Circulatory monitoring of children during anaesthesia in low-field magnetic resonance imaging.

Anaesthesia for patients in a Magnetic Resonance Imaging (MRI) scanner provides some problems for the design of both the anaesthetic and the monitoring equipment. This report presents a technique for continuously displaying the heart rate during anaesthesia for children in an MRI scanner. The monitoring system used light to detect differences in skin capillary circulation, and the light was transferred to and from the patient via fiberoptic cables. After amplification, the signal was displayed "on line" on a cardioscope, thus continuously presenting heart rate and, in part, a qualitative view of the skin vascular resistance.