[Remote artificial respiration and anesthesia in nuclear magnetic resonance imaging]

Ferromagnetic equipment and equipment driven by alternate current cannot be used close to patients undergoing magnetic resonance imaging. Therefore, we tested a ventilator (Siemens Servo 900-D) that was placed more than 7 m away from the patient (outside the magnetic influence of 1.5 teslas) using tubing measuring 9 m in length. Tubing for children above the age of 8 and adults had a width of 22 mm; for neonates and children up to the age of 8 the width was 10 mm. Since the compressed air in such long tubes must be taken into consideration, we plotted nomograms for children and adults that helped to estimate respiratory minute volume including the compressed volume and a table to read the volume of compressed air that has to be added to respiratory volumes already established for ventilated patients from the ICU. In eight patients aged 7 weeks to 56 years (4 to 75 kg body wt.), capnography and blood gases showed that the nomograms were sufficiently accurate to allow safe ventilation. To improve safety, remote monitoring is recommended using long tubing or lines for oscillometric blood pressure measurement, capnography, and pulse oximetry as well as telemetric ECG.