NZ323604A

NZ323604A - Enteral feeding tube system used to assist in tube placement

Info

Publication number: NZ323604A
Application number: NZ323604A
Authority: NZ
Inventors: Todd C Tomba; James P Hayes; Howard Levy
Original assignee: Abbott Lab
Priority date: 1995-11-28
Filing date: 1996-11-21
Publication date: 2000-06-23
Also published as: CA2237912A1; JP2000501304A; AR004329A1; BR9611823A; EP0959869A1; WO1997019667A1; AU1059097A; MX9804173A

Abstract

A system and method are described in which myoelectric signals within a patient's body are detected by electrodes secured to the distal end of a gastrointestinal feeding tube, and are promptly displayed by some means and made available to a medical care provider while placing the tube in the patient. The signals detected indicate where the distal end of the tube is located within the gastrointestinal tract at any moment during the insertion of the tube into a patient's body.

Description

<div class="application article clearfix" id="description"> Intellectual Properly GfT.ce of New Zealand IP Summary Report Page: 1 of 1 Date: 18 May 2000 Time: 15:46:09 (iprip02 2.00.21) (51) Classification: A61B5/0488, A61J15/00 IPC Edition: IPC Status: 70 Accepted 323604 Client Ref: I P38B295 TVG/adb Version number 4 - , IP type: Patent PCT Inward <87) WO Publication number: Elected: Y (88) International Application number: US98J18777 97/10687 Date actions completed: Application Accepted 18 May 2000 Next renewal dote: 17 December 2000 (22) NZ Filing date: 17 December 1996 Date entered National phase: 31 March 1998 (30) Priority Dats: (31)95 583323 (32) 28 November 1995 (33) US (71) Applicant: ABBOTT LABORATORIES, Chad 0377/AP6D-2, 100 Abbott Park Road, Abbott Park, Illinois 60064-3500, United States of America (72) Inventors: Tomba, Todd C Hayes, James P Levy, Howard Contact: A J PARK, 6th Floor, Huddart Parker Building, 1 Post Office Square, Wellington, New Zealand Primary Examiner: GEOFF QUAYE Journal: 1452 Office title: Enteral feeding tube system used to assist In tub" placement (54) Applicant title: Enteral feeding tube system used to assist In tube placement (67) \ be tract: Patent 323804 A system and method are described in which myoelectric signals within a patient's body are detected by electrodes secured to the distal end of a gastrointestinal feeding tube, and are promptly displayed by some means and made available to a medical care provider while placing the tube In the patient. The signals detected indicate where the distal end of the tube is located within the gastrointestinal tract at any moment during the insertion of the tube into a patient's body. " End of report " WO 97/19667 PCT /US96/18777 i enteral feeding tube system used to assist in tube placement BACKGROUND AND SUMMARY OF THE INVENTION In many patients, gastrointestinal feeding is the preferred route of nutrient delivery with either the stomach or the small intestine being the areas of mayor importance. Proper positioning of the feeding end of an enteral feeding tube in the desirej area of the gastrointestinal tract has always been a problem. Even after proper positioning of the feeding end of a feeding tube in either the stomach or the small intestine, it is possible that the feeding end of the tube may unknowingly migrate from the selected area, whereupon the patient may be subjected to a risky feeding situation. A common method of initially positioning and then monitoring the position of the feeding end of such a gastrointestinal feeding tube has been to use an x-ray. To repeatedly verify proper placement in this manner is not only cumbersome, time consuming, and expensive, but it also subjects the patient to unnecessary x-ray exposure. Post-pyloric feeding is often desirable in critically ill patients. Some studies have shown that only about 5 to 15% of feeding tubes pas9 spontaneously into the small bowel in critically ill patients. Post-pyloric feeding tube placement is difficult, frequently requiring time consuming blind attempts, transport to radiology for fluoroscopic guidance or a bedside et.joscopic procedure. Proper placement and verification of a feeding tube can take an hour or more depending on all of the circumstances involved. Erythromycin is a motilin analog which promotes gastric motility by stimulating the gastric migrating motor complex. Use of erythromycin has been demonstrated to facilitate spontaneous post-pyloric passage in patients. Recording of an electromyogram (EMG) from the wall of the gastrointestinal tract allows differentiation between gastric and small Printed from Mimosa WO 97/19667 PCT/US96/18777 32360 A bowel location. The results of an EMG recorded from the stomach compared to the results of an EMG recorded from the duodenum will show a sharp contrast. For example, signals originating from the stomach will have a dominant frequency of approximately 3 cpm (cycles per minute) whereas signals originating from the duodenum will have a dominant frequency of about 11 or 12 cpm. The present invention takes advantage of the contrast between the electrical signals that can be detected from the stomach and the signals that can be detected from the small bowel. A feeding tube having at least one electrode secured on an end of the feeding tube may be used to detect signals received from the electrode(s) on the end of the feeding tube. A physician can thereby know the location of the feeding tube without resorting to x-rays or other cumbersome procedures. Accordingly, in a first aspect, the present invention provides a method for placing f? feeding tube within a patient, the method comprising the steps of (a) providing means for obtaining signals from a distal end of said feeding tube; (b) inserting said feeding tube distal end into said patient; (c) displaying graphically signals naturally occurring at a first location within the patient as said feeding tube distal end is located proximate said l irst location; (d) continuing insertion of the feeding tube into the patient while the feeding tube distal end is located proximate the first location as indicated by the graphically displayed signals; (e) displaying graphically signals naturally occurring within a second location of the patient as said feeding tube distal end enters said second location; and (e) stopping insertion of said feeding tube into said patient when the feeding tube distal end is located at the second location as indicated by the graphically displayed signals. In a further aspect, the present invention provides a method for monitoring a feeding tube placement within a patient, the method comprising the steps of (a) providing means for obtaining signals from a distal end of said feeding tube; (b) inserting the distal end of the feeding tube into the patient; and (c) displaying graphically in a continuous and real time manner said signals naturally occurring from a location within the patient proximate the distal end of the feeding tube. In a still further aspect, the present invention prov^es a system for enteral feeding utilizing gastrointestinal myoelectrography, the systei^^i^^i^^™— feeding tube having a proximal end and a distal end configure i to be in^frfbfl in I 1 JAN 2000 (followed by page 2a) RECEIVED 2a (followed by page 3) 323604 a patient; (b) at least one electrode secured to said distal end of said feeding tube to obtain signals occurring naturally within the patient; (c) a monitor configured to display graphically signals continuously obtained by the al least one electrode, the monitor in electrical communication with said at least one electrode at said distal end of said feeding tube; and (d) means in association with said monitor and said at least one electrode for detecting and promptly displaying graphically on the monitor a naturally occurring signal within said patient's stomach in substantially real time when said distal end of the feeding tube is in said stomach, and for detecting and promptly displaying graphically on the monitor a naturally occurring signal in said patient's small bowel in substantially real time when said distal end of the feeding tube is in said small bowel. Erythromycin may be administered to enhance gastric motor activity during insertion of the feeding tube. With the electrode(s) placed at the distal tip of the feeding tube, the feeding tube is first guided into the stomach. The signals obtained from the stomach are generally about 3 cpm in frequency and have relatively large amplitude. As the distal tip of the feeding tube passes into the small bowel, the resident signals increase generally to about 10 to 13 cpm in frequency at a much lower amplitude. Frequency and amplitude of the signals can be monitored in substantially real time at the bedside of the patient using, for example, a computer monitor or a printer to show the graphical representation of the frequency and/or amplitude of the signals. The present invention offers several advantages. First, the present invention allows for substantially real time feedback of the location of the feeding tube tip as it is being guided into the patient's body. Second, the present invention minimizes radiation exposure, since x-rays are no longer needed or can be minimized by use of the present invention. A third advantage of the present invention is that the elapsed time from the beginning of the insertion of the feeding tube to the RECElVFn I WO 97/19667 PCT/US96U8777 3 time in which feeding can begin may be substantially less than when using prior methods, especially if the present invention is used along with a prokinetic agent. It should also not be overlooked that the present invention is beneficial in that it may cause less discomfort to the patient 5 since the feeding tube may be placed much more quickly. A final consideration is cost, which may be signify ^.itly lower using the method of the present invention. The assignee of the present invention is also the owner of VJ.S. Patent No. 4,921,481 which issued on May 1, 1990, and is entitled Enteral 10 Feeding System Utilizing Gastrointestinal Myoelectrography. U.S. Patent No 4,921,481 is hereby incorporated by reference into the present application. Other objects and advantages of the present invention will become more apparent when considered in view of the following detailed 16 description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a plan <riew of the feeding tube of a preferred 20 embodiment of the present invention; Figure 2 is an end view taken in the direction of lines 2-2 of Figure 1; Figure 3 is a perspective view of one embodiment of a data acquisition system of the present invention; 25 Figure 4A is a view of an electromyogram signal from the stomach of a patient, showing, generally, a 3 cpm frequency; Figure 4B is a view of an electromyogram signal from the small bowel of a patient, which generally reveals a 10 cpm frequency; Figurs 4C is a view of an electromyogram signal in transition, 30 reflecting the real time contrast between Figures 4A and 4B; Figure 5 shows c schematic representation of a portion of a patient's digestive tract; Figure 6 is a schematic representation of the feeding tube of the present invention with its distal end located within a patient's stomach; Printed from Mimosa WO 97/19667 PCT/US96/I8777 4 Figure 7 is a diagrammatical representation of a preferred signal acquisition system of the present invention; and Figure 8 is a diagrammatical representation of another embodiment of the present invention in which a large physiological 5 signal acquisition monitor system incorporates the signal acquisition of the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, in Figure 1 a feeding tube 10 is 10 shown that may be used in the present invention. A Flexiflo 10F feeding tube with internal stylet 12 such as made by Ross Products Division of Abbott Laboratories in Columbus, Ohio, is shown modified by the placement of three silver wire electrodes 14, preferably arranged at four, six and eight centimeters from the tip 13 (shown in Figure 2) to record 15 EMG signals by contact with the mucosa. As shown in Figure 7, the signal transmitted from the electrode(s) is filtered and amplified by an amplifier, such as a R1000 research amplifier 16 made by Ross Products Division of Abbott Laboratories. The signal may be conditioned by a bandpass filter that may operate from 0.03 to 15 Hz with a 40 dB per 20 decade roll-off Signal gain may be controlled by an internal switch. A 2 pole high pass filter may be incorporated with a cut ofT frequency of 0.03 Hz and a 6 pole low puss filter may be set with a cut ofT frequency of 1 Hz. A variety of electrode configurations may be used containing, preferably two or more electrodes 36, 38 to obtain a signal. One of the 25 electrodes would be used to provide a reference. Three or more electrodes may be used at the distal end of the tube to offset naturally occurring noise levels in the gut. The myoelectrical gastrointestinal signal may be digitized, preferably, by a 12 bit A/D board on a personal computer 20 and can be 30 stored on disc or printed as a real time amplitude-time plot. Gastric signals 40 in the stomach are generally of relatively high amplitude with a frequency of 3 cycles per minute as shown in Figure 4A, while the duodenal signals 42 are generally low amplitude with frequencies of 10 Printed from Mimosa WO 97/i 9667 PCT/US96/18777 5 to 13 cycles per minute as shown in Figure 4B. Erythromycin lactobionate may be infused at initiation of the procedure of inserting the feeding tube 10 into a patient 11, at a preferred dose of 3 mg/Kg given over ten minutes. The erythromycin enhances the 5 gastric migratory motor complex activity and accelerate gastric emptying, which may result in a more rapid duodenal placement of the feeding tube tip. The feeding tube 10 may be of a nasoenteric type to be ultimately located in the stomach 30 or small bowel 32, and its position confirmed 10 by auscultation and EMG real time printout. The tube i3 then slowly advanced into the patient until the duodenal EMG is detected on a continuous record. If the small bowel 32 signal is not detected, the feeding tube 10 is withdrawn and advanced again until it is successfully located in a postpyloric position. Figures 5 and 6 show the placement of IS a feeding tube 10 within a patient 11. A medical care provider, such as a physician, may carefully monitor the progression of the feeding tube into the patient, by viewing a display monitor 26 or a continuous printout 25 from a chart printer 24 for example, as shown in Figure 3. The monitor 26 or printer 24 may be 20 placed on a mobile cart 27 and moved to a patient's bedside prior to introducing the feeding tube. The feeding tube is electrically connected to the monitor or printer so that signals detected by the electrodes on the feeding tube are received by the display device. The medical care provider would be trained to look for the characteristic signals on the 25 display monitor or printout which reveal the location of the feeding tube during the insertion procedure. As the feeding tube enterB the patient's stomach, the medical care provider will be able, simultaneously, to see the frequency and amplitude characteristics of stomach signals 40, on the monitor or real-time printout. 30 Figure 4A is a representation of what the medical care provider would see on a monitor or printout as the feeding tube enters the patient's stomach. As the feeding tube continues to be inserted, it will arrive in the Printed from Mimosa WO 97/19667 PCT/US96/18777 6 duodenum. The medical care provider will be able, simultaneously, to see the frequency and amplitude characteristics of duodenum signals 42, on the monitor or real-time printout. Figure 4B is a representation of what the medical care provider 5 would see on a monitor or printout as the feeding tube enters the patient's duodenum. Figure 4C shows the transition over time (i.e. - over several seconds or a few minutes, depending on the rate at which the medical care provider is inserting the feeding tube) as the feeding tube moves 10 from the patient'8 stomach to the patient's duodenum. The noticeable change in the frequency and amplitude of the signal shown in Figure 4C is an indication that the feeding tube has moved from the stomach to the duodenum. With this live source of up-to-the-minute, accurate, bedside information, medical care providers can quickly and properly place a 15 feeding tube within a patient. The feeding tubes may be initially inserted into a patier.t 11 through the nose, but may also be inserted through the mouth or even through the skin in the abdominal region of the patient. An enteral tube can be used for feeding the patient, for checking food absorption levels, 20 as a means for inputting drugs, and as a means for degassing the stomach, among other uses known to those of skill in the art. In a preferred embodiment of the present invention erythromycin is used as a motility agent to assist in the advancement of the tube into the small bowel of the patient; however, other prokinetic agents may be used 25 which would alBo stimulate the gut. The tube may be physically advanced by a medical care provider carefully guiding the tube into the patient until the distal end 13 of the tube 10 arrives at its intended location. The tube may also be inserted into the patient and then allowed to naturally migrate into the region .10 where it is intended to supply its function. Figure 8 shows the present invention aB a part of a physiological patient monitor system in which multiple signals are obtained from a plurality of different data monitors. A total patient condition record may Pt iri'.ed from Mimosa WO 97/19667 PCT /US96/18777 7 be stored at a channel bank 50 which forms a part of the system. While there has been shown and described several possible embodiments of the invention, it will be obvious to those of skill in the art that changes and modifications may be made without departing from the invention, and it is intended by the appended claims to cover all such changes and modifications aa fall within the true spirit and scope of the invention. Printed from Mimosa </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 8 323604 WHAT WE CLAIM IS:

1. A method for placing a feeding tube within a patient, the method comprising the steps of: providing means for obtaining signals from a distal end of said feeding tube; inserting said feeding tube distal end into said patient; displaying graphically signals naturally occurring at a first location within the patient as said feeding tube distal end is located proximate said first location; continuing insertion of the feeding tube into the patient while the feeding tube distal end is located proximate the first location as indicated by the graphically displayed signals; displaying graphically signals naturally occurring within a second location of the patient as said feeding tube distal end enters said second location; and stopping insertion of said feeding tube into said patient when the feeding tube distal em' is located at the second location as indicated by the graphically displayed signals.

2. The method of claim 1, wherein the step of providing means for obtaining signals from said feeding tube includes providing at least one electrode on the distal end of said feeding tube.

3. The method of claim 1, wherein at least one of the steps of displaying signals includes providing a display monitor and displaying on said monitor a graphical representation of said signals.

4. The method of claim 1, wherein the steps of displaying are performed in a substantially continuous manner throughout the insertion of said feeding tube within said patient. OF N.Z. 323604

5. The method of claim 1, wherein at least one of the steps of displaying is performed using a display monitor.

6. The method of claim 1, wherein at least one of the steps of displaying is performed using a strip chart printer providing substantially continuous graphical output representing said signals.

7. The method of claim I, wherein at least one of the steps of displaying is performed in a substantially real time manner.

8. The method of claim 1, wherein the step of inserting the feeding tube distal end includes the step of administering erythromycin to enhance feeding tube insertion.

9. The method of claim 8, wherein the step of administering erythromycin is performed at a dose of 3 mg/Kg over a period of ten minutes.

10. A method for monitoring a feeding tube placement within a patient, the method comprising the steps of: providing means for obtaining signals from a distal end of said feeding tube; inserting the distal end of the feeding tube into the patient; and displaying graphically in a continuous and real time manner said signals naturally occurring from a location within the patient proximate the distal end of the feeding tube.

11. A system for enteral feeding utilizing gastrointestinal myoelectrography, the system comprising: a feeding tube having a proximal end and a distal end configured to be inserted in a patient; at least one electrode secured to said distal end of said feeding tube to obtain signals occurring naturally within the patient; a monitor configured to display graphically signals continuously obtained by the al least one electrode, the monitor in electrical communication with said at least one electrode at si feeding tube; and 0F N z f 1 1 JAN 2000 32360 4 means in association with said monitor and said at least one electrode for detecting and promptly displaying graphicallyon the monitor a naturally occurring signal within said patient's stomach~ real time when said distal end of the feeding tube is in said stomach, and h for detecting and promptly displaying graphically on the monitor a naturally occurring signal in said patient's small bowel in substantially real time when said distal end of the feeding tube is in said small bowel.

12. The system of claim 11, wherein said means in association with said monitor and said at least one electrode includes a signal conditioner plus amplifier.

13. The system of claim 11, wherein said monitor is a personal computer display monitor.

14. The system of claim 11, wherein said monitor is a strip chart printer.

15. The system of claim 11, wherein said feeding tube is a nasoenteric tube.

16. The system of claim 11, wherein said signal detected within said patient's stomach is about 3 cycles per minute in frequency.

17. The system of claim 11, wherein said signal detected in said small bowel is about 10 to 13 cycles per minute in frequency.

18. A method as defined in claim 1 for placing a feeding tube within a patient substantially as herein described with reference to any example thereof and with or without reference to the accompanying drawings.

19. A method as claimed in claim 10 for monitoring a feeding tube placement within a patient substantially as herein described with reference to any example thereof and with or without reference to the accompanying drawings.

20. A system as defined in claim 11 for enteral feeding utilizing gastrointestinal myoelectrography substantially as herein described with reference to any example thereof and will to the accompanying drawings. I . . 11 JAN 2000 By tho authorised aQOfltS I A J PARK & SON Ireceh" Pw /U^ </div>