the homeostasis and functional adreno-cortical axis of buffaloes under anaesthesia improves the success rate of DH surgeries. The balanced anaesthetic combination of Atropine/xylazine/ butorphanol/propofol/isoflurane has been found to be most satisfactory till date in buffaloes undergoing DH surgery. The studies on muscle relaxants, blood gas analysis and end tidal carbon dioxide (EtCO2) in buffaloes are scarce. Moreover, many drugs have been used in combinations in clinical cases on the basis of extrapolation from other species; but in buffaloes the effect of individual drug (like dose sparing effect of analgesics, minimum alveolar concentration (MAC) of inhalants) has to be still studied.

Development of NMDA receptors contributes to the enhancement of electroencephalogram oscillations under volatile anesthetics in rats.

Volatile anesthetics including sevoflurane and isoflurane enhance oscillations of cortical electroencephalogram (EEG), partly by their modulations on glutamate-mediated excitatory synaptic transmission. Expression of NMDA receptors is increased during neonatal development. However, how the development of NMDA receptors influences EEG under volatile anesthesia remains unclear. Expressions of NMDA receptor subtypes (NR1, NR2A, and NR2B) during neonatal development were measured by Western blotting. MAC (minimal alveolar concentration) of isoflurane and sevoflurane that inducing loss of righting reflex (LORR) and no response to tail-clamp (immobility) were measured to verify the effect of NR1 expression on anesthetic potency during neonatal development. Cortical electroencephalogram recording was used to examine the influence of NR1 expression on the power density of EEG. The expressions of GluNR1, GluNR2A and GluNR2B receptors were gradually increased during neonatal development in cortex, hippocampus and thalamus of rats. Knockdown of NR1 enhanced the sedative potency of volatile anesthetics but not on immobility potency in postnatal day 14 (P14)-P17 rats. For cortical EEG, along with the increased concentration of volatile anesthetics, cortical slow-delta oscillations of P5 rats were inhibited, theta and alpha oscillations were not changed significantly; while these oscillations were enhanced until high anesthetic concentrations in P21 rats. Knockdown of NR1 in forebrain suppressed the enhancement of cortical EEG oscillations in P21 rats. The development of NMDA receptors may contribute to the enhancement of cortical EEG oscillations under volatile anesthetics.

Incidence of the Oculocardiac Reflex using Isoflurane &amp; Halothane during Enucleation Surgery under General Anaesthesia at NIO&amp;H - A Comparative Study

Background: The Oculocardiac reflex (OCR) is a well-known complication of ocular surgery involving direct or indirect manipulation of the eye or ocular adnexa. While most commonly associated with eye muscle surgery, with a reported incidence of 40-93%, it is prevalent during traction on the extraocular or eyelid muscles, compression of the globe, intraocular and retro bulbar injection, iris traction, retinal reattachment surgery and enucleation procedures and may manifest as a wide range of arrhythmias including ventricular bigeminy, bradycardia and asystole. Occurrence of the reflex in eye muscle surgery has been documented to increase with hypoxia and decrease with aging and premedication with anticholinergics, namely glycopyrrolate or atropine.&#x0D; Objective: The purpose of our study was to determine the degree of change in heart rate (HR) and systolic blood pressure (SBP) during Enucleation surgery in patients anaesthetized with equipotent concentrations of Isoflurane or Halothane breathing via a laryngeal mask airway (LMA).&#x0D; Methods: The study was designed as a prospective randomizedstudy. Fifty patients, having selected for Enucleation were randomized to Isoflurane (I) or halothane (H) in 66% nitrous oxide at 1.3 minimum alveolar concentration. Patients breathed through a laryngeal mask airway (LMA) and were not pretreated with anticholinergics.&#x0D; Results: The Oculocardiac reflex (OCR), defined as a 20% decrease in heart rate (HR) from baseline, dysrhythmias or sinoatrial arrest concomitant with ocular muscle traction occurred less frequently with Isoflurane than with halothane (I: 37%, H:78%, P = 0.009). The HR during induction was higher with Isoflurane (I: 110 ± 13 bpm, H: 100 ± 15 bpm, P = 0.002). The lowest HR occurred with halothane (I: 94 ± 22 bpm, H: 72 ± 19 bpm, P = 0.001). The incidence of dysrhythmias was higher in the halothane group (I 4%, H: 42%, P = 0.004). Isoflurane may be a more suitable anaesthetic than halothane for operations involving traction on the ocular muscles with controlled respiration in patients because of reduced incidence of OCR with slightly higher airway irritability.&#x0D; Conclusion: Some patients experience a sudden slowing of the heart when the surgeon pulls on the eye muscles during Enucleation operations under anaesthesia. We found that Isoflurane was associated with a lower incidence of the OCR but relatively higher airway irritability compared with halothane. The oculocardiac reflex possesses the potential for significant morbidity and mortality. While some have documented factors affecting the OCR during eye muscle surgery, our data could not prove such a relationship during enucleation.&#x0D; J. Natl. Inst. Ophthalmol. 2022;5(1):21-26