Paediatric Anaesthesia and Intensive Care
Background and Goal of Study: Recent studies has reported significant increases in body temperature in pediatric patients undergoing magnetic resonance imaging (MRI) under anaesthesia/sedation. We, therefore aimed to evaluate body temperature changes in pediatric patients undergoing MRI scanning under general anaesthesia.
Materials and Methods: 30 patients aged between 0-7 and undergoing cranial/orbital MRI scan under general anaesthesia were included to this prospective study. Children were taken to MRI suite while their parents were accompanied to them. Anaesthesia was induced with sevoflurane (8%) via facemask. We used an MRI-compatible anaesthesia machine and an MRI-compatible vital signs monitor. After an i.v. route was established, anaesthesia was maintained with sevoflurane in oxygen 100% via laryngeal mask airway. Scans were performed on a 1.5-Tesla MR system. Tympanic temperature was monitored on right ear just before the patient was positioned in the head coil. At the end of MRI scan, temperature monitoring was performed again. Shapiro-Wilk, unpaired and paired t test and Mann Whitney-U were used for data analysis.
Results and Discussion: Mean age of the patients was 19.3 months. Body temperature was found as decreased 0.4 °C, when pre-scan and post-scan temperatures were compared (< 0,001). Body temperature was decreased in 21 patients (70.0%), was increased in 8 (26.7%), and showed no change in 1 patient (3.3%) in the study. Increases were not above 1 °C in any patient. When patients whose body temperatures were decreased or showed no change were compared with those whose body temperatures were increased, mean age of patients with increases were detected as lower than the others (p=0.008). MRI scanner generates radiofrequency radiation which is absorbed by the patient. This can cause local or systemic warming during scanning. Conversely, cool environment with low humidity required for proper magnet function is a potential cause for a decrease in body temperature. Children are known to be more prone to hypothermia. Anaesthesia/sedation also impairs thermoregulation. So, either warming or cooling may occur in these patients depending of these opposite factors.
Conclusion(s): Anaesthesiologists should be aware of that both a rise or a decrease in body temperature can be seen in anaesthetised pediatric MRI patients. Temperature monitoring should be implemented in these cases.