Children undergoing magnetic resonance imaging (MRI) are expected to lie immobile in a dimmed, noisy and narrow tunnel, which may cause anxiety and fear. Thus, most of them need procedural sedation. An ideal sedation protocol should have minimal effects on respiration and hemodynamics, maintain the children calm and immobile during the procedure, but allow rapid recovery and discharge.
There are many MRI sedation protocols available for pediatric patients, employing traditional anesthetics such as propofol, barbiturates, benzodiazepines, chloral hydrate, ketamine, remifentanil or sevoflurane.[1–3] Most of these anesthetics may cause respiratory depression or hypotension, which in extreme cases are harmful to the child.[2,4] Sedation with propofol and remifentanil as well as sedation with sevoflurane may require mechanical ventilation, but also other sedation protocols involve risks of respiratory complications when performed with spontaneous breathing.[1,3]
Dexmedetomidine is an α2-adrenoceptor-activating drug used in sedation of adult intensive care patients. In addition to its sedative effects, dexmedetomidine has analgesic and antiemetic effects. Compared to conventional anesthetic agents, patients sedated with dexmedetomidine remain arousable. Dexmedetomidine also has only minimal effects on respiration.[7,8] Due to its many beneficial properties, dexmedetomidine is currently quite commonly employed in off-label use in pediatric intensive care. In addition, dexmedetomidine has been used in children for other purposes, such as MRI sedation, and several previous reports describe its use in ambulatory sedation of pediatric patients.[10–13]
Dexmedetomidine has been shown to reduce the requirements for intravenous anesthetics,[14,15] volatile anesthetics[16,17] and opioids.[18,19] In pediatric patients undergoing MRI, premedication with dexmedetomidine reduced propofol consumption, but did not alone cause sufficient sedation in most patients.[20,21] In adults, dexmedetomidine reduced the dose of thiopental needed for sedation,[14,22] but to our knowledge there are no reports on the effect of dexmedetomidine on the need of barbiturates in sedation of pediatric patients.
Thiopental has been used for decades in sedation of pediatric patients for MRI and recently reported to be a safe and efficacious ambulatory sedative agent for children.[1,2,23–25] In Turku University Hospital (TUH) thiopental has been used over 20 years for procedural sedation of pediatric patients undergoing MRI. Sedation with thiopental has mainly been conducted without ventilatory support. In the autumn of 2016, TUH started to use intranasal (IN) dexmedetomidine as premedication for all children scheduled for MRI to reduce the amount of other sedatives. Our primary aim in this study was to compare thiopental requirements after IN dexmedetomidine premedication was added to pediatric MRI sedation protocol. Our secondary aims were to compare the lowest HR and SpO2 values recorded during the MRI, and the need for supplemental oxygen during the MRI. We hypothesized that IN dexmedetomidine would markedly reduce the amount of additional sedatives needed for MRI sedation, thus further reducing the risk of respiratory depression.
BMC Anesthesiol. 2019;19(22) © 2019 BioMed Central, Ltd.