Combination of Dexmedetomidine and Ketamine for Magnetic Resonance Imaging Sedation

Objectives: The use of dexmedetomidine and ketamine (DEX-KET) combination for magnetic resonance imaging (MRI) sedation has not been evaluated. We investigated the efficacy and safety of DEX-KET for sedation of patients undergoing MRI of the brain. Methods: This quasi-experimental study was conducted to compare the DEX-KET combination and midazolam for MRI sedation. We included 72 patients undergoing brain MRI following bolus injection of midazolam or DEX-KET. In August 1, 2016 a new MRI sedation protocol was implemented. After protocol implementation, bolus doses of DEX-KET were administered (DEX-KET group). Thirty-six patients from the MIDA group and 36 patients from the DEX-KET group underwent MRI sequences and were compared regarding the MRI scan time and sedation-related complications (desaturation, hypotension, cardiorespiratory arrest, and aspiration pneumonia). Results: All MRI sequences were completed for 30 patients (83.3%) from the MIDA group and for 33 patients (91.7%) from the DEX-KET group (P = 0.476). The median MRI scan time was 100.0 min (interquartile range, 87.0-111.5 min) in the MIDA group and 53.5 min (interquartile range, 45.0-60.5 min) in the DEX-KET group (P < 0.001). Complications occurred in 24 (66.7%) and 8 (22.2%) patients of the MIDA and DEX-KET group, respectively (P < 0.001). Conclusions: The efficacy of DEX-KET sedation was comparable to that of midazolam for MRI examination. DEX-KET was related to shorter scan time and lower occurrence of complications compared to midazolam.