New articles relating to Magnetic Resonance Imaging (MRI)

Liu W, Yu Q, Jiang R, Liu F, Dong Y, Tang W. Comparison of Low-Dose Sevoflurane Inhalation With Intranasal Ketamine as Rescue Sedation After Intranasal Dexmedetomidine Failure in Outpatient Children Undergoing MRI: A Randomized Control Trial. J Perianesth Nurs. 2021 Jul 10:S1089-9472(20)30342-7. doi: 10.1016/j.jopan.2020.11.001. Epub ahead of print. PMID: 34257012.

Abstract
Purpose: The present study aimed to evaluate the effectiveness and safety of low-dose inhalation of sevoflurane through a face mask as a rescue remedy for sedation compared with intranasal ketamine in outpatient children undergoing magnetic resonance imaging (MRI).

Design: A prospective randomized control study. A total of 336 children scheduled for 3.0T MRI but were inadequately sedated after initial intranasal dexmedetomidine (3 μg/kg) were randomly divided into two groups.

Methods: We used the following protocol for each group: group S, inhalation of low-dose sevoflurane (end-expiratory concentration, 0.4%) through a face mask; group K, intranasal ketamine (2 mg/kg). The success rates were compared between groups as the primary endpoint. The induction time, scan time, recovery time, time to return to baseline functional status, parental and radiologist satisfaction, occurrence of adverse events, and other secondary endpoints were also compared.

Findings: Successful rescue sedation in groups S and K was achieved in 160 (95.2%) and 138 (82.1%) patients, respectively. Compared with group K, group S needed fewer repeat sequences and showed a significantly shorter induction time (5.7 ± 0.5 vs. 10.9 ± 2.7 min; P < 0.001), recovery time (27.4 ± 6.3 vs. 53.8 ± 15.2 min; P < 0.001), and time to return to baseline functional status (3.4 ± 0.6 vs. 6.1 ± 1.1 h; P < 0.001). Radiologist satisfaction, parental satisfaction, and parental desire to repeat the same sedation method were significantly higher in the sevoflurane group.

Conclusion: Our results suggest that the inhalation of low-dose sevoflurane through a face mask can provide effective and safe rescue sedation in 1- to 6-year-old outpatient children undergoing MRI, and yields a higher success rate, shorter induction and recovery times, and higher satisfaction than the intranasal ketamine method.

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Vinson AE, Peyton J, Kordun A, Staffa SJ, Cravero J. Trends in Pediatric MRI sedation/anesthesia at a tertiary medical center over time. Paediatr Anaesth. 2021 May 25. doi: 10.1111/pan.14225. Epub ahead of print. PMID: 34036674.

Abstract
Background: Each year, hundreds of thousands of children require sedation/anesthesia to facilitate MRI scans. Anesthetic techniques for accomplishing sedation/anesthesia vary widely between institutions and providers, with unclear implications for patient safety.

Aims: We sought to establish trends in anesthetic practice for pediatric MRI sedation/anesthesia across a 7-year period and determine rates of adverse events, considering technique used, age, and ASA physical classification status (ASA-PS).

Methods: Using established data resources, we analyzed 24 052 anesthetics performed by anesthesiologists for MRI scans between 5/1/2013 and 12/31/2019 on patients less than 18 years old, focusing on medications used, trends of use, and associated adverse events. Adverse events (hypoxia, hypotension, bradycardia) were defined by deviation from age norms and accessed via the electronic anesthetic record database. The Cochran-Armitage test was used to assess trends over time in categorical data, and one-way ANOVA was used to analyze continuous data. Multivariable logistic regression analysis was implemented to determine the independent associations between anesthetic technique and adverse events while adjusting for age, ASA-PS, and weight.

Results: The most significant trends noted were a decrease in “propofol-only” anesthetic techniques and an increase in propofol and dexmedetomidine combination techniques. Mild desaturation (80-89% SpO2 ) occurred in 4.22% of cases with more significant hypoxia much rarer (0.44% of cases having desaturation <70% SpO2 ). Bradycardia occurred in 2.39% of cases and hypotension in 1.75% of cases. Major adverse events were rare.

Conclusions: We provide the largest report of the nature of MRI sedation/anesthesia as practiced by anesthesiologists in a large children’s hospital. We demonstrate that, even in a large system, anesthetic techniques are pliable and shift significantly over time. Our data also support a high level of safety within our system, despite a case mix likely higher in risk than those in most of the previously published studies.

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Kim JY, Kim KN, Kim DW, Lim HJ, Lee BS. Effects of dexmedetomidine sedation for magnetic resonance imaging in children: a systematic review and meta-analysis. J Anesth. 2021 Aug;35(4):525-535. doi: 10.1007/s00540-021-02946-4. Epub 2021 May 18. PMID: 34002258.

Abstract
Purpose: Pediatric sedation is commonly required to obtain high-quality images in magnetic resonance imaging (MRI). We performed a systematic review and meta-analysis to assess the effects of dexmedetomidine sedation for MRI in children.

Methods: A systematic review was conducted to find all randomized controlled trials concerning dexmedetomidine sedation for MRI in children. We searched databases using the Ovid platform in the Cochrane Controlled Trials Register, MEDLINE, and EMBASE. This study was registered in the PROSPERO database: CRD42020198368.

Results: Seven studies and 753 participants were included. Dexmedetomidine sedation showed a significantly delayed onset time [weighted mean differences (WMD) = 8.13 min, 95% confidence interval (CI) 4.64 to 11.63, I2 = 98%] and recovery time (WMD = 5.22 min, 95% CI 0.35 to 10.09, I2 = 92%) compared to propofol, ketamine, and midazolam sedation. There was no difference in quality of sedation [risk ratio (RR) = 1.25, 95% CI 0.92 to 1.69, I2 = 89%], or incidence of sedation failure (RR = 1.39, 95% CI 0.53 to 3.66, I2 = 83%) between groups. Although a significantly decreased heart rate (WMD = – 17.34 beats/minute, 95% CI – 22.42 to – 12.26, I2 = 96%) was observed, bradycardia that required treatment was not increased (RR = 8.00, 95% CI 1.02 to 62.64, I2 = 0%). Dexmedetomidine sedation had a lower incidence of desaturation events (RR = 0.42, 95% CI 0.20 to 0.86, I2 = 4%). However, there was no difference in incidence of postoperative vomiting (RR = 0.42, 95% CI 0.15 to 1.17, I2 = 17%) between groups.

Conclusions: Dexmedetomidine sedation provided a similar sedation quality with a reduced incidence of desaturation events. However, the delayed onset and recovery times were drawbacks. The clinical significance of bradycardia is considered to be low. GRADE assessment revealed the quality of the evidence in this meta-analysis ranged from very low to moderate.

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Gürcan HS, Ülgey A, Öz Gergin Ö, Pehlivan SS, Yildiz KM. Investigation Of The Effects Of Propofol/Ketamine Versus Propofol/Fentanyl On Nausea-Vomiting Administered For Sedation In Children Undergoing Magnetic Resonance Imaging: A Prospective Randomized Double-Blinded Study. Turk J Med Sci. 2021 May 7. doi: 10.3906/sag-2009-98. Epub ahead of print. PMID: 33957724.

Abstract
Purpose: In this study, we aimed to compare the effects of propofol-ketamine and propofol-fentanyl sedations on post-procedure nausea-vomiting in children undergoing magnetic resonance imaging (MRI).

Materials and methods: This study included 100 pediatric patients (2-10 years old) who had propofol-ketamine and propofol-fentanyl for sedation to undergo MRI. The patients were divided into two groups, and sedation was performed through propofol-ketamine (Group K; n=50) or propofol-fentanyl (Group F; n=50). For sedation induction, intravenous (IV) bolus of 1.2 mg/kg propofol and 1 mg/kg ketamine were administered in Group K, IV bolus of 1.2 mg/kg propofol and 1 µg/kg fentanyl in Group F. All patients received 0.5 mg/kg IV bolus propofol in additional doses when the Ramsey Sedation Score (RSS) was below 4 for maintenance. Perioperative heart rate, systolic arterial pressure, peripheral oxygen saturation, respiratory rate, and nausea-vomiting scores were recorded for each patient.

Results: There was no difference between the groups in terms of nausea incidences at the 1st hour. However, the rate of vomiting was significantly higher in Group K.

Conclusion: In our study, we showed that the vomiting rate was higher in the 1st hour in Group K compared to Group F.

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Artunduaga M, Liu CA, Morin CE, Serai SD, Udayasankar U, Greer MC, Gee MS. Safety challenges related to the use of sedation and general anesthesia in pediatric patients undergoing magnetic resonance imaging examinations. Pediatr Radiol. 2021 May;51(5):724-735. doi: 10.1007/s00247-021-05044-5. Epub 2021 Apr 16. PMID: 33860861; PMCID: PMC8049862.

Abstract
The use of sedation and general anesthesia has facilitated the significant growth of MRI use among children over the last years. While sedation and general anesthesia are considered to be relatively safe, their use poses potential risks in the short term and in the long term. This manuscript reviews the reasons why MRI examinations require sedation and general anesthesia more commonly in the pediatric population, summarizes the safety profile of sedation and general anesthesia, and discusses an amalgam of strategies that can be implemented and can ultimately lead to the optimization of sedation and general anesthesia care within pediatric radiology departments.

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