Sedation and monitoring of paediatric patients undergoing open low-field MRI

The purpose of this study was to determine the need, effectiveness and safe ty of sedation and monitoring in infants and children in a paediatric open low-field MRI system. Of 274 patients (median age 9 y) examined, only 74 ch ildren (median age 25 mo) needed sedation. Sedation was achieved by intrave nous administration of midazolam (0.2 mg/kg) and etomidate (0.2 mg/kg). Mea n total doses required were 0.28 and 0.27 mg/kg, respectively. With the exc eption of eight primarily ventilated patients, all children breathed sponta neously. O-2 saturation, arterial blood pressure and ECG were monitored. Th e low resonance frequency of the MRI system required a specially designed h igh frequency (HF) shielding of the monitor system to avoid HF artifacts. T he overall sedation rate was markedly lower (74/274 = 27%) compared to a co ntrol group previously examined in a closed high-field MRI system (52/111 = 47%). This was due to a significant lower need for sedation in patients ag ed up to 10 y (p less than or equal to 0.0001) in the open MRI unit. Genera l anaesthesia could be avoided in all patients. No significant movement art ifacts occurred in any of the MRI examinations and no serious side effects were observed. Conclusions: MRI of children is easier in an open MRI system and with fewer sedations, as in closed high-held systems. Sedation by a combination of mi dazolam and etomidate is highly effective and safe Monitoring devices fur h igh-field systems may have to be modified for low-field systems. An in-hous e paediatric MRI unit with an open and special paediatric design is of majo r advantage for imaging paediatric patients.