Target‐controlled infusion of dexmedetomidine effect‐site concentration for sedation in patients undergoing spinal anaesthesia

Comparison of the efficacy and safety of ciprofol and propofol in sedating patients in the operating room and outside the operating room: a meta-analysis and systematic review

BACKGROUND

As a new type of intravenous anesthetic, ciprofol has the advantages of fast onset of action, fast recovery and high clearance rate. This study aimed to investigate the effectiveness and safety of ciprofol versus traditional propofol for anesthesia and sedation in and out of the operating room.

METHODS

We searched the literature in PubMed, Web of Science, Cochrane Library, and Embase databases from January 2021 to December 2023. All clinical studies comparing the sedative effects of propofol and ciprofol, both inside and outside the operating room, were included in our trial. The main outcome measures were induction time and incidence of injection-site pain. Data are merged using risk ratio and standardized mean difference with 95% confidence interval. Subgroup analysis, meta-regression, sensitivity analysis, and publication bias were performed. The study protocol was prospectively registered with PROSPERO (CRD42023447747).

RESULTS

A total of 15 randomized, controlled trials involving 2002 patients were included in this study. Compared with propofol, ciprofol has a longer induction time in the operating room but a shorter induction time in non-operating room settings. Ciprofol can effectively reduce the risk of injection-site pain and respiratory depression both inside and outside the operating room. In addition, the risk of drug-related hypotension induced with ciprofol in the operating room is lower, but the awakening time is also longer. Meta-regression analysis showed that neither age nor BMI were potential sources of heterogeneity. Funnel plot, egger and begg tests showed no significant publication bias. Sensitivity analyzes indicate that our results are robust and reliable.

CONCLUSION

Ciprofol has absolute advantages in reducing the risk of injection-site pain and respiratory depression, both in and outside operating room. Intraoperative use of ciprofol reduces the risk of drug-related hypotension and may also reduce the risk of intraoperative physical movements. However, ciprofol may have longer induction and awakening time than propofol.

Intravenous Ganaxolone: Pharmacokinetics, Pharmacodynamics, Safety, and Tolerability in Healthy Adults

Ganaxolone, a neuroactive steroid anticonvulsant that modulates both synaptic and extrasynaptic γ-aminobutyric acid type A (GABAA ) receptors, is in development for treatment of status epilepticus (SE) and rare epileptic disorders, and has been approved in the United States for treatment of seizures associated with cyclin-dependent kinase-like 5 deficiency disorder in patients ≥2 years old. This phase 1 study in 36 healthy volunteers evaluated the pharmacokinetics, pharmacodynamics, and safety of intravenous ganaxolone administered as a (i) single bolus, (ii) infusion, and (iii) bolus followed by continuous infusion. After a single bolus over 2 minutes (20 mg) or 5 minutes (10 or 30 mg), ganaxolone was detected in plasma with a median Tmax of 5 minutes, whereas a 60-minute infusion (10 or 30 mg) or a bolus (6 mg over 5 minutes) followed by infusion (20 mg/h) for 4 hours achieved a median Tmax of approximately 1 and 3 hours, respectively. Cmax was dose and administration-time dependent, ranging from 73.8 ng/mL (10 mg over 5 minutes) to 1240 ng/mL (30 mg over 5 minutes). Bolus doses above 10 mg of ganaxolone markedly influenced the bispectral index score with a rapid decline; smaller changes occurred on the Modified Observer's Assessment of Alertness/Sedation scale and in quantitative electroencephalogram. Most adverse events were of mild severity, with 2 events of moderate severity; none were reported as serious. No effects on systemic hemodynamics or respiratory functions were reported. Overall, ganaxolone was generally well tolerated at the doses studied and demonstrated pharmacokinetic and pharmacodynamic properties suitable to treat SE.

EEG response of dexmedetomidine during drug induced sleep endoscopy

Introduction

Dexmedetomidine is one of the anesthetics of choice for drug induced sleep endoscopy (DISE), with advantages including limited respiratory depression, analgesia, and decreased incidence of emergence delirium. However, challenges with determining sedation levels and prolonged recovery have limited its usage. An improved understanding of the effect of dexmedetomidine on the level of sedation and the corresponding electroencephalographic (EEG) changes could help overcome these barriers.

Methods

Fifty-one patients received dexmedetomidine sedation with Richmond Agitation-Sedation Scale (RASS) score assessment and continuous EEG monitoring via SedLine for DISE. We constructed a pharmacokinetic model to determine continuous dexmedetomidine blood concentration. From the SedLine, we extracted the patient state index (PSI), and from the EEG we calculated the spectral edge frequency 95% (SEF95) and the correlation dimension (CD), a type of fractal dimension used to assess the complexity of a system. These metrics were subsequently compared against one another and with the dexmedetomidine concentration.

Results

Our pharmacokinetic model yielded a two-compartment model with volumes of 51.8 L and 106.2 L, with clearances of 69.5 and 168.9 L/h, respectively, and a time to effect of 9 min, similar to prior studies. Based on this model, decreasing RASS score, SEF95, CD, and PSI were all significantly associated with increasing dexmedetomidine concentration (p < 0.001, p = 0.006, p < 0.001 respectively). The CD, SEF95, and PSI better captured the effects of increasing dexmedetomidine concentration as compared to the RASS score. Simulating dexmedetomidine concentration based on titration to target levels derived from CD and PSI confirmed commonly used dexmedetomidine infusion dosages.

Conclusion

Dexmedetomidine use for DISE confirmed previous pharmacokinetic models seen with dexmedetomidine. Complex EEG metrics such as PSI and CD, as compared to RASS score and SEF95, better captured changes in brain state from dexmedetomidine and have potential to improve the monitoring of dexmedetomidine sedation.

Comparison of the performance of phase lag entropy and bispectral index for monitoring the depth of sedation under dexmedetomidine sedation: A prospective, observational, and non-inferiority trial

STUDY OBJECTIVE

Although the performance of phase lag entropy (PLE), a new depth-of-sedation monitor based on the diversity of temporal patterns in the phase relationships in electroencephalogram (EEG) data, during propofol sedation has been proven through several studies, since different sedatives have different effects on EEG, we aimed to evaluate the performance of the PLE in comparison with the bispectral index (BIS) during dexmedetomidine sedation.

DESIGN

A prospective, observational, and non-inferiority trial.

SETTING

Tertiary university hospital operating room.

PATIENTS

Forty-two patients aged 20-80 years who were scheduled to undergo elective surgery under spinal anesthesia and had American Society of Anesthesiologists (ASA) physical status I to III were enrolled in this study.

INTERVENTIONS

Dexmedetomidine was administered with a loading dose of 0.5-1 μg/kg for 10 min, followed by a maintenance dose of 0.3-0.6 μg/kg/h.

MEASUREMENTS

The depth of sedation was assessed using the modified observer's assessment of alertness/sedation (MOAA/S) scale; the data for PLE and BIS were collected; and vital signs, including blood pressure, heart rate, EKG, and pulse oximetry, were evaluated.

MAIN RESULTS

215,082 data points for the MOAA/S score and PLE and BIS values were analyzed. The baseline variabilities of PLE and BIS were 4.53% and 7.02%, respectively. The Spearman correlation coefficients of the MOAA/S score with PLE and BIS were 0.599 and 0.566, respectively. The prediction probabilities of the MOAA/S score with PLE and BIS were 0.647 and 0.636, respectively. When the MOAA/S score was 3 points, the mean (SD) values of PLE and BIS were 68.35 (15.68) and 75.85 (9.81), respectively, However, the mean (SD) values of PLE and BIS for an MOAA/S score of 1 point were 56.08 (12.49) and 68.29 (12.65), respectively.

CONCLUSIONS

PLE shows potential as a hypnotic depth indicator during dexmedetomidine sedation, and its performance was not inferior to that of BIS.

The efficacy and safety of ciprofol use for the induction of general anesthesia in patients undergoing gynecological surgery: a prospective randomized controlled study

Background

Ciprofol is a recently developed, short-acting γ-aminobutyric acid receptor agonist sedative that is more potent than propofol, but there have been few clinical studies of this agent to date. Here, we sought to examine the safety and efficacy of ciprofol use for the induction of general anesthesia in individuals undergoing gynecological surgery.

Methods

Women between the ages of 18 and 60 years (ASA physical status 1 or 2) who were scheduled to undergo elective gynecological surgery under general anesthesia were randomly assigned to two equally sized groups in which anesthesia induction was performed using either ciprofol or propofol. General anesthesia induction success rates were the primary outcome for this study, while secondary outcomes included changes in BIS during the 10 min following the first administration of the study drug, the duration of successful induction, and adverse event incidence.

Results

A total of 120 women were included in the study. A 100% rate of successful induction was achieved in both the ciprofol and propofol groups, with no significant differences between these groups with respect to the duration of successful induction (34.8 ± 15.5 s vs 35.4 ± 9.5 s, P = 0.832), the time to the disappearance of the eyelash reflex (33.7 ± 10.6 s vs 34.0 ± 6.5 s, P = 0.860), or tracheal intubation (58.2 ± 31.1 s vs 53.9 ± 25.4 s, P = 0.448). Adverse event rates, including intubation responses, were significantly lower in the ciprofol group as compared to the propofol group(20% vs 48.33%, P = 0.0019). Ciprofol was associated with reduced injection pain relative to propofol (16.7% vs 58.3%, P < 0.001).

Conclusions

Ciprofol exhibits comparable efficacy to that of propofol when used for the induction of general anesthesia in individuals undergoing gynecological surgery and is associated with fewer adverse events.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01782-7.

Population Pharmacokinetics of Intranasal Dexmedetomidine in Infants and Young Children

BACKGROUND

Intranasal dexmedetomidine provides noninvasive, effective procedural sedation for pediatric patients, and has been widely used in clinical practice. However, the dosage applied has varied fourfold in pediatric clinical studies. To validate an appropriate dosing regimen, this study investigated the pharmacokinetics of intranasal dexmedetomidine in Chinese children under 3 yr old.

METHODS

Intranasal dexmedetomidine 2 µg · kg-1 was administered to children with simple vascular malformations undergoing interventional radiological procedures. A population pharmacokinetic analysis with data from an optimized sparse-sampling design was performed using nonlinear mixed-effects modeling. Clearance was modeled using allometric scaling and a sigmoid postmenstrual age maturation model. Monte Carlo simulations were performed to assess the different dosing regimens.

RESULTS

A total of 586 samples from 137 children aged 3 to 36 months were included in the trial. The data were adequately described by a two-compartment model with first-order elimination. Body weight with allometric scaling and maturation function were significant covariates of dexmedetomidine clearance. The pharmacokinetic parameters for the median subjects (weight 10 kg and postmenstrual age 101 weeks) in the authors' study were apparent central volume of distribution 7.55 l, apparent clearance of central compartment 9.92 l · h-1, apparent peripheral volume of distribution 7.80 l, and apparent intercompartmental clearance 61.7 l · h-1. The simulation indicated that at the dose of 2 µg · kg-1, 95% of simulated individuals could achieve a target therapeutic concentration of 0.3 ng · ml-1 within 20 min, and the average peak concentration of 0.563 ng · ml-1 could be attained at 61 min.

CONCLUSIONS

The pharmacokinetic characteristics of intranasal dexmedetomidine were evaluated in Chinese pediatric patients aged between 3 and 36 months. An evidence-based dosing regimen at 2 µg · kg-1 could achieve a preset therapeutic threshold of mild to moderate sedation that lasted for up to 2 h.

EDITOR’S PERSPECTIVE

Pharmacokinetic Pharmacodynamic Modelling Contributions to Improve Paediatric Anaesthesia Practice

The use of pharmacokinetic-pharmacodynamic models has improved anaesthesia practice in children through a better understanding of dose-concentration-response relationships, developmental pharmacokinetic changes, quantification of drug interactions and insights into how covariates (e.g., age, size, organ dysfunction, pharmacogenomics) impact drug prescription. Simulation using information from these models has enabled the prediction and learning of beneficial and adverse effects and decision-making around clinical scenarios. Covariate information, including the use of allometric size scaling, age and consideration of fat mass, has reduced population parameter variability. The target concentration approach has rationalised dose calculation. Paediatric pharmacokinetic-pharmacodynamic insights have led to better drug delivery systems for total intravenous anaesthesia and an expectation about drug offset when delivery is stopped. Understanding concentration-dependent adverse effects have tempered dose regimens. Quantification of drug interactions has improved the understanding of the effects of drug combinations. Repurposed drugs (e.g., antiviral drugs used for COVID-19) within the community can have important effects on drugs used in paediatric anaesthesia, and the use of simulation educates about these drug vagaries.

Application of Different Doses of Dexmedetomidine Combined with General Anesthesia in Anesthesia of Patients with Traumatic Tibiofibular Fractures and Its Effect on the Incidence of Adverse Reactions

Objective

To explore the application of different doses of dexmedetomidine combined with general anesthesia in patients with traumatic tibiofibular fractures.

Methods

A total of 120 patients with traumatic tibiofibular fractures treated in our hospital (January 2018–January 2021) were selected as the research subjects and equally grouped into group A, group B, group C, and group D according to the dosage of dexmedetomidine. Group B, group C, and group D were pumped with 0.3 μg/kg, 0.5 μg/kg, and 0.8 μg/kg load doses of dexmedetomidine before anesthesia induction, with the same doses for maintenance during surgery. Group A was intravenously pumped with the same amount of normal saline and received tracheal intubation after anesthesia induction, with propofol and remifentanil to maintain general anesthesia during surgery.

Results

No notable differences in general data were observed among the groups (P > 0.05). Ramsay sedation scores of all groups showed a downward trend after drug withdrawal. At 10 min, 30 min, and 60 min, the scores of groups C and D were markedly higher than those of groups A and B (P < 0.05), and the scores were higher in group D than those in group C (P < 0.05). The HR changes at each period were close between groups A and B (P > 0.05). The HRs at T1 and T2 in group C were slightly lower than those in group D (P > 0.05), and the HRs at T1 in groups A and B were remarkably higher than those in groups C and D, and were higher than those at T0 and T2 (P < 0.05). The SBP levels of all groups began to rise at T0, peaked at T1, and decreased to a lower level at T2 than that at T0. Moreover, the SBP levels of groups C and D at T1 and T2 were notably lower compared with groups A and B (P < 0.05). With a lower DBP level in group C than the other three groups at T1, the DBP levels were notably lower in groups C and D than those in groups A and B at T2 (P < 0.05). With no statistical difference in the MAP levels at T0 among the four groups (P > 0.05), the MAP levels in group A at T1 and T2 were obviously higher compared with groups C and D (P < 0.05). The extubation time in group A was notably longer than that that in groups B, C, and D (P < 0.05), with longer extubation time in group B than that in groups C and D (P < 0.05). The orientation recovery time in group D was markedly shorter than that in groups A, B, and C (P < 0.05). The incidence of cognitive dysfunction, chills, and restlessness in groups C and D was notably lower compared with groups A and B (P < 0.05), with a higher incidence of chills, intraoperative hypotension, and delayed awakening in group D than in group C (P < 0.05).

Conclusion

Dexmedetomidine at doses of 0.5 μg/kg and 0.8 μg/kg has a better effect in the maintenance of general anesthesia for patients with traumatic tibiofibular fractures, with faster orientation recovery, better recovery of postoperative cognitive function, and a lower incidence of adverse reactions. Dexmedetomidine at 0.5 μg/kg is recommended in view of the increased risk of excessive sedation, chills, restlessness, and intraoperative hypotension in patients at 0.8 μg/kg.

Verification of the performance of the Bispectral Index as a hypnotic depth indicator during dexmedetomidine sedation

Background

Differences in the effects of propofol and dexmedetomidine sedation on electroencephalogram patterns have been reported previously. However, the reliability of the Bispectral Index (BIS) value for assessing the sedation caused by dexmedetomidine remains debatable. The purpose of this study is to evaluate the correlation between the BIS value and the Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) scale in patients sedated with dexmedetomidine.

Methods

Forty-two patients aged 20–80 years, who were scheduled for surgery under spinal anesthesia were enrolled. Spinal anesthesia was performed using 0.5% bupivacaine, which was followed by dexmedetomidine infusion (loading dose, 0.5–1 μg/kg for 10 min; maintenance dose, 0.3–0.6 μg/kg/h). The MOAA/S score was used to evaluate the level of sedation.

Results

A total of 215082 MOAA/S scores and BIS data pairs were analyzed. The baseline variability of the BIS value was 7.024%, and BIS value decreased, as the MOAA/S scored decreased. The correlation coefficient and prediction probability between the two measurements were 0.566 (P < 0.0001) and 0.636, respectively. The mean ± standard deviation values of the BIS were 87.22 ± 7.06, 75.85 ± 9.81, and 68.29 ± 12.65 when the MOAA/S scores were 5, 3, and 1, respectively. Furthermore, the cut-off BIS values in the receiver operating characteristic analysis at MOAA/S scores of 5, 3, and 1 were 82, 79, and 73, respectively.

Conclusions

The BIS values were significantly correlated with the MOAA/S scores. Thus, the BIS along with the clinical sedation scale might prove useful in assessing the hypnotic depth of a patient during sedation with dexmedetomidine.

Pharmacokinetic concepts for dexmedetomidine target-controlled infusion pumps in children

Pharmacokinetic parameter estimates are used in mathematical equations (pharmacokinetic models) to describe concentration changes with time in a population and are specific to that population. Simulation using these models and their parameter estimates can enrich understanding of drug behavior and serve as a basis for study design. Pharmacokinetic concepts are presented pertaining to future designs of dexmedetomidine target-controlled infusion pumps in children. This manuscript provides the pediatric anesthesiologist with an understanding of the nuances that should be considered when using target-controlled infusion pumps; how the central volume may differ between populations, how clearance changes with age, and the impact of adverse effects on dose. In addition, the ideal loading dose and rate of delivery to achieve target concentration without adverse cardiovascular effects are reviewed, and finally, dose considerations for obese children, based on contact-sensitive half-time, are introduced. An understanding of context-sensitive half-time changes with age enables anesthetic practitioners to better estimate duration of effect after cessation of dexmedetomidine infusion. Use of these known pharmacokinetic parameters and covariate information for the pediatric patient could readily be incorporated into commercial target-controlled infusion pumps to allow effective and safe open-loop administration of dexmedetomidine in children.