Device, apparatus and method for obtaining physiological signals by way of a feeding tube

Abstract

A neonatal feeding tube ( 10 ) includes electronics and instrumentation for monitoring a neonate and for provides nourishment to the neonate. The tube ( 10 ) includes electrodes ( 20 ) for sensing ECG signals of the neonate. Thermistors ( 22, 24, 28, 30 ) are placed at various points along the tube ( 10 ) to measure the neonate's temperature at those points. Breathing effort is measured by calculating a pressure differential at two pressure ports ( 32, 34 ). Pulse and SpO 2 are measured at a fiber optic window ( 35 ). The electrodes ( 20 ), a distal electrode ( 64 ) and a light source ( 66 ) aid in helping a caregiver position the tip ( 12 ) of the tube ( 10 ) correctly in the stomach of the neonate.

1 . An orogastric or nasogastric feeding tube comprising:
 a molded or jacketed build up of discrete parts such as lumen, wires, electromechanical components;   wire layered onto a center lumen that is over-molded, cast, or encapsulated after layering;   molded in-wall wires in a single lumen or a multi-lumen extrusion; or   a discrete wire bundle installed into one of multiple lumens, the multiple lumens physically separate a feeding path in one of the lumens from the electro-mechanical components;   tubular construction defining at least one lumen that provides a pathway for nourishment from outside of a subject into the stomach or small intestine of the subject; and,   at least one thermistor located within the tube, wherein the positioning of the tube automatically locates at least one thermistor to measure at least one of esophageal, nasopharyngeal, oropharyngeal and hypopharengeal temperature.   
     
     
         2 . The feeding tube of  claim 1 , wherein the tubular construction includes at least one of:
 a molded or jacketed build up of discrete parts such as lumen, wires, electromechanical components;   wire layered onto a center lumen that is over-molded, cast, or encapsulated after layering;   molded in-wall wires in a single lumen or a multi-lumen extrusion; or   a discrete wire bundle installed into one of multiple lumens, the multiple lumens physically separate a feeding path in one of the lumens from the electro-mechanical components.   
     
     
         3 . The feeding tube of  claim 1 , further including:
 a plurality of lumens, a wiring bundle, and/or optical fiber bundles substantially in a center of the lumens.   
     
     
         4 . The feeding tube of  claim 1 , further including:
 an oropharynx thermisto for monitoring a temperature and ΔT synonymous with flow of the subject in a region of the subject's pharynx;   a hypopharynx thermistor for monitoring a temperature of the subject inferior to the pharynx of the subject;   an esophageal thermistor for monitoring core temperature of the subject, and   wherein optionally at least one of the thermistor is a segmented thermistor.   
     
     
         5 . The esophageal feeding tube of  claim 1 , wherein:
 a supra-diaphragmatic pressure port for monitoring a pressure of the subject superior to the diaphragm of the subject;   a sub-diphragmatic pressure port for monitoring a pressure of the subject inferior to the diaphragm of the subject;   flush fibers.   
     
     
         6 . The esophageal feeding tube of  claim 1 , wherein at least one of:
 fiber-optic filaments that provide light to a fiber optic window adjacent to the jacket that senses pulse and SpO 2 ;   a soft molded tip that is attached to a distal end of the feeding tube; or   a light source at the tip of the feeding tube for visually tracking the tip of the feeding tube; or   a distal electrode at the tip of the feeding tube for indicating when the tip of the feeding tube passes into the stomach of the subject.   
     
     
         7 . The feeding tube of  claim 1  which implements a monitoring algorithm to select which of the electrodes has an optimal signal, whereby the algorithm can be implemented when the feeding tube is inserted or periodically as the subject grows and the feeding tube is repositioned. 
     
     
         8 . A method of inserting an esophageal feeding tube into a subject comprising:
 inserting the feeding tube into the esophagus of the subject;   advancing the feeding tube to a position estimated to place a tip of the feeding tube in a selected location in a stomach or small intestine of the subject;   sensing cardiac activity with at least two electrodes, of which at least two are active at any given time;   processing the sensed cardiac activity to compare waveforms at each of the segments measured; and,   analyzing the relative waveforms to determine when the feeding tube is located at the selected location, such as when the active electrode is adjacent an SA node to position the tip based on biometric or demographic information related to the patient, e.g. biometric information, age, gender, head circumference, or the like, and confirm that the tube is properly placed, should be further advanced, or should be retracted.   
     
     
         9 . The method of  claim 8 , wherein there are at least three electrodes and further including:
 selecting a subset of the electrodes that detect the equipotential cardiac signals to continuously monitor cardiac activity of the subject.   
     
     
         10 . The method of  claim 9 , further including at least one of:
 monitoring respiration signal or core temperature of the subject with an esophageal thermistor;   monitoring a temperature of the subject in a region of the pharynx of the subject with an oropharynx thermistor; or   monitoring a temperature of the subject inferior to the pharynx of the subject with a hypopharynx or esophageal thermistor.   
     
     
         11 . The method of  claim 10 , including:
 measuring a respiration effort by:   monitoring a pressure of the subject superior to the diaphragm of the subject with a supra-diaphragmatic pressure port;   monitoring a pressure of the subject inferior to the diaphragm of the subject with a sub-diphragmatic pressure port; and,   calculating a change in pressure to generate a respiration effort signal.   
     
     
         12 . The method of  claim 11 , wherein the feeding tube includes a tubular construction with at least one lumens that provides a pathway for nourishment and further including:
 providing light to a fiber optic window adjacent to the tubular construction with fiber optic filaments.   
     
     
         13 . The method of  claim 12 , including:
 visually tracking the tip through the thorax or abdomen with a light source and fiber optic component;   tracking the position of the tip with a distal electrode that conducts when in contact with the esophageal wall, and changes conductivity when it passes into the stomach of the subject;   tracking the tip during insertion by monitoring at least one of temperature and/or pressure for a fluctuating reading indicative of air flow channels and a constant reading indicative of location in the esophagus; and, As such, if ΔT or ΔP equals zero, then the tube is correctly placed into the esophagus;   verifying the tip is in the stomach after insertion by measuring the pH at the tip.   
     
     
         14 . The method of  claim 13 , wherein the analyzing step includes sensing relative strength of signals from the electrodes to select which of the electrodes are to be active and, optionally, as the patient grows, repeating the analyzing step to re-select which of the electrodes are to be active without repositioning the feeding tube.