The role of perioperative sedative anesthetics in preventing postoperative delirium: a systematic review and network-meta analysis including 6679 patients

OBJECTIVE

Postoperative delirium is a common and debilitating complication that significantly affects patients and their families. The purpose of this study is to investigate whether there is an effective sedative that can prevent postoperative delirium while also examining the safety of using sedatives during the perioperative period.

METHODS

The net-meta analysis was used to compare the incidence of postoperative delirium among four sedatives: sevoflurane, propofol, dexmedetomidine, and midazolam. Interventions were ranked according to their surface under the cumulative ranking curve (SUCRA).

RESULTS

A total of 41 RCT studies involving 6679 patients were analyzed. Dexmedetomidine can effectively reduce the incidence of postoperative delirium than propofol (OR 0.47 95% CI 0.25-0.90), midazolam (OR 0.42 95% CI 0.17-1.00), normal saline (OR 0.42 95% CI 0.33-0.54) and sevoflurane (OR 0.39 95% CI 0.18-0.82). The saline group showed a significantly lower incidence of bradycardia compared to the group receiving dexmedetomidine (OR 0.55 95% CI 0.37-0.80). In cardiac surgery, midazolam (OR 3.34 95%CI 2.04-5.48) and normal saline (OR 2.27 95%CI 1.17-4.39) had a higher rate of postoperative delirium than dexmedetomidine, while in non-cardiac surgery, normal saline (OR 1.98 95%CI 1.44-2.71) was more susceptible to postoperative delirium than dexmedetomidine.

CONCLUSION

Our analysis suggests that dexmedetomidine is an effective sedative in preventing postoperative delirium whether in cardiac surgery or non-cardiac surgery. The preventive effect of dexmedetomidine on postoperative delirium becomes more apparent with longer surgical and extubation times. However, it should be administered with caution as it was found to be associated with bradycardia.

Haemodynamic effects of labetalol in isoflurane-anaesthetized dogs that received dexmedetomidine: A randomized clinical trial

OBJECTIVE

To test whether labetalol improved cardiovascular function in anaesthetized dogs injected with dexmedetomidine.

STUDY DESIGN

Prospective, randomized, blinded, clinical trial.

ANIMALS

A group of 20 healthy client-owned dogs undergoing ovariohysterectomy.

METHODS

Each dog received dexmedetomidine (5 μg kg-1) and methadone (0.2 mg kg-1) intramuscularly. General anaesthesia was induced with propofol and maintained with isoflurane in oxygen. All dogs were mechanically ventilated, and epidural anaesthesia with lidocaine was performed. Standard anaesthetic monitoring, invasive blood pressure, oesophageal Doppler and near-infrared tissue perfusion/oxygenation were applied. Peak velocity (PV), mean acceleration and stroke distance (SD) from the oesophageal Doppler were recorded. Arterial elastance (Ea) was calculated. Tissue oxygenation (rStO2) was also recorded. Prior to surgery, animals received either 0.1 mg kg-1 of labetalol intravenously (IV) over 60 seconds or the equivalent volume of saline. Data were recorded for 20 minutes. Age, weight and propofol dose were compared with a Wilcoxon rank-sum test. The effects of time, treatment and their interaction with haemodynamic and perfusion variables were analysed with mixed-effect models and Tukey's post hoc tests.

RESULTS

Significant effects of the interaction between treatment and time were observed whereby heart rate (HR) was higher in dogs given labetalol (p = 0.01), whereas arterial blood pressure and Ea were lower (p < 0.01). Similarly, PV, SD and rStO2 were higher in the labetalol group, and significant effects were detected for the interaction between treatment and time (p < 0.01).

CONCLUSIONS AND CLINICAL RELEVANCE

Labetalol at a dose of 0.1 mg kg-1 IV in dogs under general anaesthesia and administered a pre-anaesthetic medication of dexmedetomidine produced mild vasodilation (reduction of Ea), resulting in an increase in HR and left ventricular outflow. Although labetalol could be an effective option to achieve haemodynamic optimization after dexmedetomidine-induced vasoconstriction, future studies are needed to assess long-term effects.

Bispectral Index Changes Following Boluses of Commonly Used Intravenous Medications During Volatile Anesthesia Identified From Retrospective Data

BACKGROUND

Although patients are commonly monitored for depth of anesthesia, it is unclear to what extent administration of intravenous anesthetic medications may affect calculated bispectral (BIS) index values under general anesthesia.

METHODS

In a retrospective analysis of electronic anesthesia records from an academic medical center, we examined BIS index changes associated with 14 different intravenous medications, as administered in routine practice, during volatile-based anesthesia using a novel screening approach. Discrete-time windows were identified in which only a single drug bolus was administered, and subsequent changes in the BIS index, concentration of volatile anesthetic, and arterial pressure were analyzed. Our primary outcome was change in BIS index, following drug administration. Adjusted 95% confidence intervals were compared to predetermined thresholds for clinical significance. Secondary sensitivity analyses examined the same outcomes, with available data separated according to differences in baseline volatile anesthetic concentrations, doses of the administered medications, and length of time window.

RESULTS

The study cohort was comprised of data from 20,170 distinct cases, 54.7% of patients were men, with a median age of 55. In the primary analysis, ketamine at a median dose of 20 mg was associated with a median (confidence limits) increase in BIS index of 3.8 (2.5-5.0). Midazolam (median dose 2 mg) was associated with a median decrease in BIS index of 3.0 (1.5-4.5). Neither of these drug administrations occurred during time periods associated with changes in volatile anesthetic concentration. Analysis for dexmedetomidine was confounded by concomitant decreases in volatile anesthetic concentration. No other medication analyzed, including propofol and common opioids, was associated with a significant change in BIS index. Secondary analyses revealed that similar BIS index changes occurred when midazolam and ketamine were administered at different volatile anesthetic concentrations and different doses, and these changes persisted 11 to 20 minutes postadministration.

CONCLUSIONS

Modest, but persistent changes in BIS index occurred following doses of ketamine (increase) and midazolam (decrease) during periods of stable volatile anesthetic administration.

Propofol Reversibly Attenuates Short-Range Microstate Ordering and 20 Hz Microstate Oscillations

Microstate sequences summarize the changing voltage patterns measured by electroencephalography, using a clustering approach to reduce the high dimensionality of the underlying data. A common approach is to restrict the pattern matching step to local maxima of the global field power (GFP) and to interpolate the microstate fit in between. In this study, we investigate how the anesthetic propofol affects microstate sequence periodicity and predictability, and how these metrics are changed by interpolation. We performed two frequency analyses on microstate sequences, one based on time-lagged mutual information, the other based on Fourier transform methodology, and quantified the effects of interpolation. Resting-state microstate sequences had a 20 Hz frequency peak related to dominant 10 Hz (alpha) rhythms, and the Fourier approach demonstrated that all five microstate classes followed this frequency. The 20 Hz periodicity was reversibly attenuated under moderate propofol sedation, as shown by mutual information and Fourier analysis. Characteristic microstate frequencies could only be observed in non-interpolated microstate sequences and were masked by smoothing effects of interpolation. Information-theoretic analysis revealed faster microstate dynamics and larger entropy rates under propofol, whereas Shannon entropy did not change significantly. In moderate sedation, active information storage decreased for non-interpolated sequences. Signatures of non-equilibrium dynamics were observed in non-interpolated sequences, but no changes were observed between sedation levels. All changes occurred while subjects were able to perform an auditory perception task. In summary, we show that low dose propofol reversibly increases the randomness of microstate sequences and attenuates microstate oscillations without correlation to cognitive task performance. Microstate dynamics between GFP peaks reflect physiological processes that are not accessible in interpolated sequences.

The Effect of Central Sensitization on Postoperative Neurocognitive Dysfunction in Hospitalized Elderly Patients: A Prospective Cohort Clinical Trial

OBJECTIVE

To investigate whether central sensitization (CS) in elderly patients was a predictive risk factor for postoperative neurocognitive dysfunction (PNCD).

METHODS

One hundred and thirty-three aged patients undergoing total knee arthroplasty (TKA) who received femoral nerve block and general anesthesia were recruited in this research and prospectively assigned into two groups according to the Central Sensitization Inventory (CSI) score: group C (n = 106, CSI score less than 40) and group CS (n = 27, CSI score higher than 40). Scores of Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), Confusion Assessment Method (CAM), Numerical Rating Scale (NRS) and Quality of recovery-40 (QoR-40) questionnaires were assessed. Basic information and clinical records of all participants were also collected.

RESULTS

PNCD occurred in 24 (22.6%) of patients in group C and 16 (59.3%) in group CS (p < .05). Multivariate logistic regression analysis revealed that patients with CSI score ≥40 before surgery exhibited higher risk of PNCD after adjustment for other risk factors (p < .05). Compared to group C, the pre- and post-operative NRS scores, pain duration, the WOMAC score, and propofol consumptions for anesthesia induction were significantly increased in group CS (p < .05).

CONCLUSION

Hospitalized elderly patients with clinical symptoms of CS scores may have increased risk of PNCD following TKA.

Effect of moderate versus deep sedation on recovery following outpatient gastroscopy in older patients: a randomized controlled trial

BACKGROUND

Although gastrointestinal endoscopy with sedation is increasingly performed in older patients, the optimal level of sedation remains open to debate. In this study, our objective was to compare the effects of moderate sedation (MS) and deep sedation (DS) on recovery following outpatient gastroscopy in elderly patients.

METHODS

In this randomized, partially blinded, controlled trial, we randomly divided 270 patients older than 60 years who were scheduled for elective outpatient gastroscopy into the MS or DS group based on the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale. The primary outcome was the duration of stay in the post-anesthesia care unit (PACU). Secondary outcomes included the duration of the total hospital stay, frequency of retching, bucking, and body movements during the examination, endoscopist and patient satisfaction, and sedation-associated adverse events during the procedure.

RESULTS

A total of 264 patients completed the study, of whom 131 received MS and 133 received DS. MS was associated with a shorter PACU stay [16.15 ± 9.01 min vs. 20.02 ± 11.13 min, P < 0.01] and total hospital stay [27.32 ± 9.86 min vs. 30.82 ± 12.37 min, P < 0.05], lesser hypoxemia [2.3% (3/131) vs. 12.8% (17/133), P < 0.01], use of fewer vasoactive drugs (P < 0.001), and more retching (P < 0.001). There was no difference in the incidence of bucking and body movements or endoscopist and patient satisfaction between the two groups.

CONCLUSION

Compared to deep sedation, moderate sedation may be a preferable choice for American Society of Anesthesiologists (ASA) Grade I-III elderly patients undergoing outpatient gastroscopies, as demonstrated by shorter PACU stays and total hospital stays, lower sedation-associated adverse events, and similar levels of endoscopist and patient satisfaction.

Supplemental low-dose esketamine to propofol versus propofol alone on perioperative characteristics in children undergoing surgery: a prospective randomized controlled trial

BACKGROUND

Limited data exist regarding the use of the esketamine-propofol combination (esketofol) in pediatric surgery. This study aimed to investigate the effect of esketofol versus propofol alone on the perioperative characteristics of children undergoing minor surgery.

METHODS

Eighty-four children aged two to six years were randomly assigned to either the propofol group or the esketofol group. Intraoperative outcomes included bispectral index, dosage of anesthetics, and extubation time. Postoperative outcomes comprised oropharyngeal airway usage, time to orientation, time to eye-opening, length of stay in the post-anesthesia care unit, the need for rescue opioids, pain rating using the Face, Legs, Activity, Cry, Consolability (FLACC) Scale, Pediatric Anesthesia Emergence Delirium Score, nausea and vomiting, and psychotomimetic symptoms. The FLACC pain score was the primary outcome, and the remaining parameters were considered secondary outcomes.

RESULTS

The FLACC Score (2 [1, 3.3] vs. 4 [3, 5.3], P<0.001) and frequency of rescue opioids (14.3% vs. 33.3%, P=0.040) were significantly lower, while Bispectral Index (BIS) was higher (P<0.001) in the esketofol group compared with the propofol group. Moreover, the time to orientation and length of stay in the post-anesthesia care unit (PACU) were significantly longer in the esketofol group compared with the propofol group (P=0.029 and P=0.025, respectively). The other outcomes were similar between the two groups.

CONCLUSIONS

Esketofol reduces postoperative pain and the need for rescue opioids, but it extends recovery time in the PACU and increases BIS without affecting other outcomes.

Accuracy of closed-loop and open-loop propofol delivery systems by bispectral index monitoring in breast surgery patients: a prospective randomized trial

BACKGROUND

This randomized and controlled prospective study tested the hypothesis that closed-loop Target-Controlled Infusion (TCI) of propofol would be associated with better system performance when compared with open-loop controlled delivery of propofol.

METHODS

Patients scheduled for elective breast surgery were randomly assigned to two groups: a closed-loop group, in which propofol infusion was performed by a closed-loop TCI system that used the Bispectral Index (BIS) as a feedback parameter to titrate the rate of propofol infusion, and an open-loop group, in which propofol infusion was performed manually and guided by the bispectral index.

RESULTS

A total of 156 patients were recruited for this study (closed-loop group n = 79; open-loop group n = 77). The Global Score (GS) of the closed-loop group was lower than that of the open-loop group (34.3 and 42.2) (p = 0.044). The proportions of time with a BIS value between 40 and 60 were almost identical in the closed-loop group and the open-loop group (68.7 ± 10.6% and 66.7 ± 13.3%) (p = 0.318). The individuals in the closed-loop group consumed more propofol compared with those in the open-loop group (7.20 ± 1.65 mg.kg-1.h-1 vs. 6.03 ± 1.31 mg.kg-1.h-1, p < 0.001). No intraoperative recall, somatic events or adverse events occurred. No significant difference in heart rate was observed between the two groups (p = 0.169).

CONCLUSION

The closed-loop protocol was associated with lower BIS variability and lower out-of-range BIS values, at the cost of a greater consumption of propofol when compared to the open loop group.

REGISTER NUMBER

ChiCTR-INR-17010399.

Effect of fentanyl constant-rate infusions with or without medetomidine on the minimum infusion rate of propofol required to prevent motor movement in dogs

Propofol is a potential injectable anesthetic agent used in total intravenous anesthesia. However, the sparing effect of fentanyl and medetomidine on the required propofol dose in dogs remains unclear. We aimed to investigate the effect of fentanyl constant-rate infusion (CRI) with or without medetomidine on the minimum infusion rate of propofol required to prevent motor movement (MIRNM) in dogs. Six healthy purpose-bred dogs were anesthetized on three occasions with propofol alone (loading dose [LD], 8 mg/kg to effect; initial infusion rate [IR], 0.70 mg/kg/min); propofol (LD, 6 mg/kg to effect; IR, 0.35 mg/kg/min) and fentanyl (LD, 2 µg/kg; IR, 0.10 µg/kg/min); or propofol (LD, 4 mg/kg to effect; IR, 0.25 mg/kg/min), fentanyl (LD, 2 µg/kg; IR, 0.10 µg/kg/min), and medetomidine (LD, 2 µg/kg; IR, 0.5 µg/kg/hr) under controlled ventilation. The MIRNM was determined by observing the response to a noxious electrical stimulus. Heart rate, blood pressure, and blood gas analyses were performed at 1, 2, 3, and 4 hr after initiating CRI. The MIRNM (mean [range]) was significantly lower in the propofol-fentanyl-medetomidine group (0.16 [0.10-0.27] mg/kg/min) than that in the propofol-alone group (0.63 [0.47-0.82] mg/kg/min) (P=0.0004). Fentanyl combined with medetomidine did not significantly decrease the mean arterial pressure in dogs receiving propofol CRI 1-3 hr after initiating CRI compared with propofol CRI alone (P>0.9999, P=0.1536, and P=0.0596, respectively), despite inducing a significantly lower heart rate.

Remimazolam Dosing for Gastroscopy: A Randomized Noninferiority Trial

BACKGROUND

Remimazolam, an ultra-short-acting benzodiazepine, may provide adequate sedation for endoscopy while causing less cardiovascular or respiratory disturbance than propofol. Although fixed-dose administration is suggested, body weight affects the volume of the central chamber and thus affects the sedation depth that can be achieved by the first dose. This study aimed to compare the efficacy and safety of different doses of remimazolam and propofol by body weight for sedation during gastroscopy.

METHODS

This multicenter, randomized, single-blind, parallel-controlled noninferiority trial recruited patients from five centers between March 2021 and July 2022. A total of 1,883 patients scheduled to undergo gastroscopy were randomized to groups receiving 0.15 mg/kg remimazolam, 0.2 mg/kg remimazolam, or 1.5 mg/kg propofol. The noninferiority margin was set to 5%. The primary outcome was the success rate of sedation. Adverse events were recorded to evaluate safety.

RESULTS

The sedation success rate of the 0.2 mg/kg remimazolam group was not inferior to that of the 1.5 mg/kg propofol group (98.7% vs. 99.4%; risk difference, -0.64%; 97.5% CI, -2.2 to 0.7%, meeting criteria for noninferiority). However, the sedation success rate of the 0.15 mg/kg remimazolam group was 88.5%, and that of the 1.5 mg/kg propofol group was 99.4% (risk difference, -10.8%; 97.5% CI, -14.0% to -8.0%), demonstrating inferiority. Simultaneously, the overall adverse events rate of remimazolam was lower than that of propofol, and the incidence of bradycardia, hypotension, subclinical respiratory depression, and hypoxia in the remimazolam groups was significantly lower than that in the propofol group.

CONCLUSIONS

This trial established the noninferior sedation success rate of remimazolam (0.2 mg/kg but not 0.15 mg/kg) compared with propofol (1.5 mg/kg), with a superior safety profile.

EDITOR’S PERSPECTIVE

Comparison of recovery profiles between total intravenous anaesthesia with propofol or remimazolam reversed with flumazenil in patients undergoing breast surgery: A randomised controlled trial

BACKGROUND

Remimazolam, a short acting benzodiazepine, is being used for general anaesthesia. The results of studies comparing recovery after propofol with that of remimazolam are inconsistent. Given that flumazenil reverses the sedative effects of remimazolam, we hypothesised that it would speed up recovery from remimazolam general anaesthesia.

OBJECTIVES

The aim of this trial was to compare the speed of recovery from general anaesthesia between propofol and remimazolam reversed with flumazenil in patients undergoing minimally invasive breast surgery.

DESIGN

Randomised, single-centre, double-blind controlled trial.

SETTING

A tertiary teaching hospital in South Korea from August 2022 to December 2022.

PATIENTS

Adult patients (≥19 years of age) about to undergo general anaesthesia for scheduled breast cancer surgery.

INTERVENTIONS

Patients were randomly allocated to either the propofol or the remimazolam/flumazenil group. The emergence process was monitored by only one anaesthesiologist.

MAIN OUTCOME MEASURES

The primary outcome was the time to eye opening to command during recovery from the general anaesthesia. Time to removal of the supraglottic airway (SGA) time to discharge, and the Riker sedation agitation scale (SAS) score (1 to 4) during emergence were compared as secondary outcomes.

RESULTS

The remimazolam group had a significantly shorter mean time to eye opening than the propofol group [127 ± 51 vs. 314 ± 140 s; mean difference 187 s (95% confidence interval (CI), 133 to 241 s; P  < 0.001]. The remimazolam group also had shorter times to SGA removal [169 ± 51 vs. 366 ± 149 s; mean difference 198 s (95% CI, 140 to 255 s); P  < 0.001] and time to discharge from the operating room [243 ± 55 vs. 449 ± 159 s; mean difference 206 s (95% CI, 145 to 267 s); P  < 0.001]. The SAS scores during emergence also differed significantly, with 1 patient in the propofol group and 25 in the remimazolam group attaining scores of 4 ( P  < 0.001).

CONCLUSION

Administration of remimazolam with flumazenil may be a promising option for patients undergoing breast cancer surgery, providing faster recovery and better SAS scores than propofol during emergence from general anaesthesia.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT05435911).

Comparison of hemodynamic changes with general or local anesthesia during dental treatment in pediatric patients: A prospective clinical study

BACKGROUND AND AIM

Severe hemodynamic fluctuations during dental treatment can trigger highly undesirable physical reactions. A study was made to determine whether the administration of propofol and sevoflurane contributes to the stabilization of hemodynamic parameters during dental treatment in pediatric patients versus the use of local anesthesia alone.

MATERIALS AND METHODS

Forty pediatric patients needing dental treatment were assigned to either general anesthesia with local anesthesia (study group [SG]) or local anesthesia alone (control group [CG]). Two percent sevoflurane in oxygen (100% oxygen, 5 L/min) and continuous propofol infusion (target-controlled infusion [TCI], 2 μg/mL) were used as general anesthesia agents in SG; and 2% lidocaine with 1:80,000 adrenaline was used as local anesthesia in both groups. Heart rate, blood pressure and oxygen saturation were measured before starting dental treatment (baseline) and every 10 min during dental treatment.

RESULTS

Blood pressure (p < .001), heart rate (p = .021) and oxygen saturation (p = .007) decreased substantially after the administration of general anesthesia. The levels of these parameters subsequently remained low and then recovered at the end of the procedure. On the other hand, the oxygen saturation values remained closer to baseline in SG versus CG. In contrast, the hemodynamic parameters experienced lesser fluctuations in CG than in SG.

CONCLUSIONS

General anesthesia affords more favorable cardiovascular parameters during the entire dental treatment in comparison to local anesthesia alone (blood pressure and heart rate decrease significantly and oxygen saturation proves more stable and with values closer to baseline), and allows dental treatment to be performed on healthy, lacking cooperative ability children who otherwise could not be treated with local anesthesia alone. No side effects were observed in either group.

Effect of esketamine on the EC50 of remifentanil for blunting cardiovascular responses to endotracheal intubation in female patients under general anesthesia: a sequential allocation dose-finding study

BACKGROUND

This study aimed to investigate the effect of esketamine on the dose-effect relationship between remifentanil and the cardiovascular response to endotracheal intubation during target-controlled infusion (TCI) of propofol.

METHODS

Patients underwent elective gynecological laparoscopic surgery under general anesthesia with endotracheal intubation, aged 18-65 years, American Society of Anesthesiologists class I or II, 18 kg/m2 ≤ body mass index ≤ 30 kg/m2, were randomly divided into the control (group C) and esketamine groups (group E). Before anesthesia induction, group E received an intravenous injection of 0.3 mg/kg of esketamine, while group C received an equal dose of physiological saline. TCI of propofol to the effect-site concentration (EC) of 3.0 μg/mL, and then TCI of remifentanil to the effect room and intravenous injection of rocuronium 0.6 mg/kg after MOAA/S was 0. Endotracheal intubation was performed after 2 min. Dixon's modified sequential method was used, and the initial EC of remifentanil was 3.0 ng/mL. The EC of remifentanil was determined according to the intubation response of the previous patient, with an adjacent concentration gradient of 0.3 ng/mL. The EC50 and EC95 values and their 95% confidence intervals (CIs) were determined using probit regression analysis.

RESULTS

The EC50 for cardiovascular response inhibition to endotracheal intubation using remifentanil was 3.91 ng/mL (95% CI: 3.59-4.33 ng/mL) and EC95 was 4.66 ng/mL (95% CI: 4.27-6.23 ng/mL) with TCI of propofol 3.0 μg/mL. After intravenous administration of 0.3 mg/kg of esketamine, the EC50 of remifentanil was 3.56 ng/mL (95% CI: 3.22-3.99 ng/mL) and EC95 was 4.31 ng/mL (95% CI: 3.91-5.88 ng/mL).

CONCLUSIONS

Combined with TCI of propofol 3.0 μg/mL for anesthesia induction, esketamine significantly reduced the EC50 and EC95 of remifentanil to inhibit the cardiovascular response to endotracheal intubation.

TRIAL REGISTRATION

The trial was registered in the Chinese Clinical Trials Registry ( www.chictr.org.cn ; registration number: ChiCTR2200064932; date of registration:24/10/2022).

Effective dose of propofol combined with intravenous esketamine for smooth flexible laryngeal mask airway insertion in two distinct age groups of preschool children

BACKGROUND

There is limited research on the combined use of propofol and esketamine for anesthesia induction during flexible laryngeal mask airway (FLMA) in pediatric patients, and the effective dosage of propofol for FLMA smooth insertion remains unclear. We explored the effective dose of propofol combined with intravenous esketamine for the smooth insertion of FLMA in two distinct age groups of preschool children.

METHODS

This is a prospective, observer-blind, interventional clinical study. Based on age, preschool children scheduled for elective surgery were divided into group A (aged 1-3 years) and group B (aged 3-6 years). Anesthesia induction was started with intravenous administration of esketamine (1.0 mg.kg- 1) followed by propofol administration. The FLMA was inserted 2 min after propofol administration at the target dose. The initial dose of propofol in group A and group B was 3.0 mg.kg- 1 and 2.5 mg.kg- 1, respectively. The target dose of propofol was determined with Dixon's up-and-down method, and the dosing interval of propofol was 0.5 mg.kg- 1. If there was smooth insertion of FLMA in the previous patient, the target dose of propofol for the next patient was reduced by 0.5 mg.kg- 1; otherwise, it was increased by 0.5 mg.kg- 1. The median 50% effective dose (ED50) for propofol was estimated using Dixon's up-and-down method and Probit analysis, while the 95% effective dose (ED95) was estimated through Probit analysis. Vital signs and adverse events during induction were recorded.

RESULTS

Each group included 24 pediatric patients. Using Dixon's up-and-down method, the ED50 of propofol combined with esketamine for smooth insertion of FLMA in group A was 2.67 mg.kg- 1 (95%CI: 1.63-3.72), which was higher than that in group B (2.10 mg. kg- 1, 95%CI: 1.36-2.84) (p = 0.04). Using Probit analysis, the ED50 of propofol was calculated as 2.44 (95% CI: 1.02-3.15) mg.kg- 1 in group A and 1.93 (95% CI: 1.39-2.32) mg.kg- 1 in group B. The ED95 of propofol was 3.72 (95%CI: 3.07-15.18) mg.kg- 1 in group A and 2.74 (95%CI: 2.34-5.54) mg.kg- 1 in group B. In Group B, one pediatric patient experienced laryngospasm.

CONCLUSION

The effective dose of propofol when combined with intravenous esketamine for smooth insertion of FLMA in children aged 1-3 years is 2.67 mg.kg- 1, which is higher than that in children aged 3-6 years (2.10 mg. kg- 1).

TRIAL REGISTRATION

Chinese Clinical Trial Registry Center (Registration Number: ChiCTR2100044317; Registration Date: 2021/03/16).

The 50% and 95% effective dose of remimazolam tosilate for anaesthesia induction in sleep disorders patients undergoing laparoscopic cholecystectomy: an up-and-down sequential allocation trial

PURPOSE

Previous reports argue that preoperative sleep conditions of patients can influence the dosage of general anaesthesia drugs. Therefore, we aimed to investigate the dose-effect relationship of preoperative sleep disorders on the induction of general anaesthesia with remimazolam tosilate and calculate the Median effective (ED50) and 95% effective (ED95) dosages.

METHODS

Included in our study were 56 patients who underwent laparoscopic cholecystectomy at our hospital. A separate group of 27 patients with sleep disorders (SD group) and 29 patients without sleep disorders (NSD group) using the Pittsburgh Sleep Quality Index (PSQI) were also included. According to the Dixon 'up-and-down' design, patients received remimazolam at preselected concentrations starting at 0.2 mg/kg. After the administration of remimazolam, loss of consciousness was observed. By observing whether consciousness disappeared within a minute, we adjusted the dose of remimazolam by 0.1 mg/kg (up and down) in the following patient. The Median effective dose (ED50), 95% effective dose (ED95), and 95% confidence interval (CI) of remimazolam for effective sedation were calculated.

RESULTS

The ED50 of remimazolam was 0.226 mg/kg (95%CI 0.221-0.232 mg/kg) in the SD group and 0.191 mg/kg (95%CI, 0.183-0.199 mg/kg) in the NSD group. The ED95 of remimazolam was 0.237 mg/kg (95%CI 0.231-0.262 mg/kg) in the SD group and 0.209 mg/kg (95%CI 0.200-0.254 mg/kg) in the NSD group.

CONCLUSIONS

In the SD group, the ED50 and ED95 of remimazolam during anaesthesia induction were 0.226 and 0.237 mg/kg, respectively. The induction dose of remimazolam in the SD group was significantly higher than that in the NSD group.

Sleep loss, caffeine, sleep aids and sedation modify brain abnormalities of mild traumatic brain injury

Little evidence exists about how mild traumatic brain injury (mTBI) is affected by commonly encountered exposures of sleep loss, sleep aids, and caffeine that might be potential therapeutic opportunities. In addition, while propofol sedation is administered in severe TBI, its potential utility in mild TBI is unclear. Each of these exposures is known to have pronounced effects on cerebral metabolism and blood flow and neurochemistry. We hypothesized that they each interact with cerebral metabolic dynamics post-injury and change the subclinical characteristics of mTBI. MTBI in rats was produced by head rotational acceleration injury that mimics the biomechanics of human mTBI. Three mTBIs spaced 48 h apart were used to increase the likelihood that vulnerabilities induced by repeated mTBI would be manifested without clinically relevant structural damage. After the third mTBI, rats were immediately sleep deprived or administered caffeine or suvorexant (an orexin antagonist and sleep aid) for the next 24 h or administered propofol for 5 h. Resting state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI) were performed 24 h after the third mTBI and again after 30 days to determine changes to the brain mTBI phenotype. Multi-modal analyses on brain regions of interest included measures of functional connectivity and regional homogeneity from rs-fMRI, and mean diffusivity (MD) and fractional anisotropy (FA) from DTI. Each intervention changed the mTBI profile of subclinical effects that presumably underlie healing, compensation, damage, and plasticity. Sleep loss during the acute post-injury period resulted in dramatic changes to functional connectivity. Caffeine, propofol sedation and suvorexant were especially noteworthy for differential effects on microstructure in gray and white matter regions after mTBI. The present results indicate that commonplace exposures and short-term sedation alter the subclinical manifestations of repeated mTBI and therefore likely play roles in symptomatology and vulnerability to damage by repeated mTBI.

Postoperative Sleep Quality of Insomnia Patients After TIVA Anesthesia: A Prospective Study

PURPOSE

The purpose of this study is to observe the postoperative sleep quality of insomnia patients undergoing laparoscopic gynecologic oncology surgery after total intravenous anesthesia.

DESIGN

Prospective study.

METHODS

We conducted a prospective, observational study in our hospital. All patients underwent propofol-remifentanil anesthesia without other sedative medications before or during the operation. Pittsburgh Sleep Quality Index (PSQI) scores of the baseline value, night-1 (the first night after surgery), night-3, night-5, and night-30 were observed.

FINDINGS

Sixty-nine female insomnia patients were allocated based on the results of the PSQI and the diagnostic criteria of insomnia. The PSQI global scores were respectively 6 (5-8), 5 (4-6), 5 (3-6), and 6 (5-7) on night-1, night-3, night-5, and night-30, significantly lower than the baseline 7 (6-8) (P < 0.05). The 5 components (subjective sleep quality, sleep latency, sleep duration, sleep efficiency and daytime dysfunction) had significant changes at different postoperative time points (P < 0.05). The daytime dysfunction could also be improved 1 month after the surgery (P < 0.05). In contrast, the variations of sleep disturbance and use of sleep medication had no statistical differences.

CONCLUSIONS

The sleep quality of female patients with insomnia was improved on the first night after surgery in the sides of sleep latency and daytime dysfunction, and the improvement could also be obtained 1 month after propofol-remifentanil general anesthesia.

Sedation with propofol/remifentanil versus dexmedetomidine / remifentanil for patients undergoing transcatheter aortic valve implant: A retrospective study between 2012 and 2019

BACKGROUND AND OBJECTIVES

Percutaneous implantation of an aortic valve prosthesis is a therapeutic alternative for patients with severe aortic stenosis. The procedure is traditionally performed under general anaesthesia; however, sedation is now gaining in popularity because it reduces the need for vasoactive drugs and shortens the patient's stay in the critical care unit and on the ward. The aim of this study is to evaluate the clinical efficacy, safety and potential benefits of sedation with dexmedetomidine in patients undergoing percutaneous implantation of an aortic valve prosthesis in terms of haemodynamic and respiratory complications.

MATERIALS AND METHODS

We performed a retrospective study of 222 patients that had undergone percutaneous implantation of an aortic valve prosthesis between 2012 and 2019 under sedation with either dexmedetomidine plus remifentanil (DEX-RMF) or propofol plus remifentanil (PROPO-RMF). We collected data on complications, mainly haemodynamic and respiratory, during and after the procedure.

RESULTS

No significant differences were found between sedation with dexmedetomidine and propofol (in combination with remifentanil) in terms of haemodynamic stability and intraprocedural cerebral blood oxygen. In the DEX-RMF group, however, mean blood pressure, midazolam dose, and duration of anaesthesia were lower compared with the PROPO-RMF group, but the incidence of haemodynamic and respiratory complications did not differ significantly between groups.

CONCLUSIONS

Our results show that sedation, particularly with adjuvant dexmedetomidine, is a valid anaesthetic techniques in percutaneous aortic valve prosthesis implantation.

Safety and efficacy of low-dose esketamine in laparoscopic cholecystectomy: a prospective, double-blind randomized controlled trial

BACKGROUND

Esketamine, recognized for its analgesic, sedative, and anti-inflammatory qualities, is integral in multimodal analgesia. However, the potential opioid-sparing effects of intravenous esketamine, along with its impact on inflammatory responses, and cognitive function during laparoscopic surgery, remain unexplored.

METHODS

In this study, 90 patients scheduled for laparoscopic cholecystectomy were equally randomized into three groups: a normal saline control group (NS), a low-dose esketamine group (LS) and a high-dose esketamine group (HS). Subsequently, we monitored several parameters: hemodynamics, levels of stress and inflammatory responses, intraoperative doses of sufentanil, remifentanil, and propofol, and 24-hour postoperative sufentanil requirements. We also evaluated alterations in cognitive function, perioperative indicators, and potential adverse reactions among the three groups.

RESULTS

Compared to their levels 5 minutes prior to anesthesia (T0) and 30 minutes post-operation (T4), the NS group exhibited a more significant decrease in Mean Arterial Pressure (MAP) and Heart Rate (HR) at various time intervals: 5 minutes after the skin incision (T1), 30 minutes post-incision (T2), and at the conclusion of the operation (T3), compared to the LS and HS groups(P < 0.05). Furthermore, the NS group exhibited a greater increase in levels of adrenaline (AD), noradrenaline (NE), endothelin (ET), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) at T1, T2, and T3, more so than the other two groups(P < 0.05). 24 hours after the surgery, patients in the LS group and HS group had significantly higher Montreal Cognitive Assessment (MoCA) scores than those in the NS group(P < 0.05). The LS and HS groups required lower doses of propofol, remifentanil, and sufentanil during surgery (P < 0.05), experienced shorter postoperative recovery times, and had lower incidences of nausea, vomiting, and respiratory depression compared to the NS group (P < 0.05).

CONCLUSION

The administration of low-dose esketamine has been shown to be safe, effective, and dependable in the context of laparoscopic gallbladder surgery. It has the capacity to stabilize hemodynamic responses, ameliorate both stress and inflammatory reactions from surgery, and hastens anesthesia recovery. Furthermore, it fosters the restoration of postoperative cognitive function. Notably, when combined with nalbuphine, it exhibits opioid-sparing effects, reducing postoperative adverse outcomes.

TRIAL REGISTRATION

The trial is registered with the China Clinical Trials Registry Registration Number: ChiCTR2300067596. Retrospectively registered (date of registration: 12/01/2023).

Performance of closed-loop systems for intravenous drug administration: a systematic review and meta-analysis of randomised controlled trials

Closed-loop drug delivery systems are autonomous computers able to administer medication in response to changes in physiological parameters (controlled variables). While limited evidence suggested that closed-loop systems can perform better than manual drug administration in certain settings, this technology remains a research tool with an uncertain risk/benefit profile. Our aim was comparing the performance of closed-loop systems with manual intravenous drug administration in adults. We searched MEDLINE, CENTRAL, and Embase from inception until November 2022, without restriction to language. We assessed for inclusion randomised controlled trials comparing closed-loop and manual administration of intravenous drugs in adults, intraoperatively or in the Intensive Care Unit. We identified 32 studies on closed-loop administration of propofol, noradrenaline, phenylephrine, insulin, neuromuscular blockers, and vasodilators. Most studies were at moderate or high risk of bias. The results showed that closed-loop systems reduced the duration of blood pressure outside prespecified targets during noradrenaline (MD 14.9%, 95% CI 9.6-20.2%, I2 = 66.6%) and vasodilators administration (MD 7.4%, 95% CI 5.2-9.7%, I2 = 62.3%). Closed-loop systems also decreased the duration of recovery after propofol (MD 1.3 min, 95% CI 0.4-2.1 min, I2 = 58.6%) and neuromuscular blockers (MD 9.0 min, 95% CI 7.9-10.0 min, I2 = 0%). The certainty of the evidence was low or very low for most outcomes. Automatic technology may be used to improve the hemodynamic profile during noradrenaline and vasodilators administration and reduce the duration of postanaesthetic recovery.Registration: This systematic review was registered with PROSPERO (CRD42022336950) on the 7th of June 2022.

Effects of propofol, desflurane, and spinal anesthesia on intraocular pressure during lumbar disc herniation surgery: a randomized controlled study

OBJECTIVE

This study aims to evaluate the effects of total intravenous anesthesia (propofol), volatile anesthesia (desflurane), and spinal anesthesia on intraocular pressure (IOP) during lumbar disc herniation surgery in the prone position.

PATIENTS AND METHODS

This randomized controlled trial was conducted between January 2022 and January 2023. The study included 75 patients with lumbar disc herniation between the ages of 18-75, with the American Society of Anesthesiologists (ASA) 1-2. The patients were randomly divided into 3 groups: propofol, desflurane, and spinal. IOP was measured at 5-time points throughout surgery, including baseline (T1), 10 minutes after anesthesia (T2), 10 minutes after prone positioning (T3: early prone), 30 minutes after prone positioning (T4: late prone), and 10 minutes after returning to the supine position (T5). Hemodynamic parameters were measured at these time points. Hemoglobin and hematocrit values were measured preoperatively and on the first postoperative day.

RESULTS

There were 25 patients in each group. The groups were similar in terms of all characteristics except for weight and body mass index, which were lower in the spinal group. Propofol recipients had significantly higher T3 (prone) IOP compared to desflurane recipients (p = 0.001). We found no significant differences between groups in terms of T1, T2, T4, and T5 IOP. Multivariable linear regression revealed that diabetes mellitus (p = 0.016) and high T1 IOP (p = 0.001) were independently associated with higher T3 IOP. In addition, we found that the desflurane (p < 0.001) and spinal (p = 0.002) groups had significantly lower T3 IOP compared to propofol recipients after adjusting for diabetes mellitus and T1 IOP.

CONCLUSIONS

Our findings suggest that volatile anesthesia (desflurane) and spinal anesthesia are linked to lower IOP in the prone position among patients undergoing spinal surgery, in comparison to those receiving total intravenous anesthesia. There is a need to test the results with more comprehensive, population-based studies in different patient groups. ClinicalTrials gov ID: NCT06070480.

Total intravenous anaesthesia with propofol and remifentanil is associated with reduction in operative time in surgery for glioblastoma when compared with inhalational anaesthesia with sevoflurane

BACKGROUND

Total intravenous anaesthesia (TIVA) is emerging as a preferred neuroanaesthetic agent compared with inhalational anaesthetic (IA) agents. We asked if TIVA with propofol and remifentanil was associated with shorter operative times compared to IA using sevoflurane in brain tumour surgery under GA.

METHODS

We performed a retrospective analysis of all patients undergoing surgery for glioblastoma (GBM). We assessed choice of GA agent (TIVA or IA) with total time patient was under GA (anaesthetic time), operative time and time taken to recover fully from GA (recovery time).

RESULTS

Over a two year period 263 patients underwent surgery under GA for their GBM including 188 craniotomy operations, 63 burr hole biopsy procedures and 12 open biopsy procedures. Of these, 79 operations took place under TIVA and 184 operations under IA. TIVA was associated with significantly reduced mean operative time including time taken to wake up in theatre (104 min with TIVA, 129 min with IA; p = 0.02). TIVA was also associated with trends toward shorter mean recovery time (118 min, versus 135 min with IA; p = 0.08) and shorter mean anaesthetic time (163 min, versus 181 min with IA; p = 0.07). There was no difference between TIVA and IA groups as regards duration of inpatient stay, readmission rates, complications or survival.

CONCLUSIONS

TIVA with propofol and remifentanil may reduce anaesthetic, operative and recovery times in patients undergoing surgery for their GBM. These findings may be attributable to favourable effects on intracranial pressure and cerebral perfusion, as well as rapid recovery from GA. In addition to clinical advantages, there may be financial and logistical benefits.

Population pharmacokinetic/pharmacodynamic modeling and exposure-response analysis of ciprofol in the induction and maintenance of general anesthesia in patients undergoing elective surgery: A prospective dose optimization study

AIM

This study aimed to establish a population pharmacokinetic and pharmacodynamic (PK-PD) model to explore the optimal maintenance dose and appropriate starting time of maintenance dose after induction of ciprofol and investigate the efficacy and safety of ciprofol for general anesthesia induction and maintenance in patients undergoing elective surgery.

METHOD

A total of 334 subjects with 3092 concentration measurements from nine clinical trials and 115 subjects with 5640 bispectral index (BIS) measurements from two clinical trials were used in the population PK-PD analysis. Exposure-response relationships for both efficacy endpoints (duration of anesthesia successful induction, time to recovery from anesthesia, time to respiratory recovery, and time from discontinuation to the 1st/3rd consecutive Aldrete score ≥ 9) and safety variables (hypotension, bradycardia, and injection site pain) were evaluated based on the data gathered from 115 subjects in two clinical trials.

RESULT

Ciprofol pharmacokinetics (PK) were adequately described by a three-compartment model with first-order elimination from the central compartment and redistribution from the deep and shallow peripheral compartments. An inhibitory sigmoidal Emax model best described the relationship between ciprofol effect-site concentrations and BIS measurements. Body weight, age, sex, blood sampling site, and study type (short-term infusion vs long-term infusion) were identified as statistically significant covariates on the PK of ciprofol. No covariates were found to have a significant effect on the pharmacodynamic (PD) parameters. The PK-PD simulation results showed that the optimal maintenance dose was 0.8 mg/kg/h and the appropriate time to start the maintenance dose was 4-5 mins after the induction dose of ciprofol. Within the exposure range of this study, no meaningful correlations between ciprofol exposures and efficacy or safety endpoints were observed.

CONCLUSION

A population PK-PD model was successfully developed to describe the ciprofol PK and BIS changes. Efficacy was consistent across the exposure range with a well-tolerated safety profile indicating no maintenance dose adjustment is required for patients undergoing elective surgery.