[Monitoring of anesthesia during magnetic resonance imaging]

Clinical employment of magnetic resonance scanning presents great diagnostic possibilities, partly in the form of the quality of the imaging and also on account of the possibilities for carrying out spectroscopic measurements by mens of which in vivo non-invasive chemical analysis of drug concentrations in the tissues may be performed. In anticipation of the possibility of employing MR-scanning as an important diagnostic aid for assessing the causes of unconsciousness in patients in intensive care, attempts have been made to establish reliable and justifiable equipment for monitoring which can render possible investigation of unconscious or anaesthetized patients in scanners with magnetic fields of over 1.5 Tesla. The medical technical difficulties involved are mentioned and the solutions which are employed in the Danish scientific Centre for Magnetic Resonance in Hvidovre Hospital in Copenhagen are described. This monitoring includes continuous ECG recording, measurements of pulse and blood-pressure once per minute and continual monitoring of respiration including concentrations of carbon dioxide in the inspired and expired air and the concentration of oxygen in the inspired air. In addition, model solutions have be outlined for establishing mechanical ventilation with the servorespirator and the possibility of producing an employable pulse oxymeter is described. It is stated that, provided all of the elements in the above mentioned model solution for monitoring during anaesthesia in the MR laboratory have been carried out, it is considered justifiable to place all patients, including children, in the MR-scanner.