Kim SY, Booth JM, Staffa SJ, Kordun A, Yu J, Cravero JP. A dose-ranging pilot trial of dexmedetomidine-propofol in children undergoing magnetic resonance imaging. J Anesth. 2025 May 11. doi: 10.1007/s00540-025-03511-z. Epub ahead of print. PMID: 40349256.

Full text access for Children’s and Emory users.

Abstract
The optimal sedation/anesthesia technique for magnetic resonance imaging (MRI) scans has not been established. The combination of propofol with dexmedetomidine has been reported, but without systematic dosing data. Our primary aim was to determine the propofol-sparing effect of dexmedetomidine (DEX) when added to propofol for MRI scan sedation/anesthesia utilizing a dose-ranging protocol for four distinct regimens (Propofol-Only, DEX-High, DEX-Low, DEX-Bolus). Our secondary aims were to document adverse events, scan interruptions due to patient movements, and determine recovery time. Seventy-nine patients aged 1-12 years scheduled for MRIs under anesthesia were sequentially enrolled. A 60% reduction in propofol dose required was found in the dexmedetomidine cohorts. There was no difference (p = 0.161) in recovery time between Propofol-Only and DEX-Bolus groups. There were no differences in episodes of hypotension (p = 0.464), bradycardia (p = 0.558), or patient movement (p = 0.273) between the Propofol-Only and dexmedetomidine cohorts. Recovery time was prolonged for DEX-High and DEX-Low groups compared to DEX-Bolus or Propofol-Only. The addition of dexmedetomidine significantly decreased the necessary dose of propofol. Propofol combined with a single bolus of dexmedetomidine (no infusion) provided effective sedation/anesthesia without adverse events or extending recovery time.

---

Tu H, Gao J, Bao C, Zhao J, Tang J, Hu Y. Determination of optimal combined doses of oral midazolam and intranasal dexmedetomidine for use in pediatric magnetic resonance imaging. World J Pediatr Surg. 2025 May 28;8(2):e001000. doi: 10.1136/wjps-2025-001000. PMID: 40444265; PMCID: PMC12121563.

Free full text access.

Abstract
Background: Sedation is often required for infant and preschool children to obtain clear magnetic resonance imaging (MRI). This study was designed to determine the 95% effective dose (ED95) of oral midazolam (MID) and intranasal dexmedetomidine (DEX) in combination for sedation in pediatric MRI.

Methods: We have used a biased coin design up-and-down sequential methodology. Initially, 144 patients were split into two groups. A total of 72 patients were randomly assigned to determine the ED95 of DEX in combination with a fixed dose of 0.5 mg/kg MID, and 72 were given various doses of MID combined with a fixed dose of DEX at 1 µg/kg to determine the ED95 of MID. ED95 was calculated using isotonic regression. At last, the plan was to include 225 cases to test the sedation success rate of DEX combined with MID ED95 dose. Adverse events were recorded.

Results: The ED95 of DEX was 0.89 µg/kg (95% confidence interval (CI) 0.68 to 0.95) combined with a fixed dose of MID at 0.5 mg/kg. The ED95 of MID was 0.47 mg/kg (95% CI 0.30 to 0.50) combined with a fixed intranasal dose of 1 µg/kg DEX. Using 1 µg/kg DEX combined with 0.5 mg/kg MID, the sedation success rate was 95.1% in a verification group of 225 children.

Conclusions: This study reports relatively low ED95 doses of intranasal DEX and oral MID when DEX is determined with a fixed dose of MID and MID determined with a fixed dose of DEX. The combination provides efficient and safe sedation for young children for MRI scanning. Further validation is required.

Trial registration number: ChiCTR2300068611.

---

Bruckman H, Blazier LA, Wing SE, Boyle FA, Radhakrishnan R, Stefanescu BM. Impact of a Sedation Reduction Protocol in Infants Undergoing MRI Scanning. Adv Neonatal Care. 2025 Apr 1;25(2):120-128. doi: 10.1097/ANC.0000000000001243. Epub 2025 Mar 21. PMID: 40117522.

Full text access for Children’s and Emory users.

Abstract
Background: Brain magnetic resonance imaging (MRI) is an important diagnostic tool for infants with possible brain abnormalities. While sedation may be necessary for high quality images, it carries risks of complications. The sedation rate for MRI procedure varies widely, ranging from 0% to 100%, influenced by infant characteristics and institutional practices, with an increasing focus on non-sedated or minimally sedated approaches to reduce risks.

Purpose: We studied sedation utilization in infants undergoing MRI scanning before and after implementing an MRI bundle.

Methods: This cohort study utilized a pre- post-intervention design. An MRI bundle, including a process map, a safety checklist and a questionnaire collecting detailed information on sedation, were developed for our off-unit MRI suite. Pre-intervention group included infants scanned March 2018 to February 2019, and Post-intervention group March 2019 to February 2022. We hypothesized that sedation rates would significantly decrease following the intervention.

Results: In the study, 229 infants in the Pre-Intervention group and 764 infants in the Post-Intervention group underwent MRI scanning. Sedation use decreased by 62%, from 29% pre-intervention to 18% post-intervention ( P = 0.0003). Post-intervention infants were 47.6% less likely to be sedated, adjusting for gestation-corrected age (OR 0.524 [0.369, 0.745]; P < 0.01). Each 1-week increase in gestation-corrected age was associated with a 7.1% increase in the odds of sedation, controlling for the intervention time-period (OR 1.071 [1.022, 1.122]; P = 0.004). The questionnaire was completed 72% of the time in the post-intervention group.

Implication for practice and research: A standardized approach and protocol development can significantly reduce sedation for neonatal MRI. This study offers guidance for future research and integrated care interventions across medical teams.