Surgery – Diagnostic testing – Cardiovascular
Reexamination Certificate
2000-01-14
2001-11-13
Lacyk, John P. (Department: 3736)
Surgery
Diagnostic testing
Cardiovascular
C600S485000, C600S481000, C600S500000, C600S561000, C600S593000
Reexamination Certificate
active
06315733
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains to a method and a device for the continuous measurement of portal blood pressure. The method and device use an inflatable tamponade balloon inserted into the esophagus and a sensor to monitor the portal blood pressure.
2. The Prior Art
U.S. Pat. No. 5,653,240 to Zimmon, the disclosure of which is herein incorporated by reference, discloses a method and device for measuring portal blood pressure. That invention provides a device and a technically simple method for measuring portal venous pressure in patients with esophageal varices and or portal systemic collateral veins during upper gastrointestinal endoscopy or without endoscopy by positioning the tamponade and sensor with an instrument passed from the mouth into the stomach to provide a rail for introduction and removal. These instruments include an oral-gastric tube, balloon introducer, wire guided dilator, bougie or other similar device. The oral-gastric tube method allows the measurement of portal pressure after tamponade for bleeding without the need for expensive and technically demanding gastrointestinal endoscopy. Such measurements are essential to evaluate the patient's response to drug therapy and determine the therapeutic action required for prevention of recurrent bleeding. An advantage of the above mentioned invention is that in the non-bleeding patient, it allows endoscopic surveillance of esophageal varices combined with measurement of portal venous pressure as a single procedure using only conscious sedation.
However, the use of a large endoscope such as used in the patent mentioned above to observe the collapse of esophageal varices is cumbersome and difficult for the patient, since it requires sedation. It would be desirable to find a method for measuring portal blood pressure that eliminates the need for endoscopy and makes the use of tamponade with sensors available to those without endoscopic skills.
Furthermore there have been numerous endoscopic attempts to measure portal pressure or pressure in esophageal varices. These methods are cumbersome and fail because of the difficulty of identifying the collapse of esophageal varices. The problem is increased when the varices are small. The visual endoscopic methods are limited to operators with considerable endoscopic skill and accept the disabilities of esophageal peristalsis and the need to inflate the esophagus with air that both provokes peristalsis and raises intra-esophageal pressure to limit the accuracy of measurement. This is in contrast to the tamponade method that provides a deflated stomach for continuous esophageal decompression through an esophagogastric sphincter that is breached by the tamponade lumen. Methods requiring needle puncture of varices accept the risk or hemorrhage and are of necessity performed only when endoscopic injection sclerosis of varices in indicated and necessary. Otherwise the risk of bleeding from varix puncture or late bleeding from ulceration associated with varix sclerosis would not be acceptable. All of these esophageal methods measure pressure during continuous flow of blood in the varices in a resistance loop between the portal circulation and a central outflow site that is a derivative pressure. Since the precise site of measurement and its position in the resistance loop is not known, the relationship of the measured pressure to intra-abdominal portal pressure cannot be known and the measurement cannot be reproducible.
REFERENCES
1. Moismann R. Nonaggressive assessment of portal hypertension using endoscopic measurement of variceal pressure. American J Surgery 1982;143:212-214.
2. Bosch J. et al. Noninvasive measurement of the pressure of esophageal varices using an endoscopic gauge: comparison with measurements by variceal puncture in patients undergoing endoscopic sclerotherapy. Hepatology 1986;6:667-672.
3. Fenyves D. et al. Intrahepatic pressure measurement: not an accurate reflection of portal vein pressure. Hepatology 1988;8:211-216.
4. Rigau J. et al. Endoscopic measurement of variceal pressure in cirrhosis: correlation with portal pressure and variceal hemorrhage. Gastroenterology 1989;96:873-880.
5. Polio J. et al. Critical evaluation of a pressure-sensitive capsul for measurement of esophageal varix pressure. Gastroenterology 1987;92:1109-1115.
6. Sarin SK. et al. Predictors of variceal bleeding: an analysis of clinical, endoscopic and haemodynamic variables with special reference to intravariceal pressure. Gut 1989;30:1757-1764.
7. Gertsch P. et al. Manometer of esophageal varices: comparison of an endoscopic balloon technique with needle puncture. Gastroenterology 1993;105:1159-1166.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a device and a technically simple method for the continuous measurement of portal pressure during balloon tamponade using sensors as alternatives to standard endoscopic techniques.
These and other objects are accomplished by a device for measuring portal blood pressure comprising a tube with proximal and distal open ends, an esophageal inflatable balloon mounted over the tube, a first inflation lumen opening into the esophageal inflatable balloon for directing pressurized fluid to inflate the esophageal inflatable balloon, a gastric inflatable balloon mounted over the tube between the esophageal inflatable balloon and the distal open end, a second inflation lumen opening into the gastric inflatable balloon for directing pressurized fluid to inflate the gastric balloon, and a non-visual sensor mounted on the esophageal balloon or a small endoscope or video camera that is inserted through the tube, to detect the changes resulting from tamponade.
The invention also comprises a method of measuring the portal pressure by backloading the device on an endoscope by passing the endoscope through the open ends of the tube, passing the endoscope down the esophagus advancing the device along the endoscope and down the esophagus to a location within the diaphragmatic hiatus, positioning the gastric balloon inside the stomach and inflating the gastric balloon, pulling the balloon against the proximal stomach and the diaphragmatic hiatus with a traction means to seat the gastric balloon against the gastric cardia, inflating the esophageal inflatable balloon to fix the device across the diaphragmatic hiatus by the two opposed balloons, releasing the traction means, locating the sensor to a position above or adjacent to the esophageal inflatable balloon, to observe esophageal varices, gradually inflating the balloons until blood flow in the portal veins traversing the diaphragmatic hiatus occludes, so that the esophageal varices collapse or blood flow ceases or is reduced to a nadir as detected by said sensor, and monitoring the pressure inside said esophageal inflatable balloon and gastric inflatable balloon as sensed by the sensor to obtain an indication of the portal blood pressure. By serially inflating and deflating the balloons while monitoring the state of blood flow in the varices, portal pressure is measured continuously in a fashion similar to automated systemic blood pressure monitoring.
The device preferably also includes a bridle attached to the tube to extend up the esophagus to a traction means. The bridle is manipulated to position the proximal end of the device within the digestive tract and maintain the device in traction.
In addition, an aspiration tube is positioned within the stomach and a fluid supply tube is positioned adjacent to the esophageal balloon. The gastric aspiration tube and lumen of the tamponade device serves the important function of continuously reducing gastric and distal esophageal pressure to ambient pressure. Otherwise the continued swallowing of air and saliva combined with esophageal peristalsis would raise the esophageal pressure and bias the measurement of portal pressure. Similarly the tamponade lumen allows emptying of the esophagus into the stomach to prevent the risk and discomfort of esophageal obstruction. The patient d
Collard & Roe P.C.
Lacyk John P.
Natnithithadha Navin
Zimmon Science Corp.
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