Abstract: A method and apparatus for more precisely determining mean left atrial pressure. A catheter including a balloon is inserted into an esophagus with the balloon positioned adjacent the left atrium and inflated to provide a signal of balloon pressure oscillations effected by the left atrium. By use of the fast Fourier transform, the amplitude of each of simple harmonic wave forms (or a corresponding portion thereof) making up the balloon pressure oscillation signal is corrected for characteristics of the catheter and the corrected wave forms combined into a corrected signal of balloon pressure oscillations. The balloon pressure is measured when the amplitude of the corrected balloon pressure oscillation signal is at a peak, wherein the measured balloon pressure is determined to be mean left atrial pressure.

Abstract: A method for detecting a site of interest in a gastrointestinal tract, wherein the method includes sensing a length traveled by a sensor in a gastrointestinal tract from a reference point to a site of interest in the gastrointestinal tract.

Abstract: A method and apparatus for more precisely determining mean left atrial pressure. A catheter including a balloon is inserted into an esophagus with the balloon positioned adjacent the left atrium and inflated to provide a signal of balloon pressure oscillations effected by the left atrium. By use of the fast Fourier transform, the amplitude of each of simple harmonic wave forms (or a corresponding portion thereof) making up the balloon pressure oscillation signal is corrected for characteristics of the catheter and the corrected wave forms combined into a corrected signal of balloon pressure oscillations. The balloon pressure is measured when the amplitude of the corrected balloon pressure oscillation signal is at a peak, wherein the measured balloon pressure is determined to be mean left atrial pressure.

Abstract: An esophageal probe useful for invasively monitoring the cardiac output of a patient generally comprises a chassis with an electrical cable extending from the proximal end of the chassis and with the cable terminating at an electrical plug configured for connection to a cardiac output monitor. The probe includes an electrode assembly configured to generate and transmit electrical signals that are indicative of the impedance variation of the thorax. The probe further includes a deployment device attached to the chassis for stabilizing the probe within the esophagus. The probe may also be configured to include other sensing devices, for example, a temperature measuring device and an acoustic monitor.

Abstract: A method and a device for the intermittent or continuous measurement of portal blood pressure using a tamponade balloon inserted into the esophagus and stomach and a sensor positioned on the bridle, tamponade shaft or esophageal balloon. The tamponade balloons mounted over a tube are placed across the diaphragmatic hiatus and are gradually inflated through a lumen that runs from the balloons to a position that is external from the patient. The measured pressure within the tamponade is increased until the blood flow in the collateral portal veins that traverse the diaphragm are occluded. The cessation of the blood flow into the esophageal varices is signaled when the sensor identifies a change in diameter of the varices, a change in the color of the esophageal wall, or a change in velocity of blood flow. The measured tamponade pressure at the nadir of variceal blood flow is equivalent to portal blood pressure.

Abstract: Apparatus for measuring length in a blood vessel includes an inner barrel slideably fitting within an outer barrel. The apparatus also preferably includes a zero ring for initializing a position of the inner barrel relative to the outer barrel, wherein the zero ring is rotatably positioned on the outer barrel. The apparatus further includes a small-diameter clamp extending outwardly from the inner barrel for holding a catherization mechanism for visualizing a blood vessel, wherein the catherization mechanism includes a marker and a scale is positioned on the inner barrel for indicating a displacement of the inner barrel relative to the outer barrel in response to the catherization mechanism marker. A device for measuring the inside diameter of a vessel according to the invention includes a tube, measuring wires, and a knob. A central lumen that runs the entire length of the tube is surrounded by a plurality of other lumens which stop a short distance from the tip of the tube.

Abstract: Methods and devices are provided for assessing impairment of blood circulation in a patient, such as that in perfusion failure, by measurement of blood flow in the gastrointestinal tract or upper respiratory/digestive tract of the patient. The method comprises introducing a blood-flow sensor into the gastrointestinal tract or the upper respiratory/digestive tract of a patient, placing the sensor adjacent a mucosal surface therein, and measuring blood flow in adjacent tissue to determine blood flow in that tissue. The method may also involve measurement of PCO2 and/or pH in combination with the blood flow determination. The invention affords rapid measurement and detection of perfusion failure.

Abstract: A method and apparatus for characterizing gastrointestinal sounds includes a microphone array to be positioned on a body for producing gastrointestinal sound signals. The signals are digitized and their spectra and duration is determined by a processor. A characterization as to the state of the gastrointestinal tract is made on the basis of the spectra and duration of the sound or event.

Abstract: Methods and devices are provided for assessing impairment of blood circulation in a patient, such as that in perfusion failure, by measurement of blood flow in the gastrointestinal tract or upper respiratory/digestive tract of the patient. The method comprises introducing a blood-flow sensor into the gastrointestinal tract or the upper respiratory/digestive tract of a patient, placing the sensor adjacent a mucosal surface therein, and measuring blood flow in adjacent tissue to determine blood flow in that tissue. The method may also involve measurement of PCO2 and/or pH in combination with the blood flow determination. The invention affords rapid measurement and detection of perfusion failure.

Abstract: A monitoring catheter that inserts into the patient's esophagus alone or in combination with an existing catheter, such as a feeding or aspiration tube. The monitoring catheter includes a pair of EMG electrodes on an exposed surface that contact the patient's esophageal wall to measure the activity of the diaphragm and/or a pair of pressure detecting mechanisms that measure the pressures within the patient at separate locations. The electrodes are sized and spaced from one another so as to maximize detection of diaphragm muscle activity while minimizing detection of noise. The pressure detecting mechanisms are sized and spaced apart to measure the patient's esophageal and gastric pressures, for example. If necessary, an attaching mechanism secures at least a portion of the monitoring catheter to the existing catheter so that the monitoring catheter uses the existing catheter as a tracking guide.

Abstract: Apparatus and method for noninvasively determining cardiac performance parameters including 1) lengths of systolic time intervals, (2) contractility index, (3) pulse amplitude ratios while performing the Valsalva maneuver, (4) cardiac output index, and (5) a pulse wave velocity index. A catheter having at least one balloon is inserted into the esophagus and pressurized and positioned adjacent the aortic arch to sense aortic pressure. The effects of aortic pressure on the balloon are utilized to determine at least one of the cardiac performance parameters. The catheter may include a second balloon which is spaced from the aortic balloon a distance such that when the second balloon is in a position adjacent the left atrium to sense left atrial pressure the aortic balloon is in a position adjacent the aortic arch to sense aortic pressure, this distance being related to the distance between the left atrium and aortic arch in most adult persons.

Abstract: A food intake restriction device for forming a stoma opening in the stomach or esophagus of a patient, comprises an elongated restriction member to be formed into at least a substantially closed loop defining a restriction opening, and a controllable adjustment device for adjusting the restriction member in the loop to change the size of the restriction opening. The device further comprises a wireless remote control for controlling the adjustment device from outside the patient's body in a non-invasive manner to assist in treating the patient for morbid obesity.

Abstract: Apparatus and method for noninvasively determining cardiac performance parameters including 1) lengths of systolic time intervals, (2) contractility index, (3) pulse amplitude ratios while performing the Valsalva maneuver, (4) cardiac output index, and (5) a pulse wave velocity index. A catheter having at least one balloon is inserted into the esophagus and pressurized and positioned adjacent the aortic arch to sense aortic pressure. The effects of aortic pressure on the balloon are utilized to determine at least one of the cardiac performance parameters. The catheter may include a second balloon which is spaced from the aortic balloon a distance such that when the second balloon is in a position adjacent the left atrium to sense left atrial pressure the aortic balloon is in a position adjacent the aortic arch to sense aortic pressure, this distance being related to the distance between the left atrium and aortic arch in most adult persons.

Abstract: Apparatus (10) for measuring the anorectal angle comprises an outer rubber-like sheath (12), which may be a suitably modified catheter, within which is disposed an elongate angular deflection detector (14) which provides on display (16) a read-out of the angular deflection of the apparatus. The sheath (12) may include pressure ports with associated pressure lines back to the proximal end of the sheath to allow the pressure to be read at different points along the anal canal.

Abstract: A food intake restriction device for surgical application in the abdomen of a patient for forming a stoma opening in the stomach or esophagus of the patient comprises an elongated non-inflatable restriction member, a forming device for forming the elongated restriction member into at least a substantially closed loop around the stomach or the esophagus to define a restriction opening, and a post-operation non-invasive adjustment device for mechanically adjusting the restriction member in the loop to change the size of the restriction opening. The components are of bio-compatible material and are effective for treating morbid obesity over an extended period of time always in a non-invasive manner.

Abstract: A method and apparatus for characterizing gastrointestinal sounds includes a microphone array to be positioned on a body for producing gastrointestinal sound signals. The signals are digitized and their spectra and duration is determined by a processor. A characterization as to the state of the gastrointestinal tract is made on the basis of the spectra and duration of the sound or event.

Abstract: An apparatus for sensing muscular activity of the rectosigmoid region, rectum, and the anorectal canal of a subject is disclosed. This apparatus includes an elongate probe having a distal end opposing a proximal end which is configured for insertion into the patient's anorectal canal and includes a pressure sensor, an electromyography sensor, and a stimulus balloon. Multiple pressure sensors may be included to evaluate muscular activity in the anorectal canal. In addition, pressure sensors may be distributed along the length of the probe to simultaneously measure the response of other portions of the anorectal canal besides the anal sphincter muscle. A pressure sensor is also located inside the stimulus balloon for monitoring intraballoon pressure.

Abstract: Non-invasive apparatus and method for obtaining a quantitative determination of mean left atrial transmural pressure or otherwise obtaining a quantitative determination of a left atrial pressure value. A balloon is inserted by means of a catheter into the esophagus and positioned adjacent the left atrium. The balloon is gradually inflated. A tracing of mean balloon pressure is obtained as the balloon is inflated. In addition, a tracing of balloon pressure on a steady baseline and with low frequency oscillations due to respiration filtered out is obtained whereby the tracing represents balloon pressure oscillations effected by left atrial pressure. In accordance with the oscillometric principle the mean balloon pressure is measured when the intensity of a sound wave, after its transmission through the balloon, is at a peak. This mean balloon pressure, after adjustment for the effect, if any, of heart weight, is indicative of approximate mean left atrial pressure.

Abstract: A device and method relate to closing a user's gastroesophageal valve to prevent acid reflux from the user's stomach. The device includes a belt having an inner surface and at least one fastener, the belt being sized to fit around an upper abdominal area of the user. A pliable triangular insert contains a gel material, the insert being attachable to the inner surface of the belt and sized to fit over the triangular area between the ribs and directly below the breast bone of the user. The insert conforms to the shape of the user's body and imparts pressure to the upper abdominal area of the user over the user's lower esophagus and gastroesophageal valve when the belt is tightly fastened around the user.

Abstract: The invention provides a method and apparatus for automatically detecting loss of normal gastric myoelectrical activity and certain gastric dysrhythmias which indicate an imminent onset of nausea. Analog signals indicative of gastric myoelectrical activity are detected via electrodes, conditioned and then digitized. The resulting digital signals are passed through a digital band pass filter which has a pass band with a lower limit set at or near zero Hz, and the digitally conditioned signals are compared in a digital computer with stored predetermined signal patterns that are known to be indicative of the onset of imminent nausea. Upon detection of a match, an alarm is activated.

Abstract: A gauging esophageal catheter or stethoscope which is insertable into the esophagus or stomach of a subject or patient, has an elongated, flexible body portion having an instrument carried on a distal end. The catheter has a series of user visible gradations for permitting selective positioning of the instrument at a predetermined insertion depth within the subject. The gradations are calibrated to the height, weight or body surface area of the subject. The gradations may be printed on the body portion, or the body portion may have a transparent portion, and the gradations may be carried on a member internal thereto which is visible through the transparent portion.

Abstract: An ambulatory system for recording and analyzing gastroesophageal reflux is presented. The system includes a digital recorder, an analysis software package and a catheter for measurement of changes in esophageal impedance. For the first time, gastroesophageal reflux can be detected with a pH above 4 (called alkaline reflux), which is the normal pH environment of the healthy esophagus. In addition, one embodiment of the invention allows for the determination of the direction of flow of the detected material in the esophagus, thus enabling the system to distinguish between swallowed saliva and alkaline gastroesophageal reflux. In yet a further embodiment, the present invention allows for recording and analysis of reflux on a non-invasive basis, by using pairs of externally worn impedance sensors. In another embodiment, the invention measures impedance simultaneously with other bio-parameters, such as pH or pressure.

Abstract: To control a lung ventilator comprising an inspiratory implement to be worn by the patient, an air supply system for supplying air to the inspiratory implement, and a control unit for controlling the air supply system, electromyographic signals produced by the patient's diaphragm are detected by an array of electrodes passing through the center of the patient's diaphragm depolarizing region. The position of the center of the patient's diaphragm depolarizing region is determined through detection of a reversal of polarity of the electromyographic component of the electrode-detected electromyographic signals.

Abstract: Devices and methods for measuring the weakness of body lumens, and in particular, urethral sphincters and similar valves, are disclosed. In one embodiment of the invention, a catheter with a hollow fluted distal end can be inserted into a lumen. The hollow fluted distal end of the catheter is then expanded into an enlarged configuration. The measurement of resistance to withdrawal of the catheter in the enlarged configuration provides an indication of weakness of the lumen. In one aspect of the invention, the catheter is inserted into a bladder via the urethral sphincter and the weakness of the urethral sphincter is measured. In another aspect of the invention, a device for measuring weakness of a body lumen, such as a urethral sphincter and similar valves, can consist of a catheter with a hollow fluted distal end having of an array of wings, and an expanding means for radially expanding the wings into an enlarged configuration.

Abstract: An exercise device conveniently measures, monitors, and reports electromyograph (EMG) information to the user, for use in effectively strengthening selected muscles. The exercise device includes a sensor circuit responsive to electrical activity in tensioning muscles, and a control circuit responsive to an output signal produced by the sensor circuit. In a preferred embodiment the control circuit regulates an audio device, by attenuating the audio device output signal when the sensor output signal declines to below a preset threshold. Alternatively, the control circuit selectively activates an indication device, such as a vibrator, when the sensor output signal falls too low. The exercise device provides information as to muscle activity to the user in an entertaining fashion, and in a way that the user is not required to pay constant attention and refer to an output meter or other conventional display.