Intervention description {11a}
Teleflex MAD130, breast milk, hyperextension, pain
On the sedation day, the child will be fasting according to our institutional protocol: the fasting period is 2h for clear liquids (water and fruit juices without pulp), 4h for breast milk, and 6h for infant formula, non-human milk, and solid foods. The medical team will verify that the child is still eligible for the study and that informed consent has been signed by the parents or the legal representative. Child’s state of health will be verified, and vital signs will be recorded before the premedication, as for any anesthesia procedure.Unblinded authorized site staff (nurse anesthesiologist or research nurse) will prepare the premedication that will be administered by a blinded member of the nursing staff in syringes labeled with the identity of the patient:
A dose of 0.02 ml/kg of an intranasal solution containing either dexmedetomidine (which corresponds to a dosage of 2 mcg/kg of dexmedetomidine (Dexdor®, 100 mcg/ml) in group dexmedetomidine-propofol) or matching placebo (physiological saline), depending on the group assigned to the patient. This intranasal solution will be administered using a 1-ml syringe with an intranasal Mucosal Atomization Device (Teleflex MAD130®).A dose of 0.125 ml/kg of an oral solution containing either midazolam (which corresponds to a dosage of 0.25 mg/kg midazolam (Ozalin®, 2 mg/ml), with a maximum of 20 mg, in group midazolam-propofol) or matching placebo (physiological saline), depending on the group assigned to the patient. This oral solution will be administered using the dedicated applicator, provided by Primex Pharmaceuticals Oy.A patch of local anesthetic (Emla® or Rapydan®) will be placed on the skin to reduce the pain associated with the insertion of an intravenous (I.V.) catheter, which will be necessary for the administration of propofol. At the same time, the patient will receive the premedication following the double-dummy technique. After the administration of the premedication, vital signs will be recorded.After 30 min, the child will be taken to the induction room, located next to the MRI room, and an intravenous catheter will be inserted by the anesthesiologist in the previously anesthetized skin area. The sedation will be carried out by this anesthesiologist, blinded to the premedication received by the child, using propofol. A propofol I.V. bolus of 2 to 6 mg/kg will be administered until deep sedation (i.e., a University of Michigan Sedation Scale score greater than or equal to 3) [The usual MRI-compatible monitoring (Philips Expression MR400®) that will be used includes an electrocardiogram, a pulse oximeter, and a capnograph. The respiratory rate will be calculated from the capnography trace. It will be completed by measuring non-invasive blood pressure at the reception of the child in the 1-day clinic (reference measurement), when the patient will be placed on the MRI table, and at the end of the examination (to avoid any stimuli that could cause a reaction movement). The child’s neck will be held in hyperextension using a roller under the shoulder and an oxygen mask applied to the child's face, under which the capnograph probe will be slipped. If necessary, the anesthesiologist may fix the inferior jaw to maintain the cervical spine in hyperextension, use a Guedel cannula, a laryngeal mask, or an endotracheal tube.After the sedation, the child will be monitored in the post-anesthesia care unit (P.A.C.U.). During the entire awakening period, parameters such as oxygen saturation, breathing rate, blood pressure and heart rate will be recorded on a monitoring sheet. Moreover, the patient will be assessed every 10 min, using Aldrete and Chung scores. The Aldrete score determines when the child can start consuming clear drinks, as well as the withdrawal of the infusion if the drink is well tolerated. The Chung score determines when the patient can leave the monitoring room. Monitoring will be stopped as soon as a score greater than or equal to 9 (out of 10) is obtained using the two scores. In addition, the times of arrival in the recovery room, and time of discharge will be recorded.Two radiologists will evaluate the quality of MRI images based on the presence of motion-related artifacts. The examinations will be classified as “no artifact” or “with artifact.” The second category (“with artifacts”) will be assessed for the occurrence of motion artifacts based on the full duration of the examinations. Radiologists will not be aware of the type of premedication that has been administered to the patient.All data will be collected on the case report form (REDCap database).