Dexmedetomidine Sedation in Children Before MRI Examinations

Dexmedetomidine is a beneficial sedative for children. It provides a sedation equivalent to a natural deep sleep with negligible respiratory effects. The sedative can be administered intravenously, intranasally or buccally. Administration via the nose provides better absorption and faster impact effect. The drug does not taste and does not sting when administered. Dexmedetomidine is easy to administer and results in fewer anxious and upset patients. Monitoring the patient during the waiting period after application, during the examination itself and during the recovery period is a must. The study shows that a drug that can be administered intranasally, is practical and not invasive and means that the patient's anxiety is reduced, which can be considered an effective and safe method. Within the MRI unit at the pediatric radiology department, it has been necessary to design new routines for simple sedation, mainly due to the increased need for MRI examinations on children. Anesthesia and radiology staff have developed a new way of working where Dexmedetomidine is given nasally. These routines, including the referral flow, patient flow and staffing, have now been well established for about four years with very good results. The patient, who does not need to be fasting before the examination, receives a spray dose of the drug in the nose, falls into a deep sleep, is examined and then sleeps for about 30 minutes to an hour under supervision before returning home. It is the anesthetist who assesses which children are suitable for the type of sedation and radiology staff who are responsible for drug administration / monitoring of the patient. A preparation room is dedicated to these patients.

The patients were scheduled according to regular routine for dedicated Dexmedetomidine sedation sessions and only scans with an anticipated duration of maximum 1 hour were selected for the Dexmedetomidine protocol.

Following admission to the radiology out-patient clinic it was confirmed that the child's health condition had not changed since the last visit to the pediatrician, that there were no signs of an ongoing respiratory infection. No fasting requirements was used, and the child could eat and drink freely until arrival to the radiology clinic . Following admission and a brief period for the child to adapt to the new environment, heart rate (HR), pulse oximetry saturation and non-invasive blood pressure (NIBP) was recorded. The clinic was thereafter noticed from the MRI suite approximately 30 minutes prior to the scheduled time for the MRI examination. At this time the radiographer administered intra-nasal Dexmedetomidine. The child was then left with the accompanying caregiver/-s and the clinic nurses and checked after 15-20 min on how the sedation process evolved.

When called for, the patient was transported to the MRI suite together with the caregivers. If asleep or clearly sedated the child was placed in the MRI and prepared for the examination, which included ear plugs and noise protection earphones. A pulse oximeter probe was attached to monitor oxygenation and pulse rate. Noninvasive blood pressure or supplemental oxygen was not used during the scan since this may, according to previous clinical experience, awake the patients during the scanning procedure.

If the patient was deemed not sedated enough, an additional dose of intranasal Dexmedetomidine was administered and the child was left alone with the caregiver to allow it to settle following the administration. The child was thereafter continuously supervised by the radiographer. As the child developed a sufficient level of sedation the patient was then transferred to the scanner in the way described immediately above.

If two doses of intranasal Dexmedetomidine did not provide the desired result, the child was cancelled and rescheduled for a dedicated general anesthesia MRI session at a later occasion.

Following the scanning procedure, the ear plugs, and the noise protectors were removed, and the child was transferred from the gantry to the patient stretcher in the MRI suite area. Patients were allowed to wake up spontaneously during this process, no active efforts to wake them up were made. The pulse oximeter was left in place throughout transfer and until the child was deemed sufficiently alert in the clinic. When the child appeared reasonably awake and stable, a consensus decision made by the radiology personnel and the caregivers, the child and caregivers could return home. Before this, a new set of HR, NIBP and saturation was recorded.

Inclusion criteria

• Healthy children, according to the American Society of Anesthesiologists (ASA) risk classification. Children with ASA risk class 1 or 2 were selected by the anesthesiologist as suitable for radiographer handled sedation with Dexmedetomidine.

Exclusion criteria

• Children with significant comorbidity (ASA risk class 3 or 4) that were deemed to need presence of an anesthesia team (anesthesiologist plus certified anesthesia nurse) for safety reasons.
• Children that due to the specific nature of the MRI scan would need a general anesthetic to provide a secure airway (e.g., laryngeal mask airway or endotracheal intubation) during the scan (e.g., mild neck manipulation to assess cervical instability in Mb Down patients, multiple different MRI investigations requested or need for apnea).
• Children that present minimal cold symptoms the day of imaging.