Maintenance of anaesthesia

During closed-loop control, a drug infusion is continually adjusted according to a measure of clinical effect (e.g., an electroencephalographic depth of hypnosis (DoH) index). Inconsistency in population-derived pediatric pharmacokinetic/pharmacodynamic models and the large interpatient variability observed in children suggest a role for closed-loop control in optimizing the administration of intravenous anesthesia. To clinically evaluate a robustly tuned system for closed-loop control of the induction and maintenance of propofol anesthesia in children undergoing gastrointestinal endoscopy. One hundred and eight children, aged 6-17, ASA I-II, were enrolled. Prior to induction of anesthesia, NeuroSENSE™ sensors were applied to obtain the WAVCNS DoH index. An intravenous cannula was inserted and lidocaine (0.5mg·kg(-1) ) administered. Remifentanil was administered as a bolus (0.5μg·kg(-1) ), followed by continuous infusion (0.03μg·kg(-1) ·min(-1) ). The propofol infusion was closed-loop controlled throughout induction and maintenance of anesthesia, using WAVCNS as feedback. Anesthesia was closed-loop controlled in 102 cases. The system achieved and maintained an adequate DoH without manual adjustment in 87/102 (85%) cases. Induction of anesthesia (to WAVCNS ≤60) was completed in median 3.8min (interquartile range (IQR) 3.1-5.0), culminating in a propofol effect-site concentration (Ce ) of median 3.5μg·ml(-1) (IQR 2.7-4.5). During maintenance of anesthesia, WAVCNS was measured within 10 units of the target for median 89% (IQR 79-96) of the time. Spontaneous breathing required no manual intervention in 91/102 (89%) cases. A robust closed-loop system can provide effective propofol administration during induction and maintenance of anesthesia in children. Wide variation in the calculated Ce highlights the limitation of open-loop regimes based on pharmacokinetic/pharmacodynamic models.

In this clinical study, we tested the hypothesis that a marked systolic blood pressure decrease >35% (DeltaSBP >35%) from preanesthetic baseline during the induction and maintenance of anesthesia is associated with more postoperative nausea and vomiting (PONV). In 300 ASA physical status I and II women undergoing elective gynecological surgery with general anesthesia, the maximum DeltaSBP during the induction as well as maintenance of general anesthesia were calculated. Observers blinded to hemodynamic variables assessed the incidence of PONV. The overall incidence of nausea (visual analog scale >4) and vomiting within the immediate observation period (0-2 h) was 39% and 25%, respectively. Frequency of nausea and vomiting in the late observation period was 21% and 9%, respectively. Women with a DeltaSBP >35% during the induction of anesthesia suffered from a more frequent incidence of PONV within the immediate (57% versus 35% and 41% versus 22%, respectively; P < 0.01) and within the late observation period (33% versus 18% and 19% versus 7%, respectively; P < or = 0.01). In women with a DeltaSBP >35% during maintenance of anesthesia, a more frequent incidence of nausea within the immediate observation period (53% versus 36%; P < 0.05) was found. We conclude that a maximum DeltaSBP >35% during the anesthetic induction is associated with an increased incidence of PONV after gynecological surgery during general anesthesia. A prospective clinical investigation revealed that a marked systolic blood pressure decrease >35% (DeltaSBP >35%) during the induction of general anesthesia is associated with an increased incidence of postoperative nausea and vomiting (PONV). The association between a DeltaSBP >35% during maintenance of general anesthesia and PONV is less pronounced.

To compare the effects of remifentanil and fentanyl on intraocular pressure during the maintenance and recovery of anaesthesia in patients undergoing elective non-ophthalmic surgery. Thirty-two patients (ASA I-II) were randomized into two groups to receive either a continuous infusion of remifentanil (0.25-0.5 microg kg(-1) min(-1), n =16, Group R) or an intermittent bolus of fentanyl (2-5 microg kg(-1), n = 16, Group F) during the maintenance of anaesthesia. For the induction of anaesthesia, Group R received remifentanil 1 microg kg(-1) and Group F received fentanyl 2 microg kg(-1); both groups then received propofol 2 mg kg(-1) with vecuronium 0.1 mg kg(-1). Anaesthesia in both groups was maintained with a continuous infusion of propofol 4-8 mg kg(-1) h(-1). Ventilation of the lungs was controlled to a constant end-tidal PCO2 of 4.7-5.4 kPa. Blood pressure, electrocardiography, heart rate and oxygen saturation were monitored throughout anaesthesia. Intraocular pressure was determined before surgery, during the maintenance of anaesthesia, 2 min after emergence and in the recovery room using a Perkins hand-held applanation tonometer by an ophthalmologist blinded to the anaesthetic technique. After induction of anaesthesia, a significant decrease in intraocular pressure in the remifentanil group from 13.6 +/- 2.6 to 7.1 +/- 3.1 mmHg (P < 0.001) and in the fentanyl group from 13.7 +/- 2.2 to 9.7 +/- 3.4 mmHg (P < 0.001) was observed and maintained during anaesthesia. Thirty minutes after the end of anaesthesia, intraocular pressure returned to baseline values in both groups (remifentanil: 13.9 +/- 2.8 mmHg, P = 0.28; fentanyl: 13.6 +/- 2.3 mmHg, P = 0.59). The intraocular pressure and haemodynamic variables did not differ significantly between the two groups (intraocular pressure, P = 0.7327; blood pressure, P = 0.1295; heart rate, P = 0.8601). Remifentanil maintains intraocular pressure at an equally reduced level compared with fentanyl.

Background and objective: To compare the effects of remifentanil and fentanyl on intraocular pressure during the maintenance and recovery of anaesthesia in patients undergoing elective non-ophthalmic surgery. Methods: Thirty-two patients (ASA I-II) were randomized into two groups to receive either a continuous infusion of remifentanil (0.25-0.5 μg kg−1 min−1, n = 16, Group R) or an intermittent bolus of fentanyl (2-5 μg kg−1, n = 16, Group F) during the maintenance of anaesthesia. For the induction of anaesthesia, Group R received remifentanil 1 μg kg−1 and Group F received fentanyl 2 μg kg−1; both groups then received propofol 2 mg kg−1 with vecuronium 0.1 mg kg−1. Anaesthesia in both groups was maintained with a continuous infusion of propofol 4-8 mg kg−1 h−1. Ventilation of the lungs was controlled to a constant end-tidal PCO2 of 4.7-5.4 kPa. Blood pressure, electrocardiography, heart rate and oxygen saturation were monitored throughout anaesthesia. Intraocular pressure was determined before surgery, during the maintenance of anaesthesia, 2 min after emergence and in the recovery room using a Perkins hand-held applanation tonometer by an ophthalmologist blinded to the anaesthetic technique. Results: After induction of anaesthesia, a significant decrease in intraocular pressure in the remifentanil group from 13.6 ± 2.6 to 7.1 ± 3.1 mmHg (P < 0.001) and in the fentanyl group from 13.7 ± 2.2 to 9.7 ± 3.4 mmHg (P < 0.001) was observed and maintained during anaesthesia. Thirty minutes after the end of anaesthesia, intraocular pressure returned to baseline values in both groups (remifentanil: 13.9 ± 2.8 mmHg, P = 0.28; fentanyl: 13.6 ± 2.3 mmHg, P = 0.59). The intraocular pressure and haemodynamic variables did not differ significantly between the two groups (intraocular pressure, P = 0.7327; blood pressure, P = 0.1295; heart rate, P = 0.8601). Conclusions: Remifentanil maintains intraocular pressure at an equally reduced level compared with fentanyl.

Remimazolam is an ultra-short-acting benzodiazepine sedative drug. This study aimed to compare the efficacy and safety of remimazolam with propofol for induction and maintenance of general anaesthesia in children undergoing elective surgery. Children (aged 3-6 y, ASA physical status 1 or 2, BMI 14-25 kg.m-2) undergoing elective surgery under general anaesthesia with tracheal intubation were eligible for inclusion. Children were allocated randomly using a web-based system to receive either remimazolam or propofol in a 3:1 ratio. After receiving fentanyl 3 μg.kg-1, children received their allocated drug for both induction and maintenance of general anaesthesia. Induction doses were remimazolam 0.3 mg.kg-1 or propofol 2.5 mg.kg-1, with a second dose given should they not achieve loss of consciousness. After neuromuscular blockade and tracheal intubation, maintenance anaesthesia was achieved with an infusion either remimazolam 1-3 mg.kg-1.h-1 or propofol 4-12 mg.kg-1.h-1, alongside a remifentanil infusion (0.1-0.5 μg.kg-1.min-1) titrated to surgical stimulus and haemodynamic parameters. Primary outcomes were the incidence of successful induction and maintenance of anaesthesia. Secondary outcomes included: time to loss of consciousness, awakening and tracheal extubation; incidence of emergence delirium and moderate or severe pain in post-anaesthesia care unit; incidence of negative behaviour change after surgery at postoperative day 3; and incidence of adverse events. A total of 187 children were analysed (140 allocated to remimazolam and 47 to propofol). All children achieved successful induction of anaesthesia. Successful maintenance of anaesthesia was achieved in 139 (99%) children who received remimazolam compared with 46 (98%) who received propofol (rate difference 1.4%, 95%CI -2.9-5.8%, p = 0.441). Adverse events occurred in 27 (19%) children who received remimazolam and 23 (49%) who received propofol. Remimazolam was well tolerated for the induction and maintenance of general anaesthesia in pre-school-age children and was non-inferior to propofol.

The aim of this study was to investigate the effect of popular non-inhaled and inhaled general anesthetics on the respiratory function of dogs during operative delivery. Experimental studies have been performed on pregnant bitches that have been subjected to caesarean section. The selection of animals was carried out according to pre-selected criteria, the age of the animals participating in the experiment was from 2 to 6 years, the average body weight was 22 ± 4.6 kg. Animals were divided into 3 groups. Dogs in the first group received intravenous anesthetic propofol at a dose of 4-6 mg/kg for induction and maintenance of general anesthesia. he dogs of the second group used an inhaled halogen-containing anesthetic isoflurane 0.5–2.0 vol% for the administration and maintenance of anesthesia. For the induction and maintenance of general anesthesia in animals of the third group, a more modern inhalation anesthetic sevoflurane 1.0–2.0 vol% was used. Each group included 20 animals. Analyzing the results obtained on the study of the functions of external respiration of dogs during caesarean section under general anesthesia, it can be argued that the most significant changes in the studied parameters occurred at the initial stages of anesthesia with propofol, which are associated with an increase in the concentration of this anesthetic in the blood and a more pronounced depression of the respiratory center compared to with inhalation anesthetics.

Introduction: Remimazolam is an ultra-short-acting benzodiazepine sedative agent commonly used in general anesthesia, procedural sedation, and intensive care unit (ICU) sedation. This study aimed to explore the efficacy and safety of remimazolam versus propofol for the induction and maintenance of general anesthesia in preschool-age children undergoing elective surgery. Methods and analysis: In this multicenter, randomized, single-blind, positive-controlled non-inferior clinical trial, one hundred ninety-two children aged 3-6years will be randomly allocated as a 3:1 ratio into two groups: Group R with an intravenous dose of remimazolam 0.3mg/kg for the induction of anesthesia followed by a constant infusion rate of remimazolam 1-3mg/kg/h to maintain anesthesia, and Group P with an intravenous dose of propofol 2.5mg/kg for the induction of anesthesia followed by a constant infusion rate of propofol 4-12mg/kg/h to maintain anesthesia. The primary outcome will be the rate of the successful induction and maintenance of anesthesia. The secondary outcomes will include the time to LoC, the Bispectral Index (BIS) value, awakening time, extubation time, post-anesthesia care unit (PACU) discharge time, usage of additional sedative drugs during the induction period, usage of remedial drugs in PACU, emergence delirium, pain in PACU, behavior scores at day 3 after surgery, parental and anesthesiologists' satisfaction, and adverse events. Ethics and dissemination: This study has been approved by the ethics review boards at all participating hospitals. The Ethics Committee of the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University (Reference No. LCKY 2020-380, November 13, 2020) is the central ethics committee.

In this clinical study, we tested the hypothesis that a marked systolic blood pressure decrease >35% (ΔSBP >35%) from preanesthetic baseline during the induction and maintenance of anesthesia is associated with more postoperative nausea and vomiting (PONV). In 300 ASA physical status I and II women undergoing elective gynecological surgery with general anesthesia, the maximum ΔSBP during the induction as well as maintenance of general anesthesia were calculated. Observers blinded to hemodynamic variables assessed the incidence of PONV. The overall incidence of nausea (visual analog scale >4) and vomiting within the immediate observation period (0–2 h) was 39% and 25%, respectively. Frequency of nausea and vomiting in the late observation period was 21% and 9%, respectively. Women with a ΔSBP >35% during the induction of anesthesia suffered from a more frequent incidence of PONV within the immediate (57% versus 35% and 41% versus 22%, respectively;P < 0.01) and within the late observation period (33% versus 18% and 19% versus 7%, respectively;P ≤ 0.01). In women with a ΔSBP >35% during maintenance of anesthesia, a more frequent incidence of nausea within the immediate observation period (53% versus 36%;P < 0.05) was found. We conclude that a maximum ΔSBP >35% during the anesthetic induction is associated with an increased incidence of PONV after gynecological surgery during general anesthesia.

서 론 외상이나 수술침습 및 마취 등의 스트레스 하에서는 부 신피질 호르몬을 포함하는 스트레스 호르몬의 분비가 영향 을 받게 되며, 대사 작용에 광범위한 영향을 미치게 되어 지방과 단백질의 분해가 증가되고 당 환원 작용, 당 이용의 장애를 일으킨다. 1) 스트레스에 대한 대사성 및 내분비 반응 은 자극의 강도, 2) 기간, 3) 환자의 나이, 4) 마취방법과 5) 수술기 술 6) 등과 같은 여러 가지 요소들에 따라서 달라진다고 한 다. 흡입마취제는 외과적 스트레스 반응에 억제효과가 적은 반면에, 7) 최근 많이 사용되는 propofol 마취 시에는 시상하 부-뇌하수체-부신피질 반응의 억제로 혈당농도의 술중증가 를 약화시킨다고 알려져 있다.또한 propofol 마취 시 흔히

Investigation of anaesthetic potentials of various extracts of Annona muricata (sour sop) in Wister albino rat and dog

Quantifying Anesthetic Drug Interaction

Sevoflurane anaesthesia in children after induction of anaesthesia with midazolam and thiopental does not cause epileptiform EEG

The administration of the anesthetic agents is known to alter the electroencephalogram (EEG) signal significantly with the brain being their primary target. In this study, we analyzed the EEG recorded from six ASA I/II patients undergoing a 1-2 hour surgery. The EEG was collected before and during induction, maintenance and recovery of anesthesia using the 10/20 lead-system. A combination of fentanyl and propofol (± rocuronium) was used for induction and a Sevoflurane in air/O(2) mixture was administered through an endotracheal tube to achieve the steady minimum alveolar concentration (MAC). This study showed that 0 to 4 Hz signal power was most sensitive to the changes associated with induction of anesthesia whereas the 4 to 12 Hz power was important in classifying states during maintenance of anesthesia. Anesthesia also promoted heightened phase coherence in 8 to 16 Hz and 16 to 30 Hz ranges during maintenance and induction of anesthesia, respectively. Additionally, strong cross-frequency coupling between 7 to 20 Hz and 10 to 40 Hz was observed during anesthesia suggesting alteration of neural coding.

Eight captive ostriches (Struthio camelus), ranging in age from 9 to 11 months, were given a combination of medetomidine and ketamine, administered intramuscularly, and propofol, administered intravenously, for induction and maintenance of anesthesia. Medetomidine (80 μg/kg IM) and ketamine (2 mg/kg IM) resulted in profound sedation and sternal recumbency within a mean time of 14.6 ± 10.0 minutes in 6 birds. Two birds remained standing but were moderately sedated. Propofol, used for induction (3 mg/kg IV) and maintenance (0.2 mg/kg/min constant rate infusion) of anesthesia, enabled intubation and provided muscle relaxation sufficient for restraint lasting 30 minutes. Apnea was observed after propofol administration, but spontaneous ventilation resumed within 60 to 90 seconds. All birds were bradycardic throughout the anesthetic event. Both the heart rate and the cloacal body temperature decreased significantly at 25 and 30 minutes, respectively, after induction. By 5 minutes after induction, the respiratory rate increased significantly and remained high throughout the remainder of the 30-minute evaluation period. During the anesthetic period, systolic, mean, and diastolic blood pressures, as well as arterial pH, arterial oxygen and carbon dioxide partial pressures, and end tidal carbon dioxide partial pressure showed no significant changes. The relative arterial oxygen saturation (SpO2) was significantly elevated at 15, 25, and 30 minutes after induction. The SpO2 was less than 90% at 2, 5, 10, and 20 minutes after induction; however, arterial blood gas analysis indicated adequate arterial oxygenation. Anesthetic reversal with the α2-antagonist atipamezole (400 μg/kg, one half IV and one half SC) was smooth and resulted in a mean recovery time of 21.0 ± 7.3 minutes. The combination of IM medetomidine-ketamine and IV propofol used in this study proved to be effective for sedation as well as the induction and maintenance of anesthesia in captive ostriches.

Remimazolam, an ultra-short-acting benzodiazepine sedative is equally effective as propofol in induction and maintenance of general anesthesia with improved hemodynamic stability in American Society of Anesthesiologists (ASA) Class I and II patients. This trial investigated remimazolam's efficacy and safety in vulnerable patients (ASA Class III) undergoing elective general surgery. A multicenter, randomized, double-blind, parallel-group trial in 67 adult surgical patients undergoing general anesthesia with two remimazolam induction doses (6mgkg-1h-1-group A and 12mgkg-1h-1-group B) has been conducted in 6 trials sites in Japan. Remimazolam was infused up to 2mgkg-1h-1 for maintenance of anesthesia in both groups. The functional anesthetic capability of the investigated drug was 100% in both arms. The mean time to loss of consciousness (LoC) was significantly shorter in group B (81.7s) compared to group A (97.2s), p = 0.0139. The mean bispectral index (BIS) value during maintenance of anesthesia ranged from 46.0 to 68.0 and from 44.7 to 67.5 in group A and B, respectively. There was no statistically significant difference between the remimazolam arms concerning the incidence of blood pressure (BP) decrease (67.7% in group B vs. 54.8% in group A), recovery profile or the incidence or severity of adverse events (AEs) or adverse drug reactions (ADRs). Both induction regimens (6 and 12mgkg-1h-1) were equally efficacious and safe in surgical patients ASA Class III. A significantly shorter time to LoC was observed with the higher remimazolam dosage. Clinical trial registration This trial is registered with the Japan Pharmaceutical Information Center-Clinical Trials Information (JapicCTI). JapicCTI number: 121977.