Moderate sedation for MRI in young children with autism

Effectiveness of pharmacological procedural sedation in children with autism spectrum disorder: A systematic review and meta-analysis

AIM

Management of primary healthcare and routine minor procedures for children with autism spectrum disorder (ASD) can be challenging; therefore, when behavioural strategies fail, sedative medications are often employed. We evaluated the effectiveness of the current pharmacological strategies for managing children with ASD.

METHODS

We performed a systematic review and meta-analysis of the current approaches for procedural sedation in children with ASD.

RESULTS

Twenty studies met inclusion criteria. Dexmedetomidine, midazolam, propofol and chloral hydrate were the most efficient agents for successful procedures, while propofol had the highest number of adverse events. The most frequently used agents were dexmedetomidine and midazolam or a combination of the two, and the effectiveness of dexmedetomidine plus midazolam was superior to dexmedetomidine alone.

CONCLUSION

Multiple effective drug regimens exist for procedural sedation in children with ASD. These results could support the development of specific guidelines for procedural sedation in children with ASD.

Medical Management of Children With Autism in the Emergency Department

ABSTRACT

Autism spectrum disorder (ASD) is an increasingly prevalent diagnosis characterized by impairment of social communication and behavioral regulation. Children with ASD seek care more frequently in the emergency department (ED) than their neurotypical peers and the approach to medical evaluation of this population requires heightened attention to a variety of factors. Communication with caregivers, attention to environmental stimulation, identification of accommodation needs, and understanding frequently associated medical conditions are important considerations in ED encounters. Gastrointestinal problems, seizure disorders, and metabolic disease are common causes for ED presentation in children with ASD. A high index of suspicion for underlying medical issues must be maintained, even when children with ASD present primarily for behavioral concerns. Autism spectrum disorder (ASD) is an increasingly prevalent diagnosis characterized by impairment of social communication and behavioral regulation. Children with ASD seek care more frequently in the emergency department (ED) than their neurotypical peers and the approach to medical evaluation of this population requires heightened attention to a variety of factors. Communication with caregivers, attention to environmental stimulation, identification of accommodation needs, and understanding frequently associated medical conditions are important considerations in ED encounters. Gastrointestinal problems, seizure disorders, and metabolic disease are common causes for ED presentation in children with ASD. A high index of suspicion for underlying medical issues must be maintained, even when children with ASD present primarily for behavioral concerns.

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

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

Is there any relationship between autism and pineal gland volume?

Purpose

Abnormalities in melatonin physiology and circadian rhythm are detected in patients with autism. Melatonin is produced predominantly in the pineal gland and the amount of melatonin released is proportional to the pineal gland volume. This study aimed to examine whether the pineal gland volume in children with autism is different from that in healthy children.

Material and methods

Brain magnetic resonance images (MRI) of 120 paediatric patients with autism and 82 control paediatric subjects were examined; pineal parenchymal volume (PPV), pineal cyst rate (PCR), and total pineal gland volume (TPGV) were measured using a multimodality viewer (MMV), but only the TPGVs were measured using a tumour tracking (TT) method. Measurements were taken by 2 separate radiologists.

Results

In patients with autism, the PPV and TPGV according to MMV, and the TPGV according to TT were significantly lower, and the PCR was significantly higher. Moreover, the ratio of PPV to TPGV was significantly lower in the autism patient group. In both groups, the TPGVs were significantly lower in the autism patient group than the controls among all age groups.

Conclusions

Our study was the first to examine TPGVs in detail in paediatric patients with autism using 2 different methods. Low PPV-TPGV and high PCR have been observed in autism. This study also provides comparable reference values for pineal gland size in healthy children or autistic children aged 2-17 years. These results show promising potential for further research to understand the relationship between autism pathogenesis and the pineal gland.

Low-motion fMRI data can be obtained in pediatric participants undergoing a 60-minute scan protocol

Performing functional magnetic resonance imaging (fMRI) scans of children can be a difficult task, as participants tend to move while being scanned. Head motion represents a significant confound in fMRI connectivity analyses. One approach to limit motion has been to use shorter MRI protocols, though this reduces the reliability of results. Hence, there is a need to implement methods to achieve high-quality, low-motion data while not sacrificing data quantity. Here we show that by using a mock scan protocol prior to a scan, in conjunction with other in-scan steps (weighted blanket and incentive system), it is possible to achieve low-motion fMRI data in pediatric participants (age range: 7-17 years old) undergoing a 60 min MRI session. We also observe that motion is low during the MRI protocol in a separate replication group of participants, including some with autism spectrum disorder. Collectively, the results indicate it is possible to conduct long scan protocols in difficult-to-scan populations and still achieve high-quality data, thus potentially allowing more reliable fMRI findings.

Drug selection for sedation and general anesthesia in children undergoing ambulatory magnetic resonance imaging

The demand for drug-induced sedation for magnetic resonance imaging (MRI) scans have substantially increased in response to increases in MRI utilization and growing interest in anxiety in children. Understanding the pharmacologic options for deep sedation and general anesthesia in an MRI environment is essential to achieve immobility for the successful completion of the procedure and ensure rapid and safe discharge of children undergoing ambulatory MRI. For painless diagnostic MRI, a single sedative/anesthetic agent without analgesia is safer than a combination of multiple sedatives. The traditional drugs, such as chloral hydrate, pentobarbital, midazolam, and ketamine, are still used due to the ease of administration despite low sedation success rate, prolonged recovery, and significant adverse events. Currently, dexmedetomidine, with respiratory drive preservation, and propofol, with high effectiveness and rapid recovery, are preferred for children undergoing ambulatory MRI. General anesthesia using propofol or sevoflurane can also provide predictable rapid time to readiness and scan times in infant or children with comorbidities. The selection of appropriate drugs as well as sufficient monitoring equipment are vital for effective and safe sedation and anesthesia for ambulatory pediatric MRI.

A Comparison of Intranasal Dexmedetomidine and Dexmedetomidine Plus Buccal Midazolam for Non-painful Procedural Sedation in Children with Autism

Children with autism often need sedation for diagnostic procedures and they are often difficult to sedate. This prospective randomized double-blind control trial evaluates the efficacy and safety using intranasal dexmedetomidine with and without buccal midazolam for sedation in children with autism undergoing computerized tomography and/or auditory brainstem response test. The primary outcome is the proportion of children attaining satisfactory sedation. One hundred and thirty-six children received intranasal dexmedetomidine and 139 received intranasal dexmedetomidine with buccal midazolam for sedation. Combination of intranasal dexmedetomidine and buccal midazolam was associated with higher sedation success when compared to intranasal dexmedetomidine. Since intranasal and buccal sedatives required little cooperation this could be especially useful technique for children with autism or other behavioral conditions.

Procedural sedation in children with autism spectrum disorders in the emergency department

BACKGROUND AND OBJECTIVES

Children with autism spectrum disorder (ASD) present more frequently to the emergency department (ED) than children with normal development, and frequently have injuries requiring procedural sedation. Our objective was to describe sedation practice and outcomes in children with ASD in the ED.

METHODS

We performed a retrospective chart review of children with ASD who underwent sedation at two tertiary care EDs between January 2009-December 2016. Data were collected on children 1-18 years of age with ASD who were sedated in the ED.

RESULTS

There were 6020 ED visits by children with ASD, 126 (2.1%) of whom received sedation. The most frequent indications for sedation were laceration repair (24.6%), incision and drainage (17.5%), diagnostic imaging (14.3%), and physical examination (11.9%). The most common sedatives used were ketamine (50.8%) and midazolam (50.8%). Ketamine was most commonly given intravenously (71.9%), while midazolam was usually given intranasally (71.9%). Procedures could not be completed in 4 (3.2%) patients, and adverse events were noted in 23 (18.3%) patients. Only four (3.2%) patients required supplemental oxygenation, and one received positive pressure ventilation.

CONCLUSIONS

Children with autism in the ED commonly received sedation; one in four of which were for non-painful diagnostic procedures or physical examination. Over one-third received sedation via a non-parenteral route for intended minimal sedation. Sedative medication dosing and observed adverse events were similar to those reported previously in children without ASD. Emergency providers must be prepared to meet the unique sedation needs of children with ASD.

Methods for acquiring MRI data in children with autism spectrum disorder and intellectual impairment without the use of sedation

BACKGROUND

Magnetic resonance imaging (MRI) has been widely used in studies evaluating the neuropathology of autism spectrum disorder (ASD). Studies are often limited, however, to higher functioning individuals with ASD. MRI studies of individuals with ASD and comorbid intellectual disability (ID) are lacking, due in part to the challenges of acquiring images without the use of sedation.

METHODS

Utilizing principles of applied behavior analysis (ABA), we developed a protocol for acquiring structural MRI scans in school-aged children with ASD and intellectual impairment. Board certified behavior analysts worked closely with each child and their parent(s), utilizing behavior change techniques such as pairing, shaping, desensitization, and positive reinforcement, through a series of mock scanner visits to prepare the child for the MRI scan. An objective, quantitative assessment of motion artifact in T1- and diffusion-weighted scans was implemented to ensure that high-quality images were acquired.

RESULTS

The sample consisted of 17 children with ASD who are participants in the UC Davis Autism Phenome Project, a longitudinal MRI study aimed at evaluating brain developmental trajectories from early to middle childhood. At the time of their initial scan (2-3.5 years), all 17 children had a diagnosis of ASD and development quotient (DQ) <70. At the time of the current scan (9-13 years), 13 participants continued to have IQs in the range of ID (mean IQ = 54.1, sd = 12.1), and four participants had IQs in the normal range (mean = 102.2, sd = 7.5). The success rate in acquiring T1-weighted images that met quality assurance for acceptable motion artifact was 100 %. The success rate for acquiring high-quality diffusion-weighted images was 94 %.

CONCLUSIONS

By using principles of ABA in a research MRI setting, it is feasible to acquire high-quality images in school-aged children with ASD and intellectual impairment without the use of sedation. This is especially critical to ensure that ongoing longitudinal studies of brain development can extend from infancy and early childhood into middle childhood in children with ASD at all levels of functioning, including those with comorbid ID.

Autism spectrum disorder (ASD) and its perioperative management

Autism spectrum disorder (ASD) is now diagnosed in more than 1 in 100 children, so it is not surprising that anesthetists are increasingly providing care for children with this diagnosis. The diagnostic classification for ASD has recently changed and our understanding of the causes and management of ASD are also changing rapidly. This review provides a timely update to increase understanding and awareness of the problems that children with ASD experience, and to minimize perioperative problems. Current literature on premedication and the increasing use of alpha-2 agonists such as clonidine and dexmedetomidine as well as the use of old favorites midazolam and ketamine is reviewed. Some simple strategies that will improve care and decrease anxiety, like social stories, the use of tablet computers, other comfort items or games for distraction, and using favorite drinks to disguise the bitter taste of medications, are described. Remember, the parents are their child's expert and will know what agitates and settles them. Talking to them prior to the day of the procedure is ideal. The importance of staff training and having a clinical practice guideline available at every institution cannot be overstated.

Management of Autism in the Adult Intensive Care Unit

Autism comprises a growing segment of the population and can be a management challenge in the intensive care unit (ICU). We present the case of a 22-year-old male with severe autism and intellectual disorder who developed respiratory failure and required a prolonged ICU course. This patient exhibited severe distress, aggression, and self-injurious behavior. Management challenges included sedation, weaning from sedation, and liberation from mechanical ventilation. Success was achieved with a multispecialty team and by tailoring the environment and interactions to the patient’s known preferences. The use of dexmedetomidine to wean high-dose benzodiazepines and opiates also permitted successful liberation from mechanical ventilation.

Brief report: approaches to 31P-MRS in awake, non-sedated children with and without autism spectrum disorder

We piloted a suite of approaches aimed to facilitate a successful series of up to four brain and muscle (31)Phosphorus-Magnetic Resonance Spectroscopy ((31)P-MRS) scans performed in one session in 12 awake, non-sedated subjects (ages 6-18), 6 with autism spectrum disorders (ASD) and 6 controls. We targeted advanced preparation, parental input, physical comfort, short scan protocols, allocation of extra time, and subject emotional support. 100% of subjects completed at least one brain scan and one leg muscle scan: 42 of 46 attempted scans were completed (91%), with failures dominated by exercise muscle scans (completed in 6/6 controls but 3/6 cases). One completed scan lacked usable data unrelated to subject/scan procedure (orthodonture affected a frontal brain scan). As a group, these methods provide a foundation for conduct and enhancement of future MR studies in pediatric subjects with ASD.

Williams syndrome: a relationship between genetics, brain morphology and behaviour

BACKGROUND

Genetically Williams syndrome (WS) promises to provide essential insight into the pathophysiology of cortical development because its ∼28 deleted genes are crucial for cortical neuronal migration and maturation. Phenotypically, WS is one of the most puzzling childhood neurodevelopmental disorders affecting most intellectual deficiencies (i.e. low-moderate intelligence quotient, visuospatial deficits) yet relatively preserving what is uniquely human (i.e. language and social-emotional cognition). Therefore, WS provides a privileged setting for investigating the relationship between genes, brain and the consequent complex human behaviour.

METHODS

We used in vivo anatomical magnetic resonance imaging analysing cortical surface-based morphometry, (i.e. surface area, cortical volume, cortical thickness, gyrification index) and cortical complexity, which is of particular relevance to the WS genotype-phenotype relationship in 22 children (2.27-14.6 years) to compare whole hemisphere and lobar surface-based morphometry between WS (n = 10) and gender/age matched normal controls healthy controls (n = 12).

RESULTS

Compared to healthy controls, WS children had a (1) relatively preserved Cth; (2) significantly reduced SA and CV; (3) significantly increased GI mostly in the parietal lobe; and (4) decreased CC specifically in the frontal and parietal lobes.

CONCLUSION

Our findings are then discussed with reference to the Rakic radial-unit hypothesis of cortical development, arguing that WS gene deletions may spare Cth yet affecting the number of founder cells/columns/radial units, hence decreasing the SA and CV. In essence, cortical brain structure in WS may be shaped by gene-dosage abnormalities.

Pediatric CT sedation: comparison of dexmedetomidine and pentobarbital

OBJECTIVE

Our institution replaced pentobarbital with dexmedetomidine for pediatric CT sedation. The purpose of this study was to compare the efficacy, incidence of adverse events, and cardiovascular and respiratory profiles of these two sedatives.

MATERIALS AND METHODS

Quality assurance data were accessed for a review of demographics, outcome parameters, and adverse events among all children who received either pentobarbital or dexmedetomidine.

RESULTS

From January 2004 through June 2009 there were 388 pentobarbital sedations and 1,274 dexmedetomidine sedations. Age, sex, weight, and duration of imaging study were similar in the two groups. Average time to achieve sedation was 12 ± 4 minutes with dexmedetomidine and 6 ± 3 minutes with pentobarbital (p < 0.001). Recovery time was 32 ± 18 minutes with dexmedetomidine and 95 ± 28 minutes with pentobarbital (p < 0.001). There were no differences between groups in incidence of oxygen desaturation and need for brief positive pressure ventilation. The odds of needing additional sedative agents to complete the study were significantly higher with pentobarbital than with dexmedetomidine (odds ratio, 4.0; 95% CI, 2.0-8.4; p < 0.001). There was a significantly lower incidence of agitation and rage with dexmedetomidine (p < 0.01) but higher risk of hypotension (p < 0.01). There was one failed sedation in each group (p = 0.99).

CONCLUSION

Dexmedetomidine is a safe and effective alternative to pentobarbital for pediatric CT, being associated with a much shorter recovery time and less need for adjuvant sedatives.

Management of the uncooperative child

The management of a child who requires a medical procedure is a challenging issue for the oral and maxillofacial surgeon (OMS) and practitioners in the dental specialties. The office of the OMS is traditionally one in which short outpatient procedures are performed within brief appointment times often using only local anesthesia. For typical children, this brief procedure may be difficult, and for children with behavioral challenges, it may be impossible without the use of behavioral management techniques or pharmacologic modalities. Practitioners must be aware of current trends in pediatric mental health and should develop treatment protocols to avoid complications.

Effects of dexmedetomidine sedation on the EEG in children

OBJECTIVES

To examine the effects of dexmedetomidine sedation on EEG background and epileptiform activity in children, comparing it to natural sleep.

AIM

To provide quantitative and qualitative descriptions of the effect of dexmedetomidine sedation on the EEG of children.

BACKGROUND

Children with intractable epilepsy admitted for surgery undergo 5 days of continuous EEG monitoring as well as nuclear medicine imaging studies with dexmedetomidine for sedation. Continuous EEG monitoring of each child during both natural sleep and dexmedetomidine-induced sedation provides a unique opportunity to evaluate the effects of dexmedetomidine on the EEG of children.

MATERIALS/METHODS

Sixteen children undergoing dexmedetomidine sedation for nuclear medicine studies and simultaneous continuous EEG monitoring were studied. EEG segments during sedation were compared to samples of naturally occurring stage II sleep from the same child. Standard visual EEG analysis, quantification of delta, theta, alpha, beta, and total RMS power, number and location of spike foci, and frequency of spike activity were compared.

RESULTS

The EEG during dexmedetomidine sedation resembled stage II sleep. During sedation, statistically significant increases in power of 16% for theta (P = 0.01), 21% for alpha (P = 0.03), and 40% for beta (P < 0.01) were observed, but not for delta (P = 0.63) or total EEG power (P = 0.61). Spike frequency increased by 47% during sedation but no new spike foci or seizures were observed.

CONCLUSION

Dexmedetomidine sedation elicited an EEG pattern similar to that of Stage II sleep with modest increases in theta, alpha, and beta activity. Dexmedetomidine does not hinder interpretation of the EEG, suggesting that it may be a uniquely useful agent for EEG sedation in children.

Longitudinal study of amygdala volume and joint attention in 2- to 4-year-old children with autism

CONTEXT

Cerebral cortical volume enlargement has been reported in 2- to 4-year-olds with autism. Little is known about the volume of subregions during this period of development. The amygdala is hypothesized to be abnormal in volume and related to core clinical features in autism.

OBJECTIVES

To examine amygdala volume at 2 years with follow-up at 4 years of age in children with autism and to explore the relationship between amygdala volume and selected behavioral features of autism.

DESIGN

Longitudinal magnetic resonance imaging study.

SETTING

University medical setting.

PARTICIPANTS

Fifty autistic and 33 control (11 developmentally delayed, 22 typically developing) children between 18 and 35 months (2 years) of age followed up at 42 to 59 months (4 years) of age.

MAIN OUTCOME MEASURES

Amygdala volumes in relation to joint attention ability measured with a new observational coding system, the Social Orienting Continuum and Response Scale; group comparisons including total tissue volume, sex, IQ, and age as covariates.

RESULTS

Amygdala enlargement was observed in subjects with autism at both 2 and 4 years of age. Significant change over time in volume was observed, although the rate of change did not differ between groups. Amygdala volume was associated with joint attention ability at age 4 years in subjects with autism.

CONCLUSIONS

The amygdala is enlarged in autism relative to controls by age 2 years but shows no relative increase in magnitude between 2 and 4 years of age. A significant association between amygdala volume and joint attention suggests that alterations to this structure may be linked to a core deficit of autism.

Sedation medication received and adverse events related to sedation for brain MRI in children with and without developmental disabilities

BACKGROUND

There are few studies on sedation medication requirements and sedation related adverse events in developmentally disabled children.

OBJECTIVES

The objectives of our study were to compare sedation medication received and sedation related adverse events for brain magnetic resonance imaging (MRI) between children with and without developmental disabilities. We hypothesized that developmentally disabled children would require increased doses of sedative medications and will have increased frequency of adverse events when compared with normal children.

METHODS

We conducted a retrospective chart review on children 1-18 years, who required sedation for an elective brain MRI. Children were excluded if they required sedation for diagnostic imaging other than brain MRI, belonged to ASA category >3, or required general anesthesia. Data on developmental status, demographics and details of sedation medications received along with adverse events were collected.

RESULTS

About 53.5% (260/486) of the patients were classified as developmentally disabled. Pentobarbital and fentanyl were the two most common medications used for sedation in children with and without developmental disability. There was no difference in the mean dosages of pentobarbital (3.02 mg x kg(-1) vs 3.06 mg x kg(-1); P = 0.2) and fentanyl (1.01 mcg x kg(-1) vs 1.02 mcg x kg(-1); P = 0.81) in the two groups. There was a threefold increased incidence of hypoxia noted in children with developmental disability (11.9% vs 4.9%; P < 0.01). Presence of developmental disability alone was significantly associated with sedation related hypoxia (OR = 3.2, 95% CI: 1.8, 6.94; P < 0.01).

CONCLUSIONS

Children with developmental disabilities have similar requirements for sedation medications but are three times more likely to experience hypoxia when compared with normal children.

High dose dexmedetomidine as the sole sedative for pediatric MRI

OBJECTIVE

This large-scale retrospective review evaluates the sedation profile of dexmedetomidine.

AIM

To determine the hemodynamic responses, efficacy and adverse events associated with the use of high dose dexmedetomidine as the sole sedative for magnetic resonance imaging (MRI) studies.

BACKGROUND

Dexmedetomidine has been used at our institution since 2005 to provide sedation for pediatric radiological imaging studies. Over time, an effective protocol utilizing high dose dexmedetomidine as the sole sedative agent has evolved.

METHODS/MATERIALS

As part of the ongoing Quality Assurance process, data on all sedations are reviewed monthly and protocols modified as needed. Data were analyzed from all 747 consecutive patients who received dexmedetomidine for MRI sedation from April 2005 to April 2007.

RESULTS

Since 2005, the 10-min loading dose of our dexmedetomidine protocol increased from 2 to 3 microg.kg(-1), and the infusion rate increased from 1 to 1.5 to 2 microg.kg(-1).h(-1). The current sedation protocol progressively increased the rate of successful sedation (able to complete the imaging study) when using dexmedetomidine alone from 91.8% to 97.6% (P = 0.009), reducing the requirement for adjuvant pentobarbital in the event of sedation failure with dexmedetomidine alone and decreased the mean recovery time by 10 min (P < 0.001). Although dexmedetomidine sedation was associated with a 16% incidence of bradycardia, all concomitant mean arterial blood pressures were within 20% of age-adjusted normal range and oxygen saturations were 95% or higher.

CONCLUSION

Dexmedetomidine in high doses provides adequate sedation for pediatric MRI studies. While use of high dose dexmedetomidine is associated with decreases in heart rate and blood pressure outside the established 'awake' norms, this deviation is generally within 20% of norms, and is not associated with adverse sequelae. Dexmedetomidine is useful as the sole sedative for pediatric MRI.

Brief report: methods for acquiring structural MRI data in very young children with autism without the use of sedation

We describe a protocol with which we achieved a 93% success rate in acquiring high quality MRI scans without the use of sedation in 2.5-4.5 year old children with autism, developmental delays, and typical development. Our main strategy was to conduct MRIs during natural nocturnal sleep in the evenings after the child's normal bedtime. Alternatively, with some older and higher functioning children, the MRI was conducted while the child was awake and watching a video. Both strategies relied heavily on the creation of a child and family friendly MRI environment and the involvement of parents as collaborators in the project. Scanning very young children with autism, typical development, and developmental delays without the use of sedation or anesthesia was possible in the majority of cases.