Modular design of a real-time passive magnetic localization system for enhanced safety in nasogastric intubation

Nasogastric (NG) intubation is a commonly performed clinical procedure to gain direct access to the stomach. This procedure is usually done blind without visual feedback; and final confirmation of correct placement is usually achieved using radiography. Hence lacking of real-time localization, the current clinical practice poses high risks of erroneous placement which could potentially cause morbidity and mortality. In this paper, we present a modular design of a passive magnetic field-based, real-time localization system to detect possible erroneous placements at key locations along the upper gastrointestinal tract. Three high risk areas during the intubation process were identified and three independent modules were developed to target these three regions of interest namely: laryngopharynx, carina of the lungs and stomach respectively. A modular approach and design allows the system to be easily adapted to different patients by positioning the modules with reference to the corresponding anatomical landmarks. Verification tests were performed on a manikin model and a soft cadaver. In both environments, the proposed modular system is efficacious in detecting different types of misplacements, such as incorrect insertion to the respiratory system and tube coiling. With the proposed modular system, the clinician can determine and prevent any erroneous placement in real-time. It is expected that this approach could eventually replace the radiography confirmation, which is both expensive and time-consuming, in the current clinical routine.