Dexmedetomidine, has been used in the past 4-5 years as an alternative sedation method for
      children at the pediatric radiology department in order to reduce the waiting lists and the
      use of general anesthesia with its risks and side effects in magnetic resonance and computed
      tomography examinations.

Dexmedetomidine Sedation in Children Before MRI Examinations

Deep Sedation

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.

Dexmedetomidine

Safe Sedation of Children During Radiological Examinations

During the scan the following important safety issue was followed: oxygen desaturation (SpO2 < 95 %) monitored by pulse oximetry. Low SpO2 was defined as a level below the mean value for age. If the SpO2 dropped below these levels, appropriate actions were taken (i.e., contact anesthesiologist).
Since no fasting restrictions is part of the Dexmedetomidine-MRI protocol, specific attention was paid to the potential occurrence of regurgitation of stomach contents and/or aspiration during the entire sedation period.
Pre- and post-sedation SpO2 (recorded in the radiology clinic pre- vs. post-scan) was compared to identify any negative effects on HR and NIBP during the early post-scan phase.

During the scan the following important safety issue was followed: heart rate, monitored by pulse oximetry. Low heart rate was defined as a level below the mean value for age. If the heart rate dropped below these levels, appropriate actions were taken (i.e., contact anesthesiologist).
Pre- and post-sedation heart rate (recorded in the radiology clinic pre- vs. post-scan) were compared to identify any negative effects on SpO2 and NIBP during the early post-scan phase.

During the scan the following important safety issue was followed: NIBP monitored. Low or high systolic and/or dyastolic blood preassure was defined according the mean value for age. If any of parameters changed below/above the normal levels for age, appropriate actions were taken (i.e., contact anesthesiologist).
Pre- and post-sedation NIBP (recorded in the radiology clinic pre- vs. post-scan) were compared to identify any negative effects on HR and SpO2 during the early post-scan phase.

Associate Professor

All scans were reviewed by a certified pediatric MRI radiologist. Scan quality was classified as optimal, slight sub-optimal but of acceptable quality to answer the diagnostic question or inadequate to allow any acceptable radiologic interpretation.

Drug used: Dexmedetomidine. Given in increments of 0.2 ml at the time with atomizer (MAD Nasal™, Wayne Pennsylvania). Administered by radiology staff.
Dose 1 of nasal dexmedetomidine: 4 mcg/kg max 200 mcg Dose 2 of nasal dexmedetomidine: 2 mcg/kg max 100 mcg

Dexmedetomidine Sedation in Children Before MRI Examinations

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