Pharmacokinetics of intravenous dexmedetomidine in children under 11 yr of age

Comparative evaluation of the effectiveness and acceptance of intranasal dexmedetomidine and intranasal midazolam for sedation in children aged 5-8 years using a mucosal atomizer device: a randomized controlled clinical study

Background

Patient age, preoperative anxiety, dental requirement, risks associated with pharmaceutical management, safety, parental expectations, and cost influence the choice of pharmacological behavior management. Thus, this randomized controlled clinical study aimed to compare the effectiveness and acceptance of intranasal dexmedetomidine and midazolam for sedation in children aged 5-8 years using a mucosal atomizer device (MAD).

Methods

A total of 48 participants with Frankl's II behavior were randomly divided into two groups: Group I received intranasal midazolam (0.25 mg/kg), and Group II received intranasal dexmedetomidine (1.5 µg/kg). The primary outcomes assessed were drug acceptance, onset and effectiveness of sedation, and pre-and post-treatment anxiety levels. Secondary measures were also evaluated pre- and post-treatment.

Results

Intranasal dexmedetomidine demonstrated significantly better drug acceptance (P < 0.001). Midazolam had a faster onset but was less effective than dexmedetomidine (P < 0.001). Additionally, dexmedetomidine exhibited better anxiolytic properties than midazolam (P < 0.001).

Conclusion

Dexmedetomidine was better accepted by children aged 5-8 years, was more effective, and had superior anxiolytic properties compared with midazolam.

Optimizing Pediatric Sedation: Evaluating Remimazolam and Dexmedetomidine for Safety and Efficacy in Clinical Practice

Daily, children undergo countless investigations and interventions, which require sedation and immobilization to ensure safety and accuracy. This remains associated with a persistent risk of sedation-induced life-threatening events as children are particularly vulnerable to adverse medical events and complications. Consequently, there is an urgent need to increase the safety of pediatric sedation and anesthesia. An ideal approach involves the use of drugs with fewer intrinsic side effects. In this context, on the basis of their pharmacokinetic properties, remimazolam (RMZ) and dexmedetomidine (DEX) were evaluated for their suitability as ideal sedatives. RMZ and DEX, both of which are currently available in pediatric medicine, have shown great promise in initial publications. To date, only very limited data concerning RMZ in small children are available. RMZ is a novel, ultrashort-acting benzodiazepine that is metabolized by tissue esterase, largely independent of organ function. It has a context-sensitive half-life of approximately 10 min, with minimal accumulation even with prolonged use. Its effects can be completely reversed with flumazenil. DEX, an isomer of medetomidine, is a potent α2-receptor-agonist with multiple indications in anesthesia and intensive care medicine. It has coanalgesic potential, allows for 'arousal sedations' and has a low profile for cardiorespiratory side effects. DEX is metabolized in the liver and is predominantly excreted renally. Both drugs show potential in the prevention and treatment of delirium, with DEX having additional neuroprotective effects. DEX and RMZ possess several properties of an optimal sedative, including clinically insignificant main metabolites and a broad dosage range, indicating their potential to reduce the incidence of sedation-related life-threatening events in children. However, further clinical research is necessary to better evaluate their potential risks.

Development and Evaluation of Ontogeny Functions of the Major UDP-Glucuronosyltransferase Enzymes to Underwrite Physiologically Based Pharmacokinetic Modeling in Pediatric Populations

Uridine 5'-diphospho-glucuronosyltransferases (UGTs) demonstrate variable expression in the pediatric population. Thus, understanding of age-dependent maturation of UGTs is critical for accurate pediatric pharmacokinetics (PK) prediction of drugs that are susceptible for glucuronidation. Ontogeny functions of major UGTs have been previously developed and reported. However, those ontogeny functions are based on in vitro data (i.e., enzyme abundance, in vitro substrate activity, and so on) and therefore, may not translate to in vivo maturation of UGTs in the clinical setting. This report describes meta-analysis of the literature to develop and compare ontogeny functions for 8 primary UGTs (UGT1A1, UGT1A4, UGT1A6, UGT1A9, UGT2B7, UGT2B10, UGT2B15, and UGT2B17) based on published in vitro and in vivo studies. Once integrated with physiologically based pharmacokinetics modeling models, in vivo activity-based ontogeny functions demonstrated somewhat greater prediction accuracy (mean squared error, MSE: 0.05) compared to in vitro activity (MSE: 0.104) and in vitro abundance-based ontogeny functions (MSE: 0.129).

Using Real-World Data to Externally Evaluate Population Pharmacokinetic Models of Dexmedetomidine in Children and Infants

Dexmedetomidine is a sedative used in both adults and off-label in children with considerable reported pharmacokinetic (PK) interindividual variability affecting drug exposure across populations. Several published models describe the population PKs of dexmedetomidine in neonates, infants, children, and adolescents, though very few have been externally evaluated. A prospective PK dataset of dexmedetomidine plasma concentrations in children and young adults aged 0.01-19.9 years was collected as part of a multicenter opportunistic PK study. A PubMed search of studies reporting dexmedetomidine PK identified five population PK models developed with data from demographically similar children that were selected for external validation. A total of 168 plasma concentrations from 102 children were compared with both population (PRED) and individualized (IPRED) predicted values from each of the five published models by quantitative and visual analyses using NONMEM (v7.3) and R (v4.1.3). Mean percent prediction errors from observed values ranged from -1% to 120% for PRED, and -24% to 60% for IPRED. The model by James et al, which was developed using similar "real-world" data, nearly met the generalizability criteria from IPRED predictions. Other models developed using clinical trial data may have been limited by inclusion/exclusion criteria and a less racially diverse population than this study's opportunistic dataset. The James model may represent a useful, but limited tool for model-informed dosing of hospitalized children.

Comparison of intranasal ketamine with intranasal midazolam and dexmedetomidine combination in pediatric dental patients for procedural sedation: A crossover study

BACKGROUND

The main goal of the pediatric dentist is to address and reduce children's fear and anxiety during the dental treatment, especially when conventional behavior-guiding strategies fail. In such cases, the use of pharmacological agents becomes an essential factor to consider.

OBJECTIVE

The objective of the study was to compare the efficacy, safety, and acceptability of intranasal ketamine (INK) with the combination of intranasal midazolam and dexmedetomidine (INMzD) in pediatric dental patients for the procedural sedation.

PATIENTS AND METHODS

Forty-seven children aged 3-9 years who required dental procedures such as extractions, pulpectomy, and restorations were randomly distributed into two groups using the envelope drawing method. Group INK received 7 mg/kg INK, whereas Group INMzD received a combination of midazolam spray (0.3 mg/kg) and atomized dexmedetomidine (3 μg/kg).

RESULTS

INK showed faster onset, faster recovery, and shorter discharge time than INMzD. Both groups had acceptable physiological parameters and no postoperative complications. INK was more accepted by the patients than INMzD.

CONCLUSIONS

In terms of efficacy, safety, and acceptability, INK outperformed the combination of INMzD for the procedural sedation.

Dexmedetomidine as an Adjuvant to Nerve Block for Cancer Surgery: A Systematic Review and Meta-Analysis

Background/Objectives: Our understanding of dexmedetomidine, as an adjuvant to nerve blocks in cancer surgery, is characterized by a current lack of compelling evidence, and it remains unknown whether the potential benefits of use outweigh the risks. The aim of the study was to evaluate the benefit and safety profiles of dexmedetomidine as an adjuvant to nerve blocks in cancer surgery. Methods: Systematic searches were conducted in MEDLINE, ScienceDirect, Cochrane Library, Springer, medRxiv, and Scopus up to 17 May 2024. Risk ratios (RR) for binary outcomes and standardized mean differences (SMDs) for continuous outcomes were quantified. Results: Twenty studies were identified. In breast cancer surgery, the use of dexmedetomidine reduced 24 h total morphine consumption (SMD = -1.99 [95% CI -3.01 to -0.98], p = 0.0001, I2 = 91%, random effects) and prolonged the requirement for morphine rescue analgesia (SMD = 2.98 [95% CI 0.01 to 5.95], p = 0.05, I2 = 98%, random effects). In abdominal cancer surgery, the dexmedetomidine group had lower total sufentanil consumption (SMD = -1.34 [95% CI -2.29 to -0.40], p = 0.005, I2 = 84%, random effects). Dexmedetomidine reduced the VAS score and decreased postoperative nausea and vomiting (PONV). No studies using dexmedetomidine reported serious adverse events. Conclusions: Using dexmedetomidine as an adjuvant to nerve blocks in cancer surgery could lower the VAS pain score and prolong the regional anesthesia duration, which would lead to a decrease in total opioid consumption and possibly contribute to fewer PONV events. Furthermore, the reports of no serious adverse events indicate its good safety profile.

Preoperative Anxiolytic and Sedative Effects of Intranasal Remimazolam and Dexmedetomidine: A Randomized Controlled Clinical Study in Children Undergoing General Surgeries

Purpose

Remimazolam, an ultra-short-acting and fast-metabolized sedative, has only been sporadically investigated in children. This study was performed to determine the beneficial effects of intranasal remimazolam or dexmedetomidine on preoperative anxiety in children undergoing general surgeries.

Patients and Methods

Ninety children were randomly and equally assigned to Group R (intranasal remimazolam 1.5mg kg-1), Group D (intranasal dexmedetomidine 2 mcg kg-1), and Group C (intranasal distilled water). The primary outcomes were the preoperative anxiety scores using the modified Yale preoperative anxiety scale (m-Ypas). The secondary outcomes included the cooperation behaviour of intranasal drug application, preoperative sedation levels, parental separation anxiety scores (PSAS), and mask acceptance scores (MAS).

Results

Group R showed a significant low anxiety at 10 min after intranasal premedication (vs group C, P=0.010; vs group D, P = 0.002) and at anaesthesia induction (vs group C, P = 0.004). Group D showed a significantly low anxiety score only prior to anaesthesia induction (vs group C, P = 0.005). Most children in group R achieved mild sedation at 10 min (vs group C, P < 0.001; vs group D, P < 0.001), with a few progressing to deep sedation afterwards, while group D tended toward deep sedation. Compared to Group C, patients in Group R performed significantly better on the MAS (P = 0.014) and PSAS (P = 0.008). However, remimazolam did cause poor cooperation behavior to the intranasal application due to its mucosal irritation (vs group C, P = 0.001; vs group D, P = 0.010).

Conclusion

Both intranasal remimazolam and dexmedetomidine can effectively alleviate preoperative anxiety in children. While intranasal remimazolam has a rapid onset, it produces only mild sedation and causes substantial nasal irritation.

Trial Registration

NCT04720963, January 22, 2021, ClinicalTrials.Gov.

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).

Efficacy of intranasal administration of dexmedetomidine in combination with midazolam for sedation in infant with cleft lip and palate undergoing CT scan: a randomized controlled trial

BACKGROUND

There is a great challenge to sedation for infants with cleft lip and palate undergoing CT scan, because there is the younger age and no consensus on the type, dosage, and route of drug administration.

OBJECTIVE

This study aimed to evaluate the efficacy of intranasal administration of dexmedetomidine combined with midazolam as a sedative option for infants with cleft lip and palate under imaging procedures.

METHODS

Infants scheduled for cleft lip and palate repair surgery were randomly assigned to the IND group (intranasal dexmedetomidine 2 µg/kg alone) and the INDM group (intranasal dexmedetomidine 2 µg/kg combined with midazolam 0.05 mg/kg). The primary outcome was the proportion of infants underwent successful computed tomography (CT) scans under intranasal sedation. The secondary outcomes included onset time and duration of sedation, recovery time, Ramsay sedation scale, hemodynamic parameters during sedation, and adverse events. Data analyses involved the unpaired t-test, the repeated-measures analysis of variance test, and the continuity correction χ2 test.

RESULTS

One hundred five infants were included in the analysis. The proportion of infants underwent successful CT scans under sedation was significantly greater in the INDM group than in the IND group (47 [95.9%] vs. 45 [80.4%], p = 0.016). Additionally, the INDM group had a shorter onset time and a longer duration of sedation statistically (12 [8.5, 17] min vs. 16 [12, 20] min, p = 0.001; 80 [63.6, 92.5] min vs. 68.5 [38, 89] min, p = 0.014, respectively), and their recovery time was significantly longer (43 [30, 59.5] min vs. 31.5 [20.5, 53.5] min, p = 0.006). The difference in Ramsay sedation scale values 20 min after administration was statistically significant between the groups. No statistically significant difference was found between the groups in changes in heart rate and respiratory rate.

CONCLUSION

Intranasal administration of dexmedetomidine in combination with midazolam resulted in higher sedation success in comparison with sole dexmedetomidine. However, it has a relatively prolonged duration of sedation and recovery time.

TRIAL REGISTRATION

ChiCTR2100049122, Clinical trial first registration date: 21/07/2021.

Off-label use of dexmedetomidine in paediatric anaesthesiology: an international survey of 791 (paediatric) anaesthesiologists

PURPOSE

The purpose of this international study was to investigate prescribing practices of dexmedetomidine by paediatric anaesthesiologists.

METHODS

We performed an online survey on the prescription rate of dexmedetomidine, route of administration and dosage, adverse drug reactions, education on the drug and overall experience. Members of specialist paediatric anaesthesia societies of Europe (ESPA), New Zealand and Australia (SPANZA), Great Britain and Ireland (APAGBI) and the USA (SPA) were consulted. Responses were collected in July and August 2019.

RESULTS

Data from 791 responders (17% of 5171 invitees) were included in the analyses. Dexmedetomidine was prescribed by 70% of the respondents (ESPA 53%; SPANZA 69%; APAGBI 34% and SPA 96%), mostly for procedural sedation (68%), premedication (46%) and/or ICU sedation (46%). Seventy-three percent had access to local or national protocols, although lack of education was the main reason cited by 26% of the respondents not to prescribe dexmedetomidine. The main difference in dexmedetomidine use concerned the age of patients (SPA primarily < 1 year, others primarily > 1 year). The dosage varied widely ranging from 0.2-5 μg kg-1 for nasal premedication, 0.2-8 μg kg-1 for nasal procedural sedation and 0-4 μg kg-1 intravenously as adjuvant for anaesthesia. Only ESPA members (61%) had noted an adverse drug reaction, namely bradycardia.

CONCLUSION

The majority of anaesthesiologists use dexmedetomidine in paediatrics for premedication, procedural sedation, ICU sedation and anaesthesia, despite the off-label use and sparse evidence. The large intercontinental differences in prescribing dexmedetomidine call for consensus and worldwide education on the optimal use in paediatric practice.

A Universal Pharmacokinetic Model for Dexmedetomidine in Children and Adults

A universal pharmacokinetic model was developed from pooled paediatric and adult data (40.6 postmenstrual weeks, 70.8 years, 3.1-152 kg). A three-compartment pharmacokinetic model with first-order elimination was superior to a two-compartment model to describe these pooled dexmedetomidine data. Population parameter estimates (population parameter variability%) were clearance (CL) 0.9 L/min/70 kg (36); intercompartmental clearances (Q2) 1.68 L/min/70 kg (63); Q3 0.62 L/min/70 kg (90); volume of distribution in the central compartment (V1) 25.2 L/70 kg (103.9); rapidly equilibrating peripheral compartment (V2) 34.4 L/70 kg (41.8); slow equilibrating peripheral compartment (V3) 65.4 L/70 kg (62). Obesity was best described by fat-free mass for clearances and normal fat mass for volumes with a factor for fat mass (FfatV) of 0.293. Models describing dexmedetomidine pharmacokinetics in adults can be applied to children by accounting for size (allometry) and age (maturation). This universal dexmedetomidine model is applicable to a broad range of ages and weights: neonates through to obese adults. Lean body weight is a better size descriptor for dexmedetomidine clearance than total body weight. This parameter set could be programmed into target-controlled infusion pumps for use in a broad population.

Comparison of dexmedetomidine with chloral hydrate as sedatives for pediatric patients: A systematic review and meta-analysis

BACKGROUND

Dexmedetomidine (Dex) and chloral hydrate (CH) are the most frequently used sedative agents in pediatric patients. We aimed to systematically review the literature comparing the efficacy and safety of Dex and CH for sedation in pediatric patients.

METHODS

Seven electronic databases and 3 clinical trial registry platforms were searched for articles published prior to October 2019. Randomized controlled trials (RCTs) evaluating the efficacy and safety of Dex versus CH for sedation in children were examined by 2 reviewers. The extracted information included the success rate of sedation, sedation latency, sedation duration, sedation recovery time, and adverse events. Moreover, the extracted data included 5 subgroups: the effects of 1, 1.5, 2, 2.5, and 3 μg/kg doses of Dex were compared with the effect of CH on the success rate of sedation. We also formed separate subgroups for different types of adverse events (incidence of vomiting, hypotension, bradycardia, etc). The outcomes were analyzed by Review Manager 5.3 software and are expressed as relative risks (RR) or the mean difference (MD) with the 95% confidence interval (CI). Heterogeneity was assessed with I-squared (I) statistics.

RESULTS

A total of 15 RCTs involving 2128 children with Dex versus CH for sedation were included in the meta-analysis. The dose range of Dex ranged from 1 to 3 μg/kg. Compared with CH, the Dex group had a significantly higher success rate of sedation (RR = 1.14, 95% CI [1.05, 1.25], I = 79%, P = .003). Additionally, subgroup analysis revealed that there was no significant difference in the success rate of sedation between the CH group and the 1, 1.5, 2.5, and 3 μg/kg Dex groups; only the 2 μg/kg Dex group had a significantly higher success rate than the CH group (RR = 1.15, 95% CI [1.03, 1.29], I = 80%, P = .02). There was no significant difference in the number of subjects who required 2 doses or the duration of sedation between the CH and Dex groups. Furthermore, compared with the Dex group, the CH group had a significantly longer sedation latency (MD = -3.54, 95% CI [-5.94, -1.15], I = 95%, P = .004), sedation recovery time (MD = -30.08, 95% CI [-46.77, -13.39], I = 99%, P = .0004), and total time from sedative administration to discharge (MD = -12.73, 95% CI [-15.48, -9.97], I = 0%, P < .05), as well as a higher number of adverse events in total (RR = 0.25, 95% CI [0.11, 0.61], I = 89%, P = .002). Moreover, the subgroup analysis of adverse events revealed that CH was associated with higher risks of vomiting (RR = 0.07, 95% CI [0.03, 0.17], I = 0%, P < .0001), crying or resisting (RR = 0.22, 95% CI [0.07, 0.71], I = 60%, P = .01), and cough (RR = 0.15, 95% CI [0.05, 0.44], I = 0%, P = .0006); there was no significant difference in the risk of hypotension, supplemental oxygen, or respiratory events between CH and Dex. However, Dex was associated with a higher risk of bradycardia (RR = 4.08, 95% CI [1.63, 10.21], I = 0%, P = .003).

CONCLUSIONS

Dex is an appropriate effective alternative to CH for sedation in pediatrics. However, considering the possibility of bradycardia, Dex should be used with caution.

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

STUDY OBJECTIVE

Intranasal dexmedetomidine (DEX) can provide adequate sedation during short examinations in children. However, we found no data regarding the 95% effective dose (ED₉₅) of intranasal DEX for children's pulmonary function testing (PFT).

DESIGN

Prospective study and a biased coin design up-and-down sequential method.

SETTING

Sedation center of Children's Hospital of Chongqing Medical University.

PATIENTS

Children aged 1-3 years undergoing pulmonary function testing.

INTERVENTION

The dose of DEX for each subsequent patient was determined by the response of the previous patient with the biased coin design up-and-down sequential method with an interval of 0.25 μg∙kg^-1.

MEASUREMENTS

Children aged 1-3 years who received pulmonary function testing were involved in this dose-finding trial. Intranasal DEX started at a dose of 2 μg∙kg^-1 on the first patient. The dose of DEX for each subsequent patient was determined by the response of the previous patient with the biased coin design up-and-down sequential method with an interval of 0.25 μg∙kg^-1. The sedation was assessed by the Modified Observer Assessment of Alertness and Sedation (MOAA/S) scale, and recovery was assessed by the modified Aldrete recovery score. The ED₉₅ was calculated using isotonic regression. Other variables, including the sedation onset time, examination time, wake-up time, blood pressure (BP), heart rate (HR), respiratory rate (RR), and oxyhaemoglobin desaturation (SpO₂), were recorded. Adverse events such as hypotension, bradycardia, respiration depression, oxyhaemoglobin desaturation, regurgitation and vomiting were recorded.

MAIN RESULTS

A total of 68 children were enrolled for the study; 62 children had successful sedation, and 6 had failed sedation. The ED₉₅ of intranasal DEX was estimated to be 2.64 μg∙kg^-1 [95% confidence interval (CI), 2.49-2.87 μg∙kg^-1]. The sedation onset time for all patients was 15.0 (12.3-19.0) min. The sedation onset time of successful sedation patients was 15.0 (12.0-19.0) min, the sedation onset time of failed sedation patients was 16.0 (15.0-27.8) min, the examination time was 8 (7-10) min, and the wake-up time was 40 (35-43) min. There were no adverse events during the whole procedure.

CONCLUSION

The ED₉₅ of intranasal DEX sedation in children aged 1-3 years undergoing PFT was 2.64 μg∙kg^-1.

Randomised Comparison between the Efficacy of Two Doses of Nebulised Dexmedetomidine for Premedication in Paediatric Patients

Objective

Nebulised dexmedetomidine can be an easy alternative for preoperative sedation in paediatric patients, but data regarding its efficacy are very limited.

Methods

This prospective, randomised, double-blind study included 66 patients aged between 1 and 8 years. Patients were divided into two groups as D2 and D3. The D2 group received 2 μg kg⁻¹ of nebulised dexmedetomidine, and the D3 group received 3 μg kg⁻¹ of nebulised dexmedetomidine preoperatively. All the patients received general anaesthesia and caudal epidural analgesia with 0.75 mL kg⁻¹ of 0.2% ropivacaine. Parental Separation Anxiety Scale at 30 min after the end of nebulisation, Mask Acceptance Score (MAS) during induction, haemodynamic variables, emergence agitation and duration of caudal analgesia were compared between the groups. Statistical analysis was done using Mann-Whitney U test and chi-square test. A p-value <0.05 was accepted as significant.

Results

All the parameters were comparable between the D2 and D3 groups; however, significantly more number of younger children was observed in the D3 group. Hence, further analysis was done after division into the lower age (1–3 years) and higher age (4–8 years) groups. In lower age group children, satisfactory parental separation was achieved in 100% of the patients in the D3 group compared to 20% of those in the D2 group (p=0.00). MAS was significantly better in the D3 group in both the lower (p=0.019) and higher (p=0.036) age groups.

Conclusion

We conclude that nebulised dexmedetomidine in a dose of 3 μg kg⁻¹ provides better parental separation and mask acceptance in younger children.

A Population Pharmacokinetic Model of Intravenous Dexmedetomidine for Mechanically Ventilated Children after Neurosurgery

Dexmedetomidine is a selective alpha-2 adrenergic agonist with concurrent sedative and analgesic effects, and it is being increasingly used in pediatric anesthesia and intensive care. This study aimed to investigate the pharmacokinetics of intravenous dexmedetomidine in mechanically ventilated children in the intensive care unit (ICU) after neurosurgery. Pediatric patients aged 2–12 years, who were mechanically ventilated in ICU after neurosurgery, were allocated into a low-dose (n = 15) or high-dose (n = 14) group. The low-dose group received dexmedetomidine at a loading dose of 0.25 µg/kg for 10 min, followed by a maintenance dose of 0.25 µg/kg/h for 50 min, whereas the high-dose group received dexmedetomidine at a loading dose of 0.5 µg/kg for 10 min, followed by a maintenance dose of 0.5 µg/kg/h for 50 min. Serial blood samples were collected for a pharmacokinetic analysis up to 480 min after the end of the infusion. The sedative effect of dexmedetomidine was assessed using the Bispectral Index and University of Michigan Sedation Scale. Adverse reactions, electrocardiography findings, and vital signs were monitored for a safety assessment. A population pharmacokinetic analysis was performed using non-linear mixed effects modeling. Dexmedetomidine induced a moderate-to-deep degree of sedation during infusion in both groups. The pharmacokinetics of dexmedetomidine were best described by a two-compartment disposition model with first-order elimination kinetics. The parameters were standardized for a body weight of 70 kg using an allometric power model. The population estimates (95% confidence interval) per 70 kg body weight were as follows: clearance of 81.0 (72.9–90.9) L/h, central volume of distribution of 64.2 (50.6–81.0) L, intercompartment clearance of 116.4 (90.6–156.0) L/h, and peripheral volume of distribution of 167 (132–217) L. No serious adverse reactions or hemodynamic changes requiring the discontinuation of dexmedetomidine were observed. Dexmedetomidine had increased clearance and volume of distribution in mechanically ventilated children in ICU after neurosurgery, thereby indicating the need to adjust the dosage to obtain a target plasma concentration.

The comparison of dexmedetomidine and midazolam premedication on postoperative anxiety in children for hernia repair surgery: A randomized controlled trial

BACKGROUND

Perioperative anxiety is common in pediatric patients undergoing surgery.

AIMS

The aim of this study was to determine whether an infusion of dexmedetomidine prior to hernia repair in children provides better postoperative anxiety outcomes that a preoperative infusion of midazolam.

METHODS

Ninety 6-11-year-old children, who were scheduled to undergo elective hernia repair, were enrolled for this double-blind, randomized controlled trial. Group D (n = 45) received an intravenous infusion of dexmedetomidine (0.5 μg/kg) and Group M (n = 45) received an intravenous infusion of midazolam (0.08 mg/kg) in 20 mL of normal saline for 10 minutes before the induction of anesthesia. Pre- and postoperative scores on the modified Yale Preoperative Anxiety Scale were the main outcomes. Secondary outcomes included systolic blood pressure, diastolic blood pressure, heart rate, and postoperative pain measured on a visual analogue scale and patient satisfaction using a numerical rating scale.

RESULTS

Postoperative anxiety in Group D was significantly lower than preoperative anxiety (2 hours postoperatively mean difference [95% CI]: 2.83 [0.87-4.79], P = 0.036, 4 hours postoperatively mean difference [95% CI]: 3.29 [1.39-5.20], P = 0.005). Preoperative and postoperative anxiety in Group M was similar. Anxiety scores in Group D were also significantly lower than anxiety in Group M 2 hours (mean difference [95% CI]: 1.89 [0.52-3.26], P = 0.01) and 4 hours (mean difference [95% CI]: 3.32 [1.98-4.66], P < 0.001) postoperatively. Systolic blood pressure, diastolic blood pressure and heart rate were lower in Group D than in Group M after administration of sedative drugs until children left PACU (SBP mean difference [95% CI]: 13.87 [10.30-17.43], P < 0.001, DBP mean difference [95% CI]: 5.96[3.80-8.11], P < 0.001, HR mean difference [95% CI]: 10.36 [7.58-13.13], P < 0.001). Pain was also significantly lower in Group D than in Group M at 2 hours (median difference [95% CI]: 1 [0.26-1.34], P = 0.004), 4 hours (median difference [95% CI]: 1 [0.31-1.02], P = 0.003), and 1 day (median difference [95% CI]: 0 [0.22-0.76], P = 0.003) postoperatively. Patient satisfaction scores were significantly higher in Group D than in Group M 1 day (median difference [95% CI]: 0 [-0.83 to -0.24], P = 0.006) and somewhat higher 1 week (median difference [95% CI]: 0 [-0.67 to -0.04], P = 0.06) postoperatively.

CONCLUSION

Compared with midazolam, a single preoperative intravenous dose of dexmedetomidine appears to provide better postoperative anxiolytic effects for children undergoing same-day surgery.

Median effective dose of intranasal dexmedetomidine sedation for transthoracic echocardiography examination in postcardiac surgery and normal children: An up-and-down sequential allocation trial

BACKGROUND

Dexmedetomidine (DEX) has been used for sedation in young infants and children undergoing transthoracic echocardiography (TTE). The median effective dose of intranasal DEX has not been described for postcardiac surgery children. Postcardiac surgery children could require more DEX to achieve satisfactory sedation for TTE examination than children suspected of congenital heart disease.

OBJECTIVES

To study whether postcardiac surgery children need a larger dose of DEX for TTE than normal children.

DESIGN

A double-blind sequential allocation trial with doses determined by the Dixon and Massey up-and-down method.

SETTING

A tertiary care teaching hospital from 25 October to 30 November 2016.

PATIENTS

Children under the age of 3 years requiring intranasal DEX for TTE.

INTERVENTIONS

Children were allocated to a postcardiac surgery group (n = 20) or a normal group (n = 19). The first patient in both groups received intranasal DEX (2 μg kg): using the up-and-down method of Dixon and Massey, the next dose was dependent on the previous patient's response.

MAIN OUTCOME MEASURES

Median effective dose was estimated from the up-and-down method of Dixon and Massey and probit regression. A second objective was to study haemodynamic stability and adverse events with these doses.

RESULTS

The median effective dose (95% confidence interval) of intranasal DEX was higher in postcardiac surgery children than in normal children, 3.3 (2.72 to 3.78) μg kg versus 1.8 (1.71 to 2.04) (μg kg), respectively (P < 0.05). There were no significant differences in time to sedation, time to wake-up or TTE examination time between the two groups for successful sedation. Additionally, there were no significant adverse events.

CONCLUSION

The median effective dose of intranasal DEX for TTE sedation in postcardiac surgery children was higher than in normal children.

TRIAL REGISTRATION

chictr.org.cn identifier: ChiCTR-OOC-16009846.

Determination of blood dexmedetomidine in dried blood spots by LC-MS/MS to screen therapeutic levels in paediatric patients

Dexmedetomidine is an imidazole derivative, with high affinity for α2 adrenergic receptors, used for sedation, analgesia and adjuvant anaesthesia. In this study, an analytical method for the quantification of dexmedetomidine in dried blood spots was developed, validated and applied. The drug was extracted from dried blood spot by liquid extraction; the separation was carried out by ultra high-resolution liquid chromatography in reverse phase coupled to tandem mass spectrometry method. An X Select cyano 5 μm HSS column (2.1 X 150 mm, Waters) and a mobile phase composed of 0.1% formic acid: acetonitrile [50:50 v/v], were used. The test was linear over the concentration range of 50 to 2000 pg/mL. The coefficients of variation for the intra and interday trials were less than 15%. The drug was stable under the conditions tested. The method was successfully applied for the quantification of 6 patients, aged 0 to 2 years, with classification ASA I, who underwent ambulatory surgeries, receiving a dose of 1 μg/Kg dexmedetomidine IV. The drug concentrations in the different sampling times were in the range of 76 to 868 pg/mL.

Median Effective Dose of Intranasal Dexmedetomidine for Transthoracic Echocardiography in Children with Kawasaki Disease Who Have a History of Repeated Sedation

Background

The aim of this study was to investigate the median effective dose (ED50) of intranasal dexmedetomidine for echocardiography in children with Kawasaki disease who had a history of repeated sedation.

Material/Methods

There were 73 pediatric Kawasaki disease patients aged 1 to 36 months enrolled in this study who had American Society of Anesthesiologists (ASA) I–II, were scheduled to undergo echocardiography under sedation. They were assigned to 2 groups (group A: age 1–18 months, and group B: age 19–36 months). Intranasal dexmedetomidine was administered before echocardiography. The dose of intranasal dexmedetomidine was determined with the up-down sequential allocation, and the initial dose was 2 μg/kg with an increment/decrement of 0.2 μg/kg. The ED50 of intranasal dexmedetomidine for sedation was determined with the up-and-down method of Dixon and Massey and probit regression. The time to effective sedation, time to regaining consciousness, vital signs, oxygen saturation, echocardiographic examination time, clinical side-effects, and characteristics of regaining consciousness were recorded and compared.

Results

The ED50 of intranasal dexmedetomidine for sedation was 2.184 μg/kg (95% CI, 1.587–2.785) in group A and 2.313 μg/kg (95% CI, 1.799–3.426) in group B. There were no significant differences in the time to sedation and time to regaining consciousness between groups. Additionally, change in hemodynamic and hypoxemia were not noted in both groups.

Conclusions

The ED50 of intranasal dexmedetomidine was determined in children with Kawasaki disease who had a history of repeated sedation to be appropriate for repeated-routine sedation of echocardiographic examination in pediatric patients. The ED50 of intranasal dexmedetomidine for echocardiography in this circumstance is similar to that in children receiving initial sedation.

Dexmedetomidine Use in a Tertiary Care NICU: A Descriptive Study

BACKGROUND

Continuous infusions of dexmedetomidine are increasingly used for sedation in critically ill pediatric patients. Emerging data suggest potential benefits when used for sedation in neonates, including reduced sedative requirements and earlier enteral feeds.

OBJECTIVE

To describe the use, adverse effects, and signs of withdrawal in a cohort of neonates receiving dexmedetomidine, the majority of whom were receiving concomitant opioids.

METHODS

This was a retrospective, descriptive review of 38 neonates receiving dexmedetomidine in a medical surgical neonatal intensive care unit, including data on duration of use, dose, adverse effects, weaning, and signs of withdrawal.

RESULTS

Dexmedetomidine was used for a median of 183 hours, at a median maximum dose of 0.5 µg/kg/h. Premature infants were started on dexmedetomidine at a later chronological age than term infants (41 vs 9 days, P = 0.004). Of 18 patients receiving an opioid infusion at the time of dexmedetomidine initiation, 67% had a dose reduction in opioids by 24 hours. The majority (89%) of neonates had at least 1 potentially related adverse effect during the dexmedetomidine infusion, though no discontinuations were needed as a result. In all, 80% of patients had their dexmedetomidine gradually weaned off, and 71% had at least 1 sign of withdrawal.

CONCLUSIONS AND RELEVANCE

In this cohort, dexmedetomidine was often used in a postsurgical setting, with concomitant opioids, over prolonged periods. These factors appear to affect and likely confound the rates of adverse effects and withdrawal signs from dexmedetomidine. Clinicians considering the use of dexmedetomidine in a similar population can draw guidance from our data.

Impact of CYP2A6 gene polymorphism on the pharmacokinetics of dexmedetomidine for premedication

BACKGROUND

Dexmedetomidine is a widely used sedative in clinic, which is mainly metabolized by cytochrome P450 2A6 (CYP2A6). Dexmedetomidine was rarely reported for off-label usage of premedication, but lacking relevant pharmacokinetic investigations. Therefore, our study determined the dexmedetomidine pharmacokinetics of CYP2A6*4 allele in Chinese patients pretreated with dexmedetomidine whose mutation frequency of CYP2A6*4 are high, in order to provide clinical references.

METHODS

Thirty-one elective surgery patients received premedication with 0.5 μg/kg dexmedetomidine via intravenous pump. Their plasma concentrations at multiple time-points and polymorphism of CYP2A6*4 were determined and statistically analyzed.

RESULTS

9 patients were *1/*4 or *4/*4, and 22 patients were *1/*1. The main pharmacokinetic parameters were area under curve (AUC) 1396.19 ± 332.47h· ng· l^-1, peak blood concentration (C_max) 495.50 ± 104.90ng· l^-1, distribution volume (V) 0.68 ± 0.20 L/kg, clearance (CL) 0.38 ± 0.11 L/h/kg, distribution half-life (t_1/2α) 0.05 ± 0.01h, elimination half-life (t_1/2β) 2.53 ± 0.04h. No significant pharmacokinetic differences were found among CYP2A6*1/*1, *1/*4, and *4/*4 patients.

CONCLUSIONS

In Chinese patients pretreated with dexmedetomidine, T_1/2β was consistent with that published, but T_1/2α, V and Cl were lower. It was unnecessary to consider the mutation when developing the precision regimen of dexmedetomidine.

Application of pre-injection of dexmedetomidine of different doses in pediatric intravenous general anesthesia without tracheal intubation

This study observed the clinical efficacy of pre-injection of dexmedetomidine of different doses before surgery and the adverse reactions during the recovery period in pediatric intravenous general anesthesia without tracheal intubation. Pediatric patients who received general anesthesia without tracheal intubation before surgery from January 2016 to March 2017 were randomly divided into four groups (n=30), and were respectively treated with intravenous pump infusion of loaded dexmedetomidine of high-dose (2.5 µg/kg), middle-dose (1.5 µg/kg) and low-dose (0.5 µg/kg), while the children in the control group received injection of normal saline in same dose. Then, the mean arterial pressure (MAP) at different time points (5 and 10 min after administration, after anesthesia and after surgery), heart rate, Ramsay sedation score changes and adverse reactions during recovery period of anesthesia of pediatric patients were compared among four groups. At 5 and 10 min after administration, Ramsay scores of high-dose group and middle-dose group were higher than that of the control group, and the differences had statistical significance (P<0.05). There was no significant difference in comparison of Ramsay scores between low-dose group and the control group. The MAP and heart rate after anesthesia and after surgery of pediatric patients with pump infusion of dexmedetomidine in the three groups were decreased significantly compared to those of the control group, and the differences had statistical significance (P<0.05). The incidence rate of adverse reaction of pediatric patients during the recovery period after pump infusion in the three groups and the control group was, respectively, 13/30, 8/30, 7/30 and 8/30, and the differences were statistically significant (P<0.05). The sedative effect and safety of pre-injection of dexmedetomidine in pediatric intravenous general anesthesia without tracheal intubation are promising, and the medium dosage can maximize the anesthetic effect with less side effects.

Median effective dose of intranasal dexmedetomidine sedation for transthoracic echocardiography in pediatric patients with noncyanotic congenital heart disease: An up-and-down sequential allocation trial

BACKGROUND

Intranasal dexmedetomidine can provide adequate sedation during short procedures. However, previous literature investigating the single-dose use of intranasal dexmedetomidine for sedation during transthoracic echocardiography in younger children is scarce, and the effects of age on sedation with intranasal dexmedetomidine remain controversial.

OBJECTIVE

This study was to determine the 50% effective dose and estimate the 95% effective dose of single-dose intranasal dexmedetomidine to induce sedation in pediatric patients with noncyanotic congenital heart disease, and also determine the effect of age on the dose required for sedation.

METHODS

Patients were stratified into three age groups of 1-6 months, 7-12 months, and 13-36 months. Intranasal dexmedetomidine started at a dose of 2 μg kg^-1 on the first patient. The dose of dexmedetomidine for each subsequent patient was determined by the previous patient's response using Dixon's up-and-down method with an interval of 0.25 μg kg^-1 . Sedation scale and recovery were assessed by the Modified Observer Assessment of Alertness and Sedation Scale and Modified Aldrete Recovery Score. The 50% effective dose was determined by Dixon's up-and-down method. In addition, both 50% effective dose and 95% effective dose were obtained using a probit regression approach. Other variables included sedation onset time, echocardiography time, wake-up time, discharge time, heart rate, blood pressure, oxygen saturation, respiratory rate, and adverse events such as vomiting, regurgitation, and apnea.

RESULTS

The study population was comprised of 70 patients. The 50% effective dose (95% confidence interval) and the 95% effective dose (95% confidence interval) of intranasal dexmedetomidine for sedation were 1.8 (1.58-2.00) μg kg^-1 and 2.2 (1.92-5.62) μg kg^-1 in patients aged 1-6 months, 1.8 (1.61-1.95) μg kg^-1 and 2.1 (1.90-2.85) μg kg^-1 in patients aged 7-12 months, 2.2 (1.92-2.37) μg kg^-1 and 2.7 (2.34-6.88) μg kg^-1 in patients aged 13-36 months, respectively. The 50% effective dose in age group 13-36 months was higher than those of age group 1-6 months (P = .042) and 7-12 months (P = .043). There were no differences in sedation onset time, echocardiography time, wake-up time, and discharge time between groups. None of the patients experienced oxyhemoglobin desaturation, hypotension, or bradycardia during the procedure. No significant adverse events occurred.

CONCLUSION

Single-dose of intranasal dexmedetomidine was an effective agent for patients under the age of 3 years requiring sedation for transthoracic echocardiography. The 50% effective dose of intranasal dexmedetomidine for transthoracic echocardiography sedation in children aged 13-36 months was higher than in children <13 months.

Population Pharmacokinetics of Dexmedetomidine in Infants

Despite limited pharmacokinetic (PK) data, dexmedetomidine is increasingly being used off-label for sedation in infants. We aimed to characterize the developmental PK changes of dexmedetomidine during infancy. In this open-label, single-center PK study of dexmedetomidine in infants receiving dexmedetomidine per clinical care, ≤10 blood samples per infant were collected. A set of structural PK models and residual error models were explored using nonlinear mixed-effects modeling in NONMEM. Covariates including postmenstrual age (PMA), serum creatinine, and recent history of cardiac surgery requiring cardiopulmonary bypass were investigated for their influence on PK parameters. Univariable generalized estimating equation models were used to evaluate the association of hypotension with dexmedetomidine concentrations. A total of 89 PK samples were collected from 20 infants with a median PMA of 44 weeks (range, 33-61). The median maximum dexmedetomidine infusion dose during the study period was 1.8 μg/(kg·h) (0.5-2.5), and 16/20 infants had a maximum dose >1 μg/(kg·h). A 1-compartment model best described the data. Younger PMA was a significant predictor of lower clearance. Infants with a history of cardiac surgery had ∼40% lower clearance compared to those without a history of cardiac surgery. For infants with PMA of 33 to 61 weeks and body weight of 2 to 6 kg, the estimated clearance and volume of distribution were 0.87 to 2.65 L/(kg·h) and 1.5 L/kg, respectively. No significant associations were found between dexmedetomidine concentrations and hypotension. Infants with younger PMA and recent cardiac surgery may require relatively lower doses of dexmedetomidine to achieve exposure similar to older patients and those without cardiac surgery.

A prospective randomized controlled double-blind trial to assess the effects of dexmedetomidine during cleft palate surgery

Background

We investigated whether the intraoperative administration of dexmedetomidine would attenuate the profound sympathoadrenal response associated with cleft palate (CP) surgery.

Methods

Sixty children aged 6 months to 12 years undergoing CP surgery under general anesthesia were randomly assigned to the control (C) or dexmedetomidine (D) groups. Group C received benzodiazepine (0.05 mg/kg midazolam followed by infusion of normal saline) fentanyl isoflurane anesthesia, and Group D received dexmedetomidine (loading 1 µg/kg followed by infusion of 0.5 µg/kg/h) fentanyl isoflurane anesthesia. Heart rate (HR), mean blood pressure (MBP), intraoperative fentanyl and isoflurane requirements, recovery scores, emergence agitation, pain scores, time and requirement of rescue analgesic, and surgeon satisfaction were noted.

Results

Intraoperative HR and MBP in Group D were significantly lower than the corresponding values in Group C (P < 0.001). HR decreased up to 16% in Group D. By contrast, HR increased up to 20% in Group C. Group D had comparable MBP to its baseline, whereas Group C had higher MBP until extubation (P = 0.015). Two children in Group D developed bradycardia and hypotension, which was successfully treated. The fentanyl and isoflurane requirements decreased by 43% and 30%, respectively, in Group D patients compared to those in Group C (P < 0.001). Group D had lower pain scores and less emergence agitation (P < 0.001). Time until requirement of first rescue analgesic was longer in Group D than that in Group C (P < 0.001). Surgeon satisfaction was higher in Group D than that in Group C.

Conclusions

Intravenous dexmedetomidine during CP surgery attenuated hemodynamic responses with excellent surgeon satisfaction. Close monitoring of hemodynamics is recommended.

Population Pharmacokinetics of Dexmedetomidine After Short Intravenous Infusion in Chinese Children

BACKGROUND AND OBJECTIVE

Dexmedetomidine is a highly selective alpha2-adrenoceptor agonist with sedative and analgesic properties which is also used in pediatric anesthesia. Although the pharmacokinetics of dexmedetomidine have been studied in pediatric patients, there are no data for Chinese children available. As alterations in pharmacokinetics due to ethnicity cannot be ruled out, it was the aim of this study to characterize the pharmacokinetics of dexmedetomidine in Chinese pediatric patients.

METHODS

Thirty-nine children aged 1-9 years undergoing surgery were enrolled in the study. Dexmedetomidine was administered as short intravenous infusion of 1-2 µg/kg in 10 min. Venous blood samples were drawn until 480 min after stopping of infusion. Dexmedetomidine plasma concentrations were measured with high-performance liquid chromatography and mass spectrometry. Pharmacokinetic modeling was performed by population analysis using linear compartment models.

RESULTS

Data of 36 patients (age 1-9 years, weight 10-27 kg) were analyzed. The pharmacokinetics of dexmedetomidine were best described by a two-compartment model with an allometric power model and estimates standardized to 70 kg body weight. The population estimates (95 % CI) per 70 kg bodyweight were: clearance 36.2 (33.3-41.1) l/h, central volume of distribution 84.3 (70.3-91.4) l, intercompartmental clearance 82.8 (63.6-136.6) l/h, peripheral volume of distribution 114 (95-149) l, and terminal half-life 4.4 (3.6-5.3) h. Age did not show any influence on weight-adjusted parameters.

CONCLUSIONS

Chinese children showed a similar clearance, but larger volumes of distribution and longer terminal half-life when compared to studies in Caucasians.

TRIAL REGISTRATION

ChiCTR-OPC-14005659.

A multinational, drug utilization study to investigate the use of dexmedetomidine (Dexdor®) in clinical practice in the EU

Aims

Dexmedetomidine (dexdor®) is approved in the European Union (EU) for sedation of adults in the intensive care unit (ICU). The present observational, retrospective study was requested by the European Medicines Agency to investigate dexmedetomidine use in clinical practice, with a particular focus on off‐label use, including the paediatric population.

Methods

Study countries and sites were chosen from those with highest dexmedetomidine use, based on sales. Site selection (blind) was conducted by a multispecialist, independent group. Anonymized data on demographics, treatment indication, dexmedetomidine dosing, concomitant medications and treatment effectiveness were collected retrospectively from records of all dexmedetomidine‐treated patients at the site during the enrolment period. Informed consent was waived, to avoid influencing the prescribing of dexmedetomidine. Recruitment was completed within 18 months of first site initiation.

Results

Data from 2000 patients were collected from 16 hospitals in four EU countries (Finland 750, Poland 505, Germany 470, Austria 275). The median age was 62 years, with more males (70.2%) than females. Dexmedetomidine was primarily used in the adult ICU (86.0%) for ICU sedation (78.6%) and mostly dosed according the product label. The intended sedative effect was obtained in 84.9% of administrations. Paediatric use (5.9% of patients, mostly in Austria and Finland) occurred mainly in the adult or paediatric ICU (75.6%) for sedation (67.2%).

Conclusions

Overall, most patients were treated with dexmedetomidine according to the product labelling. Use in children was limited but significant and similar in scope to that in adults. Administrations not fully according to the product labelling usually occurred in an ICU environment and reflected extensively investigated clinical uses of dexmedetomidine.

Feasibility of dexmedetomidine as sole analgesic agent during robotic urological surgery: A pilot study

BACKGROUND AND AIMS

Opioid-free anesthesia decreases postoperative nausea and vomiting, emergence agitation, prolonged sedation, ileus, and urinary retention. The feasibility of the use of dexmedetomidine as sole analgesic agent has been shown in patients undergoing bariatric and gynecological laparoscopic surgery. We explored its use for robotic urological surgery.

MATERIAL AND METHODS

Thirty patients were randomized to receive either dexmedetomidine (Group D) or fentanyl (Group F) along with total intravenous anesthesia with propofol. The hemodynamic parameters and number of doses of rescue analgesics used intraoperatively and postoperatively were noted. Recovery parameters at the end of surgery were also recorded.

RESULTS

The dose of intraoperative rescue fentanyl was not significantly different between groups (P = 0.13). The hemodynamic profile of patients in the two groups was comparable except the heart rate was significantly more in Group D after intubation and at 60 min. The mean arterial pressure was significantly lower after the initial loading dose of study drug in Group D. The recovery profiles were not significantly different between groups.

CONCLUSION

The study reveals that dexmedetomidine has equal analgesic efficacy as fentanyl for intraoperative use and can be used as the sole analgesic agent in patients undergoing robotic urological surgery.

Relationship between dexmedetomidine dose and plasma dexmedetomidine concentration in critically ill infants: a prospective observational cohort study

Background

Dexmedetomidine is a highly selective central α₂-agonist used as a sedative in pediatric intensive care unit (PICU). However, little is known about the relationship between dexmedetomidine dose and its plasma concentration during long-term infusion. We have previously demonstrated that the sedative plasma dexmedetomidine concentration is moderately correlated with the administered dose in adults (r = 0.653, P = 0.001). We hypothesized that there would be a similar relationship between the sedative dexmedetomidine concentration and administered dose in infants.

Methods

All patients admitted to the PICU at Nagoya City University Hospital, Japan, between November 2012 and March 2013 were eligible for inclusion in the study. Plasma dexmedetomidine concentration was measured by ultra-performance liquid chromatography coupled with tandem mass spectrometry.

Results

We measured the plasma dexmedetomidine concentration in 203 samples from 45 patients. Of these, 96 samples collected from 27 patients < 2 years old were included in this study. All patients received dexmedetomidine at 0.12–1.40 µg/kg/h. The median administration duration was 87.6 hours (range: 6–540 hours). Plasma dexmedetomidine concentration ranged from 0.07 to 3.17 ng/ml. Plasma dexmedetomidine concentration was not correlated with the administered dose (r = 0.273, P = 0.007). The approximate linear equation was y = 0.690x + 0.423.

Conclusions

In infants, plasma dexmedetomidine concentration did not exhibit any correlation with administered dose, which is not a reliable means of obtaining optimal plasma concentration.

Effect of intranasal dexmedetomidine on emergence agitation after sevoflurane anesthesia in children undergoing tonsillectomy and/or adenoidectomy

BACKGROUND

Emergence agitation (EA) after sevoflurane anesthesia is common in children during recovery from general anesthesia and may result in postoperative complications. This study investigated safety and effectiveness of intranasal dexmedetomidine in reducing the incidence and severity of EA.

METHODS

This prospective, randomized double-blinded controlled trial included 86 patients scheduled for the tonsillectomy and/or adenoidectomy under general anesthesia with sevoflurane. They were randomly allocated into two groups. Group D received intranasal dexmedetomidine at 1 μg/kg, and Group C received intranasal saline 0.9% after the induction of general anesthesia. Four-point agitation scale and Face, Legs, Activity, Cry and Consolability (FLACC) scale for pain assessment were measured at six time points (after extubation, leaving the operating room, on arrival to postanesthesia care unit [PACU], 10, 20, and 30 min after arrival in PACU). Extubation, emergence, and discharge times were recorded in addition to any adverse effects.

RESULTS

There was a significant difference in the incidence of EA between Groups D and C (6.98% and 58%, respectively, with P = 0.001). The median four-point agitation scales and the median scores of FLACC pain scales of Group D were significantly lower than those of Group C at the all six time points with P < 0.05. Extubation, emergence, and discharge times were comparable in both groups, and none of the subjects reported any adverse effects.

CONCLUSION

This study demonstrates that a 1 μg/kg dose of intranasal dexmedetomidine administered after the induction of anesthesia reduces post-sevoflurane incidence and severity of EA in children undergone tonsillectomy and/or adenoidectomy with no adverse effects and smooth recovery profile.

Dexmedetomidine prevent postoperative nausea and vomiting on patients during general anesthesia: A PRISMA-compliant meta analysis of randomized controlled trials

BACKGROUND

Postoperative nausea and vomiting (PONV) is a frequent complication in postoperative period. The aim of this article was to evaluate the effect of dexmedetomidine on PONV.

METHOD

RevMan 5.3 software was applied for performing statistic analysis. Twenty-four trials with 2046 patients were included.

RESULTS

The PONV of the dexmedetomidine group was significantly lower compared with the placebo group (0.56, 95% CI: 0.46, 0.69). Subgroup analysis further confirmed the effect of dexmedetomidine (irrespective of administration mode) (P < 0.00001). Perioperative fentanyl consumption in dexmedetomidine group were also reduced significantly (P < 0.00001). Whereas, side effects such as bradycardia, hypotension increased in dexmedetomidine group (especially in loading dose mode and loading dose plus continuous infusion mode).

CONCLUSIONS

Dexmedetomidine administrated in continuous infusion mode has the advantage to prevent PONV as well as reduce side effects such as bradycardia and hypotension.

Median Effective Dose of Intranasal Dexmedetomidine for Rescue Sedation in Pediatric Patients Undergoing Magnetic Resonance Imaging

Background

The median effective dose (ED50) of intranasal dexmedetomidine after failed chloral hydrate sedation has not been described for children. This study aims to determine the ED50 of intranasal dexmedetomidine for rescue sedation in children aged 1 to 36 months, who were inadequately sedated by chloral hydrate administration during magnetic resonance imaging (MRI).

Methods

This study was performed on 120 children, who were 1 to 36 months old and underwent MRI scanning. Intranasal dexmedetomidine was administered as a rescue sedative to children not adequately sedated after the initial oral dose of chloral hydrate (50 mg/kg). Children were stratified into four age groups. ED50 values were estimated from the up-and-down method of Dixon and Massey and probit regression. Other variables included induction time, time to wake up, vital signs, oxygen saturation, MRI scanning time, and recovery characteristics.

Results

ED50 of intranasal dexmedetomidine for rescue sedation was 0.4 μg/kg (95% CI, 0.34 to 0.50) in children aged 1 to 6 months, 0.5 μg/kg (95% CI, 0.48 to 0.56) in children aged 7 to 12 months, 0.9 μg/kg (95% CI, 0.83 to 0.89) in children aged 13 to 24 months, and 1.0 μg/kg (95% CI, 0.94 to 1.07) in children aged 25 to 36 months. There were no significant differences in sedation induction time or time to wake up between the different age groups. Additionally, no significant adverse hemodynamic or hypoxemic effects were noted.

Conclusions

The authors determined the ED50 for rescue sedation using intranasal dexmedetomidine after failed chloral hydrate sedation in children. It was found that ED50 increases with advancing age during the first 3 yr of life.

Pharmacokinetics and pharmacodynamics of dexmedetomidine

Dexmedetomidine is an alpha-2 adrenoceptor agonist and has been used as a general anesthetic, sedative and analgesic for about 30 years. The aim of this paper is to review the pharmacokinetics and pharmacodynamics of dexmedetomidine, evaluate physiological factors that may affect the pharmacokinetics of dexmedetomidine, and summarize the pharmacodynamics of dexmedetomidine at different plasma levels. The pharmacokinetic parameters reported in previous studies according to noncompartmental analyses or population modeling results are compared. We concluded that the pharmacokinetic profile can be adequately described by a two-compartment model in population pharmacokinetic modeling. Body weight, height, albumin level, cardiac output, disease condition and other factors were considered to have significant influence on the clearance and/or distribution volume in different population pharmacokinetic models. The pharmacological effects of dexmedetomidine, such as sedation, heart rate reduction and biphasic change of blood pressure, vary at different plasma levels. These findings provide a reference for individualizing the dose of dexmedetomidine and achieving the desired pharmacological effects in clinical applications.

Sedation and Analgesia in Pediatric Cardiac Critical Care

OBJECTIVES

This review will focus on the pharmacokinetics (with an emphasis on the context-sensitive half-time), pharmacodynamics, and hemodynamic characteristics of the most commonly used sedative/hypnotic, analgesic, and IV anesthetics used in cardiac intensive care. In addition, the assessment of pain and agitation and withdrawal will be reviewed.

DATA SOURCE

MEDLINE, PubMed.

CONCLUSIONS

Children in the cardiac ICU often require one or more components of general anesthesia: analgesia, amnesia (sedation and hypnosis), and muscle relaxation to facilitate mechanical ventilation, to manage postoperative pain, to perform necessary procedures, and to alleviate fear and anxiety. Furthermore, these same children are often vulnerable to hemodynamic instability due to unique underlying physiologic vulnerabilities. An assessment of hemodynamic goals, postoperative procedures to be performed, physiologic vulnerabilities, and the intended duration of mechanical ventilation should be made. Based on this assessment, the optimal selection of sedatives, analgesics, and if necessary, muscle relaxants can then be made.

Comparison of rescue techniques for failed chloral hydrate sedation for magnetic resonance imaging scans--additional chloral hydrate vs intranasal dexmedetomidine

BACKGROUND

Chloral hydrate, a commonly used sedative in children during noninvasive diagnostic procedures, is associated with side effects like prolonged sedation, paradoxical excitement, delirium, and unpleasant taste. Dexmedetomidine, a highly selective α-2 agonist, has better pharmacokinetic properties than chloral hydrate. We conducted this prospective, double-blind, randomized controlled trial to evaluate efficacy of intranasal dexmedetomidine with that of a second oral dose of chloral hydrate for rescue sedation during magnetic resonance imaging (MRI) studies in infants.

METHODS

One hundred and fifty infants (age group: 1-6 months), who were not adequately sedated after initial oral dose of 50 mg · kg(-1) chloral hydrate, were randomly divided into three groups with the following protocol for each group. Group C: second oral dose chloral hydrate 25 mg · kg(-1); Group L and Group H: intranasal dexmedetomidine in a dosage of 1 and 2 mcg · kg(-1), respectively. Status of sedation, induction time, time to wake up, vital signs, oxygen saturation, and recovery characteristics were recorded.

RESULTS

Successful rescue sedation in Groups C, L, and H were achieved in 40 (80%), 47 (94%), and 49 (98%) of infants, respectively, on an intention to treat analysis, and the proportion of infants successfully sedated in Group H was more than that of Group L (P ˂ 0.01). There were no significant differences in sedation induction time; however, the time to wake up was significantly shorter in Group L as compared to that in Group C or H (P < 0.01). No significant adverse hemodynamic or hypoxemic effects were observed in the study.

CONCLUSION

Intranasal dexmedetomidine induced satisfactory rescue sedation in 1- to 6-month-old infants during MRI study, and appears to cause sedation in a dose-dependent manner.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care: Sedation, Analgesia and Muscle Relaxant

OBJECTIVE

This article reviews pharmacotherapies currently available to manage sedation, analgesia, and neuromuscular blockade for pediatric cardiac critical patients.

DATA SOURCES

The knowledge base of an expert panel of pharmacists, cardiac anesthesiologists, and a cardiac critical care physician involved in the care of pediatric cardiac critical patients was combined with a comprehensive search of the medical literature to generate the data source.

STUDY SELECTION

The panel examined all studies relevant to management of sedation, analgesia, and neuromuscular blockade in pediatric cardiac critical patients.

DATA EXTRACTION

Each member of the panel was assigned a specific subset of the studies relevant to their particular area of expertise (pharmacokinetics, pharmacodynamics, and clinical care) to review and analyze.

DATA SYNTHESIS

The panel members each crafted a comprehensive summary of the literature relevant to their area of expertise. The panel, as a whole, then collaborated to cohesively summarize all the available, relevant literature.

CONCLUSIONS

In the cardiac ICU, management of the cardiac patient requires an individualized sedative and analgesic strategy that maintains hemodynamic stability. Multiple pharmacological therapies exist to achieve these goals and should be selected based on the patient's underlying physiology, hemodynamic vulnerabilities, desired level of sedation and analgesia, and the projected short- or long-term recovery trajectory.

A prospective, randomized, double blinded comparison of intranasal dexmedetomodine vs intranasal ketamine in combination with intravenous midazolam for procedural sedation in school aged children undergoing MRI

Background:

For optimum magnetic resonance imaging (MRI) image quality and to ensure precise diagnosis, patients have to remain motionless. We studied the effects of intranasal dexmedetomidine and ketamine with intravenous midazolam for pre-procedural and procedural sedation in school aged children.

Patients and Methods:

Children were randomly allocated to one of two groups: (Group D) received intranasal dexmedetomidine 3 μg kg^–1 and (Group K) received intranasal ketamine 7 mg kg^–1. Sedation levels 10, 20 and 30 min after drug instillation were evaluated using a Modified Ramsay sedation scale. A 4-point score was used to evaluate patients when they were separated from their parents and their response to intravenous cannulation.

Results:

The two groups were comparable in terms of the child's anxiety at presentation (P = 0.245). We observed that Group K achieved faster sedation at 10 min point with P < 0.05. A comparable sedation score at 20 and 30 min were noted. The two groups were comparable regarding to the child's acceptance of nasal administration (P = 0.65). The sedation failure rate was insignificantly differ between groups (13.7% vs. 20.6% for Group D and K respectively). Heart rate and systolic blood pressure showed a significant difference between the two groups starting from the point of 20 min.

Conclusion:

Intranasal dexmedetomidine 3 μg kg^–1 or ketamine 7 mg kg^–1 can be used safely and effectively to induce a state of moderate conscious sedation and to facilitate parents’ separation and IV cannulation. Addition of midazolam in a dose not sufficient alone to produce the target sedation achieved our goal of deep level of sedation suitable for MRI procedure.

Pain management in newborns

As a standard of care for preterm/term newborns effective pain management may improve their clinical and neurodevelopmental outcomes. Neonatal pain is assessed using context-specific, validated, and objective pain methods, despite the limitations of currently available tools. Therapeutic approaches reducing invasive procedures and using pharmacologic, behavioral, or environmental measures are used to manage neonatal pain. Nonpharmacologic approaches like kangaroo care, facilitated tucking, non-nutritive sucking, sucrose, and others can be used for procedural pain or adjunctive therapy. Local/topical anesthetics, opioids, NSAIDs/acetaminophen and other sedative/anesthetic agents can be incorporated into NICU protocols for managing moderate/severe pain or distress in all newborns.

Premedication with dexmedetomidine in pediatric patients: a systematic review and meta-analysis

Premedication is important in pediatric anesthesia. This meta-analysis aimed to investigate the role of dexmedetomidine as a premedicant for pediatric patients. A systematic literature search was conducted to identify randomized controlled trials comparing dexmedetomidine premedication with midazolam or ketamine premedication or placebo in children. Two reviewers independently performed the study selection, quality assessment and data extraction. The original data were pooled for the meta-analysis with Review Manager 5. The main parameters investigated included satisfactory separation from parents, satisfactory mask induction, postoperative rescue analgesia, emergence agitation and postoperative nausea and vomiting. Thirteen randomized controlled trials involving 1190 patients were included. When compared with midazolam, premedication with dexmedetomidine resulted in an increase in satisfactory separation from parents (RD = 0.18, 95% CI: 0.06 to 0.30, p = 0.003) and a decrease in the use of postoperative rescue analgesia (RD = -0.19, 95% CI: -0.29 to -0.09, p = 0.0003). Children treated with dexmedetomidine had a lower heart rate before induction. The incidence of satisfactory mask induction, emergence agitation and PONV did not differ between the groups. Dexmedetomidine was superior in providing satisfactory intravenous cannulation compared to placebo. This meta-analysis suggests that dexmedetomidine is superior to midazolam premedication because it resulted in enhanced preoperative sedation and decreased postoperative pain. Additional studies are needed to evaluate the dosing schemes and long-term outcomes of dexmedetomidine premedication in pediatric anesthesia.

A phase II/III, multicenter, safety, efficacy, and pharmacokinetic study of dexmedetomidine in preterm and term neonates

OBJECTIVE

To investigate the safety, efficacy, and pharmacokinetic profile of dexmedetomidine in preterm and full-term neonates ≥ 28 to ≤ 44 weeks gestational age.

STUDY DESIGN

Forty-two intubated, mechanically ventilated patients (n = 42) were grouped by gestational age into group I (n = 18), ≥ 28 to <36 weeks, and group II (n = 24), ≥ 36 to ≤ 44 weeks. Within each age group, there were 3 escalating dose levels, including a loading dose (LD, μg/kg) followed by a maintenance dose (MD, μg · kg(-1) · h(-1)) for 6-24 hours: level 1, 0.05 LD/MD; level 2, 0.1 LD/MD; and level 3, 0.2 LD/MD. The primary endpoint was the number of patients requiring sedation as determined by the Neonatal Pain, Agitation, Sedation Scale.

RESULTS

During dexmedetomidine infusion, 5% of Neonatal Pain, Agitation, Sedation Scale scores were >3, indicating agitation/pain, with 4 patients (10%) requiring more sedation and 17 (40%) requiring more analgesia. Though there was significant variability in pharmacokinetic variables, group I appeared to have lower weight-adjusted plasma clearance (0.3 vs 0.9 L · h(-1) · kg(-1)) and increased elimination half-life (7.6 vs 3.2 hours) compared with group II. Fifty-six adverse events (AEs) were reported in 26 patients (62%); only 3 AEs (5%) were related to dexmedetomidine. There were no serious AEs and no AEs or hemodynamic changes requiring dexmedetomidine discontinuation.

CONCLUSION

Dexmedetomidine is effective for sedating preterm and full-term neonates and is well-tolerated without significant AEs. Preterm neonates had decreased plasma clearance and longer elimination half-life.

Dexmedetomidine infusion associated with transient adrenal insufficiency in a pediatric patient: a case report

Dexmedetomidine is a highly selective α₂-adrenoceptor agonist used for sedation due to its anxiolytic and analgesic properties without respiratory compromise. Due to its structural similarity to etomidate, there has been concern that dexmedetomidine may cause adrenal insufficiency. This concern was initially supported by animal studies, but subsequent human studies demonstrated mixed results. We describe the case of transient adrenal insufficiency in a 1-year-old male who presented with 24% total body surface 2nd degree burns. He required sedation with a prolonged, high-dose dexmedetomidine infusion with a peak infusion dose of 2.7 mcg/kg/hr and duration of 6.5 days. The patient developed lethargy and hypotension four days after discontinuation of his infusion. He had a random cortisol level which was low at 0.4 mcg/dL, and the concern for adrenal suppression was confirmed with an ACTH stimulation test with the baseline cortisol of 0.4 mcg/dL and inappropriate 60 minute post-ACTH stimulation cortisol of 7.8 mcg/dL. While further studies will be needed to clarify the risk of adrenal suppression secondary to dexmedetomidine, this case suggests that caution should be taken when administering dexmedetomidine to pediatric patients and highlights the need for future studies to look at appropriate dosing and duration of dexmedetomidine infusions.

Efficacy and safety of intraoperative dexmedetomidine for acute postoperative pain in children: a meta-analysis of randomized controlled trials

BACKGROUND

Aim of the current meta-analysis was to assess the effects of intraoperative dexmedetomidine on postoperative pain, analgesic consumption, and adverse events in comparison with placebo or opioids in children undergoing surgery.

METHODS

This meta-analysis was performed according to the recommendations of the PRISMA statement and the Cochrane collaboration. For dichotomous and continuous outcomes of efficacy and adverse events, the Revman(®) (The Nordic Cochrane Centre, Copenhagen, Denmark) statistical software was used to calculate relative risk (RR), mean difference (MD), and 95% confidence intervals (CI).

RESULTS

We included 11 randomized controlled trials - 434 children received dexmedetomidine, 440 received control. In comparison with placebo, children receiving dexmedetomidine showed a reduced RR for postoperative opioids (0.4; 95% CI: 0.26-0.62; P < 0.00001) and postoperative pain (0.51; 95% CI: 0.32-0.81; P = 0.004). Similar results were obtained for the comparison with intraoperative opioids: reduced RR for postoperative pain (0.49; 95% CI: 0.25-0.94; P = 0.03) and the need for postoperative opioids (0.77; 95% CI: 0.60-1.09; P = 0.05).

CONCLUSIONS

This meta-analysis revealed a lower risk for postoperative pain and the need for postoperative opioids following intraoperative dexmedetomidine in comparison with placebo or opioids in children undergoing surgery; however, the influence of dexmedetomidine on postoperative opioid consumption is less clear. Although there were only a limited number of adverse events, further studies focusing on procedure specific dexmedetomidine dosing and adverse events are urgently needed.