Prospective evaluation of dexmedetomidine for noninvasive procedural sedation in children

Effectiveness of Chloral Hydrate on Brain MRI in Children with Developmental Delay/Intellectual Disability Comparing with Normal Intelligence: Single Tertiary Center Experience

Neurodiagnostic investigation requirements are expanding for diagnostic and therapeutic purposes in children, especially in those with developmental delay/intellectual disability (DD/ID). Thus, determination of optimal sedatives to achieve successful sedation and immobility without further neurological compromise is important in children with DD/ID. The purpose of this study is to assess the effectiveness and adverse reactions of chloral hydrate (CH) for brain magnetic resonance imaging (B-MRI) in children with DD/ID compared to those with normal intelligence (NI). We performed a retrospective chart review of children aged from 1 day to 12 years who required elective sedation using CH for B-MRI. About 730 cases (415 with DD/ID and 315 with NI) of CH sedation were conducted for B-MRI. Children with DD/ID showed a higher failure rate (22%) than did those with NI (6%); additional CH and prolonged sedation time were required. There was no difference in incidence of adverse reactions between DD/ID and NI groups (p = 0.338). Older or heavier children with DD/ID (p = 0.036 and p = 0.013, respectively), as well as those diagnosed with epilepsy or neuropsychiatric disorders showed higher risk of sedation failure (p < 0.001 for each). In conclusion, CH was a suboptimal sedative drug for children with DD/ID compared with those with NI. Other alternative or supplementary sedatives should be taken into consideration especially for those vulnerable groups.

[Propofol-ketamine versus dexmedetomidine-ketamine for sedation during upper gastrointestinal endoscopy in pediatric patients: a randomized clinical trial]

BACKGROUND AND OBJECTIVES

Day-case pediatric sedation is challenging. Dexmedetomidine is a sedative analgesic that does not induce respiratory depression. We compared dexmedetomidine to propofol when it was added to ketamine for sedation during pediatric endoscopy, regarding recovery time and hemodynamic changes.

METHODS

We enrolled 120 patients (2-7 years in age) and randomly assigned them into two groups. Each patient received intravenous (IV) ketamine at a dose of 1 mg.kg^-1 in addition to either propofol (1 mg.kg^-1) or dexmedetomidine (0.5 μg.kg^-1). The recovery time was compared. Hemodynamics, oxygen saturation, need for additional doses, postoperative complications and endoscopist satisfaction were monitored.

RESULTS

There was no significant difference in hemodynamics between the groups. The Propofol-Ketamine (P-K) group showed significantly shorter recovery times than the Dexmedetomidine-Ketamine (D-K) group (21.25 and 29.75 minutes respectively, p <0.001). The P-K group showed more oxygen desaturation. Eleven and six patients experienced SpO₂ <92% in groups P-K and D-K, respectively. A significant difference was noted regarding the need for additional doses; 10% of patients in the D-K group needed one extra dose, and 5% needed two extra doses, compared to 25% and 20% in the P-K group, respectively (p=0.001). The P-K group showed less post-procedure nausea and vomiting. No statistically significant difference between both groups regarding endoscopist satisfaction.

CONCLUSIONS

The P-K combination was associated with a shorter recovery time in pediatric upper gastrointestinal endoscopy, while the D-K combination showed less need for additional doses.

REGISTRATION NUMBER

Clinical trials.gov (NCT02863861).

Use of Dexmedetomidine for Magnetic Resonance Imaging under Sedation in a Pediatric Patient with Phenylketonuria

Phenylketonuria (PKU) is an inborn error of metabolism caused by a deficiency of the enzyme phenylalanine hydroxylase which results in accumulation of phenylalanine. Patients of PKU presents with seizures, mental retardation, and organ damage and possess a unique challenge to the anesthesiologists when they need anesthetics for diagnostic or surgical procedures. There is limited literature regarding the safety of various anesthetic drugs in PKU patients. None of them reported the use of dexmedetomidine as safer sedative option for such patients. Therefore, we describe the management of such a case posted for magnetic resonance imaging under dexmedetomidine sedation.

Comparing Sedative Effect of Dexmedetomidine versus Midazolam for Sedation of Children While Undergoing Computerized Tomography Imaging

Background:

Pediatric anxiety and restlessness may create issues and difficulties in performing accurate diagnostic studies even noninvasive ones, such as radiological imaging. There are some agents that will help to get this goal. This study aimed to compare the intranasal effect of dexmedetomidine (DEX) and midazolam (MID) for sedation parameters of children undergoing computerized tomography (CT) imaging.

Materials and Methods:

A double-blind clinical trial was conducted on 162 eligible children who underwent CT imaging. These patients were divided into two groups including MID (n = 81) with dose of 0.3 mg.kg and DEX (n = 81) with dose of 3 μg.kg, which was consumed intranasally. The mean blood pressure (MBP), respiratory rate (RR), heart rate (HR), and oxygen saturation (O2Sat) in children were recorded. Then, time of initiation, level of sedation, and duration effect of medication were measured at 0, 10, 20, and 30 min. Parents and clinician satisfaction score was asked. All data were analyzed using the Statistical Package for the Social Sciences (SPSS) software by t test and chi-square test.

Results:

Decreasing in MBP and HR was higher in DEX group than MID group (P < 0.001), whereas decrease of O2Sat in MID group was higher than DEX group (0.009). Starting time of sedation (22.72 ± 11.64 vs. 33.38 ± 10.17, P = 0.001) was lower in DEX group. Parents (P < 0.001) and physician (P < 0.001) satisfaction score was higher in DEX group than the MID group.

Conclusion:

Using 3 μg/kg intranasal DEX for sedation of 1–6-year-old children was a suitable method to undergo noninvasive studies such as CT imaging. Intranasal DEX is superior to MID due to higher sedation satisfactory, faster starting effect of sedation, and lower side effects and complications. Nevertheless, in children with hemodynamic instability DEX is not an appropriate choice.

Propofol-ketamine versus dexmedetomidine-ketamine for sedation during upper gastrointestinal endoscopy in pediatric patients: a randomized clinical trial

Background and objectives

Day-case pediatric sedation is challenging. Dexmedetomidine is a sedative analgesic that does not induce respiratory depression. We compared dexmedetomidine to propofol when it was added to ketamine for sedation during pediatric endoscopy, regarding recovery time and hemodynamic changes.

Methods

We enrolled 120 patients (2−7 years in age) and randomly assigned them into two groups. Each patient received intravenous (IV) ketamine at a dose of 1 mg.kg^-1 in addition to either propofol (1 mg.kg^-1) or dexmedetomidine (0.5 μg.kg^-1). The recovery time was compared. Hemodynamics, oxygen saturation, need for additional doses, postoperative complications and endoscopist satisfaction were monitored.

Results

There was no significant difference in hemodynamics between the groups. The Propofol-Ketamine (P-K) group showed significantly shorter recovery times than the Dexmedetomidine-Ketamine (D-K) group (21.25 and 29.75 minutes, respectively, p < 0.001). The P-K group showed more oxygen desaturation. Eleven and 6 patients experienced SpO₂ < 92% in groups P-K and D-K, respectively. A significant difference was noted regarding the need for additional doses; 10% of patients in the D-K group needed one extra dose, and 5% needed two extra doses, compared to 25% and 20% in the P-K group, respectively (p =  0.001). The P-K group showed less post-procedure nausea and vomiting. No statistically significant difference between both groups regarding endoscopist satisfaction.

Conclusions

The P-K combination was associated with a shorter recovery time in pediatric upper gastrointestinal endoscopy, while the D-K combination showed less need for additional doses.

Registration number

Clinical trials.gov (NCT02863861).

A Comparison of Safety and Efficacy of Dexmedetomidine and Propofol in Children with Autism and Autism Spectrum Disorders Undergoing Magnetic Resonance Imaging

Children with autism and autism spectrum disorders have a high incidence of neurologic comorbidities. Consequently, evaluation with magnetic resonance imaging (MRI) is deemed necessary. Sedating these patients poses several challenges. This retrospective study compared the efficacy and safety of dexmedetomidine to propofol in sedating autistic patients undergoing MRI. There were 56 patients in the dexmedetomidine group and 49 in the propofol group. All of the patients successfully completed the procedure. Recovery and discharge times were significantly lower in the propofol group, while the dexmedetomidine group maintained more stable hemodynamics. Both propofol and dexmedetomidine proved to be adequate and safe medications in the sedation of autistic children undergoing MRI.

Safety and Efficacy of Buccal Dexmedetomidine for MRI Sedation in School-Aged Children

OBJECTIVES

Intranasal, intramuscular, and intravenous (IV) dexmedetomidine routes have been used successfully for pediatric MRI studies. We designed this retrospective study to determine efficacy and safety of buccal dexmedetomidine for pediatric MRI sedation.

METHODS

Medical records were reviewed of outpatient children ages 5 to 18 years who received buccal dexmedetomidine with or without oral midazolam for MRI sedation at a freestanding children's hospital sedation program in 2015 and 2016.

RESULTS

A total of 220 outpatient encounters received buccal dexmedetomidine for MRI. Mean age of the cohort was 10.1 ± 2.6 years (range: 5-18.7). Buccal dexmedetomidine dose administered was a mean of 2.20 ± 0.38 μg/kg (range: 0.88-3.19). Of the 220 sedation encounters, 179 (81.4%) patients had satisfactory sedation with buccal dexmedetomidine with or without oral midazolam: 84 had buccal dexmedetomidine as the sole sedative, 95 had satisfactory sedation when buccal dexmedetomidine and oral midazolam (mean: 0.33 ± 0.07 mg/kg; range: 0.21-0.53) were given together, 1 (0.4%) had satisfactory sedation when intranasal fentanyl and midazolam were administered in addition to buccal dexmedetomidine, and 35 (15.9%) required IV sedatives to achieve satisfactory sedation. All patients completed their MRI successfully except 5 (2.2%): 2 encounters were sedation failures, 2 IV sedations developed severe upper airway obstruction, and 1 IV sedation experienced MRI contrast anaphylaxis.

CONCLUSIONS

In a selected population of pediatric patients, buccal dexmedetomidine with or without midazolam provides adequate sedation for most MRI studies with few adverse effects, but given a failure rate of almost 20%, modifications to buccal dexmedetomidine dosing should be investigated.

Sedation and analgesia for procedures in the pediatric emergency room

OBJECTIVE

Children and adolescents often require sedation and analgesia in emergency situations. With the emergence of new therapeutic options, the obsolescence of others, and recent discoveries regarding already known drugs, it became necessary to review the literature in this area.

DATA SOURCES

Non-systematic review in the PubMed database of studies published up to December 2016, including original articles, review articles, systematic reviews, and meta-analyses. References from textbooks, publications from regulatory agencies, and articles cited in reviews and meta-analyses through active search were also included.

DATA SYNTHESIS

Based on current literature, the concepts of sedation and analgesia, the necessary care with the patient before, during, and after sedoanalgesia, and indications related to the appropriate choice of drugs according to the procedure to be performed and their safety profiles are presented.

CONCLUSIONS

The use of sedoanalgesia protocols in procedures in the pediatric emergency room should guide the professional in the choice of medication, the appropriate material, and in the evaluation of discharge criteria, thus assuring quality in care.

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.

Phase IV, Open-Label, Safety Study Evaluating the Use of Dexmedetomidine in Pediatric Patients Undergoing Procedure-Type Sedation

Dexmedetomidine (Precedex™) may be used as an alternative sedative in children, maintaining spontaneous breathing, and avoiding tracheal intubation in a non-intubated moderate or deep sedation (NI-MDS) approach. This open-label, single-arm, multicenter study evaluated the safety of dexmedetomidine in a pediatric population receiving NI-MDS in an operating room or a procedure room, with an intensivist or anesthesiologist in attendance, for elective diagnostic or therapeutic procedures expected to take at least 30 min. The primary endpoint was incidence of treatment-emergent adverse events (TEAEs). Patients received one of two doses dependent on age: patients aged ≥28 weeks' gestational age to <1 month postnatal received dose level 1 (0.1 μg/kg load; 0.05-0.2 μg/kg/h infusion); those aged 1 month to <17 years received dose level 2 (1 μg/kg load; 0.2-2.0 μg/kg/h infusion). Sedation efficacy was assessed and defined as adequate sedation for at least 80% of the time and successful completion of the procedure without the need for rescue medication. In all, 91 patients were enrolled (dose level 1, n = 1; dose level 2, n = 90); of these, 90 received treatment and 82 completed the study. Eight patients in dose level 2 discontinued treatment for the following reasons: early completion of diagnostic or therapeutic procedure (n = 3); change in medical condition (need for intubation) requiring deeper level of sedation (n = 2); adverse event (AE; hives and emesis), lack of efficacy, and physician decision (patient not sedated enough to complete procedure; n = 1 each). Sixty-seven patients experienced 147 TEAEs. The two most commonly reported AEs were respiratory depression (bradypnea; reported per protocol-defined criteria, based on absolute respiratory rate values for age or relative decrease of 30% from baseline) and hypotension. Four patients received glycopyrrolate for bradycardia and seven patients received intravenous fluids for hypotension. SpO₂ dropped by 10% in two patients, but resolved without need for manual ventilation. All other reported AEs were consistent with the known safety profile of dexmedetomidine. Two of the 78 patients in the efficacy-evaluable population met all sedation efficacy criteria. Dexmedetomidine was well-tolerated in pediatric patients undergoing procedure-type sedation.

Utility and Clinical Profile of Dexmedetomidine in Pediatric Cardiac Catheterization Procedures: A Matched Controlled Analysis

Background. Dexmedetomidine is increasingly used in children undergoing cardiac catheterization procedures. We compared the percentage of surgical time with hemodynamic instability and the incidence of postoperative agitation between pediatric cardiac catheterization patients who received dexmedetomidine infusion and those who did not and the incidence of postoperative agitation. Materials and methods. We matched 653 pediatric patients scheduled for cardiac catheterization. Two separate multivariable linear mixed models were used to assess the association between dexmedetomidine use and intraoperative blood pressure and heart rate instability. A multivariate logistic regression was used for relationship between dexmedetomidine and postoperative agitation. Results. No difference between the study groups was found in the duration of MAP ( P = .867) or heart rate (HR) instabilities ( P = .224). The relationship between dexmedetomidine use and the duration of negative hemodynamic effects does not depend on any of the considered CHD types (all P > .001) or intervention ( P = .453 for MAP and P = .023 for HR). No difference in postoperative agitation was found between the study groups ( P = .590). Conclusion. Our study demonstrated no benefit in using dexmedetomidine infusion compared with other general anesthesia techniques to maintain hemodynamic stability or decrease agitation in pediatric patients undergoing cardiac catheterization procedures.

Dexmedetomidine use in patients undergoing electrophysiological study for supraventricular tachyarrhythmias

BACKGROUND

Dexmedetomidine is a selective alpha-2 adrenergic agonist with sedative, analgesic, and anxiolytic properties. Dexmedetomidine has not been approved for use in pediatrics. Dexmedetomidine has been reported to depress sinus node and atrioventricular nodal function in pediatric patients; it has been suggested that the use of dexmedetomidine may not be desirable during electrophysiological studies.

AIM

We hypothesize that the use of dexmedetomidine does not inhibit the induction of supraventricular tachyarrhythmias (SVT) during electrophysiological studies and does not inhibit the ablation of such arrhythmias.

METHODS

In this retrospective, observational cohort study, we reviewed all cases presenting to the cardiac catheterization laboratory for diagnosis or treatment of SVT since 2007. All cases were performed by the same electrophysiologist. The anesthesia was provided by one of the three cardiac anesthesiologists. One cardiac anesthesiologist did not use dexmedetomidine during electrophysiological studies. A second used dexmedetomidine, but only with an infusion. The third used dexmedetomidine with a primary bolus and an infusion. Thus, the patients were stratified into three different groups: Group 1 patients did not receive any dexmedetomidine. Group 2 patients received a dexmedetomidine infusion of 0.5-1 μg·kg^-1 ·h^-1 . Group 3 patients received a dexmedetomidine infusion of 0.5-1 μg·kg^-1 ·h^-1 and a dexmedetomidine bolus prior to the infusion of 0.5-1 μg·kg^-1 . We then compared those patients for the following variables: demographic data including age, sex, height, weight; anesthetic data such as, mask vs intravenous induction, identity of induction agent, amount of sevoflurane and propofol used; amount of dexmedetomidine used; presence of congenital heart disease and other comorbidities; the need for isoproterenol and dose, the need for adenosine and dose, and the need for any other medications to affect rhythm both before and after radiofrequency ablation; the ability to induce the arrhythmia, the type of arrhythmia, the presence of Wolff-Parkinson-White syndrome, the presence of an accessory pathway, the ablation rate, and the recurrence rate.

RESULTS

There was no difference in the anesthetic agents, except there was a lesser amount of propofol used in the dexmedetomidine groups (χ²₍₂₎ = 48.2, P < 0.001). There was no difference in the electrophysiological parameters among groups, except the Group 1 patients did require the use of isoproterenol in the preablation period less often compared to the dexmedetomidine groups (χ²₍₂₎ = 15.2, P < 0.01). However, with the greater use of isoproterenol, there was no difference in the ability to induce the arrhythmia. Moreover, the percentage of patients ablated, and the recurrence rate among groups was the same.

CONCLUSIONS

We conclude that dexmedetomidine does not interfere with the conduct of electrophysiological studies for SVT and the successful ablation of such arrhythmias. However, dexmedetomidine use did result in a greater need for isoproterenol.

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.

Pediatric Procedural Sedation Using Dexmedetomidine: A Report From the Pediatric Sedation Research Consortium

OBJECTIVES

Dexmedetomidine (DEX) is widely used in pediatric procedural sedation (PPS) by a variety of pediatric subspecialists. The objective of our study was to describe the overall rates of adverse events and serious adverse events (SAEs) when DEX is used by various pediatric subspecialists.

METHODS

Patients from the Pediatric Sedation Research Consortium (PSRC) database were retrospectively reviewed and children that received DEX as their primary sedation agent for elective PPS were identified. Demographic and clinical data, provider subspecialty, and sedation-related complications were abstracted. SAEs were defined as death, cardiac arrest, upper airway obstruction, laryngospasm, emergent airway intervention, unplanned hospital admission/increased level of care, aspiration, or emergency anesthesia consult. Event rates and 95% confidence intervals (CIs) were calculated.

RESULTS

During the study period, 13 072 children were sedated using DEX, accounting for 5.3% of all sedation cases entered into the PSRC. Of the sedated patients, 73% were American Society of Anesthesiologists Physical Status class 1 or 2. The pediatric providers responsible for patients sedated with DEX were anesthesiologists (35%), intensivists (34%), emergency medicine physicians (12.7%), hospitalists (1.1%), and others (17%). The overall AE rate was 466/13 072 (3.6%, 95% CI 3.3% to 3.9%). The overall SAE rate was 45/13 072 (0.34%, 95% CI 0.19% to 0.037%). Airway obstruction was the most common SAE: 35/13 072 (0.27%, 95% CI 0.19% to 0.37%). Sedations were successful in 99.7% of cases.

CONCLUSIONS

We report the largest series of PPS using DEX outside the operating room. Within the PSRC, PPS performed using DEX has a very high success rate and is unlikely to yield a high rate of SAEs.

Dexmedetomidine versus Propofol: Is One Better Than the Other for MRI Sedation in Children?

Objective The aim of this article is to determine whether dexmedetomidine or propofol is better for MRI sedation in children. Design This study is a retrospective review of patients sedated with dexmedetomidine or propofol for MRI between July 2007 and July 2015. Dexmedetomidine group (group D) was administered a bolus of 2 µg/kg over 10 minutes followed by a 1 ug/kg/hour infusion. Propofol group (group P) received a bolus of 2 mg/kg over 2 minutes followed by 83 µg/kg/minute infusion. Results Of the 996 cases completed, 452 were in group P and 544 were in group D. Patients in group P were heavier and older than those in group D. All the patients except one in group D completed the procedures. Hypotension occurred in 59% in group P versus 4% in group D (89 ± 11.4 SBP vs. 103.80 ± 19.4; p < 0.05). Bradycardia was observed in 2.9% in group P versus 0.6% in group D. Apnea occurred in two patients in group D. Although procedure time was longer in patients receiving propofol versus dexmedetomidine (58.87 ± 28.17 vs. 45 ± 23.6; p < .05), the discharge time was significantly shorter (37. ± 12.30 vs. 92.61 ± 28.19; p < 0.05). Conclusion Dexmedetomidine appears to provide a useful alternative to propofol for MRI sedation with a longer recovery time, stable hemodynamics, and less reliable respiratory profile, while the propofol had the advantage of quicker onset and rapid recovery.

Sedation for electroencephalography with dexmedetomidine or chloral hydrate: a comparative study on the qualitative and quantitative electroencephalogram pattern

BACKGROUND

Sedation for electroencephalography in uncooperative patients is a controversial issue because majority of sedatives, hypnotics, and general anesthetics interfere with the brain's electrical activity. Chloral hydrate (CH) is typically used for this sedation, and dexmedetomidine (DEX) was recently tested because preliminary data suggest that this drug does not affect the electroencephalogram (EEG). The aim of the present study was to compare the EEG pattern during DEX or CH sedation to test the hypothesis that both drugs exert similar effects on the EEG.

MATERIALS AND METHODS

A total of 17 patients underwent 2 EEGs on 2 separate occasions, one with DEX and the other with CH. The EEG qualitative variables included the phases of sleep and the background activity. The EEG quantitative analysis was performed during the first 2 minutes of the second stage of sleep. The EEG quantitative variables included density, duration, and amplitude of the sleep spindles and absolute spectral power.

RESULTS

The results showed that the qualitative analysis, density, duration, and amplitude of sleep spindles did not differ between DEX and CH sedation. The power of the slow-frequency bands (δ and θ) was higher with DEX, but the power of the faster-frequency bands (α and β) was higher with CH. The total power was lower with DEX than with CH.

CONCLUSIONS

The differences of DEX and CH in EEG power did not change the EEG qualitative interpretation, which was similar with the 2 drugs. Other studies comparing natural sleep and sleep induced by these drugs are needed to clarify the clinical relevance of the observed EEG quantitative differences.

Options and Considerations for Procedural Sedation in Pediatric Imaging

As pediatric imaging capabilities have increased in scope, so have the complexities of providing procedural sedation in this environment. While efforts by many organizations have dramatically increased the safety of pediatric procedural sedation in general, radiology sedation creates several special challenges for the sedation provider. These challenges require implementation of additional safeguards to promote safety during sedation while maintaining effective and efficient care. Multiple agent options are available, and decisions regarding which agent(s) to use should be determined by both patient needs (i.e., developmental capacities, underlying health status, and previous experiences) and procedural needs (i.e., duration, need for immobility, and invasiveness). Increasingly, combinations of agents to either achieve the conditions required or mitigate/counterbalance adverse effects of single agents are being utilized with success. To continue to provide effective imaging sedation, it is incumbent on sedation providers to maintain familiarity with continuing evolutions within radiology environments, as well as comfort and competence with multiple sedation agents/regimens. This review discusses the challenges associated with radiology sedation and outlines various available agent options and combinations, with the intent of facilitating appropriate matching of agent(s) with patient and procedural needs.

Anesthesia and the pediatric cardiac catheterization suite: a review

Advances in technology over the last couple of decades have caused a shift in pediatric cardiac catheterization from a primary focus on diagnostics to innovative therapeutic interventions. These improvements allow patients a wider range of nonsurgical options for treatment of congenital heart disease. However, these therapeutic modalities can entail higher risk in an already complex patient population, compounded by the added challenges inherent to the environment of the cardiac catheterization suite. Anesthesiologists caring for children with congenital heart disease must understand not only the pathophysiology of the disease but also the effects the anesthetics and interventions have on the patient in order to provide a safe perioperative course. It is the aim of this article to review the latest catheterization modalities offered to patients with congenital heart disease, describe the unique challenges presented in the cardiac catheterization suite, list the most common complications encountered during catheterization and finally, to review the literature regarding different anesthetic drugs used in the catheterization lab.

High dose dexmedetomidine: effective as a sole agent sedation for children undergoing MRI

Objective. To determine the efficacy and safety of high dose dexmedetomidine as a sole sedative agent for MRI. We report our institution's experience. Design. A retrospective institutional review of dexmedetomidine usage for pediatric MRI over 5.5 years. Protocol included a dexmedetomidine bolus of 2 μg/kg intravenously over ten minutes followed by 1 μg/kg/hr infusion. 544 patients received high dose dexmedetomidine for MRI. A second bolus was used in 103 (18.9%) patients. 117 (21.5%) required additional medications. Efficacy, side effects, and use of additional medicines to complete the MRI were reviewed. Data was analyzed using Student's t-test, Fisher's exact test, and Analysis of Variance (ANOVA). Main Results. Dexmedetomidine infusion was associated with bradycardia (3.9%) and hypotension (18.4%). None of the patients required any intervention. Vital signs were not significantly different among the subgroup of patients receiving one or two boluses of dexmedetomidine or additional medications. Procedure time was significantly shorter in the group receiving only one dexmedetomidine bolus and increased with second bolus or additional medications (P < 0.0001). Discharge time was longer for children experiencing bradycardia (P = 0.0012). Conclusion. High dose Dexmedetomidine was effective in 78.5% of cases; 21.5% of patients required additional medications. Side effects occurred in approximately 25% of cases, resolving spontaneously.

Comparison of dexmedetomidine with pentobarbital for pediatric MRI sedation

BACKGROUND AND OBJECTIVE

Intravenous pentobarbital has been used in the past to sedate pediatric patients in preparation for MRI; however, the drug has unpredictable sedation time. Dexmedetomidine, because of its short half-life, is gaining popularity for pediatric MRI sedation in settings where the use of propofol is restricted for nonanesthesiologists. The objective was to compare induction time, recovery time, total sedation time, sedation failure rate, and adverse outcomes of patients sedated with pentobarbital and dexmedetomidine in preparation for pediatric MRI.

METHODS

We reviewed a sedation database that contains clinical data for all children undergoing MRI studies while sedated with pentobarbital or dexmedetomidine between May 15, 2008, and October 30, 2010.

RESULTS

During the study period, 281 sedations were induced in preparation for MRI (160 with pentobarbital, and 121 with dexmedetomidine). The 2 groups were comparable with regard to age, weight, gender, and American Society of Anesthesiologists status. The dexmedetomidine group had a significantly shorter recovery time (39 ± 21 vs 49 ± 27 minutes [P = .002]) and total sedation time (107 ± 28 vs 157 ± 44 minutes [P = .0001]). Induction time was similar between the groups. The adverse event rate for the study population was 3%.

CONCLUSIONS

Dexmedetomidine and pentobarbital can both be used successfully for MRI sedation in children. However, dexmedetomidine had a significantly shorter recovery time and total sedation time in our population.

Dexmedetomidine

Objective. To provide a general descriptive account and review of the literature regarding the use of dexmedetomidine for sedation during fiberoptic bronchscopic (FOB) intubation. Data Source. A computerized bibliographic search of the literature regarding dexmedetomidine for FOB intubation. Main Results. Several anecdotal reports describe the use of dexmedetomidine to provide sedation during FOB intubation. Additionally, 7 prospective trials were identified. These prospective trials demonstrate the efficacy of dexmedetomidine in providing sedation during FOB intubation of the airway. In a placebo-controlled trial with midazolam used as the rescue medication, dexmedetomidine decreased the need for rescue midazolam and the combination of the 2 agents was better than midazolam alone. When compared with propofol, there were fewer airway and respiratory issues as well as improved patient comfort with dexmedetomidine. Although dexmedetomidine was found to be better than fentanyl, there was a higher incidence of adverse hemodynamic effects. Although dexmedetomidine was inferior to remifentanil, the study used a lower loading dose of dexmedetomidine than other studies (0.4 vs 1.0 µg/kg). Despite its efficacy, adverse hemodynamic effects were noted. In many cases, the incidence was higher with dexmedetomidine than the comparator agent. In all reported cases, these were corrected with the administration of atropine, a vasoactive medication (phenylephrine or ephedrine), and/or fluid. Conclusions. The present literature clearly reports the advantage of using dexmedetomidine to decrease the risk of adverse respiratory effects, including airway obstruction. However, there remain unanswered questions about dexmedetomidine for sedation during FOB intubation of the airway including dosing regimens for both the bolus and infusion, techniques to limit the potential for adverse hemodynamic effects, and whether it should be the sole agent or used in combination with another agent.

A dose-response study of dexmedetomidine administered as the primary sedative in infants following open heart surgery

OBJECTIVE

To evaluate the dose-response relationship of dexmedetomidine in infants with congenital heart disease postoperative from open heart surgery.

DESIGN

Prospective open-label dose-escalation pharmacokinetic-pharmacodynamic study.

SETTING

Tertiary pediatric cardiac ICU.

PATIENTS

Thirty-six evaluable infants, 1-24 months old, postoperative from open heart surgery requiring mechanical ventilation.

INTERVENTIONS

Cohorts of 12 infants were enrolled sequentially to one of the three IV loading doses of dexmedetomidine (0.35, 0.7, and 1 mcg/kg) over 10 minutes followed by respective continuous infusions (0.25, 0.5, and 0.75 mcg/kg/hr) for up to 24 hours.

MEASUREMENTS AND MAIN RESULTS

Dexmedetomidine plasma concentrations were obtained at timed intervals during and following discontinuation of infusion. Pharmacodynamic variables evaluated included sedation scores, supplemental sedation and analgesia medication administration, time to tracheal extubation, respiratory function, and hemodynamic parameters. Infants achieved a deeper sedation measured by the University of Michigan Sedation Scale score (2.6 vs 1) despite requiring minimal supplemental sedation (0 unit doses/hr) and fewer analgesic medications (0.07 vs 0.15 unit doses/hr) while receiving dexmedetomidine compared with the 12-hour follow-up period. Thirty-one patients were successfully extubated while receiving the dexmedetomidine infusion. Only one patient remained intubated due to oversedation during the infusion. While receiving dexmedetomidine, there was a decrease in heart rate compared with baseline, 132 versus 161 bpm, but there was an increase in heart rate compared with postinfusion values, 132 versus 128 bpm. There was no statistically or clinically significant change in mean arterial blood pressure.

CONCLUSIONS

Dexmedetomidine administration in infants following open heart surgery can provide improved sedation with reduction in supplemental medication requirements, leading to successful extubation while receiving a continuous infusion. The postoperative hemodynamic changes that occur in infants postoperative from open heart surgery are multifactorial. Although dexmedetomidine may play a role in decreasing heart rate immediately postoperative, the changes were not clinically significant and did not fall below postinfusion heart rates.

Safety and efficacy of dexmedetomidine in children with heart failure

This retrospective observational study aimed to evaluate the safety and efficacy of dexmedetomidine (DEX) for children with heart failure. The study was conducted in the cardiovascular intensive care unit (CVICU) of a single, tertiary care, academic children's hospital. A retrospective review of the charts for all children (up to 18 years of age) with signs and symptoms consistent with congestive heart failure who received DEX in our CVICU between April 2006 and April 2011 was performed. The patients were divided into two groups for study purposes: the DEX group of 21 patients, who received a DEX infusion together with other conventional sedation agents, and the control group of 23 patients, who received conventional sedation agents without the use of DEX. To evaluate the safety of DEX, physiologic data were collected including heart rate, mean arterial pressure (MAP), and inotrope score. To assess the efficacy of DEX, the amount and duration of concomitant sedation and analgesic infusions in both the DEX and control groups were examined. The numbers of rescue boluses for each category before the initiation of sedative infusion and during the sedative infusion also were examined. The baseline characteristics of the patients in the two groups were similar. There was no effect of DEX infusion on heart rate, MAP, or inotrope score at the termination of infusion. The daily amount of midazolam administered was significantly less during the last 24 h of DEX infusion in the DEX group than in the control group (p = 0.04). The daily amount of morphine infusion did not differ between the DEX and control groups during any period. The numbers of sedation and analgesic rescue boluses were lower in DEX group throughout the infusion. No other significant side effects were noted. Two patients in the DEX group had a 50 % or greater drop in MAP compared with baseline in the first 3 h after initiation of DEX infusion, whereas one patient had a 50 % or greater drop in heart rate compared with baseline in the first 3 h after initiation of DEX infusion. Administration of DEX for children with heart failure appears to be safe but should be used cautiously. Furthermore, DEX use is associated with a decreased opiate and benzodiazepine requirement for children with heart failure.

Analysis of procedural sedation provided by pediatricians

BACKGROUND

Pediatric procedural sedation outside of the operating room is performed by a variety of pediatric specialists. Using the database from the Pediatric Sedation Research Consortium (PSRC), patient demographics, medications used, diagnoses, complications, and procedures involved when pediatricians provided sedation in this cohort, were described. 'Pediatrician' was defined as a general pediatrician, cardiologist, endocrinologist, gastroenterologist, hematologist/oncologist, neurologist, pulmonologist or hospitalist.

METHODS

Data were collected by the PSRC, a group of 35 institutions dedicated to improving sedation care for children. Members prospectively enrolled consecutive patients who received sedation or anesthesia for diagnostic or therapeutic procedures. Data on demographics, primary diagnoses, procedures, medications, interventions, and complications were collected and stored on a Web-based data collection tool.

RESULTS

A total of 12 113 sedations performed by pediatricians were submitted from 1 July 2004 to 31 December 2008, compared to 119 665 cases performed by non-pediatricians. Pediatrician patients were more frequently non-emergency American Society of Anesthesiologists (ASA) class I or II, aged 2-8 years old, with a neurologic primary diagnosis, being sedated for a radiologic procedure with a sedative. Distraction techniques were used more frequently in the pediatrician group (11.9% vs 3.1%). The most common complication encountered was inadequate sedation, which occurred 2.2% of the time.

CONCLUSIONS

Pediatricians sedate for a variety of patients within the PSRC, but the patients tended to be younger, predominately ASA class I or II, non-emergency, and undergoing non-painful procedures when compared to non-pediatrician providers. The patient demographics, medications used, diagnoses, complications, and procedures involved varied between the groups significantly. Complication rates were similar between the groups.

Dexmedetomidine for transport of a spontaneously breathing combative child

Interhospital transport presents a challenge for pediatricians, and airway protection is often a significant concern. The severely agitated child without respiratory compromise poses an extremely difficult dilemma, as most sedative agents can cause respiratory depression. Intubation offers definitive control of the airway but is not without risk, especially in an environment where experience and resources for pediatric intubation may be limited. Dexmedetomidine may be used for sedation in certain circumstances for the transport of a child without the need for intubation and mechanical ventilation.

In vitro clearance of dexmedetomidine in extracorporeal membrane oxygenation

Dexmedetomidine (DMET) is a useful agent for sedation, both alone and in combination with other agents, in critically ill patients, including those on extracorporeal membrane oxygenation (ECMO) therapy. The drug is a clonidine-like derivative with an 8-fold greater specificity for the alpha 2-receptor while maintaining respiratory and cardiovascular stability. An in vitro ECMO circuit was used to study the effects of both “new” and “old” membrane oxygenators on the clearance of dexmedetomidine over the course of 24 hours. Once primed, the circuit was dosed with 840 μg of dexmedetomidine for a final concentration of 0.9 μg/ml. Serial samples, both pre- and post-oxygenator, were taken at 5, 60, 360, and 1440 minutes. Concentrations of the drug were expressed as a percentage of the original concentration remaining at each time point, both for new and old circuits. The new circuits were run at a standard flow for 24 hours, after which time the circuit was considered old and re-dosed with dexmedetomidine and the trial repeated. Results show that dexmedetomidine losses occur early in the circuits and then continue to decline. Initial losses in the first hour were 11+-65% and 59-73% pre- and post-oxygenator in the new circuit and 36-50% and 42-72% in the old circuit. The clearance of the drug through the membrane oxygenator exhibits no statistical difference between pre and post or new and old circuits. Dexmedetomidine can be expected to exhibit concentration changes during ECMO therapy. This effect appears to be more related to adsorption to the polyvinyl chloride (PVC) tubing rather than the membrane oxygenator. Dosage adjustments during dexmedetomidine administration during ECMO therapy may be warranted in order to maintain adequate serum concentrations and, hence, the desired degree of sedation.*(Lack of equilibrium)

Dexmedetomidine reduces emergence agitation after tonsillectomy in children by sevoflurane anesthesia: a case-control study

OBJECTIVE

To evaluate the efficacy and safety of dexmedetomidine for emergence agitation after tonsillectomy in children.

METHODS

120 ASA physical status I and II children, aged 5-14 years, undergoing anesthesia for tonsillectomy, were randomly divided into 3 groups: Placebo group, the low dexmedetomidine concentration group and the high dexmedetomidine concentration group. Before the entrance of the operating room (OR), all of the children received intravenous injection 40 μg kg(-1) midazolam to reduce anxiety at first, and then dexmedetomidine was given intravenously at an initial loading dose of 0.5 μg kg(-1) or 1 μg/kg over a 10-min period via a computer controlled infusion pump followed by a maintenance infusion of 0.2 μg kg(-1)h(-1) or 0.4 μg kg(-1)h(-1)over the surgery. The heart rate, SpO(2) and mean arterial blood pressure were recorded for each patient in both operation room and PACU. The designated time points: at the start of the anesthetic induction, at the discontinuation of inhalational agents, at first opening of eyes, at time to remove endotracheal tube were recorded. After patient arrival at the PACU, VAS score, RSS, the occurrence of emergence agitation were recorded every 5 min for the first 30 min and every 10 min for the next 30 min after endotracheal tube was removed.

RESULTS

There was significant difference in the incidence of emergence agitation between Placebo group and the high concentration group when endotracheal tube was removed (P<0.05). There was significant difference in the VAS pain scores and in the RSS between three groups at the time of extubation, as well as 5 min and 10 min after extubation (P<0.05).

CONCLUSIONS

Dexmedetomidine appears to be safe and effective to reduce the incidence of early emergence agitation in children after tonsillectomy. Initial loading dose of 1.0 μg kg(-1) followed by a maintenance infusion of 0.4 μg kg(-1)h(-1) is better choice for children received tonsillectomy.

Dexmedetomidine for opioid and benzodiazepine withdrawal in pediatric patients

PURPOSE

The published literature on the use of dexmedetomidine as an adjunct to sedation and analgesia in the management of pediatric narcotic withdrawal was reviewed.

SUMMARY

Pediatric narcotic withdrawal syndromes are reported to be increasingly frequent in pediatric intensive care units. A number of tools specifically designed for assessment of withdrawal in newborns and infants are in current use, including the widely used Finnegan Scoring System. A limited number of studies and case reports suggest that dexmedetomidine, an α(2)-receptor agonist with a mechanism of action similar to that of clonidine but with greater α(2)-receptor specificity, might have a role in the treatment of pediatric withdrawal (by blunting withdrawal symptoms without causing respiratory depression and by permitting shorter narcotic tapering schedules) and also in the prevention of pediatric narcotic withdrawal (by reducing narcotic requirements). Potential adverse effects associated with dexmedetomidine use in pediatric patients are generally associated with use of bolus doses and mainly involve central nervous system effects (e.g., hypotension, bradycardia), with no hemodynamic manifestations. When bolus doses are used, strategies described in published reports entail a loading dose of 0.5-1.0 μg/kg administered over 5-10 minutes, followed by a continuous infusion at 0.1-1.4 μg/kg/hr for a period of 1-16 days. More research is needed to define the optimal use of dexmedetomidine in the management of pediatric narcotic withdrawal.

CONCLUSION

A limited body of published evidence from retrospective studies and case reports suggests a potential role for dexmedetomidine as an adjunct therapy to provide sedation and analgesia to reduce narcotic withdrawal symptoms in pediatric patients.

Dexmedetomidine sedation: uses in pediatric procedural sedation outside the operating room

As the field of pediatric procedural sedation continues to expand, so does the exploration of medications that have a role in such invasive and noninvasive procedures. One such medication that has emerged during the last decade is dexmedetomidine, a drug approved for use in the adult intensive care setting. Its role in pediatrics has varied in its use from sedation in ventilated children in the intensive care unit to treatment for emergence reactions from general anesthesia and in sedation needed for radiographic imaging studies, electroencephalography, and invasive procedures. This review article presents the pediatric studies that have been published thus far regarding dexmedetomidate in the nonventilated, spontaneously breathing patient and identifies those patients where the use of this agent may not be indicated.

Dexmedetomidine: applications for the pediatric patient with congenital heart disease

This study aimed to provide a general description of the cardiovascular and hemodynamic effects of dexmedetomidine and an evidence-based review of the literature regarding its use in infants and children with congenital heart disease (CHD). A computerized bibliographic search of the literature on dexmedetomidine use in infants and children with CHD was performed. The cardiovascular effects of dexmedetomidine have been well studied in animal and adult human models. Adverse cardiovascular effects include occasional episodes of bradycardia, with rare reports of sinus pause or cardiac arrest. Both hypotension and hypertension also have been reported. The latter is related to peripheral α(2B) agonism leading to vasoconstriction. No adverse effects on the pulmonary vasculature have been noted even in patients with preexisting pulmonary hypertension. Although there are no direct effects on myocardial function, decreased cardiac output may result from changes in heart rate or increases in afterload. Although not currently Food and Drug Administration (FDA)-approved for the pediatric population, findings have shown dexmedetomidine to be effective in various clinical scenarios of patients with CHD including sedation during mechanical ventilation, prevention of procedure-related anxiety, prevention of emergence delirium and shivering after anesthesia, and treatment of withdrawal. Although dexmedetomidine may have limited utility for painful or invasive procedures, preliminary data suggest that the addition of ketamine to the regimen may offer benefits. When used during the perioperative period, additional benefits include blunting of the sympathetic stress response with a reduction of endogenous catecholamine release, a decrease in intraoperative anesthetic requirements, and a limitation of postoperative opioid requirements.

Effects of dexmedetomidine added to caudal ropivacaine in paediatric lower abdominal surgeries

Purpose:

The objectives of this study were to compare the effects of caudal dexmedetomidine combined with ropivacaine to provide postoperative analgesia in children and also to establish its safety in the paediatric population.

Methods:

In a randomised, prospective, parallel group, double-blinded study, 60 children were recruited and allocated into two groups: Group RD (n=30) received 0.25% ropivacaine 1 ml/kg with dexmedetomidine 2 μg/kg, making the volume to 0.5 ml and Group R (n=30) received 0.25% ropivacaine 1 ml/kg + 0.5 ml normal saline. Induction of anaesthesia was achieved with 50% N₂O and 8% sevoflurane in oxygen in spontaneous ventilation. An appropriate-sized LMA was then inserted and a caudal block performed in all patients. Behaviour during emergence was rated with a 4-point scale, sedation with Ramsay's sedation scale, and pain assessed with face, legs, activity, cry, consolability (FLACC) pain score.

Results:

The duration of postoperative analgesia recorded a median of 5.5 hours in Group R compared with 14.5 hours in Group RD, with a P value of <0.001. Group R patients achieved a statistically significant higher FLACC score compared with Group RD patients. The difference between the means of mean sedation score, emergence behaviour score, mean emergence time was statistically highly significant (P<0.001). The peri-operative haemodynamics were stable among both the groups.

Conclusion:

Caudal dexmedetomidine (2 μg/kg) with 0.25% ropivacaine (1 ml/kg) for paediatric lower abdominal surgeries achieved significant postoperative pain relief that resulted in a better quality of sleep and a prolonged duration of arousable sedation and produced less incidence of emergence agitation following sevoflurane anaesthesia.

Perioperative use of dexmedetomidine is associated with decreased incidence of ventricular and supraventricular tachyarrhythmias after congenital cardiac operations

BACKGROUND

Postoperative tachyarrhythmias remain a common complication after congenital cardiac operations. Dexmedetomidine (DEX), an α-2 adrenoreceptor agonist, can have a therapeutic role in supraventricular tachyarrhythmias for cardioversion to sinus rhythm or heart rate control. Whether routine perioperative use of DEX decreases the incidence of supraventricular and ventricular tachyarrhythmias was studied.

METHODS

In this prospective cohort study, 32 pediatric patients undergoing cardiothoracic operations received DEX and were compared with 20 control patients who did not receive DEX.

RESULTS

Dexmedetomidine was started after anesthesia induction and continued intraoperatively and postoperatively for 38±4 hours (mean dose, 0.76±0.04 μg/kg/h). Ten control patients and 2 DEX patients sustained 16 episodes of tachyarrhythmias (p=0.001), including a 25% vs 0% (p=0.01) incidence of ventricular tachycardia and 25% vs 6% (p=0.05) of supraventricular arrhythmias in the control and DEX group, respectively. Transient complete heart block occurred in 2 control patients and in 1 DEX patient. Control patients had a higher heart rate (141±5 vs 127±3 beats/min, p=0.03), more sinus tachycardia episodes (40% vs 6%; p=0.008), required more antihypertensive drugs with nitroprusside (20±7 vs 4±1 μg/kg; p=0.004) and nicardipine (13±5 vs 2±1 μg/kg; p=0.02), and required more fentanyl (39±8 vs 19±3 μg/kg; p=0.005).

CONCLUSIONS

Perioperative use of dexmedetomidine is associated with a significantly decreased incidence of ventricular and supraventricular tachyarrhythmias, without significant adverse effects.

Procedural sedation analgesia

The number of noninvasive and minimally invasive procedures performed outside of the operating room has grown exponentially over the last several decades.Sedation, analgesia, or both may be needed for many of these interventional or diagnostic procedures. Individualized care is important when determining if a patient requires procedural sedation analgesia (PSA). The patient might need an anti-anxiety drug, pain medicine, immobilization, simple reassurance, or a combination of these interventions. The goals of PSA in four different multidisciplinary practices namely; emergency, dentistry, radiology and gastrointestinal endoscopy are discussed in this review article. Some procedures are painful, others painless. Therefore, goals of PSA vary widely. Sedation management can range from minimal sedation, to the extent of minimal anesthesia. Procedural sedation in emergency department (ED) usually requires combinations of multiple agents to reach desired effects of analgesia plus anxiolysis. However, in dental practice, moderate sedation analgesia (known to the dentists as conscious sedation) is usually what is required. It is usually most effective with the combined use of local anesthesia. The mainstay of success for painless imaging is absolute immobility. Immobility can be achieved by deep sedation or minimal anesthesia. On the other hand, moderate sedation, deep sedation, minimal anesthesia and conventional general anesthesia can be all utilized for management of gastrointestinal endoscopy.

The comparison of the effects of dexmedetomidine and midazolam sedation on electroencephalography in pediatric patients with febrile convulsion

BACKGROUND

When electroencephalogram (EEG) activity is recorded for diagnostic purposes, the effects of sedative drugs on EEG activity should be minimal. This study compares the sedative efficacy and EEG effects of dexmedetomidine and midazolam.

SUBJECTS AND METHODS

EEG recordings of 60 pediatric subjects with a history of simple febrile convulsions were performed during physiologic sleep. All of these patients required sedation to obtain follow-up (control) EEGs. Subjects in Group D received 0.5 μg·kg(-1) of dexmedetomidine, and those in Group M received 0.1 mg·kg(-1) of midazolam. For rescue sedation, the same doses were repeated to maintain a Ramsey sedation score level of between 4 and 6.

RESULTS

The mean doses that were required for sedation were 0.76 μg·kg(-1) of dexmedetomidine and 0.38 mg·kg(-1) of midazolam. Diastolic blood pressure and HR were lower in Group D than in Group M (P < 0.05). Hypoxia was observed in 11 (36.7%) subjects in Group M and none in Group D; this was statistically significant (P < 0.001). Frontal and parieto-occipital (PO) EEG frequencies were similar during physiologic sleep and dexmedetomidine sedation. However, EEG frequencies in these areas (P < 0.001) and PO EEG amplitude (P = 0.030) were greater during midazolam sedation than during physiologic sleep.

CONCLUSIONS

Dexmedetomidine is a suitable agent to provide sedation for EEG recording in children. There is less change in EEG peak frequency and amplitude after dexmedetomidine than after midazolam sedation.

Dexmedetomidine and ketamine for sedation during spinal anesthesia in children

STUDY OBJECTIVE

To evaluate the combination of dexmedetomidine and ketamine for sedation during lumbar puncture and sedation for spinal anesthesia in children.

DESIGN

Retrospective analysis of quality assurance data sheets and anesthetic records.

SETTING

Developing countries with the humanitarian group, Kids First.

PATIENTS

12 infants and children, ranging in age from two to 9 years.

INTERVENTIONS

A bolus dose of ketamine (two mg/kg) and dexmedetomidine (one μg/kg) was given over three minutes followed by a continuous infusion of dexmedetomidine (two μg/kg/hr for the first 30 min, followed by one μg/kg/hr for the duration of the case). Supplemental analgesia/sedation was provided by ketamine (0.5 mg/kg) as needed.

MEASUREMENTS

The need for supplemental ketamine, the ability to complete the procedure, and heart rate (HR), blood pressure, end-tidal carbon dioxide (ETCO(2)), and oxygen saturation values were recorded.

MAIN RESULTS

Effective sedation for lumbar puncture and performance of spinal anesthesia were achieved in all patients. One patient required a supplemental dose of ketamine (0.5 mg/kg). Following the bolus dose of ketamine and dexmedetomidine, HR increased by 11 ± 4 bpm. The greatest HR increase was 20 bpm. No patient had a HR increase ≥ 20% from baseline. The HR decrease was ≤ 30 bpm in 10 of the 12 patients, and the greatest HR decrease was 58 bpm. Systolic blood pressure (SBP) increased from baseline by 10 ± 3 mmHg after administration of the bolus dose of ketamine and dexmedetomidine. During the subsequent dexmedetomidine infusion, SBP decreased by 11 ± 9 mmHg. No patient's respiratory rate decreased to less than 10 breaths/min or increased above 24 breaths/min during the procedural sedation. The highest ETCO(2) was 45 ± 2 mmHg (P < 0.0001). Oxygen saturation remained ≥ 95% during the procedure in all patients.

CONCLUSION

A combination of ketamine and dexmedetomidine provides effective sedation during spinal anesthesia in infants and children, with limited effects on cardiovascular and ventilatory function.

High-dose dexmedetomidine sedation for pediatric MRI

OBJECTIVES

To test the hypothesis that high-dose dexmedetomidine can be successfully used for pediatric magnetic resonance imaging (MRI) sedation without significant hemodynamic compromise.

BACKGROUND

The dexmedetomidine dose required to achieve optimal sedation is often higher than its recommended dose. High doses of dexmedetomidine can lead to significant hemodynamic side effects.

METHODS

Dexmedetomidine use for pediatric MRI over a 1-year period was retrospectively reviewed. A dexmedetomidine bolus of 2 μg·kg(-1) intravenous followed by 1 μg·kg(-1)·h(-1) infusion was used. Dexmedetomidine efficacy, side effects, timing of side effects, and additional use of medications were analyzed. Data were compared by t-test, Mann-Whitney rank-sum test, Fisher's exact test, and anova.

RESULTS

High-dose dexmedetomidine was used in 77 patients, and MRI was completed in 76 (99%) patients. A second bolus of dexmedetomidine was required in 28 (36%) patients, and 22 (29%) patients required additional medications (midazolam, fentanyl, or ketamine) for adequate sedation. A 25% decrease in blood pressure (BP) was observed in 10.5%, a transient increase in BP in 3.9%, and a heart rate <60 min(-1) in 7.9% of cases. These side effects resolved spontaneously. There were no apneas or respiratory depression. Vital sign changes, recovery time, and discharge time were not significantly different in subgroups of patients receiving one or two boluses of dexmedetomidine with or without additional medications. Transient hypertension was more common in patients receiving two boluses of dexmedetomidine (P = 0.048).

CONCLUSIONS

High-dose dexmedetomidine can be successfully used for pediatric MRI sedation, but a significant number of children require additional medications for optimal control. Hemodynamic side effects resolved spontaneously. High-dose dexmedetomidine did not result in respiratory depression.

Optimal timing for the administration of intranasal dexmedetomidine for premedication in children

Previous studies have shown that 1 μg.kg(-1) intranasal dexmedetomidine produces significant sedation in children aged between 2 and 12 years. This investigation was designed to evaluate the onset time. One hundred children aged 1-12 years of ASA physical status 1-2 undergoing elective surgery were randomly allocated to five groups. Patients in groups A to D received intranasal dexmedetomidine 1 μg.kg(-1) . Patients in Group E received intranasal placebo (0.9% saline). Children from groups A, B, C, D and E had intravenous cannulation attempted at 30, 45, 60, 75 and 45 min respectively after intranasal drug or placebo administration. Vital signs, behaviour and sedation status of the children were assessed regularly until induction of anaesthesia. More children from groups A to D achieved satisfactory sedation at the time of cannulation when compared to group E (p < 0.001). The proportion of children who achieved satisfactory sedation was not significantly different among groups A to D. Overall 62% of the children who received intranasal dexmedetomidine had satisfactory sedation at the time of cannulation. The median (95% CI) time for onset of sedation was 25 (25-30) min. The median (95% CI) duration of sedation was 85 (55-100) min.

Effect of dexmedetomidine on pulmonary artery pressure after congenital cardiac surgery: A pilot study

OBJECTIVE

To characterize the effects of dexmedetomidine on the pulmonary artery pressure in patients after congenital cardiac surgery.

DESIGN

Prospective observational pilot study.

SETTING

Pediatric cardiac intensive care unit at a university hospital.

PATIENTS

Twenty-two patients who received dexmedetomidine after cardiothoracic surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

An echocardiogram was performed at three time points: 1) baseline (T0); 2) 6 mins after dexmedetomidine loading (T1); and 3) 1 hr after initiation of dexmedetomidine infusion (T2). Transthoracic echocardiography was used to estimate pulmonary artery pressure based on tricuspid regurgitant velocity (4 x Velocity2) plus central venous pressure. Twenty-two patients aged 0.9 yrs old (interquartile range, 7.9) were enrolled at a median of 1 hr (1.5) after surgery. Dexmedetomidine loading, 0.62 microg/kg (0.5), was given in all patients followed by 0.5 microg/kg/hr (0.6) at T1 and 0.65 microg/kg/hr (0.5) at T2. None of the patients had any increase in pulmonary artery pressure. Overall, the pulmonary artery pressure decreased from 30 mm Hg (13) at T0 to 24 mm Hg (10) at T1 and 26 mm Hg (8) at T2 (p < .001). The pulmonary artery pressure/systemic systolic blood pressure ratio decreased from 33% (12) at T0 to 23% (15) at T1 and 25% (13) at T2 (p = .002). There was no difference in the left ventricular function, Fio2, oxygen %, Po2, CO2, and vasoactive agents.

CONCLUSIONS

Administration of dexmedetomidine after congenital cardiac surgery was not associated with any increase in pulmonary artery pressure.

Dexmedetomidine: pediatric pharmacology, clinical uses and safety

IMPORTANCE OF THE FIELD

Dexmedetomidine is an α(2)-adrenoceptor agonist with sedative, anxiolytic and analgesic properties. It is used off-label in pediatric patients due to its efficacy and lack of adverse respiratory effects. Dexmedetomidine may cause severe circulatory complications in adults. Despite its popularity, the safety of dexmedetomidine in the pediatric population has not been extensively studied.

AREAS COVERED IN THIS REVIEW

This article reviews the current literature (up to 2010) focusing on applications and safety of dexmedetomidine administered to pediatric patients.

WHAT THE READER WILL GAIN

Dexmedetomidine is a useful sedative and anxiolytic drug in the pediatric intensive care unit as well as during diagnostic and therapeutic procedures. Deleterious effects of dexmedetomidine include hypotension and bradycardia. Additionally, hypertension may occur during the "loading dose" or with high infusion rates. Few studies have been performed to evaluate the safety of dexmedetomidine in pediatrics. The development of tolerance and withdrawal has not been studied in children.

TAKE HOME MESSAGE

Despite its favorable respiratory profile, dexmedetomidine may cause deleterious cardiovascular effects. Close monitoring of circulatory dynamics and judicious titration is recommended. Further studies are needed to better define adverse effects following long-term infusions as well as in special populations such as pre-term infants.

Professional skills and competence for safe and effective procedural sedation in children: recommendations based on a systematic review of the literature

Objectives. To investigate which skills and competence are imperative to assure optimal effectiveness and safety of procedural sedation (PS) in children and to analyze the underlying levels of evidence. Study Design and methods. Systematic review of literature published between 1993 and March 2009. Selected papers were classified according to their methodological quality and summarized in evidence-based conclusions. Next, conclusions were used to formulate recommendations. Results. Although the safety profiles vary among PS drugs, the possibility of potentially serious adverse events and the predictability of depth and duration of sedation define the imperative skills and competence necessary for a timely recognition and appropriate management. The level of effectiveness is mainly determined by the ability to apply titratable PS, including deep sedation using short-acting anesthetics for invasive procedures and nitrous oxide for minor painful procedures, and the implementation of non-pharmacological techniques. Conclusions. PS related safety and effectiveness are determined by the circumstances and professional skills rather than by specific pharmacologic characteristics. Evidence based recommendations regarding necessary skills and competence should be used to set up training programs and to define which professionals can and cannot be credentialed for PS in children.

Buccal administration of dexmedetomidine as a preanesthetic in children

PURPOSE

The objective of this study was to evaluate the efficacy and safety of buccal dexmedetomidine as a preanesthetic in children, to compare it with diazepam, and to investigate the optimal dosage for buccal dexmedetomidine administration by measuring its serum concentration.

METHODS

We performed a prospective study with 40 children who were assigned to two groups. The patients underwent an operation for inguinal or umbilical hernia. Twenty children received dexmedetomidine buccally at 3-4 microg/kg (Dex Group) and 20 received a diazepam suppository at 0.7 mg/kg (Diazepam Group) as preanesthetics 1 h before the operation. Heart rate, systolic blood pressure, SpO2, and respiratory rate were measured 1 h after premedication in all children. Sedation level was preoperatively evaluated, and compared with the Ramsay score, in the ward, at the entrance to the main operating rooms, and at anesthesia induction between the two groups. To investigate the optimal dosage of buccal dexmedetomidine, we compared the mean serum concentration of dexmedetomidine at induction between patients with a Ramsay score of 5 or greater and those with a Ramsay score less than 5. The Mann-Whitney U test was used for statistical analysis.

RESULTS

There was no significant difference between the two groups in age or body weight. Furthermore, there was no significant difference between the two groups in heart rate, systolic blood pressure, SpO2, or respiratory rate after administration of either medication. The Ramsay score of the Dex Group was significantly higher than that of the Diazepam Group at all times. The mean serum dexmedetomidine concentration at induction in patients with a Ramsay score of 5 or greater (75 +/- 50 pg/ml) was significantly higher than in those with a Ramsay score less than 5 (34 +/- 36 pg/ml, P < 0.05).

CONCLUSION

These results suggest that the buccal administration of dexmedetomidine (3-4 microg/kg) 1 h before the operation can be safely and effectively applied as a preanesthetic in children.

Update on dexmedetomidine: use in nonintubated patients requiring sedation for surgical procedures

Dexmedetomidine was introduced two decades ago as a sedative and supplement to sedation in the intensive care unit for patients whose trachea was intubated. However, since that time dexmedetomidine has been commonly used as a sedative and hypnotic for patients undergoing procedures without the need for tracheal intubation. This review focuses on the application of dexmedetomidine as a sedative and/or total anesthetic in patients undergoing procedures without the need for tracheal intubation. Dexmedetomidine was used for sedation in monitored anesthesia care (MAC), airway procedures including fiberoptic bronchoscopy, dental procedures, ophthalmological procedures, head and neck procedures, neurosurgery, and vascular surgery. Additionally, dexmedetomidine was used for the sedation of pediatric patients undergoing different type of procedures such as cardiac catheterization and magnetic resonance imaging. Dexmedetomidine loading dose ranged from 0.5 to 5 μg kg⁻¹, and infusion dose ranged from 0.2 to 10 μg kg⁻¹ h⁻¹. Dexmedetomidine was administered in conjunction with local anesthesia and/or other sedatives. Ketamine was administered with dexmedetomidine and opposed its bradycardiac effects. Dexmedetomidine may by useful in patients needing sedation without tracheal intubation. The literature suggests potential use of dexmedetomidine solely or as an adjunctive agent to other sedation agents. Dexmedetomidine was especially useful when spontaneous breathing was essential such as in procedures on the airway, or when sudden awakening from sedation was required such as for cooperative clinical examination during craniotomies.

Sedation trends in the 21st century: the transition to dexmedetomidine for radiological imaging studies

Sedation for radiological imaging studies encompasses the majority of all sedation-related procedures outside of the intensive care unit. This review will follow the evolution of pediatric sedation for radiological imaging studies in North America as well as the transition of sedation services from the oversight of radiologists to those of other providers. The evolving options for sedation agents will be reviewed, with attention given to examining the advantages, limitations, and risks of replacing the standard sedatives with dexmedetomidine.