The invention relates to an esophageal pressure measurement catheter comprising a tube having a proximal end and a distal end, wherein the distal end of the tube is arranged to be inserted into the esophagus of a patient, wherein the tube is provided with at least one pressure sensor for measuring a pressure in the esophagus region of a patient.

A problem when measuring pressures in a patient’s esophagus is that any interaction between the esophagus wall and the pressure sensor, such as the wall touching the pressure sensor, may influence the measurement in a negative manner. The invention aims at a more reliable esophageal pressure measurement catheter.

To that end, the tube is provided with at least one inflatable balloon adjacent to the at least one pressure sensor, wherein a distance between an edge of the balloon and the centre of the pressure sensor is less than 20 mm. The balloon, when inflated, acts as a spacer to keep the wall of the esophagus away from the pressure sensor, such that the measurement is more accurate.

Said at least one pressure sensor preferably is a solid state pressure sensor. The tube preferably comprises a pressure sensor lumen for accommodating a connection for the at least one pressure sensor. The tube preferably comprises a balloon inflation lumen for transporting a fluid, such as air, to the at least one inflatable balloon. The tube furthermore preferably comprises a feeding lumen for transporting liquid food, medication and/or gastric acid to and/or from the stomach of a patient.

The balloon, when inflated under normal, nominally designed operating conditions, preferably has a diameter of between 7 mm and 18 mm, more preferably between 10 mm and 15 mm. The distance between an edge of the balloon and the centre of the pressure sensor is preferably less than 10 mm, more preferably 7 mm, even more preferably less than 5mm, most preferably less than 3 mm. Preferably the balloon has a spherical shape, or the balloon has a cylindrical shape with a substantially rectangular longitudinal cross section. Preferably the balloon is located at the side of the pressure sensor that is nearer to the proximal end than to the distal end of the tube. The balloon is preferably made of urethane, PET and/or nylon. The wall thickness of the balloon is preferably between 0.01 mm and 0.06 mm. The balloon may have a leg on either side for fixating the balloon on the tube, and said leg is less preferably than 7 mm, more preferably less than 5 mm, most preferably less than 3 mm. The length of the tube is preferably at least 80 cm, preferably at least 95 cm. The diameter of the tube is preferably between 2 mm and 6 mm. The tube is preferably provided with two of said inflatable balloons adjacent and at each side of the at least one pressure sensor, wherein a distance between an edge of each of the balloons and the centre of the pressure sensor is less than 20 mm, preferably less than 10 mm, more preferably less than 7 mm, even more preferably less than 5 mm, most preferably less than 3 mm. Said tube is preferably provided with a plurality of said pressure sensors distributed along a length of the tube, each sensor being provided with at least one inflatable balloon adjacent the at least one pressure sensor, wherein a distance between an edge of the balloon and the centre of the pressure sensor is less than 20 mm, preferably less than 10 mm, more preferably less than 7 mm, even more preferably less than 5mm, most preferably less than 3 mm. At least one of said pressure sensors is preferably provided near the distal end of the tube, for instance in the last 25%, 10% or 5% of the length of the tube.

The invention will now be exemplified by means of preferred embodiments, with reference to the drawings, in which:

Figure 1 is a side view of an esophageal pressure measurement catheter in accordance with the invention;

Figure 2 is a top view of the esophageal pressure measurement catheter of figure 1 ;

Figure 3 is a cross section of the esophageal pressure measurement catheter of figure 1 ;

Figure 4 is a side view of a balloon for use with the esophageal pressure measurement catheter in accordance with the invention; and

Figure 5 is a side view of another embodiment of a balloon for use with the esophageal pressure measurement catheter in accordance with the invention.

According to figures 1 to 3 the esophageal pressure measurement catheter 1 comprises a flexible tube 2. The tube may is typically 95 - 125 cm long and approximately 4 mm in diameter. The tube is provided with an enteral feeding lumen 3, a sensor lumen 4 and a balloon inflation lumen 5, which exit the tube 2 through a trifurcation piece 6. The enteral feeding lumen 3 is used to feed a patient with liquid food, administer medication and/or suction aspirate during the pressure measurement period, which may last for more than several days.

The pressure is measured by a plurality of solid state pressure sensors 7, which are distributed along the length of the tube 2 and which are in open communication with the esophagus of the patient though corresponding holes in the wall of the tube 2. The sensors 7 are connected by connection members 71 in the sensor lumen 4 to a sensor connector 72, for instance an RJ45 connector, at the proximal outer end of the sensor lumen 4.

Adjacent each pressure sensor 7 an inflatable medical balloon 8 is provided on the tube 2. The balloons 8 may for instance be made of urethane. The distance between the edge of the inflated balloon 8 and the centre of the pressure sensor is for instance approximately 4 mm, while the diameter of the inflated balloon is for instance approximately 12 to 15 mm. In that manner the balloon acts as a spacer, which prevents that the wall of the esophagus can touch or come near the pressure sensor 7.

In another preferred embodiment, a balloon 8 is provided at each side of each pressure sensor 7 at about 3 mm distance, whereby the spacer function that prevents that the wall of the esophagus can touch or come near the pressure sensor 7 is improved compared to the embodiment with one balloon 8 for each pressure sensor 7.

Figure 4 shows an example of a balloon 8, which comprises a spherical inflatable part 81 and two leg parts 82 at each end for mounting the balloon 8 on the tube 2. The leg parts are about 3 mm long in the axial direction.

Figure 5 shows another example of a balloon 8, which comprises a cylindrical inflatable part 81 and two leg parts 82 at each end for mounting the balloon 8 on the tube 2. The leg parts are about 3 mm long in the axial direction. The inflatable part 81 has a substantially rectangular longitudinal cross section, whereby the spacer function that prevents that the wall of the esophagus can touch or come near the pressure sensor 7 is improved compared to the embodiment of figure 4.

The invention has thus been described by means of preferred embodiments. It is to be understood, however, that this disclosure is merely illustrative. Various details of the structure and function were presented, but changes made therein, to the full extent extended by the general meaning of the terms in which the appended claims are expressed, are understood to be within the principle of the present invention. The description and drawings shall be used to interpret the claims. The claims should not be interpreted as meaning that the extent of the protection sought is to be understood as that defined by the strict, literal meaning of the wording used in the claims, the description and drawings being employed only for the purpose of resolving an ambiguity found in the claims. For the purpose of determining the extent of protection sought by the claims, due account shall be taken of any element which is equivalent to an element specified therein. An element is to be considered equivalent to an element specified in the claims at least if said element performs substantially the same function in substantially the same way to yield substantially the same result as the element specified in the claims.