Patent Application
20160106364
The invention relates in general to systems and methods for monitoring human eating patterns and for training and modifying such patterns, in particular after weight loss surgery.
Morbid obesity is a chronic condition. Gastric limiting techniques (e.g. “adjustable gastric banding” or AGB) are employed by surgeons to treat morbidly obese people who cannot lose weight by traditional means. In AGB, a gastric “band” made of an elastomer is placed around the stomach near its upper end. This creates a small pouch with a narrow passage into the rest of the stomach (“stoma orifice”), thus limiting the amount of food intake (“eating”) by creating a feeling of fullness or uneasiness and by usually extending the time frame required to empty the pouch into the rest of the stomach. To control the size of the stoma orifice, the gastric band can be pressurized or depressurized by a physician. As a non-limiting example, the pouch is usually of a size of 50 cc to 5 cc, preferably 20 cc to 8 cc, and more preferably of about 15 cc. The stoma size can be increased or decreased with a saline solution by using a needle and syringe to access a small access port placed under the skin. The stoma orifice is governed by the amount of stomach tissue inside the band at the banding site. A desired passage size is about 12 mm in internal diameter.
The aim of restricting passage of food and liquids is to force the patient to change his/her eating behavior and thereby to induce a significant amount of weight loss. Researchers have demonstrated that the initial weight loss results after AGB are less predictable then those after gastric bypass. Patients after surgery are advised to chew their food thoroughly, eat slowly, take small bites, avoid certain foods, etc. Often, a large number of these patients do not adopt the required behavior and instead, eat forcefully, vomit, and intermittently suffer stoma occlusion events. These may result eventually in such complications as pouch enlargement, band erosion, reflux, and esophageal enlargement. In some cases, additional surgical interventions may be required.
The observation of gastric band action and the adjusting of stoma orifice by inflation/deflation are facilitated by X-ray imaging. A physician or technician acts to adjust (increase or decrease) the volume of fluid in the band based on inputs from the X-ray imaging. The volume decrease is done by removing an amount of fluid from the band via the external access port and fill line. Alternatively, components for adjusting the size of the gastric band may be implanted within the patient and, when a physical parameter such as intra-band pressure related to the patient food passage is determined, an external control unit outside the patient's body may be operated to power the implanted components to adjust the size of the band.
Monitoring the activity of the pouch created between the lower esophagus sphincter and the gastric band may generate important information related to the eating behavior of patients. Physiological parameters obtained by such monitoring may be useful to help a patient control his/her obesity, manage his/her diabetes, and monitor his/her gastro-esophageal reflux disease and the like.
Adjustable gastric restriction devices with sensors and actuators which enable control of the stoma orifice are disclosed for example in US patent applications No. 20070156013 by Birk and 20060173238 by Starkebaum. Birk discloses a self-regulating gastric band with pressure data processing, relates to a band adjustment assembly which is provided for implanting with the gastric band that includes a sensor for sensing fluid pressure in the expandable portion. The band adjustment assembly further includes a pump assembly connected to the expandable portion and to a controller that can operate the pump assembly to adjust the volume of the fluid in the band based on the sensed fluid pressure. Starkebaum's invention relates to a dynamically controlled gastric occlusion device that monitors at least one physiological parameter that varies as a function of food intake and controls the degree of gastric constriction of an occluding device, such as a gastric band, based on the monitored physiological parameter. In an embodiment, the dynamically-controlled gastric occlusion device controls the degree of gastric constriction based on time. The occluding device is dynamically opened or closed to either permit or prevent the passage of food through the gastrointestinal (GI) tract.
U.S. Pat. No. 5,724,025 to Tavori discloses a portable vital signs monitor in communication with a plurality of sensors capable of implantation, with two way communication, also allowing current diagnosis of a live body, possible reasons for abnormal diagnosis, based on physical data, anticipated behavior of the body and monitoring physical changes resulting from actual treatment.
A large number of studies have determined the following:
1) Pouch volume and stoma size are important determinants for the success of AGB.
2) Proper stoma adjustment can effect immediate and late results of the AGB and reduce complications such as Spherical Pouch Dilatation (SPD).
3) Fast eating or improper chewing of the food can lead to excessive pouch enlargement and impaired surgical results.
4) Adoption of favorable eating behavior is imperative for long term success of the AGB
5) Adoption of mal-eating behaviors can reduce the success rate of AGB.
Although gastric bands can limit food intake, it is worth recognizing that eating is a form of behavior that can be defined according to its structure (frequency duration and size of eating episodes). This pattern of behavior can be further analyzed at the level of a single meal, where the same structure (frequency duration and size of eating episodes—bites) rules and defines the meal size. In principle, this behavior operates through the skeletal musculature and is subject to conscious control. Therefore, people should be able to volitionally decide when and how to control their own eating. In practice, people find it extremely difficult to exert control and many obese people claim that their eating is out of (their) control.
AGB procedures are not known to provide a patient with visual data or information regarding his/her eating behavior pattern, yet the patient is expected to adopt different eating behavior with respect to frequency, duration or size of bite or meal. The realization and visualization of eating behavior patterns is required to the patient in order to induce conscious and correct eating behavior modification. Therefore there is a need for a tool that will provide the AGB obese patients a guided and controlled eating “pacer” that will enable them to learn and gain a new control over their eating behavior.
Out of the clinical literature from the last 15 years and over 500,000 patients with AGB it is clear that it is very difficult to obtain-hard quantitative data on the true food intake behavior of AGB obese patients. It is clear that in some AGB obese individuals, habitual food intake or its caloric value are greater than it is normally assumed to be and is often erratic and apparently unregulated. In order for health care givers to be able to advice and guide those patients to better regulate eating habits and behavior, there is clearly a need for a method and apparatus that will enable them to monitor and obtain objectively recorded eating behavior patterns. It would also be advantageous to have systems and methods to improve the action of AGB by automatically releasing excessive pressure buildups.
The invention provides, in various embodiments, devices, apparatuses and methods for gastric restriction and data collection, interpretation of eating behavior patterns and for training and eating behavior modification after weight loss surgery. In some embodiments, implanted sensors attached to a gastric band or extra corporal sensors sense, during a meal, at least one parameter like viscosity, density or quantity of a bolus (dose) of food or substance passing through the stoma, the number of boluses, the time of the passage of a bolus, intervals between boluses, duration of a meal, pressure exerted by the food bolus passage or substance and for macronutrient contents passing through the pouch and the stoma orifice produced by a restriction device. Each sensed parameter may be processed into an indication of the caloric value of the meal.
In some embodiments there is provided an apparatus and method for monitoring food passage through a gastric band stoma and for monitoring eating patterns and behavior by providing the patient real time visualization of his/her eating behavior as compared to a desired behavior. The data collected may be downloaded into a computer system that will chart the eating events and provide the patient, the surgeon/dietician information regarding the following:
Frequency of eating events during the day.
Number and size of meals.
Consistency of the consumed food (liquid, semi-liquid or solid).
Eating behavior data such as: speed of eating, quality of chewing, drinking during the meal, binge eating, night eating, vomiting.
Accurate adjustment to an “ideal stoma size”.
Compliance.
Eating behavior improvement.
Eating behavior adoption and assimilation.
Indication of the presence or development of a complication.
Advise patient to “stop eating” based on volume of food consumed or caloric intake.
In some embodiments, at least one sensed parameter is used to provide a command to an emergency relief valve attached to the gastric band to release pressure buildup, an action performed in prior art only manually by a physician in an emergency room.
In some embodiments, at least one sensed parameter is used to provide corrective guidance for the patient, who, with the benefit of the band's repetitive feedback capability, can adjust and change his/her eating behavior and the present perception of the body signals of hunger and satiety. This is particularly important since satiety is considered by the medical literature to be a conditioned reflex, and eating behavior is considered an acquired behavior. The patient and/or a physician or caregiver is provided with objective behavioral data regarding the patient's eating behavior. The data is used to assist the patient to adopt positive and favorable eating behaviors.
In some embodiments, at least one sensed parameter is converted into an instruction to the patient to activate an infusion pump to deliver a dose of a satiety inducing substance. The instruction generated will depend on a preset caloric level the patient is allowed to consume in that meal.
The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:
In the following description, where used, identical numbers in different figures refer to identical components.
Returning now to the figures,
In some embodiments, apparatus 100 further includes a microcontroller (processor) 110 which communicates with sensor 108 and emergency relief mechanism 106. The communication may be two way, wired or wireless, in ways known in the art. If wired, the communication may be via a cable equivalent 112. A “cable equivalent” in this disclosure may refer to one or more electrical wires; a hydraulic vessel or a pneumatic vessel, the latter two with or without a separating membrane which separates the sensor from the inner fluid of the gastric band. A hydraulic vessel cable equivalent can be used as an ultrasound (US) emitter/reflector of intra-band events. Microcontroller 110 may be used to activate, operate or read sensor 108. The data received from the sensor may be indicative of plug flow, tissue erosion, organ dilatation and the like. Microcontroller 110 is further capable of interpreting a sensed parameter and capable of supplying inputs or commands for eating behavior modification. Data processed by microcontroller 110 may be displayed to the patient and/or to a physician, stored, or transmitted to an external entity by well-known means. In some embodiments, microcontroller 110 is capable of pacing a meal, i.e. decide on the time to start, the time to swallow and the time to end the meal.
Apparatus 300 includes an intra-corporal section 301 and an extra-corporal section 321. Intra-corporal section 301 includes a gastric band 302 with an inflation mechanism 304, a communication tube 306 and a common injection port 308. Extra-corporal section 321 includes a needle 310 used to provide access into common injection port 308 and for inflation and deflation. The needle is coupled with a sensor 312 and with an emergency relief mechanism 314. Sensor 312 and an infusion pump 316 are connected via a cable equivalent 318 to a microcontroller (processor) 320. The pump can be activated automatically or manually. In some embodiments, the pump can control intra-muscular administration of a dose of a hunger controlling hormone. An exemplary such hormone is PYY36, a well known hunger controller.
In some embodiments, sensors 108, 312 or 412 may be optical sensors and in particular infrared (IR) sensors.
It is also possible to use such arrangements with common adjustable gastric bands (AGB) known in the art.
In some embodiments, sensors 108, 312 or 412 may be ultrasonic (US) sensors.
Sensing element 608 may be configured to vibrate at a frequency in a range of from about 1 MHz to about 30 MHz. In some embodiments, the transducer is configured to vibrate in a range from about 5 MHz to about 15 MHz. An angle .theta. is defined as the angle of incidence between the pulses and the direction of fluid flow:
f.sub.D=2f.sub.tV cos.theta.
where f.sub.D is the Doppler frequency, f.sub.t is the vibration frequency, c is the speed of sound in tissue and V is the measured velocity of the fluid or object in motion. Solving for velocity:
V=f.sub.D/(2f.sub.t cos.theta.)
Depending on the acoustic impedance of the material into which the output pulses are directed, the ultrasound output may generate return echoes 610. Return echoes are most efficiently created when there is a difference in the acoustic impedance between two regions or materials. For example, a stoma orifice without any substance will return an echo different from a stoma orifice filled with a substance. When a food substance passes through device 600, the added pressure and peristaltic motion may be measured by device 600 as a change from the stoma orifice without any substance. This change may be detected by acoustic impedance mismatch.
The flow of a substance (solid or liquid food) sensed by the sensor may be described as similar to flow through a “modified” orifice plate flow meter. The present inventors have determined that in the case of a gastric band, “modified” Navier-Stokes equations may be used to describe the substance flow rate, Reynolds number, mass flow, velocity, and volumetric flow. The “modified” terminology relates to the external force component of the peristaltic motion and to the influence of stoma diameter change during food passage (flexible tube vs. rigid tube). The derivation of these equations is given next.
The derivation begins with the conservation of mass, momentum, and energy being written for an arbitrary control volume. In an inertial frame of reference, the most general form of the Navier-Stokes equations can be written as:
.rho.(.differential.v.differential.t+v.gradient.v)=−.gradient.p_+.gradient.+f, (1)##EQU00001##
where V is the flow velocity, .rho. is the is the fluid density, p is the pressure. T is the (deviatoric) stress tensor, f represents body forces (per unit volume) acting on the fluid and .gradient. is the del operator. This equation is often written using the substantive derivative, making it more apparent that this is a statement of Newton's law:
.rho.DvDt=−.gradient.p+.gradient.+f. (2)##EQU00002##
The terms on the right side of the equation represent the body acting forces, the pressure gradient, and the forces due to the viscosity of the fluid. The body acting forces are proportional to the wetting behavior between the particles, surface and shape and the liquid part of the body of fluid. The velocity field is proportional to the pressure drop field. This field may oscillate, and create average downstream flow, intermittent flow or upstream flow. When the substance is composed of a liquid solution, flakes, flow in long constrictions with a small lumen diameter, flow separation regions, or turbulent energy losses in cases of severe stenosis, reduce the energy content of the fluid, and may also plug the flow.
In peristaltic motion, we can observe periodical pressure changes. However, opening pressure of the lower esophageal sphincter is proportional to pressure drop due to the stoma which may be created by gastric restriction device. The sum of peristaltic and other forces, generate another pressure which further facilitate movement of a substance within the lumen. Fluid or food does not typically pass through the stoma at a steady rate. Peristaltic contractions typically cause an intermittent or periodic flow rate reading in real time. The peak flow rate during this period can be an indicator of the effect of a tight restriction, predicting for example the likelihood of esophageal dilatation. In addition to the peak flow rate, the frequency or consistency of the peristaltic contractions (i.e., the number of contractions per time) can also be determined. By identifying typical patterns of test flow traces, patients can be grouped by severity of esophageal condition or by peristaltic pattern, to help determine not only how tightly their restriction should be adjusted, but also, for example, whether a more conservative diet should be selected.
The peristaltic phenomenon can be used in conjunction with the real time-flow measurement. For example, the restriction device may be tightened completely, causing complete occlusion at the stoma. The restriction device may then be slowly loosened until the desired stoma size is reached. By assessing a group of several peristaltic pulses, different degrees of stoma tightness can be more easily compared, without the need to ingest a large amount of a calibration food standard.
In order to more accurately describe flow through a gastric band, the basic Navier-Stokes equation is modified as follows
.rho.DV.fwdarw.Dt=.rho.B.fwdarw.−.gradient.p+.mu..gradient.2V.fwdarw.+F.fwdarw..delta.(x,y,z,.PHI.,.theta.,t,S) (3)##EQU00003##
where B represents a body force acting on a particle inside the fluid, and where the added component {right arrow over (F)}.delta.(x,y,z,.phi.,.theta.,t,S) of force per unit of shape depends on position (x,y,z), direction (.theta., .phi.), time (t), and on a value S that represents shape. S relates to volume, surface area of the body of fluid, moment of inertia, gyration radii and other dynamic functions, generated by the travel of a fluid particle in the medium. The time (t) may be substituted with frequency WO. Of course, .delta.(x,y,z,.phi.,.theta.,t,S) may be a function, independent or dependent of any of its components Expanding formula (3) gives
.rho..differential.V.fwdarw..differential.t+.rho.V.fwdarw..gradient.V.fwdarw.=−.gradient.p+.rho.g.fwdarw.+.mu..gradient.2V.fwdarw.+F.fwdarw..delta.(x,y,z,.PHI.,.theta.,t,S) (4)##EQU00004##
where
.rho..differential.V.fwdarw..differential.t ##EQU00005##
is the local acceleration, .rho.{right arrow over (V)}.gradient.{right arrow over (V)} is the convective acceleration, −.gradient.p is the pressure force per unit volume, .rho.{right arrow over (g)} is the body force per unit volume and .mu..gradient..sup.2{right arrow over (V)}, is the viscous forces per unit volume. and {right arrow over (F)}.delta.(x,y,z,.phi.,.theta.,t,S) is an externally added component of force per unit of shape. {right arrow over (F)}.delta.(x,y,z,.phi.,.theta.,t,S) may also represent the ability of the tissue in described tract to accommodate pressure, i.e. pouch enlargement and pouch slippage.
Examination of the above equation shows that each term has units of force per unit volume, or F/L.sup.3. Therefore, {right arrow over (F)}.delta.(x,y,z,.phi.,.theta.,t,S) satisfies the basic equation, since if we divide each term by a constant having those same units (F/L.sup.3) we obtain a dimensionless equation. Furthermore, the viscosity and specific gravity values also change.
In the following equations, the symbols used are as follows: D.sub.1 is pouch diameter, D.sub.2 is stoma diameter, P.sub.1 is upstream pressure, P.sub.2 is downstream pressure, .nu. is kinematic viscosity, .mu. is dynamic viscosity and .rho. is upstream density. The calculation of flow rate using an orifice plate is for incompressible flow, based on the Bernoulli principle
p1.rho.+v122+gz1=p2.rho.+v222+gz2+.DELTA.p1−2.rho. (5)##EQU00006##
where V is the velocity of the food through the stoma, g is the gravitational constant (9.81 m/s.sup.2) and z is the geodetic height. Assuming that the pressure lost is negligible (the pressure drop is obvious and included with the coefficient of discharge which is introduced below):
.DELTA.p.sub.1−2=0
and
gz.sub.1=gz.sub.2
and if velocities are substituted with flow rate
V1=4Q.pi.D12V2=4Q.pi.D22 (6)##EQU00007##
where V.sub.1 and V.sub.2 are respectively the upstream and downstream velocities before and after the stoma orifice, Q is the volumetric flow rate and D is diameter. The pressure drop through the orifice because of velocity increase can be calculated as follows:
p1−p2.rho.=12(16Q2.pi.2D24−16Q2.pi.2D14) (7)##EQU00008##
Expressing the flow rate from the previous equation leads to:
Q=11−(D2D1)4.pi.D2242(p1−p2).rho. (8)##EQU00009##
Substituting:
E=11−(D2D1)4 ##EQU00010##
the flow rate can be determined as:
Q=CeE.pi.D2242(p1−p2).rho. (9)##EQU00011##
where C is the coefficient of discharge and e is an expansion coefficient. C can be calculated using following equation (ISO):
C=0.5961+0.0261.beta.2−0.216.beta.8+0.000521(106.beta.ReD)0.7++(0.0188+0.0063(19000.beta.ReD)0.8)(106ReD)0.3.beta.3.5++(0.043+0.08−7Li)(1−0.11(19000.beta.ReD)0.8).beta.41−.beta.4−0.031(2L21−.beta.−0.8(2L21−.beta.)1.1).beta.1.3 (10)##EQU00012##
where .beta. is the diameter ratio D.sub.2/D.sub.1. Re.sub.D is the Reynolds number which can be calculated as follows:
ReD=VDv=.rho.VD.mu. (11)##EQU00013##
where .nu. is kinematic viscosity, .mu. is the dynamic viscosity and L.sub.1 and L.sub.2 are empirical functions that relate to the particular organ through which the flow is measured. The mass flow is now given by
G=.rho.Q (12)
and the velocities
V1=4Q.pi.D12V2=4Q.pi.D22 (13)##EQU00014##
The abovementioned mathematical development enables obtaining measurable parameters of an instantaneous event and converting them into a “description” of food flow through the tract. This description creates meaning to volume, flow and time, which can be processed into eating behavior variables.
When a patient is given standard foods, different components such as fat, carbohydrates and protein absorb different wavelengths of the spectrum. In step 1002 NIR spectral data is acquired for these standard foods for each patient. In step 1004, the spectral data provides “standard” empirical coefficients related to percent of fat carbohydrates and protein for each patient. In step 1006, the percent of fat carbohydrates, protein and water is calculated from the empirical coefficients. In step 1008, the calculated percent of fat carbohydrates, protein and water for each type of standard food for each particular patient is stored in memory. Based on processed data, the physician may define a maximal caloric allowance of a meal, daily or for other periods, based on weight loss program goals for each patient.
The following methods of use are described in detail with reference to apparatus 100, with the understanding that they may be performed with any other apparatus of the invention.
In this method, apparatus 100 is used to provide inputs to a patient to change his/her eating behavior. This method takes advantage of the fact that the sensor data may be interpreted to illustrate “bad” and “good” eating patterns. The method is explained with reference to pressure as a particular sensed parameter, with the understanding that other sensed parameters obtained by NIR, ultrasound or other types of sensing may serve equally well for the stated purpose.
Assume it is desired for a patient equipped with an apparatus of the invention to change eating behavior from a “bad” one (exemplified by pressure-time curves similar to those in
After the band is properly calibrated and the basic values for the different monitored parameters are stored in the memory, it is possible to start monitoring the patient's eating behavior. For example, if the data is collected from the pressure sensor, as a pressure increase event is sensed, time recording, pressure recording, a bolus counter and the NIR sensor (when applicable) are set ON. The data collected is processed using the modified Navier-Stokes and Bernoulli equations to provide a volume description of the food flow through the gastric band. From the processed pressure-time curves, the apparatus can (by comparison of the data with stored standard constants and known values) deduce the different eating behavior conditions exemplified by
In terms of eating behavior interpretation, if the pressure-time curve shows that the food passing through the band had a maximal pressure equal or less than a “solid food standard” maximum pressure value, but above a “semi-liquid food” standard maximum pressure value, and if the time for the volume of food to flow through the band was in a given range, then the patient chewed the food bolus well, as shown in
In another example, when the pressure sensor senses that the present bolus still passes through the band and a second peak of pressure is sensed prior to the stoma orifice emptying, then the system will indicate to the patient that he/she is eating to fast and he/she should slow down.
To emphasize—the information provided to the patient through his/her personal display provides the patient with insight of what happens inside his/her abdomen. It paces and trains the patient to slow down the speed of eating, informs the patient about the quality of chewing and provides the patient with positive results when achieved and negative ones if not. As the patient gets visual information regarding the size of the meal, he/she can consume until personal caloric or volume limits are met. The patient can adjust the portions taken to his/her new visually induced estimates. All these changes in patient's eating behavior will assist him/her to adopt a more suitable eating behavior in response to the new physical condition created by the AGB, instead of having to do it “blindly”, as done in common practice now.
Further examples of possible recommendations for the patient and indications for the health caregiver for behavior changes may include (but not be limited to) the following:
1. Pacing patient's food processing and consumption
2. Time to eat.
3. Food passage busy—stop
4. Food passage clear—go
5. Pace the food processing
6. Pace the food intake
7. Bite chewed less then required
8. No drinking during meal
9. Caloric intake too high
10. End of meal,
11. Stop eating system clogged
12. Visit your surgeon time for inspection
13. Visit your surgeon—band empty
14. Visit your surgeon—suspected problem detected
For the caregiver/physician:
1) Patient eats liquid food or suspected complication
2) Patient eats too fast
3) Patients eats too much
4) Patient does not chew his food enough
5) Patient eats/drinks high caloric food/liquid
6) Patients vomits too often
7) Possible complication—erosion, band leakage, port detachment
8) Possible complication—band slippage, pouch enlargement
9) Band deflated due to occlusion
10) New calibration required
The various features and steps discussed above, as well as other known equivalents for each such feature or step, can be mixed and matched by one of ordinary skill in this art to perform compositions or methods in accordance with principles described herein. Although the disclosure has been provided in the context of certain embodiments and examples, it will be understood by those skilled in the art that the disclosure extends beyond the specifically described embodiments to other alternative embodiments and/or uses and obvious modifications and equivalents thereof. Accordingly, the disclosure is not intended to be limited by the specific disclosures of embodiments herein. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the invention.
This application claims priority from U.S. Provisional Patent Application No. 60/980,153 filed 15 Oct., 2007, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60980153 | Oct 2007 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12738079 | Apr 2010 | US |
| Child | 14981491 | US |
