Sedation for MRI in Children
abstract & commentary
Source: Lawson GR. Controversy: Sedation of children for magnetic resonance imaging. Arch Dis Child 2000;82: 150-154. Subsequent commentary by R.J. Bray.
Magnetic resonance imaging (mri) of the brain is among the most commonly ordered of neurological tests. Performance of a useful MRI study requires that a patient be as still as possible for periods of 15 minutes or more; logistically, this means that most children aged 1-7 years needing these studies will also need some degree of sedation and, thus, will be exposed to some degree of risk. The article by Lawson and commentary by Bray highlight British views on this problem. There seems to be a consensus among physicians that young children require deep rather than conscious sedation due to the relatively high failure rate of the latter. Somewhat surprisingly, British and American guidelines for MRI sedation differ with respect to the need for patient monitoring by an anesthesiologist; British guidelines oppose the administration of deep sedation without an anesthesiologist present, while American guidelines permit this. Clearly, the need for an anesthesiologist would increase the cost of MRI, but would it necessarily make the procedure safer?
According to available American data (Cotè CJ, et al. Anesthesiology 1995;83:183) for the last 28 years, there were 52 sedation-related deaths among patients younger than 21 years of age, 22 of which involved patients younger than 4 years old. Fourteen of these deaths occurred in the context of radiological studies. Among the 52 deaths, 38 were associated with drug overdosage, and 25 had inadequate monitoring, presumably factors that might be greatly reduced if an anesthesiologist were present. Unfortunately, the denominators in these studies are unknown, so no incidences can be computed.
The issue of MRI sedation in children is one that a practicing child neurologist would be likely to face on a daily basis. Given this challenge, it is somewhat surprising that the literature carries little objective information about the problem. Much more work will need to be done in order to define optimal sedation protocols and to define subgroups at high risk for complications from a specific sedative.
Neurology Alert suggests that pediatric, anesthesiological, radiological, and neurology societies should work together to develop rational guidelines for the administration and monitoring of MRI sedation in children. If possible, a highly-trained practitioner (anesthesiologist or nurse anesthetist) should be available to monitor the patient and intervene as necessary. Monitoring should include both pulse oximetry and some measurement of chest movement. —rt