Effect of increasing depth of dexmedetomidine and propofol anesthesia on upper airway morphology in children and adolescents with obstructive sleep apnea

Pediatric Down Syndrome Upper Airway Stimulation: Patient Selection and Post-Implantation Optimization

OBJECTIVE

The Food and Drug Administration recently approved upper airway stimulation (UAS) for children with Down Syndrome and persistent obstructive sleep apnea who meet certain inclusion and exclusion criteria. Although there is a robust experience with this therapy in the adult population, established protocols used in adults are not directly transferrable to a complex pediatric population. This review aims to combine the protocols from several institutions for patient selection and postimplantation optimization, including a protocol for Drug-Induced Sleep Endoscopy in children with Down Syndrome, preactivation threshold measurements, device titration, and follow-up sleep studies.

STUDY DESIGN

Expert panel development of best Practice algorithm.

SETTING

Multi-institutional investigator review.

METHODS

An expert panel was assembled of pediatric otolaryngologists with extensive experience in hypoglossal nerve stimulation in children with Down Syndrome. Thirty statements were created during an initial drafting session. A modified Delphi method was used assess consensus among the panel.

RESULTS

After 2 rounds of Delphi surveys, 29 statements met criteria for consensus. One statement did not meet consensus. The statements were grouped into several categories to facilitate presentation.

CONCLUSIONS

A standardized approach to UAS for children with Down Syndrome must take into account the unique challenges inherent to treating a complex pediatric population with a high rate of sensory processing disorders. This expert panel has met consensus on several statements that will guide clinicians as this novel therapy is adopted.

Remimazolam for Pediatric Procedural Sedation: Results of an Institutional Pilot Program

Remimazolam, an ultra-short-acting benzodiazepine sedative, was first approved in 2020 in Japan as a general anesthetic for adults. However, its utilization in pediatric settings remains unexplored and, to date, is confined to isolated case reports due to a lack of specific pediatric labeling. The primary objective of our study was to evaluate the safety profile of remimazolam when used for procedural sedation in children following dosages established in adult protocols. Additional parameters, including dosage per kg of body weight, duration of the procedure, efficacy (measured as successful completion of the procedure), the necessity for supplemental medications, and changes in physiological parameters, such as the heart rate (HR) and mean arterial blood pressure (MAP), were assessed. Our study encompassed 48 children with an average age of 7.0 years. The objective Tracking and Reporting Outcomes of Procedural Sedation tool indicated no adverse events. In our cohort, propofol and ketamine were used as adjunctive treatments in 8 and 39 patients, respectively, with successful completion of all procedures. Notable hemodynamic variability was observed, with 88.4% of patients experiencing a ≥20% change (increase or decrease) and 62.8% experiencing a ≥30% change in MAP. Additionally, a ≥20% change in HR was observed in 54.3% of patients, and a ≥30% change was observed in 34.8% of patients. Nevertheless, none of the patients required pharmacological intervention to manage these hemodynamic fluctuations. Our findings suggest that remimazolam, when supplemented with propofol or ketamine, could offer a safe and effective pathway for administering procedural sedation in pediatric populations.

Procedural sedation in pediatric dentistry: a narrative review

Procedural sedation and analgesia are now considered standard care for managing pain and anxiety in pediatric dental patients undergoing diagnostic and therapeutic procedures outside of the operating room. Anxiolysis, which combines both pharmacologic and non-pharmacologic approaches, plays a significant role in procedural sedation. Non-pharmacologic interventions such as Behavior Management Technology can help reduce preprocedural agitation, ease the transition to sedation, reduce the required amount of medication for effective sedation, and decrease the occurrence of adverse events. As the introduction of novel sedative regimen and methods in pediatric dentistry, the potential role of mainstay sedatives administered by new routes, for new indications, and with new delivery techniques, should be considered. The purpose of this paper is to examine and discuss the current state of sedation techniques in pediatric dentistry.

What Is the Role of Dexmedetomidine in Modern Anesthesia and Critical Care?

Dexmedetomidine's unique sedative properties have led to its widespread use. Dexmedetomidine has a beneficial pharmacologic profile including analgesic sparing effects, anxiolysis, sympatholysis, organ-protective effects against ischemic and hypoxic injury, and sedation which parallels natural sleep. An understanding of predictable side effects, effects of age-related physiologic changes, and pharmacokinetic and pharmacodynamic effects of dexmedetomidine is crucial to maximize its safe administration in adults and children. This review focuses on the growing body of literature examining advances in applications of dexmedetomidine in children and adults.

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.

[Features of sleependoscopy in children]

OBJECTIVE

To describe the technique and determine the indications for sleep endoscopy in children.

MATERIAL AND METHODS

This study included 35 children, the average age of 5 years 1 month ± 3 years 4 months (from 1 year 6 months to 14 years 5 months). All children underwent standard polysomnography and sleep endoscopy.

RESULTS

According to polysomnography, severe obstructive sleep apnea (OSA) was diagnosed in 21 children, moderate - in 8 children and mild - in 6 children. Sleep endoscopy revealed that in most cases in unoperated children (about 70%), adenoids and palatine tonsils were the cause of obstruction. In the group of children, who previously underwent surgery for OSA, the causes of residual apnea more often were soft palate and palatine tonsils. In 5 of 8 children, tonsils pharyngoscopy size did not exceed the 1st degree. In 1 child after adenotonsillectomy, the hypertrophic tori tubarii were the cause of obstruction. Another rare cause of upper airway obstruction, lingual tonsil hypertrophy, was found in 2 primary patients.

CONCLUSION

Sleep endoscopy is a safe and useful method that makes it possible to determine the level of obstruction in children and to plan the optimal amount of surgical treatment.

Outcomes of dexmedetomidine sedation for drug-induced sleep ciné magnetic resonance imaging studies in pediatric obstructive sleep apnea patients

BACKGROUND

Dexmedetomidine is utilized as a sedative agent for drug-induced sleep cine magnetic resonance imaging studies due to its ability to mimic natural sleep and lack of respiratory depressant effects. The outcomes of dexmedetomidine sedation such as respiratory complications and unplanned admissions in obstructive sleep apnea patients undergoing these studies are currently unknown.

AIM

To describe the outcomes of dexmedetomidine sedation for outpatient drug-induced sleep magnetic resonance imaging in pediatric patients with obstructive sleep apnea.

METHODS

This is a retrospective chart review conducted in pediatric patients with obstructive sleep apnea undergoing outpatient drug-induced sleep ciné magnetic resonance imaging studies with dexmedetomidine sedation. Demographics, comorbidities, polysomnography study results, vital signs, respiratory complications, airway interventions, successful completion of the scan, and unplanned hospital admissions were measured.

MAIN RESULTS

We analyzed 337 patients aged 2-18 years (median age of 11 years). The imaging was completed with dexmedetomidine as the sole sedative agent in 61% (N = 207) patients. Ketamine was administered as additional sedative agent in 36% (N = 122) of the patients. There was no difference in sedation-related adverse events and respiratory complications with regard to the severity of sleep apnea with the exception of mild desaturation episodes (SpO2 85%-90%). Patients who received additional sedative agents had significantly longer recovery room stay (71.5 [44] vs 55 [39] minutes; 95% CI of difference [9 to 23 min], p < 0.001) and total periprocedural stay (164.5 [52] vs 138 [64] minutes; 95% CI of difference [17 to 35 min], p < .001).

CONCLUSIONS

Dexmedetomidine alone or along with ketamine provided acceptable sedation in majority of the patients with obstructive sleep apnea undergoing outpatient diagnostic sleep magnetic resonance imaging studies without significant respiratory adverse events regardless of the severity of sleep apnea. Sedation failure and unplanned admissions are rare, and routine planned admission may not be required for this patient population.

Comparative study of intranasal dexmedetomidine v/s midazolam for sedation of pediatric patients during transthoracic echocardiography

Background

Procedural sedation required to improve the quality of Transthoracic Echocardiography (TTE) in infants and children. The ideal drug and route for sedation in children should have a rapid and reliable onset, atraumatic, palatable with minimal side effects, and rapid recovery. So, the aim of our study to evaluate and compare the efficacy and safety of intranasal midazolam and intranasal dexmedetomidine in pediatric patients for sedation during TTE.

Materials and Method

Hundred children under three year of age, belonging to the American Society of Anaesthesiologists class-I and II, scheduled for TTE were divided into two groups by standard randomization technique. Patients in group-M received intranasal midazolam 0.2 mg/kg, whereas patients in group-D received intranasal dexmedetomidine 2 μg/kg prior to TTE under an adequately monitored anesthesia care. Onset and duration of sedation, heart rate, oxygen saturation, sonographer's, and parent's satisfaction scores were recorded.

Results

All patients were successfully sedated for TTE. The average onset time, sedation time, awakening time and total time for Group-M were 7.3, 18.8, 29.51, 51 min and group-D were 10.1, 14.2, 24.9, 46.3 min, respectively and all were statistically significant (P < 0.001). TTE scan time of Group-M is 8.84 min and Group-D is 9.18 min and was statistically significant. Sonographer's and Parent's average satisfaction score for Group-M was 9.88, 10 and for Group-D was 7.64, 8.76, respectively, which were statistically significant (P < 0.001).

Conclusion

Intranasal midazolam and dexmedetomidine are safe and effective for sedation in TTE. Intranasal midazolam was found to be comparatively more effective in view of onset of action, sonographers, and parental satisfaction score, while sedation time, awakening time and total duration was significantly higher as compared to intranasal dexmedetomidine.

Dexmedetomidine-induced polysomnography as a diagnostic method in obstructive sleep apnea: a reliable alternative method?

BACKGROUND

Under-diagnosis of obstructive sleep apnea (OSA) is common because of the demanding and time-consuming nature of polysomnography (PSG). Herein, we assessed the utility of a short daytime dexmedetomidine-induced PSG for diagnosis of OSA in adults.

METHODS

This was a single-center, prospective, diagnostic trial. We evaluated 86 patients using a full overnight PSG and a short diurnal drug-induced PSG (DIPSG). DIPSG was induced by continuous intravenous dexmedetomidine infusion. Sedation depth was monitored and maintained using the Narcotrend index (50-70). Diagnostic performance for DIPSG with different apnea-hypopnea index (AHI) cut-off values were calculated. Bland-Altman plots used for analysis. Sleep architecture and position were compared.

RESULTS

We studied 47 OSA patients and 39 healthy volunteers. Sensitivity and specificity for detection of OSA by DIPSG were 92% and 79%, respectively, for an AHI cut-off value of 5, 90% and 77%, respectively, for an AHI cut-off value of 15, and 95% and 85%, respectively, for an AHI cut-off value of 30. The DIPSG bias was -5 (-25; 15) for AHI and -3 (-13; 7) for minimal oxygen saturation. N2 sleep was increased (32.9% vs. 50.75%, respectively; p < 0.01) and REM sleep was decreased (21.35% vs. 1.24%, respectively; p < 0.01) during DIPSG. Twenty-eight (33%) participants had postural shifts during DIPSG. No significant adverse events were observed during DIPSG.

CONCLUSIONS

Dexmedetomidine-induced PSG had a good sensitivity and specificity, and can be used as a screening tool for diagnosis of OSA in adults.

CHINESE CLINICAL TRIAL REGISTRATION

ChiCTR1900024044.

Expert Consensus Statement: Pediatric Drug-Induced Sleep Endoscopy

OBJECTIVE

To develop an expert consensus statement on pediatric drug-induced sleep endoscopy (DISE) that clarifies controversies and offers opportunities for quality improvement. Pediatric DISE was defined as flexible endoscopy to examine the upper airway of a child with obstructive sleep apnea who is sedated and asleep.

METHODS

Development group members with expertise in pediatric DISE followed established guidelines for developing consensus statements. A search strategist systematically reviewed the literature, and the best available evidence was used to compose consensus statements regarding DISE in children 0 to 18 years old. Topics with significant practice variation and those that would improve the quality of patient care were prioritized.

RESULTS

The development group identified 59 candidate consensus statements, based on 50 initial proposed topics, that focused on addressing the following high-yield topics: (1) indications and utility, (2) protocol, (3) optimal sedation, (4) grading and interpretation, (5) complications and safety, and (6) outcomes for DISE-directed surgery. After 2 iterations of the Delphi survey and removal of duplicative statements, 26 statements met the criteria for consensus; 11 statements were designated as no consensus. Several areas, such as the role of DISE at the time of adenotonsillectomy, were identified as needing further research.

CONCLUSION

Expert consensus was achieved for 26 statements pertaining to indications, protocol, and outcomes for pediatric DISE. Clinicians can use these statements to improve quality of care, inform policy and protocols, and identify areas of uncertainty. Future research, ideally randomized controlled trials, is warranted to address additional controversies related to 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.

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.

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

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

Drug-Induced Sleep Endoscopy in Pediatric Obstructive Sleep Apnea

OBJECTIVE

To describe drug-induced sleep endoscopy (DISE) findings in children with obstructive sleep apnea and to differentiate them between surgically naïve children and children who had adenotonsillectomy performed.

STUDY DESIGN

Retrospective case series with chart review.

SETTING

Secondary care hospital.

SUBJECTS AND METHODS

A cohort of 56 children with the diagnosis of obstructive sleep apnea was submitted to DISE and subsequent upper airway surgery: 23 were surgically naïve, and 33 had persistent obstructive sleep apnea after adenotonsillectomy. Comparisons between groups were calculated with chi-square test and Student's t test. Simple linear regression was used to model polysomnographic indices.

RESULTS

In surgically naïve children, the most common sites of obstruction were the adenoids (78.2%) and the lateral pharyngeal walls/tonsils (82.6%). In children with persistent obstructive sleep apnea after adenotonsillectomy, the most common sites of obstruction were the adenoids (54.5%), followed by the supraglottis (48.5%) and the tongue base (45.5%). No correlation was found between obstructive apnea-hypopnea index and DISE findings. Simple linear regression revealed that the degree of obstruction at the tongue base (β = -0.73; 95% CI, -1.22 to -0.25; P = .004) and the presence of multilevel obstruction (β = -1.75; 95% CI, -3.20 to -0.30; P = .02) predicted saturation nadir in children with persistent obstructive sleep apnea after adenotonsillectomy.

CONCLUSION

DISE findings differed between surgically naïve children and children with persistent obstructive sleep apnea after adenotonsillectomy. Increased obstruction at the level of the tongue base and the presence of multilevel obstruction predicted a lower saturation nadir in children with persistent obstructive sleep apnea after adenotonsillectomy.

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.

Results from the Adverse Event Sedation Reporting Tool: A Global Anthology of 7952 Records Derived from >160,000 Procedural Sedation Encounters

Background: The incidence of sedation-related adverse events, inclusive of both adults and children, administered by multiple specialty providers from different countries and venues, using standardized definitions, has never been reported on an international level. We are reporting the outcome data of the adverse event sedation reporting tool as an important step toward a more complete risk assessment of sedation-related morbidity, mortality, and etiology. The analysis of the AE sedation reporting data include descriptive measures to evaluate the characteristics of the provider, the patient, sedations performed, adverse events, interventions, and outcomes. The primary outcome was the rate and nature of adverse events. Between 12/14/2010 and 12/11/2018 there were 7952 sedations, from an estimated total of 164,114 sedations administered, of which 622 were reported as adverse events. The mean age of the entire patient population is 33.0 years (0.02–98.7). The providers represented 39 countries across six continents. Oxygen desaturation (75%–90%) for <60 s is the most prevalent adverse event with a rate of 7.8 per 10,000, followed by airway obstruction at a rate of 5.42 per 10,000. Apnea occurred at a rate of 4.75 per 10,000. Significant predictors of adverse events are ≥ ASA score III (p = 0.0003), procedure time (6:00 pm–12:00 am: p < 0.0001, 12:00–6:00 am: p = 0.0003), and non-hospital location (p < 0.0001). The AE sedation reporting tool has demonstrated that the majority of adverse events in children and adults who receive procedural sedation from multi-specialists internationally required minor interventions and had outcomes of minor risk.

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.

The Effect of Sedating Agents on Drug-Induced Sleep Endoscopy Findings

OBJECTIVE

Drug-induced sleep endoscopy (DISE) has gained interest for upper airway evaluation in patients with snoring and obstructive sleep apnea (OSA), and different drugs have been used to induce sedation. Nevertheless, all drugs have presented specific advantages and disadvantages with differential effects on respiratory physiology. This study evaluated and compared the effects of midazolam, propofol and dexmedetomidine on DISE findings, O₂ nadir, and bispectral index (BIS) in the same sample of patients.

STUDY DESIGN

Case series prospective study.

METHODS

Consecutive patients who elected to undergo surgery for OSA treatment and were intolerant to conservative therapies underwent DISE with propofol, dexmedetomidine, and midazolam between July 2015 and July 2016.

RESULTS

Fifty-two patients were analyzed, and 43 (82.7%) were men. Agreement among drugs for both degree and patterns of obstruction was excellent at all sites (velum, oropharynx, and epiglottis) except for the tongue base. Dexmedetomidine had the least complete collapse sites and highest O₂ nadir and was the only drug for which apnea severity and obstruction levels (upper, lower, or combined) were correlated. The variability among drug treatments for the BIS index was considerable, and propofol had the lowest variability and average value.

CONCLUSION

Drug selection had a relevant influence in DISE findings. Compared with dexmedetomidine, midazolam and propofol presented higher incidence of tongue base collapse, lower O₂ levels, and lower BIS index values. Propofol resulted in an O₂ nadir that most resembled that observed during polysomnography. The BIS index variability differed among drugs, and its use was considered relevant for sedation orientation.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:506-513, 2019.

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 inhibits inflammatory reaction in the hippocampus of septic rats by suppressing NF-κB pathway

Dexmedetomidine (DEX) is known to provide neuroprotective effect in the central nervous system. However, the detailed mechanism remains far more elusive. This study was designed to investigate the relevant mechanisms of DEX's neuroprotective effect. Sprague-Dawley (SD) rats were injected with dexmedetomidine and/or Lipopolysaccharide (LPS) intraperitoneally, and inflammatory cytokines in serum and in the hippocampus were measured by enzyme linked immunosorbent assay (ELISA). NF-κB in the brain tissue extracts was analyzed with western-blot. Then, we investigated whether NF-κB inhibitor prevents the elevation of inflammatory cytokines in rats injected with LPS. Our results indicated that compared with the control group, the rats exposed to LPS showed significant cognitive dysfunction. When compared to controls, the levels of TNF-α and IL-6 in the serum and hippocampus homogenate were increased in rats treated with LPS. DEX pretreatment inhibited the rats' TNF-α, IL-6 and NF-κB levels induced by LPS. In response to LPS, PDTC pretreatment restrains the production of proinflammatory cytokines (TNF-α and IL-6). Rats treated with PDTC and DEX alongside LPS exhibited less TNF-α and IL-6 than the LPS treated group. In combination, PDTC and DEX showed addictive effects. Our data suggest that DEX exerts a neuroprotective effect through NF-κB in part after LPS-induced cognitive dysfunction.

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.

Dexmedetomidine for Sedation During Noninvasive Ventilation in Pediatric Patients

OBJECTIVES

To describe the use of dexmedetomidine for sedation in a large cohort of nonintubated children with acute respiratory insufficiency receiving noninvasive ventilatory support.

DESIGN

Single-center, retrospective, observational cohort study.

SETTING

A large quaternary-care PICU.

PATIENTS

The study cohort included 202 children receiving noninvasive ventilatory and a dexmedetomidine infusion within 48 hours of PICU admission over a 6-month period.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary respiratory diagnoses in the cohort (median age, 2 yr) included status asthmaticus (60%) and bronchiolitis (29%). Dexmedetomidine was infused for a median of 35 hours with a median hourly dose across the patient cohort of 0.61 μg/kg/hr (range, 0.4-0.8 μg/kg/hr). The target sedation level was achieved in 168 patients (83%) in the cohort for greater than or equal to 80% of the recorded values over the entire noninvasive ventilatory course, with dexmedetomidine as the only continuously administered sedative agent. While vital signs were frequently abnormal relative to age-based norms, clinical interventions were needed rarely to treat bradycardia (13%), hypotension (20%), and hypopnea (5%). The most frequently used of these interventions was a dexmedetomidine dose reduction, fluid bolus, and titration of noninvasive ventilatory support. Five patients (2.5%) required endotracheal intubation: three due to progression of their respiratory illness, one with septic shock, and one with apnea requiring resuscitation. In 194 of 202 patients (96%), the outcome of the noninvasive ventilatory course was successful with the patient being weaned from noninvasive respiratory support to nasal cannula or room air.

CONCLUSIONS

Dexmedetomidine was often effective as a single continuous sedative infusion during pediatric noninvasive ventilatory. Cardiorespiratory events associated with its use were typically mild and/or reversible with dose reduction, fluid administration, and/or noninvasive ventilatory titration. Prospective studies comparing dexmedetomidine with other agents in this setting are warranted.

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.

General anesthesia with a native airway for patients with mucopolysaccharidosis type III

BACKGROUND

Mucopolysaccharidosis type III is a progressive disease with worsening airway, pulmonary, and cardiac involvement that may complicate anesthetic care.

AIM

To prospectively evaluate the incidence of airway issues and complications during magnetic resonance imaging (MRI) and lumbar puncture (LP) during general anesthesia with a native airway for patients with mucopolysaccharidosis type III.

METHOD

The study was a part of the natural history study. Anesthesia was induced with sevoflurane, which was discontinued after intravenous access was obtained. General anesthesia with a native airway was provided by dexmedetomidine and propofol. Dexmedetomidine (0.5 μg·kg^-1 ) was administered over 5 min followed by a continuous infusion at 0.5 μg·kg^-1 ·h^-1 . A continuous infusion of propofol was started at 150 μg·kg^-1 ·min^-1 . A bolus dose of propofol (1 mg·kg^-1 ) was administered and the propofol infusion was increased as needed. Airway management and vital signs were recorded for the entire procedure until discharge.

RESULTS

Twenty-five patients (6.9 ± 3.1 years) received total of 43 MRI and LP procedures in the cohort. No patient failed sedation. Although mask induction with sevoflurane was not clinically problematic, upper airway obstruction was noted during 14 procedures (33%). This required the application of continuous positive airway pressure, temporary oral airway placement, jaw thrust, or shoulder roll. Airway dynamics improved once the anesthesia was transitioned to intravenous anesthetic agents. Although a small shoulder roll was needed to improve airway patency for 11 cases (26%), a large shoulder roll tended to make the upper airway obstruction worse. Oxygen desaturation (≤90%) was noted during MRI in three cases (7%).

CONCLUSION

A combination of dexmedetomidine and propofol provided effective general anesthesia with a native airway during the procedures. Although upper airway obstruction was noted, it resolved with simple airway maneuvers without further airway intervention.

Dexmedetomidine versus propofol during drug-induced sleep endoscopy and sedation: a systematic review

BACKGROUND

The purpose of the present study is to review the international literature, using a systematic review, for studies comparing propofol and dexmedetomidine for drug-induced sleep endoscopy (DISE) or sedation in which there is a description of the effect of the agents on the upper airway and associated variables (e.g., vital signs, sedation scores).

METHODS

This is a systematic review through October 4, 2016. PubMed/MEDLINE and four additional databases were accessed for this study.

RESULTS

Two hundred twenty studies were screened, 79 were downloaded, and 10 met criteria. The majority of the studies identified dexmedetomidine as the preferred pharmacologic agent for DISE due to an overall safer and more stable profile based upon hemodynamic stability. However, propofol provided greater airway obstruction with oxygen desaturations. With either agent, the degree of obstruction in the upper airway lacks some degree of validity as to whether the obstructions accurately represent natural sleep or are simply a drug-induced effect.

CONCLUSION

Dexmedetomidine and propofol have their advantages and disadvantages during DISE. Generally, dexmedetomidine was preferred and seemed to provide a more stable profile based upon cardiopulmonary status. However, propofol has a quicker onset, has a shorter half-life, and can demonstrate larger degrees of obstruction, which might more accurately reflect what happens during REM sleep. Additional research is recommended.

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.

Drug-induced sedation endoscopy in surgically naive children with Down syndrome and obstructive sleep apnea

OBJECTIVE

To describe the pattern of upper airway (UA) obstruction in surgically naive children with Down syndrome and obstructive sleep apnea (OSA), and to evaluate the outcome of drug-induced sedation endoscopy (DISE)-directed treatment.

METHODS

A prospective study of DISE in surgically naive children with Down syndrome and OSA was performed. Treatment was individually tailored based on the DISE findings and was evaluated by control polysomnography (PGS). Results are presented as median (lower-upper quartile) unless otherwise stated.

RESULTS

In 41 children, aged 4.2 years (range, 2.8-6.0) with a body mass z score of 1.04 (-0.55 to 1.82) and obstructive apnea-hypopnea index (oAHI) of 10.1/h (range, 6.3-23.0), DISE was performed. Adeno-/tonsillar obstruction was found in 75.6% of the patients, and these patients subsequently underwent UA surgery. Seven patients were non-surgically treated, and three received a combined treatment. A multilevel collapse was present in 85.4%. Tongue base obstruction was present in ten patients (24.4%) and epiglottic collapse in 48.8%. Pre- and postoperative PSG data were available for 25 children (adenotonsillectomy, n = 16; tonsillectomy, n = 7; adenoidectomy, n = 2). A significant improvement in oAHI from 11.4/h (range, 7.7-27.0) to 5.5/h (range, 2.1-7.6) was found. Persistent OSA was present in 52% of the children. No significant association between different DISE findings and persistent OSA could be found.

CONCLUSION

Most patients with Down syndrome and OSA present with multilevel collapse on DISE. Adenotonsillectomy results in a significant improvement of the oAHI; however more than half of the patients had persistent OSA, probably due to multilevel collapse. Upper airway evaluation may provide more insights into the pattern of UA obstruction in patients with persistent OSA.

Multimodality assessment of upper airway obstruction in children with persistent obstructive sleep apnea after adenotonsillectomy

OBJECTIVES/HYPOTHESIS

Children with obstructive sleep apnea (OSA) may have multiple sites of upper airway obstruction (UAO). A wide variety of techniques has been used to evaluate UAO. Our aim was to compare findings of cine magnetic resonance imaging (MRI) and drug-induced sleep endoscopy (DISE) in identifying UAO sites in children with persistent OSA after adenotonsillectomy (AT).

STUDY DESIGN

Retrospective chart review.

MATERIAL AND METHODS

The medical records of children who underwent DISE and cine MRI were reviewed. Data pertaining to demographics, past medical history, body mass index, polysomnography, findings of DISE, and cine MRI were obtained.

RESULTS

Fifteen children (11 boys, 4 girls; age range, 7-18 years) were identified. Comorbid conditions were Down syndrome in nine patients, cerebral palsy in one, attention deficit hyperactivity disorder in two, and asthma in three. Severity of OSA was moderate in five, and severe in 10. DISE and cine MRI showed the same UAO site in 10 patients: a single site (tongue) in nine and multiple sites (tongue and oropharynx/lateral walls) in one. DISE showed additional UAO sites undetected by cine MRI in three patients. Cine MRI showed additional UAO sites undetected by DISE in one patient. DISE and cine MRI showed different sites of obstruction in one patient.

CONCLUSIONS

Cine MRI and DISE documented single and multiple sites of UAO in children with persistent OSA after AT. Cine MRI and DISE findings were similar in the majority of the children. Assessment of the sensitivity and specificity of cine MRI and DISE in detecting sites of UAO merits further investigation.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:1224-1230, 2017.

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.

Comparison of dexmedetomidine and chloral hydrate sedation for transthoracic echocardiography in infants and toddlers: a randomized clinical trial

BACKGROUND

Procedural sedation using chloral hydrate is used in many institutions to improve the quality of transthoracic echocardiograms (TTE) in infants and young children. Chloral hydrate has limited availability in some countries, creating the need for alternative effective sedatives.

OBJECTIVE

The aim of our study was to compare the effectiveness of two doses of intranasal dexmedetomidine vs oral chloral hydrate sedation for transthoracic echocardiography.

METHODS

This is a randomized, prospective study of 150 children under the age of 3 years with known or suspected congenital heart disease scheduled for transthoracic echocardiography with sedation. Group CH received oral chloral hydrate 70 mg · kg(-1), group DEX2 received 2 μg · kg(-1) intranasal dexmedetomidine, and group DEX3 received 3 μg · kg(-1) intranasal dexmedetomidine. Acceptance of drug administration, sedation onset and duration, heart rate, and oxygen saturation, sonographer and parent satisfaction were recorded.

RESULTS

All patients were successfully sedated for TTE. A second sedative dose (rescue) for failed single-dose sedation was required for 4% of patients after CH, none of the patients after DEX2, and 4% of patients after DEX3. Patients in group CH had an average heart rate decline of 22% during sedation, while group DEX2 decreased 27%, and group DEX3 23% (P = 0.2180). Mean time from administration of the sedative to final patient discharge was 96 min after CH, 83 min after DEX2, and 94 min after DEX3 (P = 0.1826).

CONCLUSION

Intranasal dexmedetomidine 2 and 3 μg · kg(-1) were found to be as effective for TTE sedation as oral chloral hydrate with similar sedation onset and recovery time and heart rate changes in this study population.

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.

A comparison of dexmedetomidine versus propofol during drug-induced sleep endoscopy in sleep apnea patients

OBJECTIVES/HYPOTHESIS

In this study, we compared the effects of propofol and dexmedetomidine on the upper airway collapse pattern and cardiopulmonary parameters of patients with obstructive sleep apnea (OSA) undergoing drug-induced sleep endoscopy (DISE).

STUDY DESIGN

Prospective, single center, observational study

MATERIALS AND METHODS

The 50 patients with OSA underwent 30 minutes of DISE on 2 different days, the first time with propofol target-controlled infusion (TCI) and the second time with dexmedetomidine TCI. Both the characteristics of upper airway obstruction and cardiopulmonary parameters in response to the depth of sedation achieved with each drug were evaluated.

RESULTS

The results obtained with propofol and dexmedetomidine DISE were in excellent agreement for all sites of obstruction irrespective of the depth of sedation. Although partial or total obstruction at all areas was consistently observed using both drugs, the degree of upper airway narrowing was slightly lower with dexmedetomidine than with propofol. However, the percentage of patients with a greater than 20% change in blood pressure and heart rate compared to baseline was significantly higher in response to propofol than to dexmedetomidine (P = 0.003 and P < 0.001, respectively). Minimal oxygen saturation was significantly lower in DISE with propofol than with dexmedetomidine (P = 0.004). The percentage of patients with oxygen saturation less than 90% or 80% during DISE was significantly higher in response to propofol than to dexmedetomidine (P = 0.032 and P < 0.001, respectively).

CONCLUSION

The DISE findings achieved with propofol and dexmedetomidine were in excellent agreement. However, during DISE, dexmedetomidine provided greater hemodynamic stability and less respiratory depression than propofol.

LEVEL OF EVIDENCE

4. Laryngoscope, 126:763-767, 2016.

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.

Upper Airway Elasticity Estimation in Pediatric Down Syndrome Sleep Apnea Patients Using Collapsible Tube Theory

Elasticity of the soft tissues surrounding the upper airway lumen is one of the important factors contributing to upper airway disorders such as snoring and obstructive sleep apnea. The objective of this study is to calculate patient specific elasticity of the pharynx from magnetic resonance (MR) images using a 'tube law', i.e., the relationship between airway cross-sectional area and transmural pressure difference. MR imaging was performed under anesthesia in children with Down syndrome (DS) and obstructive sleep apnea (OSA). An airway segmentation algorithm was employed to evaluate changes in airway cross-sectional area dilated by continuous positive airway pressure (CPAP). A pressure-area relation was used to make localized estimates of airway wall stiffness for each patient. Optimized values of patient specific Young's modulus for tissue in the velopharynx and oropharynx, were estimated from finite element simulations of airway collapse. Patient specific deformation of the airway wall under CPAP was found to exhibit either a non-linear 'hardening' or 'softening' behavior. The localized airway and tissue elasticity were found to increase with increasing severity of OSA. Elasticity based patient phenotyping can potentially assist clinicians in decision making on CPAP and airway or tissue elasticity can supplement well-known clinical measures of OSA severity.

Anaesthesia for the paediatric outpatient

PURPOSE OF REVIEW

The aim of this review was to discuss recent developments in paediatric anaesthesia, which are particularly relevant to the practitioner involved in paediatric outpatient anaesthesia.

RECENT FINDINGS

The use of a pharmacological premedication is still a matter of debate. Several publications are focussing on nasal dexmedetomidine; however, its exact place has not yet been defined. Both inhalational and intravenous anaesthesia techniques still have their advocates; for diagnostic imaging, however, propofol is emerging as the agent of choice. The disappearance of codeine has left a breach for an oral opioid and has probably worsened postoperative analgesia following tonsillectomy. In recent years, a large body of evidence for the prevention of postoperative agitation has appeared. Alpha-2-agonists as well as the transition to propofol play an important role. There is now some consensus that for reasons of practicability prophylactic antiemetics should be administered to all and not only to selected high-risk patients.

SUMMARY

Perfect organization of the whole process is a prerequisite for successful paediatric outpatient anaesthesia. In addition, the skilled practitioner is able to provide a smooth anaesthetic, minimizing complications, and, finally, he has a clear concept for avoiding postoperative pain, agitation and vomiting.

Compliance Measurements of the Upper Airway in Pediatric Down Syndrome Sleep Apnea Patients

Compliance of soft tissue and muscle supporting the upper airway are two of several factors contributing to pharyngeal airway collapse. We present a novel, minimally invasive method of estimating regional variations in pharyngeal elasticity. Magnetic resonance images for pediatric sleep apnea patients with Down syndrome [9.5 ± 4.3 years (mean age ± standard deviation)] were analyzed to segment airways corresponding to baseline (no mask pressure) and two positive pressures. A three dimensional map was created to evaluate axial and circumferential variation in radial displacements of the airway, dilated by the positive pressures. The displacements were then normalized with respect to the appropriate transmural pressure and radius of an equivalent circle to obtain a measure of airway compliance. The resulting elasticity maps indicated the least and most compliant regions of the pharynx. Airway stiffness of the most compliant region [403 ± 204 (mean ± standard deviation) Pa] decreased with severity of obstructive sleep apnea. The non-linear response of the airway wall to continuous positive airway pressure was patient specific and varied between anatomical locations. We identified two distinct elasticity phenotypes. Patient phenotyping based on airway elasticity can potentially assist clinical practitioners in decision making on the treatments needed to improve airway patency.