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Simple Summary: This study investigated the application of frontal electroencephalography (EEG) to monitor isoflurane anesthesia in dogs. By varying anesthetic levels from deep to light planes, we observed distinct changes in EEG waveforms. At deep anesthesia (2–2.5× MAC-minimum alveolar concentration), EEG patterns were predominantly isoelectric with rare intermittent bursts. The dog was unresponsive to electrical stimulation, indicating complete unconsciousness. As anesthesia lightened (1–1.5× MAC), EEG patterns transitioned to alpha and beta dominance with occasional burst suppression. Responsiveness to electrical stimulation signified the recovery of consciousness. At light anesthesia (0.75× MAC) and recovery, EEG amplitudes decreased, and the frequency increased. This study found a stronger correlation between mean arterial blood pressure and the patient state index, a processed EEG parameter, compared to heart rate. These findings suggest that EEG is a valuable tool for the real-time monitoring and management of isoflurane anesthesia levels in dogs. This study investigated the use of frontal electroencephalography (EEG) to monitor varying levels of isoflurane anesthesia in dogs. The patient state index (PSI), burst suppression ratio (SR), and waveforms, were continuously recorded while mean arterial blood pressure (MBP), heart rate, responses to electric stimuli, and subjective anesthetic "depth" were assessed every 3 min. At deep anesthesia (2.5× MAC − 3.2%), the PSI (6.5 ± 10.8) and MBP (45.6 ± 16.4 mmHg) were the lowest, and SR was the highest (78.3 ± 24.0%). At 1× MAC (1.3%), the PSI and MBP increased significantly to 47.8 ± 12.6 and 99.8 ± 13.2, respectively, and SR decreased to 0.5 ± 2.5%. The EEG was predominantly isoelectric at 2×–2.5× MAC, indicating unconsciousness and unresponsiveness. As anesthesia lightened, waveforms transitioned to flatter and faster activity patterns with a response to noxious stimuli, suggesting regained consciousness. The PSI and MBP exhibited a stronger correlation (ρ = 0.8098, p = 0.001) than the relationship of PSI with heart rate (ρ = −0.2089, p = 0.249). Five of the six dogs experienced rough recovery, possibly due to high SR and low MBP. These findings suggest that EEG monitoring in dogs can be a valuable tool for the real-time tracking of brain states and can be used to guide the management of isoflurane anesthesia. [ABSTRACT FROM AUTHOR]

PingPing Jiang,1,* JingTao Tang,2,* Min Zhang,3 Dan Wang1 1Department of Anesthesia, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, People’s Republic of China; 2Department of Anesthesia, The Second People’s hospital of Neijiang, Neijiang, Sichuan, People’s Republic of China; 3Department of Clinical Medicine, North Sichuan Medical College, Nanchong, Sichuan, People’s Republic of China*These authors contributed equally to this workCorrespondence: PingPing Jiang, Department of Anesthesia, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, 637000, People’s Republic of China, Tel +86 15881496034, Email 307174907@qq.comPurpose: This study aimed to observe the effect of bilateral transverse abdominis plane (TAP) block on the MACBAR of sevoflurane in gynecological patients with laparoscopic pneumoperitoneal stimulation.Patients and Methods: Fifty patients who underwent laparoscopic surgery were randomly assigned to either the control group (n= 25) or the TAP block group (n= 25). Patients in the TAP block group were subjected to a bilateral transversal abdominal muscle plane block with 0.33% ropivacaine (20 mL on each side) guided by ultrasound. The control group received an equal volume of normal saline. The MACBAR of sevoflurane in each group was determined using a sequential allocation technique.Results: The MACBAR of sevoflurane in the TAP block group was significantly lower than that in the control group (4.20% [95% confidence interval {CI}, 4.02%– 4.38%] vs 5.03% [95% CI, 4.89%– 5.18%]).Conclusion: Bilateral TAP block can reduce the MACBAR of sevoflurane in gynecological patients with pneumoperitoneum stimulation.Trial Registration Number: ChiCTR2100046517. The trial is publicly available and registered at www.chictr.org.cn on May 18, 2021.Keywords: Transverse abdominis plane block, Adrenergic response, Minimum alveolar concentration, Pneumoperitoneum stimulation, Sevoflurane

Purpose: This study aimed to observe the effect of bilateral transverse abdominis plane (TAP) block on the MACBAR of sevoflurane in gynecological patients with laparoscopic pneumoperitoneal stimulation. Patients and Methods: Fifty patients who underwent laparoscopic surgery were randomly assigned to either the control group (n= 25) or the TAP block group (n= 25). Patients in the TAP block group were subjected to a bilateral transversal abdominal muscle plane block with 0.33% ropivacaine (20 mL on each side) guided by ultrasound. The control group received an equal volume of normal saline. The MACBAR of sevoflurane in each group was determined using a sequential allocation technique. Results: The MACBAR of sevoflurane in the TAP block group was significantly lower than that in the control group (4.20% [95% confidence interval {CI}, 4.02%– 4.38%] vs 5.03% [95% CI, 4.89%– 5.18%]). Conclusion: Bilateral TAP block can reduce the MACBAR of sevoflurane in gynecological patients with pneumoperitoneum stimulation. Trial Registration Number: ChiCTR2100046517. The trial is publicly available and registered at www.chictr.org.cn on May 18, 2021. [ABSTRACT FROM AUTHOR]

To investigate the effect of three different doses of oral pregabalin on minimum alveolar concentration of isoflurane (MAC ISO) in cats. Prospective, randomized, placebo-controlled, blinded, crossover trial. A group of eight healthy adult cats aged 24–48 months. Cats were randomly assigned to three oral doses of pregabalin (low dose: 2.5 mg kg–1, medium dose: 5 mg kg–1, high dose: 10 mg kg–1) or placebo 2 hours before MAC ISO determination, with the multiple treatments administered with a minimum 7 day washout period. Anesthesia was induced and maintained with isoflurane in oxygen until endotracheal intubation was achieved, and maintained with isoflurane with volume-controlled ventilation. MAC ISO was determined in triplicate using the bracketing technique and tail clamp method 120 minutes after pregabalin or placebo administration. Physiologic variables (including heart rate and blood pressure) recorded during MAC ISO determination were averaged and compared between the pregabalin and placebo treatments. One-way analysis of variance and the Friedman test were used to assess the difference for normally and non-normally distributed data, respectively. The Tukey test was used as a post hoc analysis. Values of p < 0.05 were considered significant. The MAC ISO with the medium- and high-dose pregabalin treatments were 1.33 ± 0.21% and 1.23 ± 0.17%, respectively. These were significantly lower than MAC ISO after placebo treatment (1.62 ± 0.13%; p = 0.014, p < 0.001, respectively), representing a decrease of 18 ± 9% and 24 ± 6%. The mean plasma pregabalin concentration was negatively correlated with MAC ISO values. Physiologic variables did not differ significantly between treatments. Doses of 5 or 10 mg kg–1 pregabalin, administered orally 2 hours before determining MAC ISO , had a significant isoflurane-sparing effect in cats. [ABSTRACT FROM AUTHOR]

Abstract Background Remimazolam is a novel ultrashort-acting intravenous benzodiazepine sedative-hypnotic. The combination of remimazolam and sevoflurane does not increase respiratory sensitivity, produce bronchospasm, or cause other adverse conditions. We aimed to observe the effects of different remimazolam doses on the minimum alveolar concentration (MAC) of sevoflurane at end-expiration during laryngeal mask insertion and evaluate the effect of sex on the efficacy of the combination of remimazolam on the suppression of laryngeal mask insertion in adult patients. Methods We included 240 patients undergoing laparoscopic surgery under general anesthesia with elective placement of a laryngeal mask (120 males and 120 females). The patients were randomly divided into four groups according to sex: a control group (randomization for female patients, RF0; randomization for male patients, RM0) and three remimazolam groups (RF1, RM1 / RM2, RF2 / RM3, RF3), with 30 patients in each group. Induction was established by vital capacity rapid inhalation induction (VCRII), using 8% sevoflurane and 100% oxygen (6 L/min) in all patients. The (RF1, RM1), (RM2, RF2), and (RM3, RF3) groups were continuously injected with remimazolam at doses of 1, 1.5, and 2.0 mg/kg/h, respectively, while the (RM0, RF0) group was injected with an equal volume of normal saline. The end-expiratory concentration of sevoflurane was adjusted to a preset value after the patient’s eyelash reflex disappeared. After the end-expiratory concentration of sevoflurane was kept stable for at least 15 min, the laryngeal mask was placed, and the patient’s physical response to the mask placement was observed immediately and within 30 s of placement. The MAC of sevoflurane was measured using the up-and-down sequential method of Dixon. Results The calculated MAC of end-expiratory sevoflurane during laryngeal mask insertion in adult females was (2.94 ± 0.18)%, (2.69 ± 0.16)%, (2.32 ± 0.16)% and (1.83 ± 0.15)% in groups RF0, RF1, RF2 and RF3; (2.98 ± 0.18)%, (2.80 ± 0.19)%, (2.54 ± 0.15)% and (2.15 ± 0.15)% in male groups RM0, RM1, RM2 and RM3, respectively. The MAC values were significantly lower in the (RF1-RF3, RM1-RM3) group when compared to the (RF0, RM0) group. There was no significant difference between (RF0, RF1) and (RM0, RM1), but the MAC value of the RF2-RF3 group was significantly lower than that of the RM2-RM3 group. Conclusions Remimazolam can effectively reduce end-expiratory sevoflurane MAC values during laryngeal mask placement in adults. When remimazolam was measured above 1.5 mg/kg/h, the effect of inhibiting laryngeal mask implantation in female patients was stronger than that in male patients. Remimazolam at a dose of 1–2 mg/kg/h combined with sevoflurane induction can be safely and effectively used in these patients.

Background: Remimazolam is a novel ultrashort-acting intravenous benzodiazepine sedative-hypnotic. The combination of remimazolam and sevoflurane does not increase respiratory sensitivity, produce bronchospasm, or cause other adverse conditions. We aimed to observe the effects of different remimazolam doses on the minimum alveolar concentration (MAC) of sevoflurane at end-expiration during laryngeal mask insertion and evaluate the effect of sex on the efficacy of the combination of remimazolam on the suppression of laryngeal mask insertion in adult patients. Methods: We included 240 patients undergoing laparoscopic surgery under general anesthesia with elective placement of a laryngeal mask (120 males and 120 females). The patients were randomly divided into four groups according to sex: a control group (randomization for female patients, RF0; randomization for male patients, RM0) and three remimazolam groups (RF1, RM1 / RM2, RF2 / RM3, RF3), with 30 patients in each group. Induction was established by vital capacity rapid inhalation induction (VCRII), using 8% sevoflurane and 100% oxygen (6 L/min) in all patients. The (RF1, RM1), (RM2, RF2), and (RM3, RF3) groups were continuously injected with remimazolam at doses of 1, 1.5, and 2.0 mg/kg/h, respectively, while the (RM0, RF0) group was injected with an equal volume of normal saline. The end-expiratory concentration of sevoflurane was adjusted to a preset value after the patient's eyelash reflex disappeared. After the end-expiratory concentration of sevoflurane was kept stable for at least 15 min, the laryngeal mask was placed, and the patient's physical response to the mask placement was observed immediately and within 30 s of placement. The MAC of sevoflurane was measured using the up-and-down sequential method of Dixon. Results: The calculated MAC of end-expiratory sevoflurane during laryngeal mask insertion in adult females was (2.94 ± 0.18)%, (2.69 ± 0.16)%, (2.32 ± 0.16)% and (1.83 ± 0.15)% in groups RF0, RF1, RF2 and RF3; (2.98 ± 0.18)%, (2.80 ± 0.19)%, (2.54 ± 0.15)% and (2.15 ± 0.15)% in male groups RM0, RM1, RM2 and RM3, respectively. The MAC values were significantly lower in the (RF1-RF3, RM1-RM3) group when compared to the (RF0, RM0) group. There was no significant difference between (RF0, RF1) and (RM0, RM1), but the MAC value of the RF2-RF3 group was significantly lower than that of the RM2-RM3 group. Conclusions: Remimazolam can effectively reduce end-expiratory sevoflurane MAC values during laryngeal mask placement in adults. When remimazolam was measured above 1.5 mg/kg/h, the effect of inhibiting laryngeal mask implantation in female patients was stronger than that in male patients. Remimazolam at a dose of 1–2 mg/kg/h combined with sevoflurane induction can be safely and effectively used in these patients. [ABSTRACT FROM AUTHOR]

BackgroundIn the era of enhanced recovery after surgery, there is significant discussion regarding the impact of intraoperative anesthetic management on short-term outcomes following liver transplantation (LT), with no clear consensus in the literature.ObjectivesTo identify whether or not intraoperative anesthetic management affects short-term outcomes after liver transplantation.Data sourcesOvid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central.MethodsA systematic review following PRISMA guidelines was undertaken. The systematic review was registered on PROSPERO (CRD42021239758). An international expert panel made recommendations for clinical practice using the GRADE approach.ResultsAfter screening, 14 studies were eligible for inclusion in this systematic review. Six were prospective randomized clinical trials, three were prospective nonrandomized clinical trials, and five were retrospective studies. These manuscripts were reviewed to look at five questions regarding anesthetic care and its impact on short term outcomes following liver transplant. After review of the literature, the quality of evidence according to the following outcomes was as follows: intraoperative and postoperative morbidity and mortality (low), early allograft dysfunction (low), and hospital and ICU length of stay (moderate).ConclusionsFor optimal short term outcomes after liver transplantation, the panel recommends the use of volatile anesthetics in preference to total intravenous anesthesia (TIVA) (Level of Evidence: Very low; Strength of Recommendation: Weak) and minimum alveolar concentration (MAC) versus bispectral index (BIS) for depth of anesthesia monitoring (Level of Evidence: Very low; Strength of Recommendation: Weak). Regarding ventilation and oxygenation, the panel recommends a restrictive oxygenation strategy targeting a PaO2 of 70-120 mmHg (10-14 kPa), a tidal volume of 6-8 ml/kg ideal body weight (IBW), administration of positive end expiratory pressure (PEEP) tailored to patient intraoperative physiology, and recruitment maneuvers. (Level of evidence: Very low; Strength of Recommendation: Strong). Finally, the panel recommends the routine use of antiemetic prophylaxis. (Level of evidence: low; Strength of Recommendation: Strong).

This study investigated the use of frontal electroencephalography (EEG) to monitor varying levels of isoflurane anesthesia in dogs. The patient state index (PSI), burst suppression ratio (SR), and waveforms, were continuously recorded while mean arterial blood pressure (MBP), heart rate, responses to electric stimuli, and subjective anesthetic “depth” were assessed every 3 min. At deep anesthesia (2.5× MAC − 3.2%), the PSI (6.5 ± 10.8) and MBP (45.6 ± 16.4 mmHg) were the lowest, and SR was the highest (78.3 ± 24.0%). At 1× MAC (1.3%), the PSI and MBP increased significantly to 47.8 ± 12.6 and 99.8 ± 13.2, respectively, and SR decreased to 0.5 ± 2.5%. The EEG was predominantly isoelectric at 2×–2.5× MAC, indicating unconsciousness and unresponsiveness. As anesthesia lightened, waveforms transitioned to flatter and faster activity patterns with a response to noxious stimuli, suggesting regained consciousness. The PSI and MBP exhibited a stronger correlation (ρ = 0.8098, p = 0.001) than the relationship of PSI with heart rate (ρ = −0.2089, p = 0.249). Five of the six dogs experienced rough recovery, possibly due to high SR and low MBP. These findings suggest that EEG monitoring in dogs can be a valuable tool for the real-time tracking of brain states and can be used to guide the management of isoflurane anesthesia.

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.

Abstract Background Low 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 presentation A 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. Conclusions This 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.

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. [ABSTRACT FROM AUTHOR]

Introduction: Early extubation and fast recovery are important to increase the efficiency of health care services, reduce morbidity, and reduce the burden of health care costs. This study was conducted to investigate the effect of bispectral index (BIS) monitoring compared to the minimum alveolar anesthetic concentration (MAC) monitoring on recovery of patients undergoing isoflurane-based general anesthesia. Materials and Methods: A total of 62 patients were randomly allocated to group B (BIS-guided) and group M (MAC-guided). Along with clinical hemodynamic monitoring for titration of isoflurane in group B, BIS was monitored and maintained between 40 and 60, whereas in group M, MAC was maintained between 0.7 and 1.3. The recovery profile was studied in terms of time to eye-opening, time to extubation, and time to achieve the modified Aldrete score ≥9 in both groups. Patients were followed up for any postoperative side effects and awareness during general anesthesia. Results: Group B and group M were comparable with respect to age, gender, duration of surgery, duration of anesthesia, and type of surgery. Median time to eye-opening was 4 min in group B and 5 min in group M (P < 0.001). The time to extubation was 8 min in group B, compared to 11 min in group M (P < 0.001). Furthermore, the time needed to achieve the modified Aldrete’s score of ≥9 was also shorter in group B (P < 0.001). No patients reported awareness during anesthesia. Conclusion: The use of BIS monitoring hastens the extubation and recovery in patients undergoing general anesthesia.

Background: Low 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 presentation: A 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. Conclusions: This 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. [ABSTRACT FROM AUTHOR]

To determine the effect of remifentanil infusion on the minimum alveolar concentration of sevoflurane preventing movement (SEVOMAC NM) and bispectral index (BIS) in dogs. Prospective, unmasked study. A total of 10 adult Beagle dogs weighing 9.0 ± 1.1 kg. Dogs were anesthetized with sevoflurane and baseline SEVOMAC NM 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 (F e′ Sevo) and BIS. SEVOMAC NM after remifentanil infusion (SEVOMAC NM-REMI) determination started 20 minutes after the start of each infusion. Venous blood samples were collected for plasma remifentanil concentration determination at baseline, SEVOMAC NM-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 F e′ Sevo, plasma remifentanil concentrations and the percentage decrease in baseline SEVOMAC NM were evaluated (p < 0.05). The overall SEVOMAC NM at baseline was 2.47 ± 0.11%. Addition of remifentanil at all infusion rates significantly decreased SEVOMAC NM , but the medium and high doses resulted in significantly greater decreases in SEVOMAC NM than the lower dose. There was no difference in SEVOMAC NM 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. All remifentanil infusions decreased SEVOMAC NM in dogs. Remifentanil infusion at any rate studied did not reduce BIS values. [ABSTRACT FROM AUTHOR]

Key goals for the maintenance phase of general anaesthesia are the provision of surgical anaesthesia while maintaining physiological parameters at levels that preserve organ function and avoid injury. Maintenance can be achieved with either inhaled or intravenous anaesthetic agents. A good understanding of the physiochemical properties of these agents is necessary for effective manipulation of depth of anaesthesia at any stage. Drugs suitable for total intravenous anaesthesia are mainly those with short context-sensitive half-times, such as propofol, remifentanil, and dexmedetomidine. Target-controlled infusion pumps utilize three compartment models in complex calculations to achieve the desired effect-site concentration. Monitoring during anaesthesia has been proven to reduce risk in the perioperative period. Sustained vigilance and good exchange of information at handover between anaesthetists are other essential aspects of safe anaesthesia during the maintenance phase. [ABSTRACT FROM AUTHOR]

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 fR, 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.

Introduction: The bispectral index monitors the unawareness component of balanced anaesthesia and gives us the depth of Anesthesia.It reflects the response of the brain to a variety of hypnotic and inhaled anaesthesia agents. The aim of this study was to see the effect of different MAC values of isoflurane on the bispectral index and hemodynamic variations at different MAC values. Materials and methods: This prospective study was conducted on 20 patients at tertiary care center for 6 months. After induction of Anesthesia, following parameters were recorded: noninvasive blood pressure measurement, heart rate, oxygen saturation, ETCo2 and BIS values. The BIS was continuously monitored and when the MAC values of isoflurane were 0.5, 0.7, 1, 1.2 and 1.5 corresponding BIS values and all the other haemodynamic parameters were noted. Results: In 11 patients out of 20 patients satisfactory BIS of 40-60 was achieved at MAC 0.5. In 16 out of 20 patients satisfactory BIS 40-60 was achieved at 0.7 MAC. In all the 20 patients satisfactory BIS was achieved at 1 MAC.In 2 out of 20 patients we couldn’t proceed beyond 1.0 MAC because of the fall in MAP to <65mm of Hg. In 4 out of 20 patients we couldn’t proceed beyond 1.2MAC because of the fall in MAP to <65mm of Hg. Conclusion: Isoflurane produced satisfactory BIS of 40-60 in 16 patients at 0.7 MAC and in all the 20 patients at 1 MAC.Use of BIS in our study helped in better titration of Isoflurane according to patient’s individual needs thereby we avoided light plane of anaesthesia or deep hypnosis and the adverse effects associated with it. [ABSTRACT FROM AUTHOR]

Introduction: Modalities like Bispectral Index Monitoring (BIS) and End Tidal Anaesthetic Gas (ETAG) concentration guided anaesthesia have been used to study the intraoperative awareness but their efficacy for achieving early tracheal extubation has not been established. Aim: To compare the effect of BIS monitoring and ETAG concentration guided anaesthesia on time to tracheal extubation and haemodynamics for isoflurane based general anaesthesia. Materials and Methods: This prospective observational cohort study was conducted in the Department of Anaesthesiology at Mahatma Gandhi Memorial Government Medical College and MY Hospital, Indore, Madhya Pradesh, India, from June 2020 to June 2021. Total 60 patients with American Society of Anesthesiologists (ASA) status I and II who received isoflurane based general anaesthesia were included in study. Depending upon the modality being used by the anaesthesiologist to monitor and maintain the depth of anaesthesia, the patients were allocated in equal numbers into two group. Group B received BIS guided anaesthesia, where BIS value was kept between 40 and 60 and group E received ETAG concentration guided anaesthesia, where Minimum Alveolar Concentration (MAC) was kept between 0.7 to 1.3. Tracheal extubation time was recorded from stopping all anaesthetic agents upto the time of extubation. Unpaired t-test was applied for analysis of data. Results: The mean tracheal extubation time was significantly longer in the BIS group (21.14±2.23 minutes) as compared to ETAG group (15.20±1.27 minutes). All hemodynamic parameters i.e., pulse rate, mean arterial pressure and saturation remained within normal limits and were comparable between the two groups at all the time intervals. Conclusion: The tracheal extubation time is significantly longer in BIS guided anaesthesia as compared to ETAG guided anaesthesia. The ETAG monitoring promotes earlier extubation of patients as compared to BIS monitoring in isoflurane based general anaesthesia. [ABSTRACT FROM AUTHOR]

ObjectiveN-butane and n-pentane can both produce general anesthesia. Both compounds potentiate γ-aminobutyric acid type A (GABAA) receptor function, but only butane inhibits N-methyl-d-aspartate (NMDA) receptors. It was hypothesized that butane and pentane would exhibit anesthetic synergy due to their different actions on ligand-gated ion channels.Study designProspective experimental study.AnimalsA total of four Xenopus laevis frogs and 43 Sprague-Dawley rats.MethodsAlkane concentrations for all studies were determined via gas chromatography. Using a Xenopus oocyte expression model, standard two-electrode voltage clamp techniques were used to measure NMDA and GABAA receptor responses in vitro as a function of butane and pentane concentrations relevant to anesthesia. The minimum alveolar concentrations (MAC) of butane and pentane were measured separately in rats, and then pentane MAC was measured during coadministration of 0.25, 0.50 or 0.75 times MAC of butane. An isobole with 95% confidence intervals was constructed using regression analysis. A sum of butane and pentane that was statistically less than the lower-end confidence bound isobole indicated a synergistic interaction.ResultsBoth butane and pentane dose-dependently potentiated GABAA receptor currents over the study concentration range. Butane dose-dependently inhibited NMDA receptor currents, but pentane did not modulate NMDA receptors. Butane and pentane MAC in rats was 39.4±0.7 and 13.7±0.4 %, respectively. A small but significant (p

PICO question In dogs undergoing anaesthesia, does the use of oral trazodone given 2 hours before induction of anaesthesia reduce injectable or inhalant anaesthetic agent requirements? Clinical bottom line Category of research question Treatment The number and type of study designs reviewed Two randomised controlled trials were critically appraised Strength of evidence Moderate Outcomes reported Trazodone was shown to have a significant isoflurane minimum alveolar concentration (MAC) sparing effect for isoflurane. There is also evidence to suggest trazodone has a similar effect on the cardiovascular system as acepromazine Conclusion Trazodone should be considered as part of a multimodal approach to anaesthesia in dogs to reduce the injectable and inhalant anaesthetic agent requirements How to apply this evidence in practice The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources. Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.

Introduction: Modalities like Bispectral Index Monitoring (BIS) and End Tidal Anaesthetic Gas (ETAG) concentration guided anaesthesia have been used to study the intraoperative awareness but their efficacy for achieving early tracheal extubation has not been established. Aim: To compare the effect of BIS monitoring and ETAG concentration guided anaesthesia on time to tracheal extubation and haemodynamics for isoflurane based general anaesthesia. Materials and Methods: This prospective observational cohort study was conducted in the Department of Anaesthesiology at Mahatma Gandhi Memorial Government Medical College and MY Hospital, Indore, Madhya Pradesh, India, from June 2020 to June 2021. Total 60 patients with American Society of Anesthesiologists (ASA) grade I and II who received isoflurane based general anaesthesia were included in study. Depending upon the modality being used by the anaesthesiologist to monitor and maintain the depth of anaesthesia, the patients were allocated in equal numbers into two group. Group B received BIS guided anaesthesia, where BIS value was kept between 40 and 60 and group E received ETAG concentration guided anaesthesia, where Minimum Alveolar Concentration (MAC) was kept between 0.7 to 1.3. Tracheal extubation time was recorded from stopping all anaesthetic agents upto the time of extubation. Unpaired t-test was applied for analysis of data. Results: The mean tracheal extubation time was significantly longer in the BIS group (21.14±2.23 minutes) as compared to ETAG group (15.20±1.27 minutes). All haemodynamic parameters i.e., pulse rate, mean arterial pressure and oxygen saturation remained within normal limits and were comparable between the two groups at all the time intervals. Conclusion: The tracheal extubation time is significantly longer in BIS guided anaesthesia as compared to ETAG guided anaesthesia. The ETAG monitoring promotes earlier extubation of patients as compared to BIS monitoring in isoflurane based general anaesthesia.

Background and Aims: We hypothesized that maintaining a patient on moderate–high doses of potent inhalational agent for greater than 30 min during the post-bypass period would be an independent predictor of initiation and usage of either inotropic and/or vasopressor infusions. Setting and Design: This study is a retrospective design and approved by the institutional review board. The setting was a single-center, academic tertiary care hospital in Detroit, Michigan. Materials and Methods: Three-hundred, ninety-seven elective cardiac surgery patients were identified for chart review. Electronic medical records were reviewed to collect demographics and perioperative data. Statistics used include a propensity score regression adjusted analysis utilizing logistic regression models and a multivariable model. Results: A propensity score regression adjusted analysis was performed and then applied in both univariate and multivariate logistic regression models with a p value of ISO ≥ 0.5MAC, 30 min) in the post-bypass period. After adjusting for propensity score, this was found to be a significant predictor of inotrope and/or vasoconstrictor use post-bypass (OR 2.49, 95% CI 1.15–5.38, p = 0.021). In the multivariate model, pulmonary hypertension (OR 5.9; 95% CI 1.33–26.28; p = 0.02), Euroscore II (2.73; 95% CI 1.35–5.5; p = 0.005), and cardiopulmonary bypass hours (OR 1.86; 95% CI 1.02–3.4; p = 0.042) emerged as significant. Conclusions: This study showed that an ETISO ≥ 0.5MAC, 30 min exposure during the immediate post-bypass period during elective cardiac surgery was an independent predictor of a patient being started on inotrope or vasoconstrictor infusions. Further research should consider a prospective design and examine depth of anesthesia during the post-bypass period.

To determine the effect of butorphanol, administered by intravenous (IV) infusion, on the minimum alveolar concentration of isoflurane (MAC ISO) in cats and to examine the dosage dependence of this effect. Randomized, placebo-controlled, crossover experimental study. A group of six healthy adult male neutered cats. Cats were anesthetized with isoflurane in oxygen. A venous catheter was placed for fluid and drug administration, and an arterial catheter was placed for measurement of arterial pressure and blood sampling. Four treatments were administered at random with at least 2 week interval between treatments: saline (control), butorphanol low dosage (treatment LD; 0.25 mg kg–1 IV bolus followed by 85 μg kg–1 minute–1 for 20 minutes, then 43 μg kg–1 minute–1 for 40 minutes, then 19 μg kg–1 minute–1), medium dosage (treatment MD, double the dosages in LD) and high dosage (treatment HD, quadruple the dosages in LD). MAC ISO was determined in duplicate using the bracketing technique and tail clamping. Pulse rate, arterial pressure, hemoglobin oxygen saturation, end-tidal partial pressure of carbon dioxide and arterial blood gas and pH were measured. Butorphanol reduced MAC ISO in a dosage-dependent manner, by 23 ± 8%, 37 ± 12% and 68 ± 10% (mean ± standard deviation) in treatments LD, MD and HD, respectively. The main cardiopulmonary effect observed was a decrease in pulse rate, significant in treatment HD compared with control. Butorphanol caused a dosage-dependent MAC ISO reduction in cats. IV infusion of butorphanol may be of interest for partial IV anesthesia in cats. [ABSTRACT FROM AUTHOR]

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Background and Aims: Optimum timing of laryngeal mask airway (LMA) removal after general anesthesia with isoflurane is debatable. The objective was to investigate the potential benefits of removing LMA ProSeal at ≤0.4 Minimum alveolar concentration (MAC) isoflurane over awake and “deep plane” extubation after short duration laparoscopic gynecological surgery. Material and Methods: In this prospective randomized trial 90 adult female patients undergoing elective laparoscopic surgery under general anesthesia using LMA ProSeal™ as airway device were included. At the end of surgery, LMA ProSeal™ was removed when the patient was awake, could open mouth following verbal command (Group A); at MAC ≤0.4 (Group B); or at MAC of 0.6 (Group C). Adverse airway events like nausea, vomiting, airway obstruction, coughing, bucking, laryngospasm were noted. Statistical analyses were done by SPSS statistical software (IBM SPSS Statistics for Mac OS X, Version 21.0. IBM Corp, Armonk, NY). Results: Baseline demographic characteristics were comparable in all three groups. Coughing or bucking at the time of LMA removal was higher in group A (P = 0.004). Snoring and airway obstruction after LMA removal was significantly higher in group C compared to group A and group B (P = 0.002 and P = 0.011, respectively). There was significant change in mean arterial pressure and heart rate between before and after LMA removal on group A (P = 0.008 and P < 0.001, respectively) but not in other groups. Conclusion: MAC ≤0.4 can be considered optimum depth of anesthesia for removal of LMA Proseal in adult patients undergoing isoflurane anesthesia.

To determine the effect of fentanyl on the minimum alveolar concentration of isoflurane (MAC ISO) and cardiovascular variables in dogs, and how the treatment of bradycardia affects them. Prospective, randomized crossover-controlled trial. A total of six male Beagle dogs weighing 9.9 ± 0.7 kg (mean ± standard deviation) and aged 13 months. To each dog, two treatments were assigned on different days: fentanyl (FENTA) or fentanyl plus glycopyrrolate (FENTA glyco) to maintain heart rate (HR) between 100 and 132 beats minute−1. Determinations of MAC ISO were performed with 10 plasma fentanyl target concentrations ([Fenta] Target (0, 0.16, 0.32, 0.64, 1.25, 2.5, 5.0, 10.0, 20.0 and 40.0 ng mL−1) for FENTA and 5 [Fenta] Target (0, 1.25, 2.5, 5.0, 10.0 ng mL−1)) for FENTA glyco. During each MAC ISO determination, cardiovascular variables [mean arterial pressure (MAP), HR and cardiac index (CI)] were measured, and systemic vascular resistance index (SVRI) calculated. Pharmacodynamic models were used to describe the plasma fentanyl concentration [Fenta]–response relationship for the effect on MAC ISO and cardiovascular variables. A mixed-model analysis of variance followed by Dunnett's or Tukey's test, and the Bonferroni adjustment were used for comparisons within and between each treatment, respectively. Significance was set as p < 0.05. Fentanyl decreased MAC ISO by a maximum of 84%. The [Fenta] producing 50% decrease in MAC, HR and CI were 2.64, 3.65 and 4.30 ng mL−1 (typical values of population model), respectively. The prevention of fentanyl-mediated bradycardia caused no significant effect on MAC ISO , but increased HR, MAP and CI, and decreased SVRI when compared with isoflurane alone. Fentanyl caused a plasma concentration-dependent decrease in MAC ISO , HR and CI and an increase in SVRI. Cardiovascular improvements associated with fentanyl in isoflurane-anesthetized dogs only occurred when the fentanyl-mediated bradycardia was prevented. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to observe the effect of bilateral transverse abdominis plane (TAP) block on the MAC BAR of sevoflurane in gynecological patients with laparoscopic pneumoperitoneal stimulation., Patients and Methods: Fifty patients who underwent laparoscopic surgery were randomly assigned to either the control group ( n = 25) or the TAP block group ( n = 25). Patients in the TAP block group were subjected to a bilateral transversal abdominal muscle plane block with 0.33% ropivacaine (20 mL on each side) guided by ultrasound. The control group received an equal volume of normal saline. The MAC BAR of sevoflurane in each group was determined using a sequential allocation technique., Results: The MAC BAR of sevoflurane in the TAP block group was significantly lower than that in the control group (4.20% [95% confidence interval {CI}, 4.02%-4.38%] vs 5.03% [95% CI, 4.89%-5.18%])., Conclusion: Bilateral TAP block can reduce the MAC BAR of sevoflurane in gynecological patients with pneumoperitoneum stimulation., Trial Registration Number: ChiCTR2100046517. The trial is publicly available and registered at www.chictr.org.cn on May 18, 2021., Competing Interests: The authors have no competing interests in this work., (© 2024 Jiang et al.)

Two randomized crossover trials evaluated the effects of nicardipine constant rate infusion (CRI) on 1) the anesthetic potency of sevoflurane and 2) the ability to attenuate dexmedetomidine-induced cardiovascular depression in anesthetized dogs. First, six healthy Beagle dogs weighing 11.7 ± 0.9 kg were allocated to one of three treatments that administered a CRI of carrier (saline) or dexmedetomidine 0.5 or 3.0 μg/kg/h following a loading dose. The minimum alveolar concentration (MAC) of sevoflurane was determined utilizing electric stimuli before and after the loading dose of nicardipine (20 μg/kg intravenously for 10 min), followed by CRI at 40 μg/kg/h with 60 min of equilibration. Subsequently, cardiovascular and blood gas variables were evaluated in another trial under sevoflurane anesthesia at the individual 1.5 MAC. After baseline measurements, the dogs were assigned to two treatments (dexmedetomidine CRI at 0.5 or 3.0 μg/kg/h following a loading dose) with sevoflurane doses adjusted to 1.5 times of MAC equivalent, and the measurements were repeated every 15 min for 120 min. After 60 min, nicardipine CRI at 40 μg/kg/h with a loading dose was added to the dexmedetomidine CRI. Dexmedetomidine infusions significantly decreased the sevoflurane MAC but nicardipine did not significantly alter the MAC either with or without dexmedetomidine CRI in dogs. Dexmedetomidine dose-dependently decreased the cardiac index and increased the systemic vascular resistance index; these effects were fully counteracted by concomitant nicardipine CRI. Nicardipine CRI can be useful for controlling the cardiovascular depression elicited by dexmedetomidine in anesthetized dogs without affecting the anesthetic potency of sevoflurane., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background and Aims: Optimum timing of laryngeal mask airway (LMA) removal after general anesthesia with isoflurane is debatable. The objective was to investigate the potential benefits of removing LMA ProSeal at ≤0.4 Minimum alveolar concentration (MAC) isoflurane over awake and "deep plane" extubation after short duration laparoscopic gynecological surgery. Material and Methods: In this prospective randomized trial 90 adult female patients undergoing elective laparoscopic surgery under general anesthesia using LMA ProSeal™ as airway device were included. At the end of surgery, LMA ProSeal™ was removed when the patient was awake, could open mouth following verbal command (Group A); at MAC ≤0.4 (Group B); or at MAC of 0.6 (Group C). Adverse airway events like nausea, vomiting, airway obstruction, coughing, bucking, laryngospasm were noted. Statistical analyses were done by SPSS statistical software (IBM SPSS Statistics for Mac OS X, Version 21.0. IBM Corp, Armonk, NY). Results: Baseline demographic characteristics were comparable in all three groups. Coughing or bucking at the time of LMA removal was higher in group A (P = 0.004). Snoring and airway obstruction after LMA removal was significantly higher in group C compared to group A and group B (P = 0.002 and P = 0.011, respectively). There was significant change in mean arterial pressure and heart rate between before and after LMA removal on group A (P = 0.008 and P < 0.001, respectively) but not in other groups. Conclusion: MAC ≤0.4 can be considered optimum depth of anesthesia for removal of LMA Proseal in adult patients undergoing isoflurane anesthesia. [ABSTRACT FROM AUTHOR]

Abstract Background Mean arterial pressure (MAP), bispectral index (BIS), and minimum alveolar concentration (MAC) represent valuable, yet dynamic intraoperative monitoring variables. They provide information related to poor outcomes when considered together, however their collective behavior across time has not been characterized. Methods We have developed the Triple Variable Index (TVI), a composite variable representing the sum of z-scores from MAP, BIS, and MAC values that occur together during surgery. We generated a TVI expression profile, defined as the sequential TVI values expressed across time, for each surgery where concurrent MAP, BIS, and MAC monitoring occurred in an adult patient (≥18 years) at the University of Pittsburgh Medical Center between January and July 2014 (n = 5296). Patterns of TVI expression were identified using k-means clustering and compared across numerous patient, procedure, and outcome characteristics. TVI and the triple low state were compared as prediction models for 30-day postoperative mortality. Results The median frequency MAP, BIS, and MAC were recorded was one measurement every 3, 5, and 5 min. Three expression patterns were identified: elevated, mixed, and depressed. The elevated pattern displayed the highest average MAP, BIS, and MAC values (86.5 mmHg, 45.3, and 0.98, respectively), while the depressed pattern displayed the lowest values (76.6 mmHg, 38.0, 0.66). Patterns (elevated, mixed, depressed) were distinct across the following characteristics: average patient age (52, 53, 54 years), American Society of Anesthesiologists Physical Status 4 (6.7, 16.1, 27.3%) and 5 (0.1, 0.6, 1.6%) categories, cardiac (2.2, 6.5, 16.1%) and emergent (5.8, 10.5, 12.8%) surgery, cardiopulmonary bypass use (0.3, 2.6, 9.8%), intraoperative medication administration including etomidate (3.0, 7.3, 12.6%), hydromorphone (47.6, 26.3, 25.2%), ketamine (11.2, 4.6, 3.0%), dexmedetomidine (18.4, 16.6, 13.6%), phenylephrine (74.0, 74.8, 83.0), epinephrine (2.0, 6.0, 18.0%), norepinephrine (2.4, 7.5, 21.2%), vasopressin (3.4, 7.6, 21.0%), succinylcholine (74.0, 69.0, 61.9%), intraoperative hypotension (28.8, 33.0, 52.3%) and the triple low state (9.4, 30.3, 80.0%) exposure, and 30-day postoperative mortality (0.8, 2.7, 5.6%). TVI was a better predictor of patients that died or survived in the 30 days following surgery compared to cumulative triple low state exposure (AUC 0.68 versus 0.62, p

Background and Aims: In children, entropy-guided titration of isoflurane and sevoflurane leads to faster recovery after anaesthesia. However, role of entropy in recovery following desflurane anaesthesia is not known. Hence, we compared laryngeal mask airway (LMA) removal time and desflurane consumption with entropy and minimal alveolar concentration–guided titration in children given low-flow desflurane anaesthesia. Methods: After ethics committee approval and parental consent, 80 American Society of Anesthesiologists grade I–II children, age 2–14 years, undergoing elective ophthalmic surgery were randomised into entropy and minimal alveolar concentration–guided groups. After LMA insertion, anaesthesia was maintained using oxygen, air (FiO2 0.5) and desflurane using low fresh gas flow of 0.75 L/min. In the entropy-guided group, desflurane was titrated to maintain state entropy between 40 and 60. In the minimal alveolar concentration–guided group, desflurane was titrated to maintain a minimal alveolar concentration between 1 and 1.3. We recorded LMA removal time (from switching off desflurane at the end of surgery till removal of LMA), haemodynamic parameters, uptake and consumption of desflurane between the groups. Results: LMA removal time was significantly decreased in the entropy-guided group in comparison to the minimal alveolar concentration–guided group (4.34 ± 2.03 vs 8.8 ± 2.33 min) (P < 0.0001). Consumption of desflurane was significantly less in the entropy-guided group compared with the minimal alveolar concentration–guided group (18.7 ± 5.07 vs 25.3 ± 8.11 mL) (P < 0.0001). Conclusion: Entropy-guided low-flow desflurane anaesthesia is associated with faster LMA removal and reduced consumption of desflurane in children undergoing ophthalmic surgery.

To evaluate the effects of combined infusions of vatinoxan and dexmedetomidine on inhalant anesthetic requirement and cardiopulmonary function in dogs. Prospective experimental study. A total of six Beagle dogs were anesthetized to determine sevoflurane minimum alveolar concentration (MAC) prior to and after an intravenous (IV) dose (loading, then continuous infusion) of dexmedetomidine (4.5 μg kg–1 hour–1) and after two IV doses of vatinoxan in sequence (90 and 180 μg kg–1 hour–1). Blood was collected for plasma dexmedetomidine and vatinoxan concentrations. During a separate anesthesia, cardiac output (CO) was measured under equivalent MAC conditions of sevoflurane and dexmedetomidine, and then with each added dose of vatinoxan. For each treatment, cardiovascular variables were measured with spontaneous and controlled ventilation. Repeated measures analyses were performed for each response variable; for all analyses, p < 0.05 was considered significant. Dexmedetomidine reduced sevoflurane MAC by 67% (0.64 ± 0.1%), mean ± standard deviation in dogs. The addition of vatinoxan attenuated this to 57% (0.81 ± 0.1%) and 43% (1.1 ± 0.1%) with low and high doses, respectively, and caused a reduction in plasma dexmedetomidine concentrations. Heart rate and CO decreased while systemic vascular resistance increased with dexmedetomidine regardless of ventilation mode. The co-administration of vatinoxan dose-dependently modified these effects such that cardiovascular variables approached baseline. IV infusions of 90 and 180 μg kg–1 hour–1 of vatinoxan combined with 4.5 μg kg–1 hour–1 dexmedetomidine provide a meaningful reduction in sevoflurane requirement in dogs. Although sevoflurane MAC-sparing properties of dexmedetomidine in dogs are attenuated by vatinoxan, the cardiovascular function is improved. Doses of vatinoxan >180 μg kg–1 hour–1 might improve cardiovascular function further in combination with this dose of dexmedetomidine, but beneficial effects on anesthesia plane and recovery quality may be lost. [ABSTRACT FROM AUTHOR]

What is known and objective: Low‐dose ketamine can reduce the minimum alveolar concentration of sevoflurane necessary to block the adrenergic response (MACBAR) in animals. However, the effects of low‐dose ketamine on the sevoflurane MACBAR in patients undergoing laparoscopic surgery are unclear. The aim of this study was to investigate the effects of three different low doses of ketamine on the MACBAR of sevoflurane in patients undergoing laparoscopic cholecystectomy. Methods: One hundred patients who underwent laparoscopic cholecystectomy were enrolled. After general anaesthesia induction and tracheal intubation, patients received sevoflurane anaesthesia in combination with a loading dose of saline followed by infusion or a loading dose of 0.5 mg/kg ketamine followed by a continuous infusion of 5 (K1 group), 10 (K2 group) and 20 μg/kg/min (K3 group). The target concentration of end‐tidal sevoflurane was maintained for at least 20 minutes before carbon dioxide pneumoperitoneum stimulus. The MACBAR of sevoflurane in each group was determined by using an up‐and‐down sequential allocation technique. Results and discussion: Seventy‐one patients completed the study. The values of MACBAR for sevoflurane were 5.3% in the K0, 4.8% in K1, 3.3% in K2 and 3.2% in K3 groups. The use of ketamine significantly reduced the MACBAR of sevoflurane compared to sevoflurane alone. The K2 and K3 groups showed significantly lower values of MACBAR than that in the K1 group. However, a higher dose of ketamine in the K3 group did not further reduce the sevoflurane MACBAR. The mean arterial blood pressure (MAP) values before pneumoperitoneum in the K2 and the K3 groups were significantly higher compared to those in the K0 and K1 groups. Compared with the values before pneumoperitoneum, the heart rate and MAP after pneumoperitoneum were significantly increased. Overall, the haemodynamics remained stable during the study period in all groups. What is new and conclusion: A loading dose of 0.5 mg/kg ketamine followed by a continuous infusion of 10.0 μg/kg/min led to a significant decrease in the MACBAR of sevoflurane in patients undergoing laparoscopic cholecystectomy. [ABSTRACT FROM AUTHOR]

Abstract Background It has been known that Dexmedetomidine pre-medication enhances the effects of volatile anesthetics, reduces the need of sevoflurane, and facilitates smooth extubation in anesthetized children. This present study was designed to determine the effects of different doses of intravenous dexmedetomidine pre-medication on minimum alveolar concentration of sevoflurane for smooth tracheal extubation (MACEX) in anesthetized children. Methods A total of seventy-five pediatric patients, aged 3–7 years, ASA physical status I and II, and undergoing tonsillectomy were randomized to receive intravenous saline (Group D0), dexmedetomidine 1 μg∙kg−1 (Group D1), or dexmedetomidine 2 μg∙kg−1 (Group D2) approximately 10 min before anesthesia start. Sevoflurane was used for anesthesia induction and anesthesia maintenance. At the end of surgery, the initial concentration of sevoflurane for smooth tracheal extubation was determined according to the modified Dixon’s “up-and-down” method. The starting sevoflurane for the first patient was 1.5% in Group D0, 1.0% in Group D1, and 0.8% in Group D2, with subsequent 0.1% up or down in next patient based on whether smooth extubation had been achieved or not in current patient. The endotreacheal tube was removed after the predetermined concentration had been maintained constant for ten minutes. All responses (“smooth” or “not smooth”) to tracheal extubation and respiratory complications were assessed. Results MACEX values of sevoflurane in Group D2 (0.51 ± 0.13%) was significantly lower than in Group D1 (0.83 ± 0.10%; P

Abstract Background Ambulatory surgery has recently gain popularity, as it is a good method of optimizing hospital resources utilization. To support ambulatory surgery, anaesthetic goals now revolve around patients’ early recovery with minimal pain and nausea, expedient discharge home and prompt resumption of activities of daily living. In this study, we evaluated the effect of a single pre-induction dose of dexmedetomidine on anaesthetic requirements, postoperative pain and clinical recovery after ambulatory ureteroscopy andureteric stenting under general anaesthesia. Methods Sixty patients were randomised to receive IV dexmedetomidine 0.5 μg.kg-1 (Group DEX, n = 30) or IV saline (Group P, n = 30). General anaesthesia was maintained with Sevoflurane: oxygen: air, titrated to BIS 40–60. Pain intensity, sedation, rescue analgesics, nausea/vomiting and resumption of daily activities were recorded at 1 h, and postoperative day (POD) 1–5. Results Group DEX patients had significant reduction in sevoflurane minimum alveolar concentration (MAC), mean (SD) DEX vs. Placebo 0.6 (0.2) vs. 0.9 (0.1), p = 0.037; reduced postoperative resting pain at 1 h (VAS 0–10) (mean (SD) 1.00 (1.84) vs. 2.63 (2.78), p = 0.004), POD 1 (mean (SD) 1.50 (1.48) vs. 2.87 (2.72), p = 0.002), POD 2 (0.53 (0.97) vs. 1.73 (1.96), p = 0.001) and POD 3 (0.30 (0.75) vs. 0.89 (1.49), p = 0.001). DEX patients also had less pain on movement POD 1 (3.00 (2.12) vs. 4.30 (3.10), p = 0.043) and POD 2 (2.10 (1.98) vs. 3.10 (2.46), p = 0.040), with higher resumption of daily activities by 48 h compared to placebo, 87% vs. 63%, p = 0.04. Conclusions We conclude that a single dose of dexmedetomidine was a useful adjuvant in reducing MAC and postoperative pain (at 1 h and POD 1–3), facilitating faster return to daily activities by 48 h. Trial registration The Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12617001120369 , 31st July 2017, retrospectively registered.

Inhalational Inducing Agents include gas like Nitrous Oxide and volatile liquids like Ether, Halogenated halothane, Enflurane, Sevoflurane, Isoflurane, Desflurane and Methoxyflurane. They have exterminated pain and anxiety control in Dentistry as well as in General Medicine for over a century. The following article outlines the detailed history, correspondence, distinction, and the clinical implementations of the few most prevailing inhalational agents used in Dentistry. [ABSTRACT FROM AUTHOR]

In this article, we present a real-time electroencephalogram (EEG) based depth of anesthesia (DoA) monitoring system in conjunction with a deep learning framework, AnesNET. An EEG analog front-end (AFE) that can compensate ±380-mV electrode DC offset using a coarse digital DC servo loop is implemented in the proposed system. The EEG-based MAC, EEGMAC, is introduced as a novel index to accurately predict the DoA, which is designed for applying to patients anesthetized by both volatile and intravenous agents. The proposed deep learning protocol consists of four layers of convolutional neural network and two dense layers. In addition, we optimize the complexity of the deep neural network (DNN) to operate on a microcomputer such as the Raspberry Pi 3, realizing a cost-effective small-size DoA monitoring system. Fabricated in 110-nm CMOS, the prototype AFE consumes 4.33 μW per channel and has the input-referred noise of 0.29 μVrms from 0.5 to 100 Hz with the noise efficiency factor of 2.2. The proposed DNN was evaluated with pre-recorded EEG data from 374 subjects administrated by inhalational anesthetics under surgery, achieving an average squared and absolute errors of 0.048 and 0.05, respectively. The EEGMAC with subjects anesthetized by an intravenous agent also showed a good agreement with the bispectral index value, confirming the proposed DoA index is applicable to both anesthetics. The implemented monitoring system with the Raspberry Pi 3 estimates the EEGMAC within 20 ms, which is about thousand-fold faster than the BIS estimation in literature. [ABSTRACT FROM AUTHOR]

To evaluate the effects of constant rate infusions (CRIs) of dexmedetomidine and remifentanil alone and their combination on minimum alveolar concentration (MAC) of sevoflurane in dogs. Randomized crossover experimental study. A total of six (three males, three females) healthy, adult neutered Beagle dogs weighing 12.6 ± 1.4 kg. Anesthesia was induced with sevoflurane in oxygen until endotracheal intubation was possible and anesthesia maintained with sevoflurane using positive-pressure ventilation. Each dog was anesthetized five times and was administered each of the following treatments: saline (1 mL kg–1 hour–1) or dexmedetomidine at 0.1, 0.5, 1.0 or 5.0 μg kg–1 loading dose intravenously over 10 minutes followed by CRI at 0.1, 0.5, 1.0 or 5.0 μg kg–1 hour–1, respectively. Following 60 minutes of CRI, sevoflurane MAC was determined in duplicate using an electrical stimulus (50 V, 50 Hz, 10 ms). Then, CRI of successively increasing doses of remifentanil (0.15, 0.60 and 2.40 μg kg–1 minute–1) was added to each treatment. MAC was also determined after 30 minutes equilibration at each remifentanil dose. Isobolographic analysis determined interaction from the predicted doses required for a 50% MAC reduction (ED 50) with remifentanil, dexmedetomidine and remifentanil combined with dexmedetomidine, with the exception of dexmedetomidine 5.0 μg kg–1 hour–1, obtained using log-linear regression analysis. The sevoflurane MAC decreased dose-dependently with increasing infusion rates of dexmedetomidine and remifentanil. Remifentanil ED 50 values were lower when combined with dexmedetomidine than those obtained during saline–remifentanil. Synergistic interactions between dexmedetomidine and remifentanil for MAC reduction occurred with dexmedetomidine at 0.5 and 1.0 μg kg–1 hour–1. Combined CRIs of dexmedetomidine and remifentanil synergistically resulted in sevoflurane MAC reduction. The combination of dexmedetomidine and remifentanil effectively reduced the requirement of sevoflurane during anesthesia in dogs. [ABSTRACT FROM AUTHOR]