Effect of increasing depth of dexmedetomidine anesthesia on upper airway morphology in children

Usefulness of deep sedation with intravenous dexmedetomidine and midazolam in cardiac catheterization procedures for pediatric patients

Background

Dexmedetomidine (DEX) is a highly selective alpha 2 receptor agonist that has the advantage of causing less respiratory depression than other sedative agents. We evaluated the add-on effects of DEX on sedation among pediatric patients who received midazolam and pentazocine during cardiac catheterization.

Methods

120 cardiac catheterization procedures in 110 patients under deep sedation at Department of Pediatrics, Kanazawa University Hospital from January 2013 to August 2018: 63 procedures without DEX (i.e., non-DEX group) and 57 procedures with DEX (i.e., DEX group). Intravenous midazolam and pentazocine were used in both groups, and DEX without an initial loading dose (0.6 μg/kg/h) was used in the DEX group. We retrospectively investigated complications during catheterization, doses of sedative agents, and changes in vital signs.

Results

Hypoxemia requiring oxygen administration during catheterization tended to be higher in the non-DEX group than in the DEX group (4.8% vs. 0%). Additional dose of midazolam was significantly lower in the DEX group (median [IQR]: 0.05 mg/kg [0-0.11]) than in the non-DEX group [0.09 mg/kg (0-0.23), p = 0.0288]. The additional dose of midazolam in the non-DEX group with hypoxemia was significantly higher than the dose used in the non-DEX group without hypoxemia. No case of bradycardia below the criteria for bradycardia occurred and no serious complications occurred in the DEX group.

Conclusion

The use of intravenous DEX in combination with midazolam and pentazocine in pediatric cardiac catheterization may reduce the need for an additional dose of midazolam and may contribute to the prevention of airway complications associated with respiratory depression caused by sedative agents.

The interaction between neuromuscular forces, aerodynamic forces, and anatomical motion in the upper airway predicts the severity of pediatric OSA

Upper airway neuromuscular response to air pressure during inhalation is an important factor in assessing pediatric subjects with obstructive sleep apnea (OSA). The neuromuscular response's strength, timing, and duration all contribute to the potential for airway collapses and the severity of OSA. This study quantifies these factors at the soft palate, tongue, and epiglottis to assess the relationship between neuromuscular control and OSA severity in 20 pediatric subjects with and without trisomy 21, under dexmedetomidine-induced sedation. The interaction between neuromuscular force and airflow pressure force was assessed based on power transferred between the airway wall and airflow calculated from airway wall motion (from cine magnetic resonance images) and air pressure acting on the airway wall (from computational fluid dynamics simulations). Airway wall motion could be asynchronous with pressure forces due to neuromuscular activation, or synchronous with pressure forces, indicating a passive response to airflow. The obstructive apnea-hypopnea index (oAHI) quantified OSA severity. During inhalation, the normalized work done through asynchronous dilation of the airway at the soft palate, tongue, and epiglottis correlated significantly with oAHI (Spearman's ρ = 0.54, 0.50, 0.64; P = 0.03, 0.03, 0.003). Synchronous collapse at the epiglottis correlated significantly with oAHI (ρ = 0.52; P = 0.02). Temporal order of synchronous and asynchronous epiglottis motion during inhalation predicted the severity of OSA (moderate vs. severe) with 100% sensitivity and 70% specificity. Subjects with severe OSA and/or trisomy 21 have insufficient neuromuscular activation during inhalation, leading to collapse and increased neuromuscular activation. Airflow-driven airway wall motion during late inhalation likely is the main determinant of OSA severity.NEW & NOTEWORTHY This is the first study that combines cine MRI and computational fluid dynamics with in vivo synchronous respiratory flow measurement to quantify the interaction between airway neuromuscular forces, aerodynamic forces, and airway anatomy noninvasively in pediatric patients with obstructive sleep apnea (OSA). The results indicate power transfer predicts OSA severity.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Outcome of CPAP Titration for Moderate-to-Severe OSA Under Drug-Induced Sleep Endoscopy: A Randomized Controlled Crossover Trial

Background

The titration pressure of continuous positive airway pressure (CPAP) is important in patients with obstructive sleep apnea (OSA). This study aimed to understand the difference between drug-induced sleep endoscopy (DISE)-guided CPAP titration and conventional sleep center (CSC) CPAP titration in patients with OSA.

Methods

In this randomized, controlled, and single-blind crossover trial, we compared the effects of 1-month CPAP treatment in patients with OSA with either DISE-guided CPAP titration or CSC CPAP titration. Twenty-four patients with OSA were recruited for the study. All patients underwent polysomnography, DISE-guided CPAP titration, and accommodation. Initially, patients were randomly assigned to receive either DISE-guided CPAP titration or CSC CPAP treatment for the first month. They were then switched to other treatments in the second month. The Epworth sleepiness scale (ESS) score was recorded at baseline, 1 and 2 months.

Results

The upper limit of the pressure of DISE-guided titration and CSC CPAP titration was not significantly different (13.9 ± 0.7 vs. 13.5 ± 0.5 cm H₂O; P = 0.92). The residual apnea-hypopnea index and compliance were also not significantly different between the groups. ESS score significantly improved from baseline to 1 month after CPAP treatment in both groups. Both epiglottis (anterior-posterior collapse) and tongue base collapse were significantly associated with 95% CPAP pressure (P = 0.031 and 0.038, respectively). After multivariate regression analyses, the epiglottis (anterior-posterior collapse) was an independent factor for 95% CPAP pressure. The incidence rate of bradycardia was 58.3%, which is a safety concern for DISE. Despite the high incidence of bradycardia, all patients with bradycardia recovered with proper management.

Conclusion

Both modalities were comparable in terms of establishing the pressure settings required to treat patients. Further large-scale studies are required to confirm these results.

Trial registration

https://clinicaltrials.gov/, NCT03523013.

Perioperative respiratory adverse events during ambulatory anesthesia in obese children

Obesity is one of the most common clinical conditions in the pediatric population with an increasing prevalence ranging from 20 to 30% worldwide. It is well known that during ambulatory anesthesia, obese children are more prone to develop perioperative respiratory adverse events (PRAEs) associated with obesity. To avoid or at least minimize these adverse effects, a thorough preoperative assessment should be undertaken as well as consideration of specific anesthetic approaches such as preoxygenation before induction of anesthesia and optimizing drug dosing. The use of short-acting opioid and nonopioid analgesics and the frequent implementation of regional anesthesia should also be included. Noninvasive airway management, protective mechanical ventilation, and complete reversion of neuromuscular blockade and awake extubation also proved to be beneficial in preventing PRAEs. During the postoperative period, continuous monitoring of oxygenation and ventilation is mandatory in obese children. In the current review, we sought to provide recommendations that might help to reduce the severity of perioperative respiratory adverse events in obese children, which could be of particular importance for reducing the rate of unplanned hospitalizations and ultimately improving the overall postoperative recovery.

Effectiveness and safety of intravenous dexmedetomidine sedation for ophthalmic surgery under regional anesthesia

PURPOSE

To assess the effectiveness and safety of intravenous (IV) dexmedetomidine for sedation in ophthalmic surgery.

METHODS

Prospective, observational, uncontrolled, single-center study. Patients were sedated with a continuous dexmedetomidine IV infusion started 15 min before regional anesthesia administration and maintained up to the end of surgery. Effectiveness of dexmedetomidine was assessed by the Modified Observer's Assessment of Alertness and Sedation (MOAA/S) targeted at 5. Safety was assessed by the incidence of patients' movements/snoring and by the incidence of respiratory and haemodynamic complications. An eleven-point numerical rating scale (NRS) was used to assess the level of satisfaction of both the surgeon and the patient.

RESULTS

123 patients (73 males, mean age: 63 ± 13) were included; 81 (81/123; 65.8%) patients reached the requested MOAA/S score of 5. Any intraoperative movement - mostly voluntary - occurred in 34 (34/123; 27.6%) cases with no need for a switch to general anaesthesia; no ocular complications related to the intraoperative movements occurred. Intraoperative snoring occurred in 30 (30/123; 24.4%) patients and it did not affect the surgical manoeuvres. Respiratory drive depression requiring manual or mechanical ventilation never occurred. Bradycardia occurred in 14 (14/123; 11.3%), cases but only 4 (4/123; 3.2%) patients required atropine administration, which was always effective. Intraoperative analgesia was consistently obtained and both the surgeons and the patients reported a high NRS satisfaction score.

CONCLUSION

Dexmedetomidine provided adequate sedation in patients undergoing ocular surgery under local anaesthesia and showed a good effectiveness and safety profile. Upper airway obstruction, apnoea and snoring can occur.

Sleep Endoscopy Findings in Children With Obstructive Sleep Apnea and Small Tonsils

OBJECTIVE

Obstructive Sleep Apnea (OSA) in children is treated primarily with adenotonsillectomy (AT). When clinical exam demonstrates small tonsils, the success of AT in resolving OSA is uncertain. The purpose of this study is to determine the utility of Drug induced Sleep Endoscopy (DISE) for children with OSA and small tonsils (Brodsky scale 1+) and to identify what obstructive trends exist in this subset of patients and to determine the utility of DISE-directed surgical intervention in patients with small tonsils.

METHODS

A retrospective chart review was performed for patients who underwent DISE at a tertiary care center over a 2-year period. Inclusion criteria were 1+ tonsils and a positive sleep study. Data collected included DISE findings, BMI, comorbid conditions, and pre-op PSG data.

RESULTS

Forty children were included with a mean age of 5.0 years (range 8 months-16 years). Mean preoperative AHI was 5.46 and mean oxygen saturation nadir was 87.1%. The most common contributor to airway obstruction was the adenoid (29 patients, 72.5%), followed by the tongue base or lingual tonsil (21 patients, 52.5%). The palatine tonsils (10 patients, 25.0%), epiglottis (10.0%), or obstruction intrinsic to the larynx (10.0%) were significantly less frequently identified as contributors to OSA when compared to the adenoid (P < .001). The majority of patients had multilevel obstruction (25 patients, 62.5%). Adenoidectomy (27 patients, 67.5%) was the most commonly performed procedure, followed by tonsillectomy (10 patients, 25.0%, P < .001) and tongue base surgery (9 patient 22.5%, P < .001).

CONCLUSION

In this group, small palatine tonsils were infrequently identified as a contributor to airway obstruction and tonsillectomy was avoided in most cases. This study illustrates the utility of DISE as a tool to personalize the surgical management of pediatric patients with OSA and small tonsils on physical exam.

The Quest for a DISE Protocol

OBJECTIVE

The objective of this quality initiative project was to modify our existing institutional drug-induced sleep endoscopy (DISE) protocol so that the surgeon could consistently determine obstructive breathing patterns while minimizing children's discomfort.

METHODS

A quality initiative study utilizing the well-described plan-do-study-act (PDSA) process was conducted at a tertiary hospital for children with polysomnogram-documented obstructive sleep apnea who were undergoing DISE. A 4-point Likert measurement tool was created. Change in each Likert rating with subsequent PDSA cycle was tested with the Wilcoxon rank sum test (Mann-Whitney), and change across all PDSA cycles was tested with the Kruskal-Wallis equality-of-populations rank test.

RESULTS

After a series of 4 PDSA cycles with 81 children, the DISE protocol was streamlined from 14 to 9 steps. There was significant improvement for all aspects of the DISE, with a final overall median rating of 1 (excellent) for intravenous (IV) placement, scope insertion, and anesthesiologist and surgeon satisfaction (P < .01).

DISCUSSION

For sleep surgeons, DISE is quickly becoming what bronchoscopy is to the airway surgeon. Utilizing inhalational agents to obtain IV access and insert the flexible scope in the rapid "on-off" fashion optimizes DISE success regardless of the primary sedation medication and allows ample time for these agents to dissipate.

IMPLICATIONS FOR PRACTICE

Adoption of a DISE protocol that includes nasal premedication and inhalational volatile gases for IV and scope insertion at the onset provides a more predictable level of sedation that is well tolerated by the patient, enabling the otolaryngologist to create an obstructive sleep apnea treatment plan.

Anesthetic management of children undergoing drug-induced sleep endoscopy: A retrospective review

OBJECTIVE

To determine the best anesthetic technique for DISE based on a retrospective review of the current literature and to highlight research gaps that should be addressed in future studies.

METHODS

A comprehensive retrospective review of the literature on anesthetic regimens for pediatric DISE through March 2020 was performed. Specific medical subject heading (MesH) terms included: drug-induced sleep endoscopy and anesthesia, DISE, child, obstructive sleep apnea, sleep disordered breathing.

RESULTS

Twelve articles were included. One study was a retrospective comparative study while the remaining 11 were case series. Five studies described anesthetic technique for DISE pre-T&A, two post-T&A, and four both pre- and post-T&A. The heterogeneity of the studies did not allow for a meta-analysis. A total of 1110 children ages 2 months to 19 years were included. Sedation depth and anesthetic outcomes with DISE were infrequently described. Eleven studies used a sevoflurane inhalational induction and mostly transitioned to a total IV anesthetic for maintenance. Propofol was the most commonly used sole anesthetic. A total of three studies used a combination of remifentanil and propofol, one used dexmedetomidine alone, one used sevoflurane alone, and one compared different regimens. Dexmedetomidine and ketamine have the most favorable profile for pediatric DISE but are not universally used. DISE completion, as reported in two studies, was 93% and 100%.

CONCLUSION

There are several anesthetic regimens for DISE that achieve good sedation and outcomes. The combination of ketamine and dexmedetomidine may be the ideal regimen. Limited data and lack of protocols/high-quality studies exist on anesthetic regimens for pediatric DISE.

Effects on the Upper Airway Morphology with Intravenous Addition of Ketamine after Dexmedetomidine Administration in Normal Children

General anesthesia decreases the tone of upper airway muscles in a dose-dependent fashion, potentially narrowing the pharyngeal airway. We examined the effects of adding ketamine on the airway configuration after dexmedetomidine administration in spontaneously breathing children with normal airways. 25 children presenting for Magnetic Resonance Imaging (MRI) of the brain/spine under general anesthesia were prospectively recruited in the study. Patients were anesthetized with dexmedetomidine bolus (2 mcg over 10 min) followed by dexmedetomidine infusion (2 mcg·kg−1·h) and ketamine and permitted to breathe spontaneously via the native airway. MR-CINE images of the upper airway were obtained with dexmedetomidine infusion alone (baseline) and 5, 10, and 15 min after administering ketamine bolus (2 mg·kg−1) in two anatomical axial planes at the nasopharynx and the retroglossal upper airway. Airway lumen is segmented with a semi-automatic image processing approach using a region-growing algorithm. Outcome measures of cross-sectional area, transverse and anterior-posterior diameters of the airway in axial planes at the level of the epiglottis in the retroglossal airway, and in the superior nasopharynx were evaluated for changes in airway size with sedation. Airway dimensions corresponding to the maximum, mean, and minimum sizes during a respiratory cycle were obtained to compare the temporal changes in the airway size. The dose-response of adding ketamine to dexmedetomidine alone condition on airway dimensions were examined using mixed-effects of covariance models. 22/25 patients based on inclusion/exclusion criteria were included in the final analysis. The changes in airway measures with the addition of ketamine, when compared to the baseline of dexmedetomidine alone, were statistically insignificant. The modest changes in airway dimensions are clinically less impactful and within the accuracy of the semi-automatic airway segmentation approach. The effect sizes were small for most airway measures. The duration of ketamine seems to not affect the airway size. In conclusion, adding ketamine to dexmedetomidine did not significantly reduce upper airway configuration when compared to dexmedetomidine alone.

Pediatric Drug-Induced Sleep Endoscopy: Technique and Scoring System

Drug-induced sleep endoscopy (DISE) is an invaluable tool for identifying sites of obstruction for patients with obstructive sleep apnea (OSA). During DISE, the patient is in a state of drug-induced sleep, and a flexible laryngoscope is passed through the nose into the upper airway. Sites of obstruction are visualized and scored to guide surgical management. Currently, there is no universally accepted method of DISE analysis and scoring. This limitation in comparability impedes large-scale analysis between clinicians, institutions, and studies. In this report, we propose a standardized method of scoring and performing DISE in children with OSA. Our DISE scoring system is internally developed, consistent through the study, and addresses all levels of potential upper airway obstruction.

Propofol versus dexmedetomidine during drug-induced sleep endoscopy (DISE) for pediatric obstructive sleep apnea

PURPOSE

To test for differences in DISE findings in children sedated with propofol versus dexmedetomidine. We hypothesized that the frequency of ≥ 50% obstruction would be higher for the propofol than dexmedetomidine group at the dynamic levels of the airway (velum, lateral walls, tongue base, and supraglottis) but not at the more static adenoid level.

METHODS

A single-center retrospective review was performed on children age 1-18 years with a diagnosis of sleep disordered breathing or obstructive sleep apnea (OSA) who underwent DISE from July 2014 to Feb 2019 scored by the Chan-Parikh scale sedated with either propofol or dexmedetomidine (with or without ketamine). Logistic regression was used to test for a difference in the odds of ≥ 50% obstruction (Chan-Parikh score ≥ 2) at each airway level with the use of dexmedetomidine vs. propofol, adjusted for age, sex, previous tonsillectomy, surgeon, positional OSA, and ketamine co-administration.

RESULTS

Of 117 subjects, 57% were sedated with propofol and 43% with dexmedetomidine. Subjects were 60% male, 66% Caucasian, 31% obese, 38% syndromic, and on average 6.5 years old. Thirty-three percent had severe OSA and 41% had previous tonsillectomy. There was no statistically significant difference in the odds of ≥ 50% obstruction between the two anesthetic groups at any level of the airway with or without adjustment for potential confounders.

CONCLUSION

We did not find a significant difference in the degree of upper airway obstruction on DISE in children sedated with propofol versus dexmedetomidine. Prospective, randomized studies would be an important next step to confirm these findings.

[Comparison of ED50 of intranasal dexmedetomidine sedation in children with acyanotic congenital heart disease before and after cardiac surgery]

OBJECTIVE

To compare the median effective dose (ED50) of intranasal dexmedetomidine for procedural sedation in uncooperative pediatric patients with acyanotic congenital heart disease before and after cardiac surgery.

METHODS

We prospectively recruited 47 children (22 in preoperative group and 25 in postoperative group) who needed sedation for transthoracic echocardiography (TTE). A modified up-and-down sequential study design was employed to determine dexmedetomidine dose for each patient with a starting dose of 2 μg/kg in both groups; dexmedetomidine doses for subsequent subjects were determined according to the responses from the previous subject using the up-and-down method at a 0.25 μg/kg interval. The ED95 was determined using probit regression. The onset time, examination time, wake-up time and adverse effects were measured, and the safety was evaluated in terms of changes in vital signs every 5 min.

RESULTS

The ED50 value of intranasal dexmedetomidine for sedation was 1.84 μg/kg (95% CI: 1.68-2.00 μg/kg) in children with congenital heart disease before cardiac surgery, and 3.38 μg/kg (95% CI: 3.21-3.54 μg/kg) after the surgery. No significant difference was found between the two groups in the demographic variables, onset time, examination time, wake-up time, or adverse effects.

CONCLUSIONS

In children with acyanotic congenital heart disease, the ED50 of intranasal dexmedetomidine for TTE sedation increases to 3.38 μg/ kg after cardiac surgery from the preoperative value of 1.84 μg/kg.

Differences in Flexible and Rigid Bronchoscopy for Assessment of Tracheomalacia

OBJECTIVES/HYPOTHESIS

Both flexible and rigid bronchoscopy can be used to assess tracheomalacia; however, there is limited evidence comparing the two techniques. The objective of this study was to compare flexible and rigid bronchoscopy for evaluating the location and severity of tracheomalacia in children.

STUDY DESIGN

Retrospective case series.

METHODS

This was a retrospective study of children with both flexible and rigid bronchoscopy under the same sedation. All bronchoscopies were reviewed by three bronchoscopists for the location and severity of tracheomalacia. The location of collapse was defined as upper, middle, or lower trachea, and the severity of collapse was defined as none (0%-25% collapse), mild/moderate (26%-75% collapse), and severe (>75% collapse).

RESULTS

Twenty-one patients were recruited for this study with a variety of neonatal respiratory diseases. There was 94% agreement (κ = 0.64) for assessment of tracheomalacia in the upper trachea. However, agreement was only 75% (κ = 0.50) in the middle trachea and 76% (κ = 0.52) in the lower trachea. In the subset of patients without tracheostomy, agreement improved to 100%, 88%, and 82% for the upper, middle, and lower trachea, respectively. There was poor correlation for tracheomalacia severity in the middle trachea (ρ = 0.30, P = .2) and moderate in the lower trachea (ρ = 0.63, P = .002).

CONCLUSIONS

Although there is moderate agreement between flexible and rigid bronchoscopy for evaluating the presence of tracheomalacia, there can be differences in the two techniques, particularly when assessing severity of airway collapse. Future studies will be needed to understand factors that result in the discordance of flexible and rigid bronchoscopy for assessing airway dynamics.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:201-204, 2021.

Upper Airway Collapsibility during Dexmedetomidine and Propofol Sedation in Healthy Volunteers: A Nonblinded Randomized Crossover Study

BACKGROUND

Dexmedetomidine is a sedative promoted as having minimal impact on ventilatory drive or upper airway muscle activity. However, a trial recently demonstrated impaired ventilatory drive and induction of apneas in sedated volunteers. The present study measured upper airway collapsibility during dexmedetomidine sedation and related it to propofol.

METHODS

Twelve volunteers (seven female) entered this nonblinded, randomized crossover study. Upper airway collapsibility (pharyngeal critical pressure) was measured during low and moderate infusion rates of propofol or dexmedetomidine. A bolus dose was followed by low (0.5 μg · kg · h or 42 μg · kg · min) and moderate (1.5 μg · kg · h or 83 μg · kg · min) rates of infusion of dexmedetomidine and propofol, respectively.

RESULTS

Complete data sets were obtained from nine volunteers (median age [range], 46 [23 to 66] yr; body mass index, 25.4 [20.3 to 32.4] kg/m). The Bispectral Index score at time of pharyngeal critical pressure measurements was 74 ± 10 and 65 ± 13 (mean difference, 9; 95% CI, 3 to 16; P = 0.011) during low infusion rates versus 57 ± 16 and 39 ± 12 (mean difference, 18; 95% CI, 8 to 28; P = 0.003) during moderate infusion rates of dexmedetomidine and propofol, respectively. A difference in pharyngeal critical pressure during sedation with dexmedetomidine or propofol could not be shown at either the low or moderate infusion rate. Median (interquartile range) pharyngeal critical pressure was -2.0 (less than -15 to 2.3) and 0.9 (less than -15 to 1.5) cm H2O (mean difference, 0.9; 95% CI, -4.7 to 3.1) during low infusion rates (P = 0. 595) versus 0.3 (-9.2 to 1.4) and -0.6 (-7.7 to 1.3) cm H2O (mean difference, 0.0; 95% CI, -2.1 to 2.1; P = 0.980) during moderate infusion of dexmedetomidine and propofol, respectively. A strong linear relationship between pharyngeal critical pressure during dexmedetomidine and propofol sedation was evident at low (r = 0.82; P = 0.007) and moderate (r = 0.90; P < 0.001) infusion rates.

CONCLUSIONS

These observations suggest that dexmedetomidine sedation does not inherently protect against upper airway obstruction.

Tracheal extubation in children: Planning, technique, and complications

Although poorly described in textbooks and rarely a topic of lecture, tracheal extubation is a critical phase of anesthetic care. It should therefore be carefully planned taking into account simple physiology-based principles to maintain the upper airway patent and avoid lung de-recruitment, but also the pharmacology of all anesthetic agents used. Although the management of most of its complications can be learned in a clinical simulation environment, the basic techniques can so far only be taught at the bedside, in the operating room. In this paper, the process of extubation is described in successive steps: preparation, return to adequate spontaneous ventilation, awake versus deep extubation, timing according to the child's breathing cycle, extubation in the operating room or in the Postanesthesia Care unit, child's management immediately after extubation, diagnosis and treatment of the early complications, and finally, how to prepare for a difficult reintubation.

Efficacy of premedication with intranasal dexmedetomidine for removal of inhaled foreign bodies in children by flexible fiberoptic bronchoscopy: a randomized, double-blind, placebo-controlled clinical trial

Background

Tracheobronchial foreign body aspiration in children is a life-threatening, emergent situation. Currently, the use of fiberoptic bronchoscopy for removing foreign bodies is attracting increasing attention. Oxygen desaturation, body movement, laryngospasm, bronchospasm, and breath-holding are common adverse events during foreign body removal. Dexmedetomidine, as a highly selective α₂-adrenergic agonist, produces sedative and analgesic effects, and does not induce respiratory depression. We hypothesized that intranasal dexmedetomidine at 1 μg kg − 1 administered 25 min before anesthesia induction can reduce the incidence of adverse events during fiberoptic bronchoscopy under inhalation general anesthesia with sevoflurane.

Methods

In all, 40 preschool-aged children (6–48 months) with an American Society of Anesthesiologists physical status of I or II were randomly allocated to receive either intranasal dexmedetomidine at 1 μg·kg − 1 or normal saline at 0.01 ml kg^− 1 25 min before anesthesia induction. The primary outcome was the incidence of perioperative adverse events. Heart rate, respiratory rate, parent-child separation score, tolerance of the anesthetic mask, agitation score, consumption of sevoflurane, and recovery time were also recorded.

Results

Following pre-anesthesia treatment with either intranasal dexmedetomidine or saline, the incidences of laryngospasm (15% vs. 50%), breath-holding (10% vs. 40%), and coughing (5% vs. 30%) were significantly lower in patients given dexmedetomidine than those given saline. Patients who received intranasal dexmedetomidine had a lower parent–child separation score (P = 0.017), more satisfactory tolerance of the anesthetic mask (P = 0.027), and less consumption of sevoflurane (38.18 ± 14.95 vs. 48.03 ± 14.45 ml, P = 0.041). The frequency of postoperative agitation was significantly lower in patients given intranasal dexmedetomidine (P = 0.004), and the recovery time was similar in the two groups.

Conclusions

Intranasal dexmedetomidine 1 μg·kg^− 1, with its sedative and analgesic effects, reduced the incidences of laryngospasm, breath-holding, and coughing during fiberoptic bronchoscopy for FB removal. Moreover, it reduced postoperative agitation without a prolonged recovery time.

Trail registration

The study was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR1800017273) on July 20, 2018.

The pearls of pediatric sedation: polish the old and embrace the new

Over the past decade, as the complexity and breadth of pediatric procedures increases, the actual choices of approved sedatives have remained relatively stagnant. Since the introduction of midazolam, there has not been a sedative approved for pediatric labelling until December 2018. This December, the European approval of ADV6209 (Ozalin) for pediatric usage marked the newest addition to the pediatric sedative armamentarium in over a decade. This review is timely and significant because it will provide a balanced evaluation of the most common sedatives in use today, the most recent sedative to be approved and, most importantly, a critical look at the literature supporting the latest approaches to the most commonly performed procedures.

Dexmedetomidine versus propofol at different sedation depths during drug-induced sleep endoscopy: A randomized trial

OBJECTIVES/HYPOTHESIS

The aim of this study was to compare the effect of dexmedetomidine and propofol on airway dynamics, cardiorespiratory system, and emergence following drug-induced sleep endoscopy (DISE).

STUDY DESIGN

Prospective, randomized, single-blinded study.

METHODS

Sixty patients age 18 to 65 years in American Society of Anesthesiologists physical status groups 1 and 2 scheduled to undergo DISE were randomly allocated to either Group P (N = 30; receiving propofol infusion at 50-150 μg/kg/min) or Group D (N = 30; receiving dexmedetomidine bolus of 1 μg/kg followed by infusion at 0.5-1.0 μg/kg/hr). DISE was done at light sleep and deep sleep. Airway obstruction at tongue base was recorded as primary outcome. Airway obstruction at velum, oropharyngeal lateral wall, and epiglottis level during light and deep sedation, hemodynamic and respiratory parameters, time to attain sufficient sedation, time for emergence from sedation, and any adverse events during DISE with the two study drugs were recorded as secondary outcomes.

RESULTS

There was a greater degree of obstruction at the tongue base level (P = 0.001) and Oropharynx level (P = 0.017) in Group P compared with Group D during deep sedation. Increase in airway obstruction from light to deep sleep was seen with propofol at the oropharynx (P = 0.0185) and tongue base (P = 0.0108) levels. Two patients (6.6%) in Group D and 10 patients (33.3%) in Group P showed oxygen saturation below the minimum oxygen saturation recorded during polysomnography. Time to open eyes to call after stopping sedation was significantly less in Group P (P = 0.005).

CONCLUSIONS

Dexmedetomidine shows a lesser degree of airway collapse and higher oxygen saturation levels at greater sedation depth during DISE. Propofol has a faster onset and emergence from sedation.

LEVEL OF EVIDENCE

1b Laryngoscope, 130:257-262, 2020.

A retrospective comparison of propofol to dexmedetomidine for pediatric magnetic resonance imaging sedation in patients with mucopolysaccharidosis type II

BACKGROUND

Mucopolysaccharidosis type II patients are reported to have an elevated incidence of difficult airway. Propofol is a commonly used sedative for magnetic resonance imaging in pediatric patients, but patients who receive it may exhibit dose-dependent upper airway obstruction and respiratory depression. Dexmedetomidine also provides adequate procedural sedation with a relatively low risk of airway obstruction. Accordingly, we introduced the use of dexmedetomidine in our practice to reduce the risk of airway obstruction during magnetic resonance imaging procedures.

AIMS

The aim of this study was to evaluate the incidence of artificial airway interventions in patients sedated with propofol and compare it to that in patients sedated with dexmedetomidine in patients with mucopolysaccharidosis type II during magnetic resonance imaging procedures.

METHODS

All mucopolysaccharidosis type II patients undergoing magnetic resonance imaging at our institution between April 2014 and February 2018 were included in this study. The patients were divided into two groups according to whether they were managed before and after the introduction of dexmedetomidine: those who were sedated with propofol (group P) and those who were sedated with dexmedetomidine (group D).

RESULTS

Forty-six sedations were performed in 27 patients. Artificial airway interventions were significantly more frequent during propofol-based than dexmedetomidine-based sedation: 14 of 32 (43.8%) in group P and 1 of 14 (7.1%) in group D (odds ratio, 10.11; 95% confidence interval, 1.18-86.85; P = 0.018). Time to awake and time to discharge were similar between groups. Changes in hemodynamic variables also did not significantly differ between groups.

CONCLUSION

Dexmedetomidine provides an adequate level of sedation and is associated with lower rates of artificial airway interventions compared to propofol. Therefore, dexmedetomidine may offer advantages for preserving the native airway compared to propofol when administered during magnetic resonance imaging scans in patients with mucopolysaccharidosis type II.

Comparison of upper airway patency in patients with mild obstructive sleep apnea during dexmedetomidine or propofol sedation: a prospective, randomized, controlled trial

Background

In addition to propofol, dexmedetomidine is a suitable alternative for intraoperative sedation in procedures requiring regional anesthesia. To date, however, little is known about the influences of each drug on upper airway patency. Accordingly, the authors investigated differences between dexmedetomidine and propofol sedation in the occurrence of upper airway obstruction and requirements for airway intervention in patients with mild obstructive sleep apnea.

Methods

Patients with an apnea/hypopnea index of 5–14/h according to Watch-PAT 200 analysis were enrolled in this study. Spinal anesthesia was routinely performed for surgery. Intraoperative sedation was initiated using either dexmedetomidine or propofol infusion at a level of modified observer’s assessment of alertness/sedation scale 3. The primary outcome was the proportion of patients exhibiting signs of upper airway obstruction. A sign of upper airway obstruction was defined as no detection of end-tidal carbon dioxide for at least 10 s despite respiratory efforts.

Results

A total of 50 patients were included in the final analysis (dexmedetomidine [n = 26]; propofol [n = 24]). During the intraoperative sedation period, there was a significantly lower proportion of patients exhibiting signs of upper airway obstruction in the dexmedetomidine group than in the propofol group (11.5% vs. 41.7%, P = 0.035). An artificial airway was inserted in 1 patients (3.8%) and 5 patient (20.8%) in the dexmedetomidine and propofol groups, respectively (P = 0.093).

Conclusion

Dexmedetomidine sedation was associated with a lower incidence of upper airway obstruction than propofol sedation in patients with mild obstructive sleep apnea.

Trial registration number

Clinical trials.gov (NCT02993718): Retrospectively registered.

Dexmedetomidine is effective and safe during NIV in infants and young children with acute respiratory failure

BACKGROUND

Noninvasive ventilation (NIV) is increasingly utilized in infants and young children, though associated with high failure rates due to agitation and poor compliance, mostly if patient-ventilator synchronization is required.

METHODS

A retrospective cohort study was carried out in an academic pediatric intensive care unit (PICU). Dexmedetomidine (DEX) was infused as unique sedative in 40 consecutive pediatric patients (median age 16 months) previously showing intolerance and agitation during NIV application.

RESULTS

During NIV clinical application both COMFORT-B Score and Richmond Agitation-Sedation Scale (RASS) were serially evaluated. Four patients experiencing NIV failure, all due to pulmonary condition worsening, required intubation and invasive ventilation. 36 patients were successfully weaned from NIV under DEX sedation and discharged from PICU. All patients survived until home discharge.

CONCLUSION

Our data suggest that DEX may represent an effective sedative agent in infants and children showing agitation during NIV. Early use of DEX in infants/children receiving NIV for acute respiratory failure (ARF) should be considered safe and capable of improving NIV, thus permitting both lung recruitment and patient-ventilator synchronization.

Magnetic resonance imaging of obstructive sleep apnea in children

Sleep-disordered breathing has a spectrum of severity that spans from snoring and partial airway collapse with increased upper airway resistance, to complete upper airway obstruction with obstructive sleep apnea during sleeping. While snoring occurs in up to 20% of children, obstructive sleep apnea affects approximately 1-5% of children. The obstruction that occurs in obstructive sleep apnea is the result of the airway collapsing during sleep, which causes arousal and impairs restful sleep. Adenotonsillectomy is the first-line treatment of obstructive sleep apnea and is usually effective in otherwise healthy nonsyndromic children. However, there are subgroups in which this surgery is less effective. These subgroups include children with obesity, severe obstructive sleep apnea preoperatively, Down syndrome, craniofacial anomalies and polycystic ovarian disease. Continuous positive airway pressure (CPAP) is the first-line therapy for persistent obstructive sleep apnea despite previous adenotonsillectomy, but it is often poorly tolerated by children. When CPAP is not tolerated or preferred by the family, surgical options beyond adenotonsillectomy are discussed with the parent and child. Dynamic MRI of the airway provides a means to identify and localize the site or sites of obstruction for these children. In this review the authors address clinical indications for imaging, ideal team members to involve in an effective multidisciplinary program, basic anesthesia requirements, MRI protocol techniques and interpretation of the findings on MRI that help guide surgery.

Low-dose dexmedetomidine as an adjuvant to propofol infusion for children in MRI: A double-cohort study

INTRODUCTION

Propofol is an effective sedative for magnetic resonance imaging. Nevertheless, it may cause hemodynamic and respiratory complications in a dose dependent fashion. We investigated the role of low-dose dexmedetomidine (0.5 μg/kg) as an adjuvant to propofol sedation for children undergoing magnetic resonance imaging. We hypothesized that dexmedetomidine would decrease the propofol dose required, airway complications, and hemodynamic instability.

METHODS

We performed a retrospective chart review of patients' age of 1 month to 20 years. Children were divided into 2 groups; group P received only propofol; group D + P received intravenous bolus of dexmedetomidine (0.5 μg/kg) and propofol.

RESULTS

We reviewed 172 children in P and 129 in D + P (dexmedetomidine dose, median: 0.50 μg/kg (IQR: 0.45-0.62). An additional dexmedetomidine bolus was given to 17 children for sedation lasting longer than 2 hours. Total propofol dose (μg/kg/min) was significantly higher in group P than D + P; 215.0 (182.6-253.8) vs 147.6 (127.5-180.9); Median Diff = -67.8; 95%CI = -80.6, -54.9; P < .0001. There was no difference in recovery time (minutes); P: 28 (17-39) vs D + P: 27 (18-41); Median Diff = -1; 95%CI = -6.0, 4.0; P = .694. The need for airway support was significantly greater in P compared to D + P; 15/172 vs 3/129; OR = 0.25; 95%CI = 0.07 to 0.90; P = .02 (2-sample proportions test). Mean arterial pressure was significantly lower in P compared to D + P across time over 60 minutes after induction (coef = -0.06, 95%CI = -0.11, -0.02, P = .004).

DISCUSSION & CONCLUSION

A low-dose bolus of dexmedetomidine (0.5 μg/kg) used as an adjuvant can decrease the propofol requirement for children undergoing sedation for magnetic resonance imaging. This may decrease the need for airway support and contribute to improved hemodynamic stability without prolonging recovery time.

Dexmedetomidine as Single Continuous Sedative During Noninvasive Ventilation: Typical Usage, Hemodynamic Effects, and Withdrawal

OBJECTIVES

Dexmedetomidine use in pediatric critical care is increasing. Its prolonged effects as a single continuous agent for sedation are not well described. The aim of the current study was to describe prolonged dexmedetomidine therapy without other continuous sedation, specifically the hemodynamic effects, discontinuation strategies, and risk factors for withdrawal.

DESIGN

Retrospective chart review.

SETTING

Large, single-center, quaternary care pediatric academic institution.

PATIENTS

Data from 382 children, less than 18 years old admitted to the PICU who received dexmedetomidine for more than 24 hours without other infusions for sedation during noninvasive positive pressure ventilation.

INTERVENTIONS

Usual care practices for dexmedetomidine use were described. Discontinuation strategies were categorized as abrupt discontinuation, wean from dexmedetomidine infusion, and transition to enteral clonidine.

MEASUREMENTS AND MAIN RESULTS

Median peak and cumulative doses with interquartile range were 1 µg/kg/hr (0.6-1.2 µg/kg/hr) and 30 µg/kg (20-50 µg/kg), respectively, and median duration was 45 hours (34-66 hr). Four hours after reaching peak dose, we observed a decrease in heart rate (p < 0.01) with 28% prevalence of bradycardia and an increase in systolic blood pressure (p < 0.01) with 33% prevalence of hypertension and 2% hypotension. During the escalation phase, the prevalence of bradycardia and hypotension were 75% and a 30%, respectively. Three-hundred thirty-six patients (88%) had abrupt discontinuation, 37 (10%) were weaned, and nine (2%) were transitioned to clonidine. Nineteen patients (5%) experienced withdrawal. Univariate risk of withdrawal was most associated with duration: odds ratio equal to 1.5 (1.3-1.7) for each 12-hour period (p < 0.01). By multivariate analysis including age, discontinuation group, dexmedetomidine cumulative dose, and peak dose, only cumulative dose remained significant with an odds ratio equal to 1.3 (1.1-1.5) for each 10 μg/kg (p < 0.01).

CONCLUSIONS

Dexmedetomidine use for noninvasive positive pressure ventilation sedation in pediatric critical care has predictable hemodynamic effects including bradycardia and hypertension. Although withdrawal was associated with higher cumulative dose, these symptoms were effectively managed with short-term enteral clonidine.

Airway Dimensions in Children with Neurological Disabilities During Dexmedetomidine and Propofol Sedation for Magnetic Resonance Imaging Study

Objective

Children with neurological disabilities are at an increased risk of airway complications during anaesthesia for magnetic resonance imaging (MRI) with spontaneous respiration. The primary objective of this study was to evaluate airway dimensions during propofol and dexmedetomidine sedation for MRI in children with neurological disabilities. The secondary objective was to examine the adverse respiratory and sedation-related events.

Methods

Seventy-two children aged 1-6 years undergoing MRI were randomly selected to receive sedation with either 2 mg kg^-1 h^-1 of propofol or 2 μg kg^-1 h^-1 of dexmedetomidine. The airway dimensions were measured at soft palate, the base of tongue and mid-epiglottis. Adverse airway events were noted, and the quality of sedation was determined based on the need for dose modification, patient movement and repeat imaging requirements.

Results

There was no significant difference in airway dimensions observed between the dexmedetomidine and propofol groups, except for maximum and minimum transverse diameter (15.4±3.4 vs. 13.4±4.7, p=0.04 and 14.6±3.3 vs. 12.4±4.7, p=0.02 respectively) at soft palate and for cross sectional area difference at the base of tongue (14.5±13.9 vs. 20.1±19.3, p=0.03). Airway obstruction (2/36 vs. 3/36), apnoea (0/36 vs. 3/36) and desaturation (0/36 vs 2/36) occurred less frequently with dexmedetomidine. Additional requirement of sedation (6 vs. 3 patients; p=0.48), movement during imaging (9 vs. 5 patients; p=0.37) and poor image quality necessitating re-acquisition (4 vs. 0 patients; p=0.08) were more frequent with propofol.

Conclusion

Airway dimensions were similar during dexmedetomidine and propofol sedation, except for the transverse diameters at soft palate, and for cross-sectional area difference at the base of tongue in spontaneously breathing children with neurological disabilities. Airway complications were less frequent and the quality of sedation was better with dexmedetomidine.

Characterization of upper airway obstruction using cine MRI in children with residual obstructive sleep apnea after adenotonsillectomy

OBJECTIVES/BACKGROUND

Tonsillectomy and adenoidectomy (T&A) lead to resolution of obstructive sleep apnea (OSA) in most children. However, OSA persists in about 25-40% of children. Cinematic magnetic resonance imaging (cine MRI) can aid the management of persistent OSA by localizing airway obstruction. We describe our experience in implementing and optimizing a cine MRI protocol by using a 3 Tesla MRI scanner, and the use of dexmedetomidine for sedation to improve reproducibility, safety, and diagnostic accuracy.

PATIENTS/METHODS

Patients aged 3-18 years who underwent cine MRI for the evaluation of persistent OSA after T&A and failed positive airway pressure (PAP) therapy were included. Clinical data and the apnea-hyponea index were compared with quantitative and qualitative estimates of airway obstruction from imaging sequences.

RESULTS

A total of 36 children were included with a mean age of 9.6 ± 4.6 (SD) years with 40% over 12 years of age. Two-thirds of them were boys. Seventeen out of 36 children (47%) had Down syndrome. Single site and multilevel obstruction were identified in 21 of 36 patients (58%) and in 12 of 36 patients (33%), respectively. All cine MRIs were performed without complications. Multiple regression analysis demonstrated that a combination of the minimum airway diameter and body mass index z-score best predicted OSA severity (P = 0.002).

CONCLUSIONS

Cine MRI is a sensitive, safe, and noninvasive modality for visualizing upper airway obstruction in children with persistent OSA after T&A. Accurate identification of obstruction can assist in surgical planning in children who fail PAP therapy.

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.

Upper Airway Reflexes are Preserved During Dexmedetomidine Sedation in Children With Down Syndrome and Obstructive Sleep Apnea

STUDY OBJECTIVES

The assessment of pharyngeal collapsibility is difficult to perform in children under normal sleep. An alternative is to perform the assessment under an anesthetic, such as dexmedetomidine (DEX), that induces non-rapid eye movement (NREM) sleep. The objectives of this study were to compare critical closing airway pressure (Pcrit) obtained during natural sleep to that obtained under DEX in patients with Down syndrome (DS) and persistent obstructive sleep apnea (OSA) and determine whether Pcrit measured under sedation predicts the severity of OSA.

METHODS

The passive and active Pcrit, which represent airway passive mechanical properties and active dynamic responses to airway obstruction, respectively, were measured. Upper airway reflex activity was estimated by calculating the difference between active and passive Pcrit. Subjects underwent overnight polysomnography during which Pcrit was measured during normal sleep. Pcrit was also measured during DEX sedation at a dose of 2 μg/kg/h.

RESULTS

The study included 50 patients with median age of 11.4 years (interquartile range: 7.0-13.9) and median body mass index of 23.0 kg/m² (interquartile range: 18.4-29.1), 66% male and 80% Caucasian. Passive Pcrit was significantly higher than active Pcrit when measured during normal sleep and DEX-induced sleep. There was a positive association between apnea-hypopnea index and passive Pcrit (Spearman r = 0.53, P = .0001) and active Pcrit (r = 0.55, P = .0002) under DEX-induced sleep. There were no significant differences between the Pcrit measurements during natural sleep and during DEX sedation.

CONCLUSION

Patients with OSA can compensate for airway obstruction under DEX-induced sleep. The close association between Pcrit and apnea-hypopnea index suggests that airway responses with DEX sedation parallel those seen during natural sleep.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01902407.

Pediatric Obstructive Sleep Apnea

Screening for obstructive sleep apnea (OSA) with in-laboratory polysomnography is recommended for children with sleep disordered breathing. Adenotonsillectomy is the first-line therapy for pediatric OSA, although intranasal steroids and montelukast can be considered for those with mild OSA and continuous positive airway pressure for those with moderate to severe OSA awaiting surgery, poor surgical candidates or persistent OSA. Bony or soft tissue upper airway surgery is reasonable for children failing medical management or those with persistent OSA following adenotonsillectomy. Weight loss and oral appliance therapy are also useful. A multi-modality approach to diagnosis and treatment is preferred.

A retrospective comparison of propofol alone to propofol in combination with dexmedetomidine for pediatric 3T MRI sedation

BACKGROUND AND AIM

Both propofol and dexmedetomidine have been found to be safe and effective sedation for magnetic resonance imaging (MRI). Our program experienced an increase in patients arousing and experiencing an adverse airway event during propofol sedation for MRI in the first months of using a new 3T (Tesla) MRI scanner that was found to have a longer reverberation time compared to the previous 1.5 T MRI. In an effort to decrease patient arousal and adverse airway events during MRI, we administered a dexmedetomidine load prior to our standard propofol protocol. The objective was to compare adverse events and other outcome measures of patients sedated with propofol alone (Pro) and propofol preceded by a dexmedetomidine load (D+P).

METHODS

We reviewed a sedation database and medical records for all children undergoing 3T MRI studies while sedated with propofol alone or propofol preceded by a dexmedetomidine load in 2014.

RESULTS

Two hundred and fifty-six sedations were performed for MRI (87 Pro and 169 D+P). The two groups were comparable with regard to age, weight, gender, and American Society of Anesthesiologists status. Subjects in the D+P cohort had significantly fewer adverse events (10/169 patients (5.9%) vs 23/87 patients (26.4%) [OR 0.18, 95% CI: 0.08-0.39, P < 0.001]), particularly upper airway obstruction. Mean discharge time was longer in the D+P cohort compared to the Pro cohort (87.1, SD 26.3 min vs 69.7, SD 23.6; [mean difference 17.7 min, 95% CI: 10.6-24.8, P < 0.001]).

CONCLUSIONS

The addition of a dexmedetomidine infusion prior to our propofol MRI sedation protocol resulted in fewer sedation-related adverse events, particularly upper airway obstruction. Further studies are needed to evaluate the potential for a reduction on adverse events with this drug combination.

Does dexmedetomidine cause less airway collapse than propofol when used for deep sedation?

STUDY OBJECTIVE

The risk of airway collapse in patients undergoing deep sedation is a major concern. In this study, we compared the airway patency of deep sedation provided by propofol with the airway patency of deep sedation provided by dexmedetomidine in magnetic resonance imaging (MRI) procedures. This comparison was done using MRI static and dynamic images and comparing these images to baseline after sevoflurane induction.

DESIGN

After institutional review board approval, children who were scheduled for MRI procedures were given an inhalation induction, had intravenous access established, and were randomized to receive either dexmedetomidine 1-μg/kg load followed by 1-μg/(kg h) infusion or propofol infusion at 300 μg/(kg min) reduced to 250-μg/(kg min) infusion. MR images were then obtained. Airway patency and collapse were assessed at the level of the posterior midtongue in the axial and sagittal planes. The degree of airway collapse was assessed by determining the percent change in the airway caliber from its minimum to maximum value. After conclusion of the MRI procedure, the study patients were immediately observed by a blinded observer to determine their level of sedation according to the Ramsey sedation scale.

SETTING

MRI scanner at Women and Children's Hospital of Buffalo.

PATIENTS

Forty children between the ages of 3 and 7 years.

INTERVENTION

Comparison of the utilization of propofol against dexmedetomidine infusions for deep sedation to determine the degree of airway collapse.

MEASUREMENTS

Magnetic resonance images were then obtained using a 1.5-T GE Excite 12.0 scanner. Airway patency and collapse were assessed at the level of the posterior midtongue in the axial and sagittal planes. The degree of airway collapse was assessed by determining the percent change in the airway caliber from its minimum to maximum value. After conclusion of the MRI procedure, the study patients were immediately observed by a blinded observer to determine their level of sedation according to the Ramsey sedation scale.

MAIN RESULTS

Our study demonstrated no difference in airway collapse between dexmedetomidine-based deep sedation and propofol-based deep sedation following sevoflurane induction.

CONCLUSION

In deep sedation, which is commonly associated with a loss of airway tone, it may not matter which of these intravenous study agents are used. Intravenous sedation with propofol or dexmedetomidine appears to produce the same effect on the pediatric airway.

Usability of dexmedetomidine for deep sedation in infants and small children with respiratory morbidities

BACKGROUND

Children with respiratory morbidities are at increased risk of developing adverse respiratory events while undergoing deep sedation. Dexmedetomidine possesses sedative properties with minimal respiratory depression. This report aimed to determine the usability of dexmedetomidine in children with significant respiratory morbidities who require deep sedation.

METHODS

Medical records of children with ASA classification III who had at least three characteristics of respiratory morbidities and who received dexmedetomidine sedation for magnetic resonance imaging (MRI) between January 2014 and May 2015 were retrospectively reviewed. Dexmedetomidine was administered as a bolus of 1 μg/kg over 10 min followed by 1 μg/kg/h infusion. If necessary, an additional bolus dose was given and the infusion rate was increased to 2 μg/kg/h. Respiratory morbidities, haemodynamic parameters, total dexmedetomidine dose, adverse cardiorespiratory events and sedation characteristics were analysed.

RESULTS

Nineteen out of 642 children who underwent MRI were eligible for evaluation. Seventeen children (89%) had at least four characteristics of respiratory morbidities. The median [IQR] age was 9 months [3.5-14]. All patients completed MRI scans while breathing spontaneously via the native airway. No episodes of adverse respiratory events or haemodynamic instability were observed. Children who were administered a lower dexmedetomidine dose and had a shorter sedation time were more likely to be younger than 1 year of age.

CONCLUSION

These data demonstrate that dexmedetomidine deep sedation was well-tolerated in children with significant respiratory morbidities. Moreover, children younger than 1 year of age were administered lower dexmedetomidine dose than children older than 1 year of age for the same sedation level.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02555605.

Comparison of the combination of dexmedetomidine and ketamine to propofol or propofol/sevoflurane for drug-induced sleep endoscopy in children

AIM

Examination of dynamic airway collapse in patients with obstructive sleep apnea (OSA) during drug-induced sleep endoscopy (DISE) can help identify the anatomic causes of airway obstruction. We hypothesized that a combination of dexmedetomidine and ketamine (Group DK) would result in fewer oxygen desaturations and a higher successful completion rate during DISE in children with OSA when compared to propofol (Group P) or sevoflurane/propofol (Group SP).

METHODS

In this retrospective study, we reviewed the records of 59 children who presented for DISE between October 2013 and March 2015. Data analyzed included demographics, OSA severity, and hemodynamics (heart rate and blood pressure). The primary outcomes were airway desaturation during DISE to <85% and successful completion of DISE; these were compared between the three groups: DK, P, and SP.

RESULTS

Preoperative polysomnography was available for 49 patients. There were significantly more patients with severe OSA in Group P as compared to the other two groups. The mean (±sd) bolus dose for ketamine, dexmedetomidine, and propofol were 2.0 ± 0.6 mg·kg(-1) , 1.9 ± 0.9 mcg·kg(-1) , and 1.8 ± 1.1 mg·kg(-1) , respectively. The mean (±sd) infusion rate for dexmedetomidine was 1.6 ± 0.7 mcg·kg(-1) ·h(-1) and for propofol was 248 ± 68 mcg·kg(-1) ·min(-1) in Group P and 192 ± 48 mcg·kg(-1) ·min(-1) in Group SP. Patients in Group DK had significantly fewer desaturations to <85% during DISE compared to Group P. Patients in Group DK had significantly more successful completion of DISE (100% Group DK, 92% Group P, and 79% Group SP) as compared to Group SP.

CONCLUSIONS

These results suggest that the described dose regimen of propofol used alone or in combination with sevoflurane appears to be associated with more oxygen desaturations and a lower rate of successful completion than a combination of dexmedetomidine and ketamine during DISE in children with OSA.

Intranasal dexmedetomidine: an effective sedative agent for electroencephalogram and auditory brain response testing

OBJECTIVE

Dexmedetomidine is an α2 agonist with sedative, anxiolytic, and analgesic properties. The intranasal (IN) route avoids the pain of intravenous (i.v.) catheter placement but limited literature exists on the use of IN dexmedetomidine. This study examines the effectiveness and safety of IN dexmedetomidine for sedation of patients undergoing electroencephalogram (EEG) and auditory brain response (ABR) testing.

STUDY DESIGN

This was a review of all outpatients sedated with IN dexmedetomidine for EEG or ABR between October 1, 2012 and October 1, 2014. An initial dose of 2.5-3 μg · kg(-1) IN dexmedetomidine was given with a repeat dose of 1-1.5 μg · kg(-1) IN if needed 30 min later. Prospectively entered patient information was extracted from a quality assurance database and additional information gathered via retrospective chart review.

RESULTS

Intranasal dexmedetomidine was used in 169 patients (EEG = 117, ABR = 52). First-dose success rates were 90.4% for ABR and 87.2% for EEG. Total success rates (with one or two doses of IN dexmedetomidine) were 100% for ABR and 99.1% for EEG. The median time to onset of sleep was 25 min (IQR, 20-32 min). The median duration of sedation was 107 min (IQR, 90-131 min). Adverse events included: 18 patients (10.7%) with hypotension which resolved without intervention, six patients with oxygen desaturation <90%, two of whom received supplemental oxygen, and one patient with an underlying upper airway abnormality who was treated with continuous positive airway pressure.

CONCLUSIONS

IN dexmedetomidine is an effective and noninvasive method of sedating children for EEG and ABR.

Variable Findings for Drug-Induced Sleep Endoscopy in Obstructive Sleep Apnea with Propofol versus Dexmedetomidine

OBJECTIVE

To compare VOTE classification findings (velum, oropharyngeal-lateral walls, tongue base, and epiglottis) for drug-induced sleep endoscopy (DISE) among patients with obstructive sleep apnea (OSA) using 2 sedation protocols.

STUDY DESIGN

Case series with chart review.

SETTING

Single tertiary institution.

SUBJECTS

Patients with OSA who underwent DISE.

METHODS

A total of 216 patients underwent DISE between November 23, 2011, and May 1, 2015. DISE findings based on VOTE classification were compared between patients receiving the propofol- and dexmedetomidine-based sedation protocols.

RESULTS

Patients with OSA (N = 216; age, 44.3 ± 11.7 years; body mass index, 27.9 ± 4.8 kg/m(2)) underwent DISE with intravenous administration of propofol (n = 52) or dexmedetomidine (n = 164). There were no statistically significant differences between the 2 groups in baseline apnea-hypopnea index, oxygen desaturation index, Mallampati score, tonsil size, Epworth Sleepiness Scale score, peripheral oxygen saturation nadir, age, sex, or body mass index. Patients in the propofol group had a significantly increased likelihood of demonstrating complete tongue base obstruction (75%, 39 of 52) versus partial or no obstruction (25%, 13 of 52) in the anterior-posterior dimension, as compared with the dexmedetomidine group (complete obstruction: 42.7%, 70 of 164; partial or no obstruction: 57.3%, 94 of 164; odds ratio: 4.0; 95% confidence interval: 2.0-8.1; P = .0001). Obstruction of other airway subsites was not significantly different.

CONCLUSION

Use of propofol versus dexmedetomidine to induce sedation may have a significant effect on the pattern of upper airway obstruction observed during DISE. Randomized prospective studies are indicated to confirm these initial findings.

Upper airway morphology in Down Syndrome patients under dexmedetomidine sedation

BACKGROUND AND OBJECTIVES

Children with Down Syndrome are vulnerable to significant upper airway obstruction due to relative macroglossia and dynamic airway collapse. The objective of this study was to compare the upper airway dimensions of children with Down Syndrome and obstructive sleep apnea with normal airway under dexmedetomidine sedation.

METHODS

IRB approval was obtained. In this retrospective study, clinically indicated dynamic sagittal midline magnetic resonance images of the upper airway were obtained under low (1mcg/kg/h) and high (3mcg/kg/h) dose dexmedetomidine. Airway anteroposterior diameters and sectional areas were measured as minimum and maximum dimensions by two independent observers at soft palate (nasopharyngeal airway) and at base of the tongue (retroglossal airway).

RESULTS AND CONCLUSIONS

Minimum anteroposterior diameter and minimum sectional area at nasopharynx and retroglossal airway were significantly reduced in Down Syndrome compared to normal airway at both low and high dose dexmedetomidine. However, there were no significant differences between low and high dose dexmedetomidine in both Down Syndrome and normal airway. The mean apnea hypopnea index in Down Syndrome was 16±11. Under dexmedetomidine sedation, children with Down Syndrome and obstructive sleep apnea when compared to normal airway children show significant reductions in airway dimensions most pronounced at the narrowest points in the nasopharyngeal and retroglossal airways.

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.

Dexmedetomidine Infusion to Control Agitation due to Anticholinergic Toxidromes in Adolescents, a Case Series

Dexmedetomidine is an α2-adrenergic agonist approved by the US Food and Drug Administration for the sedation of adults who are intubated on mechanical ventilation and in non-intubated adults who are undergoing surgical procedures. However, it has also recently become a commonly used sedative agent in varied clinical settings for the pediatric patient as well. We present the use of dexmedetomidine for sedation in a unique clinical scenario, the severely agitated and combative patient following the intentional misuse of anticholinergic drugs. Its applications in this situation are discussed, and previous reports in the literature are reviewed.

Pediatric cardiac catheterization procedure with dexmedetomidine sedation: radiographic airway patency assessment

Aims:

The aim of the study was to measure airway patency objectively during dexmedetomidine sedation under radiographic guidance in spontaneously breathing pediatric patients scheduled for cardiac catheterization procedures.

Subjects and Methods:

Thirty-five patients in the age group 5–10 years scheduled for cardiac catheterization procedures were enrolled. All study patients were given loading dose of dexmedetomidine at 1 μg/kg/min for 10 min and then maintenance dose of 1.5 μg/kg/h. Radiographic airway patency was assessed at the start of infusion (0 min) and after 30 min. Antero-posterior (AP) diameters were measured manually at the nasopharyngeal and retroglossal levels. Dynamic change in airway between inspiration and expiration was considered a measure of airway collapsibility. Patients were monitored for hemodynamics, recovery time and complications.

Statistical Analysis:

Student paired t-test was used for data analysis. P < 0.05 was considered significant.

Results:

Minimum and maximum AP diameters were compared at 0 and 30 min. Nasopharyngeal level showed significant reduction in the minimum (6.27 ± 1.09 vs. 4.26 ± 1.03, P < 0.0001) and maximum (6.51 ± 1.14 vs. 5.99 ± 1.03, P < 0.0001) diameters. Similarly retroglossal level showed significant reduction in the minimum (6.98 ± 1.09 vs. 5.27 ± 1.15, P < 0.0001) and maximum (7.49 ± 1.22 vs. 6.92 ± 1.12, P < 0.0003) diameters. The degree of collapsibility was greater at 30 min than baseline (P < 0.0001). There was a significant decrease in heart rate (P < 0.0001), and the average recovery time was 39.86 ± 12.22 min.

Conclusion:

Even though airway patency was maintained in all children sedated with dexmedetomidine, there were significant reductions in the upper airway dimensions measured, so all precautions to manage the airway failure should be taken.

Dexmedetomidine for Sedation during Withdrawal of Support

Agents used to control end-of-life suffering are associated with troublesome side effects. The use of dexmedetomidine for sedation during withdrawal of support in pediatrics is not yet described. An adolescent female with progressive and irreversible pulmonary deterioration was admitted. Despite weeks of therapy, she did not tolerate weaning of supplemental oxygen or continuous bilevel positive airway pressure. Given her condition and the perception that she was suffering, the family requested withdrawal of support. Despite opioids and benzodiazepines, she appeared to be uncomfortable after support was withdrawn. Ketamine was initiated. Relief from ketamine was brief, and its use was associated with a "wide-eyed" look that was distressing to the family. Ketamine was discontinued and a dexmedetomidine infusion was initiated. The patient's level of comfort improved greatly. The child died peacefully 24 hours after initiating dexmedetomidine from her underlying disease rather than the effects of the sedative.