This application claims the benefit under 119(e) of US provisional patent application 60/632,739, titled "Add on Electrode for Endoscope", filed December 1, 2004, US provisional patent application 60/653,135, titled "Endoscopic Sheath with Illumination System", filed February 16, 2005, and US provisional patent application 60/669,007, filed April 7, 2005, titled "Emergency Electrode on Medical Tube". The disclosures of all of these applications are incorporated herein by reference.

FIELD OF THE INVENTION The present invention relates generally to cardioversion and specifically to minimally invasive apparatus for tasks other than cardioversion, which are designed to be useful also for cardioversion, when necessary.

BACKGROUND OF THE INVENTION

Minimally invasive tools may be inserted through a patient's throat to the patient's stomach or esophagus.

Nasogastric and gastric tubes are used for feeding patients that have problems eating on their own. In addition, nasogastric tubes are used for pumping liquids out of the stomach. The nasogastric tube is passed through a patient's nose into the stomach. In some cases, the nasogastric tube remains in the patient's stomach for a few days. U.S. patent 4,369,789 to Leveen et al., the disclosure of which is incorporated herein by reference, describes an inflatable oral-nasal gastric tube.

It is important to verify that the distal end of the nasogastric tube is properly positioned in the patient's stomach before passing food through the tube as the tube may move out of the stomach, for example into the trachea, where administration of food may be harmful to the patient.

U.S. patent 5,316,024 to Hirschi et al., the disclosure of which is incorporated herein by reference, describes a resonance circuit attached to a tube, for allowing determination of the position of the end of the tube, by an external probe.

Other minimally invasive tools include catheters with electrodes for electrical treatment and/or ultrasonic probes for imaging. These tools are used for short term treatment of the patient's heart.

U.S. patent 5,556,425 to Hewson et al., the disclosure of which is incorporated herein by reference, describes an esophageal/stomach electrode for electrically stimulating the

ventricle of the heart. Such stimulation may be required, for example, for defibrillating and pacing the heart and/or stimulating breathing. Internal stimulation from the esophagus is generally more efficient and successful than external cardioversion. Internal stimulation uses less power, and therefore is less likely to burn the patient and/or pass dangerous current levels through sensitive body organs that may be damaged by high currents.

U.S. patent 4,960,133 to Hewson, the disclosure of which is incorporated herein by reference, suggests an esophageal catheter with electrodes for heart defibrillating or pacing. The catheter is in the form of a tube closed at its distal end, with small suction ports near the electrodes, to allow application of suction, for drawing the electrodes against the esophagus. U.S. patent 5,179,952 to Buinevicius et al., the disclosure of which is incorporated herein by reference, describes an electrocardial stimulation probe which may carry a feeding tube within it.

The insertion of the above described electrical stimulation tools into the esophagus requires some expertise. In some cases, the insertion of these tools must be performed in emergency situations when the patient's heart has failed. It is important to reduce the time required until electrical heart stimulation is performed in such emergency situations.

U.S. patent 6,363,937 to Hovda et al. and U.S. patent 6,746,447 to Davison, the disclosures of which are incorporated herein by reference, describe an electrosurgical catheter for applying electrical energy to a target location in the gastrointestinal track. The catheter includes electrodes and a channel for delivering an electrically conducting fluid to the electrode.

U.S. patent 4,735,206 to Hewson, the disclosure of which is incorporated herein by reference, suggests inserting an electrode catheter to the esophagus through a previously inserted gastric tube. U.S. patent 6,532,388 to Hill et al., the disclosure of which is incorporated herein by reference, describes an esophageal electrode device for use during surgery. Electrical signals may be applied to the heart also from the trachea. U.S. patent 4,351,330 to Scarberry, the disclosure of which is incorporated herein by reference, describes an emergency resuscitation apparatus including an endotracheal and/or esophageal tube.

U.S. patent 5,080,107 to Teves, the disclosure of which is incorporated herein by reference, describes an endotracheal tube with electrodes for atrial pacing, for use during surgery.

U.S. patent 5,125,406 to Goldstone et al., the disclosure of which is incorporated herein by reference, describes an electrode endotracheal tube, for detecting electro-myographic signals in the laryngeal muscles.

PCT publication WO 01/32249 to Geddes et al., the disclosure of which is incorporated herein by reference, describes a tracheotrode and tracheal electro-ventilation system.

SUMMARY OF THE INVENTION

An aspect of some embodiments of the present invention relates to inserting a feeding tube, such as a gastric tube or nasogastric tube, into a patient, with at least one electrode suitable for electrical stimulation of a body organ (e.g., heart) and/or suitable for signal sensing from the body organ, mounted thereon. In some embodiments of the invention, if an emergency occurs and the patient needs, for example, electrical stimulation, cardioversion or pacing, electrical signals may be applied immediately using at least one electrode on the feeding tube. The internal stimulation from within the esophagus may be performed without requiring removal of the feeding tube and insertion of a cardioversion catheter. In some embodiments of the invention, a nasogastric tube is produced with an electrode mounted toward its distal end and wires connecting to the electrode running along the length of the tube, for example embedded within the walls of the tube. Alternatively or additionally, the electrode is coupled to a circuit for wirelessly receiving power, for wirelessly receiving control signals and/or wirelessly transmitting sensed signals. Further alternatively, an add-on electrode may be added to a feeding tube before the tube is inserted into the patient, for example into a patient having a high risk for conditions requiring electrical stimulation.

The feeding tube is optionally adapted for long term use of at least 3 hours, 6 hours, 12 hours or even 24 hours. In some embodiments of the invention, the feeding tube is suitable for placement in the patient for three or more days. Optionally, the feeding tube is used in a patient at least partially not during intensive medical treatment, such as surgery. The feeding tube optionally comprises a simple tube, which is primarily directed for feeding and does not include apparatus for surgery and/or emergency handling, such as a pharyngeal cuff, laryngeal tube or a teeth shield.

An aspect of some embodiments of the present invention relates to inserting into a patient, an invasive probe adapted to perform a medical task other than electrical stimulation of an organ, with an electrode suitable for stimulation mounted thereon, although the patient does not currently require a procedure using the electrode. In some embodiments of the invention, '

the patient has a risk of requiring an electrical stimulation procedure (e.g., cardioversion) of less than 10%, 5% or even 1%, at the time the invasive probe is inserted.

In some embodiments of the invention, the electrodes are not connected to an apparatus for generating electrical stimulation signals at the time the invasive probe is inserted into the patient. Possibly, apparatus for generating electrical signals is not in the same room as the patient at the time that the invasive probe is inserted into the patient.

An aspect of some embodiments of the present invention relates to an invasive tube, which includes only a single electrode, adapted for cardioversion, mounted thereon. The placement of only a single electrode on an invasive tube is considered, in accordance with an exemplary embodiment of the invention, most cost effective for a tube that has a relatively low chance for requiring the use of the electrode. The invasive tube may include, for example, a tracheal tube or a feeding tube.

An aspect of some embodiments of the present invention relates to an invasive tube suitable for placement within a patient for at least 6 hours, not during surgery, which includes an electrode mounted thereon. Optionally, the electrode is mounted on the tube at a position best suitable for cardioversion and/or closest the heart along the tube, when the tube is in its designated position.

In some embodiments of the invention, the invasive tube comprises an endotracheal tube which is adapted for intubation and/or intensive care and not for surgery or for emergency patient handling. In some embodiments of the invention, the endotracheal tube is connected to a mechanical ventilation machine.

There is therefore provided in accordance with an exemplary embodiment of the invention, a food administering apparatus, comprising a feeding tube, having a distal outlet and proximal inlet, adapted for insertion of the distal outlet into the stomach of an adult patient while the proximal inlet is outside the patient, the tube being suitable for administering food or medicine from a proximal port to the distal outlet, and at least one electrode mounted on the tube. Optionally, the at least one electrode mounted on the tube is embedded within the tube.

Optionally, the apparatus includes an electrical port coupled to the electrode, adapted to receive electrical power from an electrical source outside a patient. Optionally, the port is adapted to receive electrical power from an electrical source outside the patient, wirelessly.

Optionally, the port is adapted to receive electrical power from an electrical source outside the patient, through wires. Optionally, the apparatus includes at least one wire leading from the at

least one electrode to a distal area of the tube. Optionally, the distal outlet has a size of at least 6 French.

Optionally, the distal outlet comprises an opening substantially perpendicular to an axis of the tube. Optionally, the distal outlet has an area greater than 70% of the cross-sectional area of the tube. Optionally, the at least one electrode comprises a plurality of electrodes. Alternatively, the at least one electrode comprises only a single electrode. Optionally, the at least one electrode is located within 2 centimeters from the distal end of the tube. Optionally, the at least one electrode surrounds the tube substantially entirely. Optionally, the at least one electrode is located along the tube at a position close to an average person's heart, when the distal end of the tube is within the person's stomach. Optionally, the tube is adapted for being positioned within a patient for at least 24 hours.

Optionally, the tube comprises a wall, having an inner side adapted for being in contact with administered food or medicine and an outer side on which the at least one electrode is mounted. Optionally, the apparatus includes only a single tube. Optionally, the single tube defines only a single channel. Optionally, the tube has a length of at least 60 centimeters.

Optionally, when the distal outlet of the tube is in the stomach, the electrode is suitable to stimulate a body organ of the patient or to sense electrical signals from a body portion of the patient.

There is further provided in accordance with an exemplary embodiment of the invention, a method of treating a patient, comprising providing a feeding tube having an electrode mounted thereon, inserting a distal end of the feeding tube into a stomach of a patient, to an orientation in which the electrode may be used to electrically stimulate a body organ of the patient, and administering food or medicine to the patient's stomach through the tube. Optionally, providing the feeding tube with an electrode mounted thereon comprises providing a tube manufactured with an electrode thereon. Optionally, providing the feeding tube with an electrode mounted thereon comprises mounting the electrode on the tube shortly before inserting the distal end of the tube into the stomach. Optionally, the feeding tube defines only a single channel. Optionally, providing the feeding tube comprises providing a tube with only a single electrode mounted thereon. There is further provided in accordance with an exemplary embodiment of the invention, a method of treating a patient, comprising providing a medical tube having an electrode mounted thereon, inserting at least a distal end of the medical tube into a patient, and performing a first of one or more heart stimulation procedures on the patient, using the

electrode mounted on the tube, at least one hour after inserting the distal end of the tube into the patient. Optionally, providing the medical tube comprises providing a tracheal tube and/or a feeding tube. Optionally, the electrode is not electrically coupled to a source of electrical stimulation, not even through one or more disconnected switches, at the time of inserting the tube into the patient. Optionally, the patient has a risk of less than 10% or less than 1% for requiring a heart stimulation procedure in the following 24 hours, at the time of insertion of the medical tube.

There is further provided in accordance with an exemplary embodiment of the invention, a medical tube apparatus, comprising a tube, having a length of at least 50 centimeters, for insertion into a patient, adapted to carry fluids into or out of the patient in accordance with a medical task and a single electrode mounted on the tube in a position and orientation selected such that when the tube is in the patient in a manner which allows the tube to operate in accordance with the medical task, the electrode may be used to stimulate a body organ of the patient. Optionally, the single electrode is mounted on the tube in a position and orientation selected such that when the tube is in the patient in a manner which allows the tube to operate in accordance with the medical task, the electrode may be used to stimulate the heart of the patient. Optionally, tube is adapted for carrying air. Optionally, the electrode is mounted at a substantially closest position to the heart when the tube is in its designated position. There is further provided in accordance with an exemplary embodiment of the invention, a medical tube apparatus, comprising a tube for insertion into a patient, adapted to carry fluids into or out of the patient in accordance with a medical task, the tube being suitable for being located in the patient for more than 12 hours and at least one electrode mounted on the tube in a position and orientation selected such that when the tube is in the patient in a manner which allows the tube to operate in accordance with the medical task, the electrode may be used to stimulate a body organ of the patient. Optionally, the tube is suitable for location in the patient for more than 24 hours. Optionally, the tube is an endotracheal tube.

BRIEF DESCRIPTION OF THE DRAWINGS Exemplary non-limiting embodiments of the invention will be described with reference to the following description of the embodiments, in conjunction with the figures. Identical structures, elements or parts which appear in more than one figure are preferably labeled with a same or similar number in all the figures in which they appear, and in which:

Fig. 1 is a schematic illustration of a nasogastric tube within a patient, in accordance with an exemplary embodiment of the invention;

Fig. 2 is a schematic sectional view of a nasogastric tube, in accordance with an exemplary embodiment of the invention; Fig. 3 is a cross-sectional view of the nasogastric tube of Fig. 2, in accordance with an exemplary embodiment of the invention; and

Fig. 4 is a schematic illustration of an electrode carrier band, in accordance with an exemplary embodiment of the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Fig. 1 is a schematic illustration of a nasogastric tube 100 within a patient, in accordance with an exemplary embodiment of the invention. Nasogastric tube 100 is shown passing through the patient's nose 150 and the esophagus 152 into the patient's stomach 154. Along esophagus 152, tube 100 passes next to heart 156. It is noted that tube 100 may be inserted to the patient through the mouth rather than through the nose. In an exemplary embodiment of the invention, tube 100 includes, at a proximal end, a fluid inlet port 102 for connecting to a syringe or other medical tool for inserting food or liquids and/or for applying suction. A distal end of tube 100 includes an outlet 114 through which fluids pass between tube 100 and stomach 154.

Along its length, tube 100 includes one or more electrodes 108, which can be used for trans-esophagus heart stimulation (such as heart pacing or cardioversion), when required. In some embodiments of the invention, tube 100 includes at least two electrodes 108, so that heart pacing can be more efficiently performed with two internal electrodes.

Fig. 2 is a schematic sectional view of tube 100, in accordance with an exemplary embodiment of the invention. Tube 100 optionally comprises a wall 122 which defines a channel 124 adapted for transfer of food and liquids.

Electrodes 108 are optionally positioned along the length of tube 100, at positions expected to be closest to the heart 156 and/or expected to close a circuit through the heart (or a specific portion of the heart) in a desired manner, when outlet 114 is in stomach 154. In some embodiments of the invention, wires 110 connect electrodes 108 to a proximal electrical port 120 near or on fluid port 102. If the patient requires electrical stimulation while tube 100 is in the patient, a source of electrical energy can be connected to port 120 and the stimulation is performed. Thus, the time required to remove tube 100 and to insert an electrical stimulation electrode, is avoided.

Electrodes

Electrodes 108 are optionally adapted to perform a stimulation task. Alternatively or additionally, one or more of electrodes 108 are suitable for sensing electrical signals from the heart. In an exemplary embodiment of the invention, electrodes 108 have a width of between about 6-8 mm, along the length of tube 100, although other widths may be used. Optionally, all the electrodes have the same tissue contact area Alternatively, different electrodes have different tissue contact areas, for example in order to accommodate for patients of different sizes. Possibly, the proximal electrodes are larger, in order to accommodate for larger patients, generally having a larger distance from the heart to the stomach. In some embodiments of the invention, electrodes 108 extend over the entire 360° of the circumference of tube 100. Alternatively, some or all of electrodes 108 extend over less than the entire circumference of tube 100, optionally over less than 270°. This embodiment is optionally used when tube 100 has a preferred orientation, such that the electrodes are aligned correctly within the esophagus. Electrodes 108 may have a structure as described in any of U.S. patents 4,369,789 to

Leveen et al., 4,574,807 to Hewson, 4,735,206 to Hewson, 5,191,886 to Bilof, 5,417,713 to Cohen, and/or 5,343,860 to Metzger et al., the disclosures of all of which are incorporated herein by reference. Alternatively or additionally, any other electrodes may be used.

In some embodiments of the invention, tube 100 includes a plurality of electrodes 108, for example at least 4 electrodes, as shown in Fig. 2, or even more than 6 or 8 electrodes. Optionally, tubes used on patients of a wide range of sizes, include at least 10 or even more than 12 electrodes. In some embodiments of the invention, tube 100 includes only a limited number of electrodes, optionally fewer than three electrodes, or even only a single electrode. In many cases, tube 100 is used on patients that have only a small chance of requiring use of the electrodes and therefore it is more cost effective to use only a limited number of electrodes, or even only a single electrode.

Alternatively to ring electrodes, other electrode configurations may be used, such as axial or trans-axial electrodes. Wires Fig. 3 is a cross-sectional view of tube 100, in accordance with an exemplary embodiment of the invention. As mentioned above, tube 100 includes an internal channel 124 defined by a wall 122. As shown in Fig. 3, in some embodiments of the invention, a bundle 116 of wires 1 10, which connect electrodes 108 to electrical port 120, run along wall 122.

Optionally, each of the electrodes 108 has a separate corresponding interface 130 (Fig. 2) on electrical port 120 and a separate leading wire 110. In some embodiments of the invention, each of interfaces 130 on electrical port 120 is marked as to the depth of its corresponding electrode 108 (indicating the depth of the electrode within the patient's esophagus). According to the extent to which tube 100 is pushed into the patient and the size of the patient, i.e., the distance from the patient's mouth to the heart, a specific interface 130 to which electrical power is applied, is selected. Another external electrode, on the patient's back or stomach, is used. Alternatively, electrical power is applied to two or more of electrodes 108, for example when there is not sufficient time to determine the exact locations of the electrodes and/or when high power levels are required.

In some embodiments of the invention, the size of the patient is estimated based on the age and/or height of the patient. The extent to which tube 100 is pushed into the patient is optionally estimated according to the length of the proximal portion of the tube outside the patient. In some embodiments of the invention, the proximal portion of tube 100 includes markings 132 (Fig. 2) that indicate which of interfaces 130 should be used for different lengths of the proximal portion of tube 100 outside the patient. Optionally, each marking indicates an interface to which it corresponds, possibly depending on one or more parameters of the patient. In selecting an interface 130, a physician optionally identifies a closest marking to the patient's nose (or mouth) and uses the interface 130 corresponding to the closest marking and the patient's parameters.

Alternatively or additionally, radio-opaque markings, magnetic markings and/or any other internal markings which can be relatively easily identified from outside the patient, are positioned on or near one or more of the electrodes within the patient. When electrification is required, a physician can use an external sensor to determine the position of one or more of the electrodes within the patient. Further alternatively or additionally, an expanding element is located toward the distal end of tube 100 at a predetermined distance from the electrodes on the tube. When the electrodes are to be used, tube 100 is pulled back until the expanding element touches the upper end of the stomach and serves as a basis for indicating the position of the electrodes along the esophagus. Wires 110 of the electrodes 108 optionally pass along tube 100 in a single bundle 116 embedded in one side of the perimeter of a wall 122 of tube 100. Alternatively, wires 110 are distributed around wall 122, allowing wall 122 to be thinner than if the wires are concentrated. In some embodiments of the invention, wires 110 are embedded within wall 122 in a manner

which strengthens the wall or at least does not weaken the wall. Alternatively, wires 110 are laid within wall 122 even if they weaken the wall. In some embodiments of the invention, for example in accordance with this alternative, the interfaces of the wires are distributed around fluid port 102 and are not located on a single electrical port 120, such that in case the tube is damaged not all wires 110 are disconnected. Alternatively or additionally, areas of wall 122 in which wires 110 are embedded are thicker than other areas of wall 122. Further alternatively or additionally, to allow for cheaper production, wires 110 pass within channel 124, fixed to the internal side of wall 122 or extending freely within the channel. Further alternatively or additionally, wires 110 extend outside of tube 100, fixed to the external side of wall 122 or extending freely.

Alternatively to each electrode 108 having a separate leading wire 110, two or more of the electrodes 108 are connected through a single wire to electrical port 120. In some embodiments of the invention, all of electrodes 108 are connected to a single wire 110.

In some embodiments of the invention, instead of, or in addition to, wires 110, one or more of electrodes 108 is coupled to a wireless power reception port 143 (Fig. 2). In some embodiments of the invention, power reception port 143 includes a coil for receiving electrical energy through magnetic coupling. Alternatively or additionally, port 143 includes a flat surface electrode, which is sufficiently large to allow inducing of currents therein. The currents optionally pass through electrode 108 to stimulate body tissue. Further alternatively or additionally, port 143 operates on any other wireless power transfer method, such as any of the methods known in the field of smart cards and/or any of the methods discussed in the above mentioned U.S. provisional patent application 60/632,739, filed December 1, 2004.

In an exemplary embodiment of the invention, wires connect electrodes 108 to a wireless port on the proximal end of tube 100. Wireless transmission from the proximal end of the tube outside the patient requires less transmission power, while still not requiring connection of wires to the tube.

In still other embodiments of the invention, a battery 149 (Fig. 2) is embedded within wall 122, to provide electrical power to one or more of electrodes 108. Optionally, battery 149 has sufficient charge for a single stimulation procedure. Alternatively, when necessary, a battery with a high charge, sufficient for a plurality of stimulation procedures may be used.

Batteries thin enough to be embedded in walls of a feeding tube are known in the art of smart cards and any of such batteries and methods of embedding may be used with a feeding tube, in accordance with the present invention.

The embedded battery is optionally coupled to one or more of electrodes 108 through a switch circuit, which is activated wirelessly from outside the patient's body. Alternatively, any other switching method may be used, for example a reed-switch means adapted to be controlled by a magnet from outside the patient. Tube

Wall 122 is optionally sufficiently durable to withstand being placed in a patient for more than 24 hours, optionally for more than 3 or even 7 days. Tube 100 optionally has a length of at least 40 centimeters, 50 centimeters or even 60 centimeters, so that its distal end can reach the patient's stomach. In some embodiments of the invention, tube 100 has a length above 90 centimeters, for example, between about 110-140 centimeters, so as to be usable even on full grown large patients. Alternatively, tube 100 may be of any other suitable length. Tube 100 optionally has a diameter of at least 8 French, or even at least 14 French, so as to allow easy passage of feeding fluids into the stomach. In some embodiments of the invention, tube 100 has a diameter smaller than 20 French, or even smaller than 14 French, so as to allow easy insertion of the tube into the patient. It is noted, however, that other diameters may be used.

Outlet 114 is optionally of an area of at least 50%, 60% or even at least 70% of the outer diameter cross-section area of tube 100, allowing easy passage of fluids into and/or out of the tube. Optionally, outlet 114 is substantially of the size of the inner diameter cross-section of tube 100 along at least most of its length. In some embodiments of the invention, outlet 114 comprises an opening in the distal end of tube 100. Optionally, a surface containing outlet 114 is substantially perpendicular to an axis of tube 100. Alternatively, outlet 114 is formed as an opening in wall 122 of tube 100, while the distal end of the tube is closed.

In some embodiments of the invention, tube 100 includes a simple tube, which is as cheap as possible. Alternatively, tube 100 is more complex, for example having inflatable walls and/or a valve preventing gastric juices from entering tube 100, on outlet 114. Further alternatively or additionally, tube 100 includes an inflatable member cuff or balloon for preventing gastric juices from exiting the stomach outside of tube 100. Optionally, in accordance with this alternative, at least some of electrodes 108 are mounted on the balloon or cuff, so that they are pushed against the esophagus wall and hence form better contact with the esophagus. Alternatively or additionally, any other device may be used to push the electrodes 108 against the esophageal wall. It is noted, however, that this alternative may add to the cost of tube 100 and therefore may optionally be used only for patients at high risk of requiring

cardioversion. In some embodiments of the invention, tube 100 includes a fuse which prevents undesired electrification of the patient.

In some embodiments of the invention, tube 100 includes only a single internal channel 124 suitable for flow of fluids. Electrodes 108 are optionally mounted on the outer surface of wall 122 of the single channel 124. Alternatively, the lumen defined by the wall 122 on which electrodes 108 are mounted, is divided into a plurality of channels, by an internal barrier connected to wall 122. Further alternatively, the lumen defined by wall 122, on which electrodes 108 are mounted, includes a plurality of sub-tubes which define sub-channels through which feed and/or suction are applied. It is noted, however, that in this embodiment, tube 100 is relatively complex. Stimulation

In some embodiments of the invention, when the patient requires emergency electrical stimulation, a stimulation generation apparatus (e.g., a defibrillator) is connected to wires leading to two or more of the electrodes 108 and the electrical stimulation is applied accordingly. Alternatively, the stimulation is applied through a single electrode on tube 100 and an external electrode on the patient.

Optionally, if necessary, signals may be sensed through one or more of the electrodes 108, for example in order to determine whether electrical stimulation was effective and/or which of the electrodes 108 should be used (e.g., which of the electrodes forms best contact with the esophagus). Alternatively or additionally, electrodes 108 are used to sense signals for determining whether stimulation is required.

In an exemplary embodiment of the invention, when electrical stimulation is required, a stimulation generation apparatus senses the electrical impedance between each two electrodes 108 on tube 100 and accordingly automatically selects the electrodes 108 through which stimulation is to be applied (or a single electrode to be used with an external electrode) and/or an amplitude or other parameter (e.g., frequency) of the applied stimulation. Alternatively or additionally to determining the electrodes to be used and/or a stimulation parameter when the stimulation is required, the most suitable electrodes and/or the stimulation parameters are selected immediately after installation of feeding tube 100 and/or at any other time before stimulation is required. The results of the determination are optionally stored in the stimulation generation apparatus for a time at which the stimulation is required. Alternatively or additionally, a micro memory chip is mounted on tube 100, optionally embedded within wall 122, and the determined information is stored on the micro memory chip. The memory chip is

optionally located at a proximal end of the tube near electrical port 120. Alternatively, the memory chip is located near electrodes 108. The memory chip communicates with the stimulation generation apparatus through wires or wirelessly.

In some embodiments of the invention, the stimulation apparatus is only connected to the patient when it is determined that the patient requires electrical stimulation. Alternatively, for example in high risk patients, a stimulation apparatus is continuously connected to electrodes 108 on tube 100. In some embodiments of the invention, the stimulation apparatus includes or is coupled to a monitor, which follows the state of the patient's heart. When the monitor determines that electrical stimulation is required, the stimulation apparatus automatically applies the stimulation. Alternatively, when the monitor determines that electrical stimulation is required, the stimulation apparatus automatically determines a best electrode and power selection for the stimulation. The monitor optionally, in parallel, generates a warning to a physician to apply the electrical stimulation. Distal end electrode While in the above description electrodes 108 are used for transesophageal stimulation, in some embodiments of the invention, an electrode is placed close to the distal end of tube 100 near outlet 114, for stimulation through the stomach. Such distal end electrode may be placed on tube 100 instead of electrode 108 or in addition to electrode 108. Optionally, tube 100 is deflectable in a controlled manner, using any method known in the art, so that the distal end electrode can be directed to a desired position within the patient. Optionally, a deflection mechanism is embedded within wall 122. Before applying the stimulation, the distal end of tube 100 is deflected so that it forms contact with a desired organ wall, for example close to the heart.

The use of a distal end electrode may be employed also on gastrostomy tubes. In the above description, the nasogastric tube is provided by the manufacturer with electrodes 108 mounted thereon. It is assumed that although not required for the majority of the patients, having the electrode on the nasogastric tube, for those patients requiring electrical stimulation, is worth the small extra cost involved in having the electrode on the many nasogastric tubes on which it is not needed. In other embodiments of the invention, one or more electrodes 108 are added at a later time, for example by a physician inserting the nasogastric tube into the patient. Thus, electrodes 108 may be added to the nasogastric tube only for patients at a high risk of requiring stimulation. In addition, electrodes 108 may be placed on the

nasogastric tube at an axial position adapted to the specific patient into which the tube is inserted. This may reduce the number of electrodes required on the tube.

Fig. 4 is a schematic illustration of an electrode carrier band 144, in accordance with an exemplary embodiment of the invention. Electrode carrier band 144 is a disposable band for mounting an electrode onto an elongate medical invasive probe. Carrier band 144 includes an electrode 137 and a wire 134 (or a group of wires), which electrically connects the electrode to a power generator, sensor, controller or other apparatus, at a proximal end of a nasogastric tube on which electrode carrier band 144 is placed. Electrode 137 is optionally mounted on a substrate 136, which serves to attach the electrode to tube 100. In some embodiments of the invention, substrate 136 is covered with an adhesive on a surface opposite electrode 137, which surface is attached to the nasogastric tube. Optionally, substrate 136 is provided with a peel off sheet (not shown), which covers the adhesive before attaching substrate 136 to the tube. Before using the nasogastric tube, the peel off sheet is removed and substrate 136 is attached to tube 100. Alternatively or additionally other fastening methods may be used to connect carrier band 144 to a feeding tube. For example, the band may surround the feeding tube entirely, with its ends connecting to each other using Velcro, adhesive, snaps or any other connection mechanism.

In some embodiments of the invention, substrate 136 comprises one or more protective layers, which protect the nasogastric tube, from heat due to the electrical energy passed through electrode 137. The protective layers include an electrically isolative material, such as silicone, polyvinylchloride, polyurethane or any other suitable isolative material. The protective layer optionally has a thickness of at least 0.1 mm or even 0.25 mm. In some embodiments of the invention, the protective layer is thinner than 0.3 mm or even thinner than 0.15 mm, in order to limit the enlargement of the cross-section of the nasogastric tube, due to the placement of electrode carrier band 144 on the tube. Alternatively, a substrate 136 is not included in carrier band 144, and electrode 137 is directly mounted on the nasogastric tube (i.e., a portion of electrode 137 serves as the substrate). The substrate together with the electrode are optionally sufficiently flexible to take the form of the nasogastric tube surface on which they are mounted. In some embodiments of the invention, the substrate together with the electrode is more flexible than the nasogastric tube, at least the area of the tube on which substrate 136 is mounted.

Electrode 137, as well as electrodes 108, optionally comprise a bio-compatible metal, such as titanium, silver, stainless steel or gold. Alternatively, the electrode comprises an alloy

of metals, optionally including one or more of the above materials. In some embodiments of the invention, electrode 137 includes a highly conductive outer film, of any suitable metal. The conductive film is optionally used to cover a material base with a lower electrical conductance.

Electrode 137 optionally covers most of the length of substrate 136, so that the electrode covers a large percentage of the circumference of the nasogastric tube. Thus, electrical stimulation can be applied efficiently from many orientations of tube 100.

In some embodiments of the invention, tube 100 is provided in a sterile package along with the electrodes mounted thereon. Alternatively, any of the add-on electrodes described in above mentioned U.S. provisional application 60/632,739, is placed on a nasogastric tube, before the tube is inserted into the patient. Further alternatively, a thin sheath carrying the electrodes is slid over the naso-gastric tube.

In some embodiments of the invention, tube 100 is adapted to receive carrier band 144, for example by including a notch adapted to receive the band, a fastening mechanism and/or a marking indicating where to place the band. In some embodiments of the invention, nasogastric tubes are produced with a marking indicating where electrode carrier band 144 is to be placed along the length of the tube. Possibly, the nasogastric tube includes a plurality of markings corresponding to the positions for different patients and/or for different types of expected stimulation situations.

Electrodes 108 and/or 137 may be used for various emergency procedures, such as cardioversion, defibrillation and/or other heart stimulation activities. Alternatively or additionally, electrodes 108 and 137 may be used for sensing electrical signals in both emergency and non-emergency procedures. Further alternatively or additionally, electrodes 108 or 137 may be used for long term pacing, for example in post-surgery patients. In accordance with this alternative, the use of the electrodes is optionally known in advance at the time of insertion of the feeding tube, and hence a feeding tube with a larger number of electrodes and/or more expensive electrodes may be used.

It is noted that the mounting of electrodes on feeding tubes is not limited to a nasogastric tube, but rather may be used with other feeding tubes (referred to also as food administering tubes), such as gastric tubes inserted through a patient's mouth. In addition, the mounting of electrodes for emergency situations may be advantageous also on other tubes and invasive probes, such as endotracheal tubes.

In one method of using feeding or endotracheal tubes with electrodes suitable for cardioversion mounted thereon, a tube having the electrode is inserted into a patient for a

procedure unrelated to cardioversion. The patient optionally has a low risk of requiring cardioversion, optionally less that 10%, 5% or even less than 1%. The tube is optionally inserted without the electrodes being connected to a source of electrical power. If a need for cardioversion arises, the electrodes are coupled to a source of electrical power and cardioversion is performed. Otherwise, the electrodes remain unused and are disposed with the tube, when the tube is removed from the patient.

It will be appreciated that the above-described methods may be varied in many ways, including, varying the type of nasogastric tubes used. It should also be appreciated that the above described description of methods and apparatus are to be interpreted as including apparatus for carrying out the methods, and methods of using the apparatus.

The present invention has been described using non-limiting detailed descriptions of embodiments thereof that are provided by way of example and are not intended to limit the scope of the invention. It should be understood that features and/or steps described with respect to one embodiment may be used with other embodiments and that not all embodiments of the invention have all of the features and/or steps shown in a particular figure or described with respect to one of the embodiments. Variations of embodiments described will occur to persons of the art. Furthermore, the terms "comprise," "include," "have" and their conjugates, shall mean, when used in the claims, "including but not necessarily limited to."

It is noted that some of the above described embodiments may describe the best, mode contemplated by the inventors and therefore may include structure, acts or details of structures and acts that may not be essential to the invention and which are described as examples. Structure and acts described herein are replaceable by equivalents which perform the same function, even if the structure or acts are different, as known in the art. Therefore, the scope of the invention is limited only by the elements and limitations as used in the claims.