PEDIATRICS Vol. 108 No. 1 July 2001, pp. 163-165

Sedation of Children for Electroencephalograms

Donald M. Olson, MD^*, , Maureen G. Sheehan, RN, PNP^*, , William Thompson, RN, BSN, Phyllis T. Hall, REEGT, and Jin Hahn, MD^*,

From the Departments of ^* Neurology and  Pediatrics, Stanford University Medical Center, Stanford, California.

	ABSTRACT

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Objective.  Sedation sometimes is necessary to perform an electroencephalogram (EEG) on a child. A dramatic decline in the need to use conscious sedation in our EEG laboratory prompted this review of our sedation experience. The purpose of this review was to determine the incidence of adverse sedation effects and to determine why the need for sedation had declined.

Methods.  All 513 attempts to administer sedation to children who were undergoing EEG studies during a 4-year period were reviewed retrospectively. Parameters studied included type and amount of the sedative agents, need for repeated dosing, successful completion of the EEG, and complications attributed to the sedative.

Results.  Sedation was attempted in 513 (18%) of 2855 EEGs performed during the 4-year period. Ninety-one percent of the EEGs performed with sedation were completed successfully. Chloral hydrate was the most frequently administered sedative. Complications (transient oxygen desaturation) occurred in 3 children, all of whom had recognized risk factors for airway compromise. The proportion of children who required sedation decreased from 32% to just 2% during that time period.

Conclusion.  Sedation of children who are undergoing EEG examinations is effective and safe. Complications are infrequent. The need for sedation can be decreased greatly by adequate preparation and by creating a less-threatening, child-friendly environment in which to perform the study.  Key words:  electroencephalography, child, conscious sedation.

In the EEG laboratory, sedation has several purposes: it allows application of recording electrodes to the scalp without causing excessive anxiety and without the need for restraints, it permits recordings with less muscle and movement artifact, and it allows the recording of the drowsy and asleep states. EEG recordings of these states often are necessary to provide the most complete data possible.¹ For most children, conscious sedation is completed easily and without complications.^2-6 However, some children are at increased risk for complications from sedation, particularly those who have an underlying problem with control of secretions or their airway.⁷

During a 4-year period, we noticed a dramatic decline in the need to use conscious sedation in our EEG laboratory. We reviewed our experience with sedation to determine whether this was attributable to a perceived improvement in the preparation of children for EEG or to some other variable such as an unacceptably high complication rate or an excessive sedation failure rate. In addition, a number of different sedation paradigms were used in our laboratory and prompted additional scrutiny of our sedation practice.

	METHODS

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Between January 1995 and December 1998, 2855 EEGs were performed. Conscious sedation was attempted during 513 (18%) of these tests. A database has been maintained by the sedation team and was used to review types of sedation administered, dosage, time until sedated, duration of sedation, successful completion of the test, and any complications that arose. All children were sedated under supervision of a sedation nurse and closely monitored in accordance with the guidelines suggested by the American Academy of Pediatrics.⁸

	RESULTS

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A total of 210 children who received sedative medication were girls (age: 2 months to 20 years; average age: 3 years), and 303 were boys (ages: 2 months to 19 years; average age: 4 years). The vast majority of the EEGs performed with the use of sedation were completed successfully (469 [91%] of 513). A total of 44 studies (9%) were incomplete (including 4 children who underwent 2 unsuccessful sedation attempts) (Table 1). An additional EEG with sedation was not attempted for the remainder.

Diagnoses before the attempt at sedation were available for 31 of the 40 patients whose studies could not be completed. Only 2 of the 31 children did not have complicating medical conditions or developmental delay. Twenty-nine of the children who could not be sedated adequately had a history of developmental delay or autism.

Chloral hydrate alone was the most commonly administered sedative, followed by a combination of chloral hydrate and hydroxyzine. Other sedatives occasionally were used alone or in combination. When medications other than chloral hydrate were used, the reason usually was that a previous sedation attempt with chloral hydrate had failed (Table 2). There was no significant difference between the average dose of chloral hydrate (55 mg/kg) used for successful and unsuccessful sedation.

Success Rate After Second Dose of Sedation

Medication often was repeated if the first dose did not sedate the child successfully. A total of 147 children (29% of all patients sedated for EEGs) received a second dose of sedative medication. EEGs were completed successfully in 114 cases (78%). A repeat dose of chloral hydrate usually was the second medication given (most often 25 mg/kg). Sometimes hydroxyzine was the second medication.

Complications

Complications were rare. Only 3 children required supplemental oxygen or airway manipulation because of desaturation as measured by transcutaneous oxygen saturation. One child, a 5-year-old with Smith-Magenis syndrome, had a history of sleep apnea and just 2 weeks earlier had undergone adenoidectomy. He had received a second dose of chloral hydrate (25 mg/kg) after the first dose (50 mg/kg) failed to provide adequate sedation. He had transcutaneous oxygen saturation that dropped from 98% to 88%. After repositioning of his head on several occasions, he was awakened. He was observed in the postanesthesia recovery unit and then sent home. The second child, a 3-year-old, had Duchenne muscular dystrophy, was sedated with 50 mg/kg of chloral hydrate, and had oxygen desaturation that fell from 98% to 82% when he was asleep during his EEG. Airway obstruction with oxygen saturation as low as 77% had prompted tonsillectomy and adenoidectomy 6 months earlier. He needed to be stimulated and awakened. The third was a 2-year-old child with Down syndrome and a large tongue. Oxygen saturation dropped transiently to 85% (from 94%), but the child responded to repositioning of his head. He had received a single 50 mg/kg dose of chloral hydrate.

For 468 children, there was information about the time it took to become sedated. The average time to sedation was 38 minutes. Recorded times ranged from 5 minutes to 180 minutes. Sedation usually lasted ~30 minutes.

	DISCUSSION

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Our findings demonstrate that sedation of children in an EEG laboratory is safe and effective. Sedation (most often with chloral hydrate) took effect rapidly and lasted long enough to permit electrode application or recording of sleep or both. The sedation team member easily treated the 3 children who experienced complications. All of those who had complications were at risk of airway compromise because of their underlying medical condition.

Most studies of the use of conscious sedation in children concern painful and frightening procedures, such as suturing, or procedures during which children must be kept very still to obtain an artifact-free study, such as radiologic imaging.^49-11 Little has been written about the effectiveness and safety of sedation in the EEG laboratory in general and in children in particular.

For EEG recording, issues other than the depth of sedation must be considered when choosing a sedative medication. It is not sufficient merely to be able to apply recording electrodes to the scalp and sample brain activity during the drowsy and asleep states. The ideal sedative agent will not suppress abnormal EEG activity (ie, provoke a false-negative recording) or induce changes in the background activity that might obscure subtle abnormalities.¹² Sedative drugs such as benzodiazepines and barbiturates may increase the amount of faster background EEG activity and make interpretation more difficult.¹³ Deep sedation and anesthesia may not only affect the background EEG activity but also suppress interictal spike discharges.¹⁴ Chloral hydrate has been the most frequently used sedation for our EEG recordings. This medication generally is considered safe when used at sedative doses.¹⁵ It has little effect on the background EEG activity.¹⁶

Airway compromise is the most likely acute complication of conscious sedation.⁵ When complications occurred in our laboratory, they were in children who were readily recognized as being at risk. Conscious sedation is recognized as conferring increased risk of complications for children with airway abnormalities, including those that are the result of neurologic disorders such as trisomy 21.⁷ The 3 children in our series who became hypoxic (as indicated by transcutaneous oxygen saturation monitoring) were identified quickly, and complications were prevented. All had identifiable risk factors for airway compromise. The necessity of close monitoring of normal children (without identified risk factors for airway compromise) remains unresolved by this review. At most, we can conclude that complications of conscious sedation in the EEG laboratory are rare when established guidelines are followed⁸ and sedative dosage is not extreme. A cost-benefit analysis of close monitoring of all children who undergo conscious sedation in the EEG laboratory is beyond the scope of this article.

There was no difference between the average dose of chloral hydrate used for successful versus failed sedation. If the first dose of sedative fails to produce the desired result, then the test should not be abandoned before a second dose is given. In this case series, the second dose of sedation was effective in permitting completion of the EEG 78% of the time. There was no greater risk of complications in the group of children who received a second sedative dose.

The ideal situation for recording EEGs of children in the EEG laboratory is to proceed without the need for medical sedation.¹ A gradually decreasing proportion of children required sedation to complete their studies in our laboratory during the period reviewed as a result of the behavior techniques practiced by an experienced and skilled technologist. These techniques decrease fear before and during electrode application and increase the likelihood of child's sleeping during the recording.

Ideally, the parent should be called a day ahead of time, and expectations for parental behavior should be discussed before the electrode application is started. Techniques used to decrease anxiety and fear during electrode application include 1) having parents stay in the EEG laboratory with the child, 2) having a parent hold and comfort the child, 3) having the child bring a familiar toy or blanket to the laboratory, 4) giving lots of positive feedback and praise, 5) distracting the child with videos or books, 6) decorating the laboratory with pictures and objects that are familiar to most young children, and 7) having the technologist behave, dress, and speak in a calm and unthreatening manner.

Measures to promote sleeping during the EEG include 1) sleep deprivation the night before the test (going to sleep an hour later and arising an hour earlier than normal), 2) staying awake in the car on the way to the laboratory, 3) avoiding hunger and thirst with reasonable fasting (NPO) time requirements, 4) emptying the bladder before starting the test, 5) allowing parents to hold the child, 6) darkening the room, and 7) playing soft background music.

	CONCLUSION

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Sedation of children who are undergoing EEG examinations is effective and safe when parents are well prepared and children's oxygen saturation is monitored carefully. Complications will be infrequent and often can be anticipated in children who are at increased risk because of their underlying medical condition. The need for sedation can be decreased greatly by adequate preparation of the patient and parents and by creating a less-threatening, child-friendly environment in which to perform the study.

	FOOTNOTES

Received for publication Oct 24, 2000; accepted Jan 16, 2001.

Reprint requests to (D.M.O.) Department of Neurology, Stanford University Medical Center, 300 Pasteur Dr, MC5235, Stanford, CA 94305-5235. E-mail: dmolson{at}stanford.edu

	ABBREVIATIONS

EEG, electroencephalogram.

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