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Sedation in Pediatric Neuroimaging: the Science and the Art

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Sedation in Pediatric Neuroimaging: the Science and the Art Sedation in Pediatric Neuroimaging: The Science and the Art RichardS. Boyer1 From the Department of Pediatric Medical Imaging, Primary Children's Medical Center, Salt Lake City, UT Recent advances in imaging technology have The focus is on safety and efficacy using a limited revolutionized the evaluation of infants and chil­ number of familiar drugs in a methodical ap­ dren with neurologic diseases ( 1). Each of the proach. Whether using sedation several times a currently used modalities, with the exception of day or once a month, the challenge is the same­ real-time ultrasound (US), requires a motionless to control patient motion safely and effectively in patient. The advent of computed tomography infants and children in order to allow the acqui­ (CT) in the 1970s required radiologists to become sition of optimal diagnostic images. increasingly involved in pediatric sedation to al­ low the long acquisition times required by the early-generation CT scanners (2). As technology Predictability vs Safety improved and faster scanners became routinely Sleep produced by a natural (nonpharmacol­ available, the need for sedation for CT was ogic) approach is inherently safer, though less avoided in most children. predictable, than medication-induced sedation. However, in the past 6 years, the increasing Therefore, whenever possible, a natural form of use of magnetic resonance (MR) imaging in pe­ sleep is preferable to pharmacologic sedation. In diatric neurodiagnosis has necessitated a reluc­ the infant, a well-timed feeding, a warm blanket tant return to the frequent use of sedation for and a quiet, dark room may stimulate a post­ pediatric brain and spine examinations. In pedi­ prandial nap that is sufficient for a noninvasive atric centers, this return has been reasonably well imaging study. However, scanners are busy and tolerated because of the greater comfort level of schedules cannot usually accommodate the lack pediatric radiologists with the challenges of se­ of predictability required by the natural approach. dation and of monitoring children, and the greater In addition, long exam times and external stimuli availability of pediatric-trained technologists and may awaken the infant and terminate the exam nurses. In contrast, personnel at many primarily prematurely. Therefore, the pharmacologic ap­ adult MR facilities now find themselves faced with proach to sedation is usually preferred for its the need to perform occasional pediatric studies, predictability. and feel discomfort or anxiety in sedating children Predictability must not be at the expense of safely. safety for the child. Safety is the most important This paper is written for those using sedation consideration in pediatric sedation. Elements of to perform the occasional neuroimaging study on an approach to pediatric sedation that favor an infant or child. The major emphasis is directed safety include: toward sedation for MR, but the basic principles 1. establishment of a written protocol in each also apply in CT, angiography, and myelography. imaging department that follows the guide­ lines for pediatric sedation developed by 1 Address reprint requests to Dr Boyer, Department of Pediatric Med­ the American Academy of Pediatrics Sec­ ical imaging, Primary Children's Medical Center, 100 North Medical Drive, tion on Anesthesiology (3) specifically ad­ Salt Lake City, UT 84 11 3. dressing such issues as candidates for se­ Index terms: Patients, sedation; Chloral hydrate; Pediatric neurora8 iology dation, facilities, equipment, informed con­ I AJNR 13:777-783, Mar/ Apr 1992 0195-6 108/ 92/1302-0777 sent, drugs and dosages, documentation, © American Society of Neuroradiology personnel, monitoring procedures, recov- 777 778 AJNR: 13, March/Apri11992 ery care, discharge criteria, and emer­ detailed consideration of the pharmacology of the gency contingencies; agents commonly used for pediatric sedation is 2. direct physician involvement in the seda­ beyond the scope of this article. Interested read­ tion process; ers are referred to standard reference texts and 3. limiting the number of drugs used for se­ pertinent review articles (4). dation to a few with which all involved Table 1 lists some common pediatric sedative personnel can become very familiar; drugs used in our department with dosage guide­ 4. regular quality assurance evaluation of lines and comments. Table 2 summarizes the complications, sedation failures, adverse order of our preferences for sedation in the dif­ reactions, and other negative outcomes ferent neuroimaging modalities stratified by pa­ with appropriate modification of protocols tient weight. and procedures; 5. routine use of state-of-the-art monitoring equipment, especially in MR , where direct MR visualization of the sedated child is more In our imaging department at a children's hos­ difficult; and pital, the most frequent use of sedation is for MR 6. employment of properly-trained person- · studies of the head, neck and spine. Children nel, preferably nurses or specially-trained under age 7 or 8 years of age are routinely technologists, to care for sedated patients. sedated, though we have had exceptionally co­ operative children as young as age 3 undergo an Techniques MR study without sedation. Pediatric sedation must be tailored to the pa­ Sleep deprivation is an important adjunct to tient, the examination, and the clinical setting. A sedation with any drug regardless of the imaging TABLE 1: Commonly used drugs for pediatric sedation' Drug Route Dose Comments Chloral hydrate P.O. or gastric 75 mg/kg (initial) Good results at this dose tube 25 mg/kg (supplement if not Safe asleep in 30 min) Many years experience Maximum total dose 2000 Flavored syrup · mg Sodium pentobarbital IV or IM 5-6 mg/kg (initial) IV more predictable and (Nembutal) 2-3 mg/kg (supplement shorter recovery after 30 min prn) Maximum total dose 200 mg Na lbuphine (Nubain) IV 0.1 mg/ kg m ixed with 0.05- Less predictable in younger + 0.1 mg/ kg children Midazolam (Versed) May repeat X 2 prn Maximum effect lasts ap- Maximum total Versed dose proximately 30 min 5 mg Partially reversed by Naloxone Nubain is a partial agonist of other narcotics "Ca rdiac cocktail" IM 25 mg (0 .5 mL) Good analgesia Meperidine (Demerol) 6.25 mg (0 .25 mL) Longer action (often >2 hr) Promethazine 6.25 mg (0.25 mL) More risk respiratory depres- (Phenergan) D9se per Table 3 sion Chlorpromazine Partially reversed by (Thorazine) Naloxone Sodium thiopental Rectal 25 mg/ kg Does not require IV access (Pentothal) Repeat lh dose in 15 min Onset 7-15 min prn • Note.-Abbreviations: IV, intravenous; IM, intramuscular; prn, pro re na'ta ("'as circumstances may require"); P.O., per os ("'by mouth"). AJNR: 13, March/ April 1992 779 TABLE 2: Sedation preferences for pediatric neuroimaging Modality Patient Group Order of Preference Comments us Infants 1. None Sedation rarely nec­ 2. Chloral hydrate essary MR Infants- small children 1. Chloral hydrate Reduce dose in neo­ (0-25 kg) 2. Nembutal nates 3. Cardiac cocktail Larger children-ado­ 1. Nembutal, Penta- Most children under lescents (25+ kg) thai 8 require sedation 2. Cardiac cocktail or Sedation usually not Nubain + Versed required, but if se­ 3. General anesthesia dation is required , this is the most dif­ ficult group CT Infants-young chil­ 1. Immobilization Sedation rarely re­ dren 2. Chloral hydrate quired for routine 3. Nembutal exams Sedation may be necessary for 3-D or thin section studies Older children-ado­ 1. Television Sedation rarely lescents 2. Versed + Nubain needed unless pa­ 3. Nembutal tient is neurologi­ cally impaired Angiography Infants-children 1. Cardiac cocktail See Table 3 (0-40 kg) Older children-ado­ 1. Nubain + Versed lescents (40 kg+) 2. Demerol (1 mg/ kg) + Phenergan (.5 mg/ kg) M yelography Infants-young chil­ 1. Cardiac cocktail dren 0-7 yr 2. Nubain + Versed Older children-ado­ 1. None Sedation rarely lescents 2. Nubain + Versed needed unless neu­ rologica lly im­ paired modality (5). Our protocol for sleep deprivation Oral chloral hydrate is the most frequently used is to keep the child up approximately 2 hours drug for pediatric sedation in North American after the usual bedtime at night and awaken them pediatric centers (6). In our pediatric MR experi­ 1 to 2 hours earlier than usual in the morning. ence since September 1986, representing more The child is not allowed to nap either in the car than 3000 sedated studies, chloral hydrate with on the way to the exam or while in the waiting sleep deprivation has been successful in over room. For afternoon studies, the usual morning 90% of sedation attempts. Our results agree with nap is denied. We even sleep-deprive older chil­ those of a recent report (7) in which sedation with dren scheduled for MR examinations even though an average dose of 58 mg/kg (range 25-81 mg/ no sedation is planned. The monotonous sounds kg) of chloral hydrate was successful on the first of the MR scanner will often put to sleep a tired attempt in 86% of 50 children. We use a routine but nonsedated patient, allowing for a better dose of 75 mg/kg to a maximum of 2000 mg. study. An additional 25 mg/kg may be given if the 780 AJNR: 13, March/April 1992 patient does not go to sleep in 30 minutes after of the infant or young child (see below), allow the first dose. The use of higher doses of chloral routine CT examinations to be performed on hydrate has been reported (8) but is associated infants and small children, with a surprisingly with increased frequency of side effects, espe­ small number of repeat scans being necessary cially vomiting and hyperactivity. Our initial dose and with little or no motion artifact. Safety and of chloral hydrate is reduced to 50-60 mg/kg for throughput are both enhanced by this nonsedated neonates, patients recently started on sedative approach to CT.
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