The 95% effective dose of intranasal dexmedetomidine sedation for pulmonary function testing in children aged 1-3 years: A biased coin design up-and-down sequential method

Reparametrized Firth's Logistic Regressions for Dose-Finding Study With the Biased-Coin Design

Finding an adequate dose of the drug by revealing the dose-response relationship is very crucial and a challenging problem in the clinical development. The main concerns in dose-finding study are to identify a minimum effective dose (MED) in anesthesia studies and maximum tolerated dose (MTD) in oncology clinical trials. For the estimation of MED and MTD, we propose two modifications of Firth's logistic regression using reparametrization, called reparametrized Firth's logistic regression (rFLR) and ridge-penalized reparametrized Firth's logistic regression (RrFLR). The proposed methods are designed by directly reducing the small-sample bias of the maximum likelihood estimate for the parameter of interest. In addition, we develop a method on how to construct confidence intervals for rFLR and RrFLR using profile penalized likelihood. In the up-and-down biased-coin design, numerical studies confirm the superior performance of the proposed methods in terms of the mean squared error, bias, and coverage accuracy of confidence intervals.

Combined sedation in pediatric magnetic resonance imaging: determination of median effective dose of intranasal dexmedetomidine combined with oral midazolam

BACKGROUND

The exact median effective dose (ED50) of intranasal dexmedetomidine combined with oral midazolam sedation for magnetic resonance imaging (MRI) examination in children remains unknow and the aim of this study was to determine the ED50 of their combination.

METHODS

This is a prospective dose-finding study. A total of 53 children aged from 2 months to 6 years scheduled for MRI examination from February 2023 to April 2023 were randomly divided into group D (to determine the ED50 of intranasal dexmedetomidine) and group M (to determine the ED50 of oral midazolam). The dosage of dexmedetomidine and midazolam was adjusted according to the modified Dixon's up-and-down method, and the ED50 was calculated with a probit regression approach.

RESULTS

The ED50 of intranasal dexmedetomidine when combined with 0.5 mg∙kg- 1 oral midazolam was 0.39 µg∙kg- 1 [95% confidence interval (CI) 0.30 to 0.46 µg∙kg- 1] while the ED50 of oral midazolam was 0.17 mg∙kg- 1 (95% CI 0.01 to 0.29 mg∙kg- 1) when combined with 1 µg∙kg- 1 intranasal dexmedetomidine. The sedation onset time of children with successful sedation in group D was longer than in group M (30.0[25.0, 38.0]vs 19.5[15.0, 35.0] min, P < 0.05). No other adverse effects were observed in the day and 24 h after medication except one dysphoria.

CONCLUSION

This drug combination sedation regimen appears suitable for children scheduled for MRI examinations, offering a more precise approach to guide the clinical use of sedative drugs in children.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, identifier: ChiCTR2300068611(24/02/2023).

Clinical Use of Adrenergic Receptor Ligands in Acute Care Settings

In this chapter, we review how ligands, both agonists and antagonists, for the major classes of adrenoreceptors, are utilized in acute care clinical settings. Adrenergic ligands exert their effects by interacting with the three major classes of adrenoceptors. Adrenoceptor agonists and antagonists have important applications, ranging from treatment of hypotension to asthma, and have proven to be extremely useful in a variety of clinical settings of acute care from the operating room to the critical care environment. Continued research interpreting the mechanisms of adrenoreceptors may help the discovery of new drugs with more desirable clinical profiles.

Median effective dose of ropivacaine for prophylactic cervical cerclage in Chinese women: a dose-finding study

BACKGROUND

Although intrathecal ropivacaine has been widely used for caesarean delivery, there are limited data for the use of ropivacaine for prophylactic cervical cerclage. We sought to determine the median effective dose of intrathecal ropivacaine for prophylactic cervical cerclage in 50% of patients (ED50) and the calculated dose required for successful block in 95% of patients (ED95).

METHODS

We included Chinese women scheduled for prophylactic cervical cerclage under combined spinal-epidural (CSE) anaesthesia in the first or second trimester. A predetermined dose of intrathecal isobaric ropivacaine was administered. If this determined dose achieved an effective block at a level not lower than T12, the next dose was decreased by 0.5 mg. Otherwise, the next dose was increased by 0.5 mg. The primary outcome was the ED50 of intrathecal ropivacaine. Secondary outcomes included the calculated ED95, time from CSE to the start of surgery and so on.

RESULTS

Forty patients were included in the study, 23 (57.5%) of 40 received an effective block only with intrathecal ropivacaine, while 17 (42.5%) patients needed extra epidural lidocaine to achieve a successful block. The ED50 of intrathecal ropivacaine confirmed by isotonic regression was 6.9 mg (95% CI, 6.68 to 7.12 mg), and the calculated ED95 was 7.8 mg (95% CI, 7.69 to 10.05 mg). When an effective block was achieved with intrathecal ropivacaine alone, the time to resolution of the sensory and motor blocks was 90 (75-100) min and 90 (60-100) min, respectively.

CONCLUSIONS

The ED50 of intrathecal ropivacaine for prophylactic cervical cerclage was 6.9 mg. Intrathecal ropivacaine (7.8 mg) is likely to produce successful anaesthesia in 95% of patients undergoing prophylactic cervical cerclage.

TRIAL REGISTRATION NUMBER

ChiCTR2100051418.

Dose Escalation Pharmacokinetic Study of Intranasal Atomized Dexmedetomidine in Pediatric Patients With Congenital Heart Disease

BACKGROUND

Atomized intranasal dexmedetomidine is an attractive option when sedation is required for pediatric patients as either premedication or the sole agent for noninvasive, nonpainful procedures. While intranasal dexmedetomidine is used frequently in this population, it is still unclear what dose and time of administration relative to the procedure will result in the optimal effect. Knowledge regarding the maximum concentration (C max ) and time to reach maximum concentration (T max ) of intranasally administered dexmedetomidine is the first step toward this. The risk of hemodynamic instability caused by increasing doses of dexmedetomidine necessitates a greater understanding of the pharmacokinetics in children.

METHODS

Sixteen pediatric patients 2 to 6 years of age undergoing elective cardiac catheterization received 2 or 4 μg/kg dexmedetomidine intranasally. Plasma concentrations were determined by liquid chromatography-tandem mass spectrometry with a validated assay. Descriptive noncompartmental analysis provided estimates of peak concentrations and time to reach peak concentrations. A population pharmacokinetic model was developed using nonlinear mixed-effects modeling. Simulations were performed using the final model to assess dose concentrations with an alternative dosing regimen of 3 µg/kg.

RESULTS

A median peak plasma concentration of 413 pg/mL was achieved 91 minutes after 2 μg/kg dosing, and a median peak plasma concentration of 1000 pg/mL was achieved 54 minutes after 4 μg/kg dosing. A 1-compartment pharmacokinetic model adequately described the data. Three subjects in the 4 μg/kg dosing cohort achieved a dose-limiting toxicity (DLT), defined as a plasma dexmedetomidine concentration >1000 pg/mL. None of these subjects had any significant hemodynamic consequences. Simulations showed that no subjects would experience a level >1000 pg/mL when using a dose of 3 µg/kg.

CONCLUSIONS

Concentrations associated with adequate sedation can be achieved with intranasal dexmedetomidine doses of 2 to 4 µg/kg in children 2 to 6 years of age. However, 50% of our evaluable subjects in this cohort reached a plasma concentration >1000 pg/mL. Doses of 3 µg/kg may be optimal in this population, with simulated concentrations remaining below this previously established toxicity threshold. Further studies correlating concentrations with efficacy and adverse effects are needed.

Combined use of intranasal Dexmedetomidine and an oral novel formulation of Midazolam for sedation of young children during brain MRI examination: a prospective, single-center, randomized controlled trial

BACKGROUND

To evaluate the safety and effectiveness of different dosages of intranasal Dexmedetomidine (DEX) in combination with oral midazolam for sedation of young children during brain MRI examination.

METHODS

Included in this prospective single-blind randomized controlled trial were 156 children aged from 3 months to 6 years and weighing from 4 to 20 Kg with ASA I-II who underwent brain MRI examination between March 2021 and February 2022. Using the random number table method, they were divided into group A (using 3 ug/kg intranasal DEX plus 0.2 mg/Kg oral midazolam) and group B (using 2 ug/kg intranasal DEX plus 0.2 mg/Kg oral Midazolam). The one-time success rate of sedation, sedation onset time, recovery time, overall sedation time, and occurrence of adverse reactions during MRI examination were compared between the two groups. The heart rate (HR), mean arterial pressure (MAP), and percutaneous SpO₂before and after drug administration were observed in both groups. Differences in sedation scores between the two groups were compared before intranasal drug administration (T0), 10 min after drug administration (T1), at the time of falling asleep (T2), at the end of examination (T3), and at the time of recovery (T4).

RESULTS

The one-time success rate of sedation in group A and B was 88.31% and 79.75% respectively, showing no significant difference between the two groups (P>0.05). The sedation onset time in group A was 24.97±16.94 min versus 27.92±15.83 min in group B, and the recovery time was 61.88±22.18 min versus 61.16±28.16 min, both showing no significance difference between the two groups (P>0.05). Children in both groups exhibited good drug tolerance without presenting nausea and vomiting, hypoxia, or bradycardia and hypotension that needed clinical interventions. There was no significant difference in the occurrence of abnormal HR, MAP or other adverse reactions between the two groups (P>0.05).

CONCLUSION

3 ug/kg or 2 ug/kg intranasal DEX in combination with 0.2 mg/kg oral Midazolam both are safe and effective for sedation of children undergoing MRI examination with the advantages of fast-acting and easy application.

TRIAL REGISTRATION

It was registered at the Chinese Clinical Trial Registry ( ChiCTR1800015038 ) on 02/03/2018.

Efficacy of different doses of intranasal dexmedetomidine in preventing emergence agitation in children with inhalational anaesthesia: A prospective randomised trial

BACKGROUND

Emergence agitation is a common paediatric complication after inhalational anaesthesia. Intranasal dexmedetomidine can prevent emergence agitation effectively, but the optimal dose is uncertain.

OBJECTIVE

The aim of our study was to investigate the 95% effective dose (ED 95 ) of intranasal dexmedetomidine for the prevention of emergence agitation after inhalational anaesthesia for paediatric ambulatory surgery.

DESIGN

A prospective, randomised, placebo-controlled, double-blind, clinical trial.

SETTING

The study was conducted in Guangzhou Women and Children's Medical Center in China from August 2017 to December 2018.

PATIENTS

Three hundred and eighteen children scheduled for ambulatory surgery were enrolled into two age groups of less than 3 years and at least 3 years.

INTERVENTIONS

The children in each age group were randomised into five equal subgroups to receive either intranasal dexmedetomidine 0.5, 1.0, 1.5 or 2.0 μg kg -1 (Groups D 0.5 , D 1.0 , D 1.5 and D 2.0 ), or intranasal isotonic saline (group C) after induction.

MAIN OUTCOME MEASURES

The primary outcome was the ED 95 dose of intranasal dexmedetomidine for preventing emergence agitation after inhalational anaesthesia for paediatric ambulatory surgery.

RESULTS

The incidences of emergence agitation for Groups C, D 0.5 , D 1.0 , D 1.5 and D 2.0 were 63, 40, 23, 13 and 3% in children less than 3 years, and 43, 27, 17, 7 and 3% in children at least 3 years. The ED 95 of intranasal dexmedetomidine for preventing emergence agitation was 1.99 μg kg -1 [95% confidence interval (CI), 1.83 to 3.80 μg kg -1 ] in children less than 3 years, and 1.78  μg kg -1 (95% CI, 0.93 to 4.29 μg kg -1 ) in children at least 3 years. LMA removal time for groups D 1.5 and D 2.0 was 9.6 ± 2.2 and 9.7 ± 2.5 min, respectively, for children less than 3 years, and 9.4 ± 2.0 and 9.9 ± 2.7 min in children at least 3 years, respectively. Length of stay in the postanaesthesia care unit for Groups D 1.5 and D 2.0 was 34.3 ± 9.6 and 37.1 ± 11.2 min, respectively, in children less than 3 years, and 34.7 ± 10.2 and 37.3 ± 8.3 min in children at least 3 years, respectively. These times were longer in the D 1.5 and D 2.0 subgroups than in the control subgroup in the two age groups of less than 3 years and at least 3 years, respectively: 7.2 ± 1.9 min in children less than 3 years and 7.3 ± 2.5 min in children at least 3 years for LMA removal time, 22.2 ± 7.9 min in children less than 3 years and 22.0 ± 7.7 min in children at least 3 years for PACU stay time in control subgroup, respectively ( P  < 0.05).

CONCLUSION

Intranasal dexmedetomidine prevented emergence agitation after paediatric surgery in a dose-dependent manner. The optimal dose of intranasal dexmedetomidine for preventing emergence agitation was higher in younger children.

TRIAL REGISTRY

chictr.org.cn: ChiCTR-IOR-17012415.

Preoperative sedation in children with congenital heart disease: 50% and 95% effective doses, hemodynamic effects, and safety of intranasal dexmedetomidine

STUDY OBJECTIVE

To determine the 50% and 95% effective doses (ED50 and ED95, respectively), hemodynamic effects, and safety of intranasal dexmedetomidine for preoperative sedation in pediatric patients with congenital heart disease (CHD) with a left-to-right shunt.

DESIGN

Double-blind sequential allocation trial.

SETTING

Pediatric preoperative waiting area.

PATIENTS

86 pediatric patients ASA physical status II-III scheduled for cardiac surgery, aged1-month to 6-years-old with left-to-right type CHD.

INTERVENTIONS

Children were divided into three groups according to age: infants (1 month-1 year), toddlers (1-3 years), and preschoolers (3-6 years). The first patient in all groups received intranasal dexmedetomidine (2 μg/kg), using the up-and-down Dixon method, and the and the next patient's dose was dependent on the previous patient's response.

MEASUREMENTS

Assessment using the Modified Observer's Assessment of Alertness/Sedation Scale and the Mask Acceptance Scale was performed before and every 5 min after treatment. Pulse oxygen saturation and heart rate were recorded at baseline, at 10-min intervals, and after admission to the operating room. Systolic pulmonary artery pressure was measured before anesthesia induction.

MAIN RESULTS

The respective ED₅₀ (95% confidence interval [CI]) and ED₉₅ (95% CI) values for preoperative sedation using intranasally administered dexmedetomidine were 3.1 (2.8-3.3) and 3.5 (3.3-4.0) μg/kg for infants; 3.4 (3.2-3.6) and 3.9 (3.7-4.4) μg/kg for toddlers; and 2.4 (2.2-2.6) and 2.9 (2.6-3.3) μg/kg for preschoolers. ED₅₀ was lower for preschoolers than for toddlers (p < 0.001) and infants (p = 0.044). No obvious difference in ED50 was found between infants and toddlers. There was no significant difference in sedation onset time among the groups, and no adverse events were observed during sedation in all patients.

CONCLUSIONS

Intranasal dexmedetomidine can be safety used for preoperative sedation in children with CHD and is effective for sedation when dosed appropriately. Trial registrationclinicaltrials.gov (ChiCTR2100047472); registered 20 June 2021.

Intranasal Dexmedetomidine for the Treatment of Pre-operative Anxiety and Insomnia: A Prospective, Randomized, Controlled, and Clinical Trial

BACKGROUND AND OBJECTIVE

Several patients with pre-operative anxiety and insomnia refuse to take sleeping pills because of the side effects of sleeping pills. This study aimed to evaluate the applicability of intranasal dexmedetomidine (DEX) in the treatment of pre-operative anxiety and insomnia.

METHODS

A total of 72 patients with insomnia and anxiety were randomly divided into two groups of intranasal DEX (n = 36) and intranasal normal saline (NS, n = 36). The primary outcomes included patients' time to fall asleep, total sleep time, insomnia severity index (ISI) after treatment, and satisfaction with the treatment effect. The secondary outcomes were mean arterial pressure (MAP), oxygen saturation (SPO₂), heart rate (HR), Narcotrend index (NI) in the first 2 h of treatment, and the incidence of adverse events within 12 h after treatment.

RESULTS

The time to fall asleep (22.08 ± 3.95 min) and total sleep time (400.06 ± 28.84 min) in the DEX group were significantly different from those in the NS group [time to fall asleep, 89.31 ± 54.56 min; total sleep time (295.19 ± 73.51 min; P < 0.001)]. ISI after treatment in the DEX group was lower than that in the NS group (P < 0.001). Satisfaction with the treatment effect was better in the DEX group than that in the NS group (P < 0.001). The general vital signs in the two groups were stable during the treatment. The drowsiness rate in the NS group was higher than that in the DEX group (P < 0.001).

CONCLUSION

Intranasal DEX can significantly improve pre-operative anxiety and insomnia.

CLINICAL TRIAL REGISTRATION

This study was registered on Chinese Clinical Trial Registry (http://www.chictr.org.cn/searchproj.aspx, ChiCTR2100044747).

Dexmedetomidine: What's New for Pediatrics? A Narrative Review

Over the past few years, despite the lack of approved pediatric labelling, dexmedetomidine’s (DEX) use has become more prevalent in pediatric clinical practice as well as in research trials. Its respiratory-sparing effects and bioavailability by various routes are only some of the valued features of DEX. In recent years the potential organ-protective effects of DEX, with the possibility for preserving neurocognitive function, has put it in the forefront of clinical and bench research. This comprehensive review focused on the pediatric literature but presents relevant, supporting adult and animal studies in order to detail the recent growing body of literature around the pharmacology, end-organ effects, organ-protective effects, alternative routes of administration, synergetic effects, and clinical applications, with considerations for the future.