EQUIPMENT FOR MONITORING RECTAL MUCOSA PERFUSION

Description

[0001] The present invention relates to the field of measuring devices for estimating metabolic parameters relating to the perfusion of an organ of a patient, in particular an organ comprising a mucosa and muscle tissues.

[0002] Such equipment can be used in many applications to monitor patients susceptible to tissue hypoperfusion. These conditions can be of various origins: hemorrhagic, infectious or inflammatory.

[0003] Monitoring biological parameters related to perfusion provides the user with information on the organ's microcirculation to help them choose treatments appropriate for the patient. Indeed, knowledge of the state of local perfusion, particularly of the digestive mucosa, is an important element in enabling the management of patients who may have alterations in this perfusion.

[0004] For example, photoplethysmography technology is a way to assess tissue perfusion over a known depth. Unfortunately, particularly for tissues such as the rectum, measurements can be disrupted by the flow of fecal matter at the interface between the sensor and the wall. If this is obstructed by a blockage, involuntary contractions of the rectum to expel the blockage will cause a change in blood flow in the measurement area and disrupt the measurements.

[0005] Document WO 2013 / 149264 discloses a device for measuring perfusion of the esophageal wall. The device is also applicable to the entire gastrointestinal tract. It includes a probe equipped with a suction attachment system to the gastrointestinal wall, a laser Doppler to measure blood circulation, and an ultrasound probe to capture muscle activity.

[0006] Also known from document US 2002 / 0173731 is an apparatus for monitoring the rectal mucosa which comprises means for applying heat to the wall of the mucosa and a thermal sensor measuring the response of the mucosa as a function of the perfusion of the tissue. The apparatus further comprises means for estimating the shock as a function of the thermal response of the rectal mucosa.

[0007] An objective of the invention is to propose an apparatus for monitoring the perfusion of a tissue whose measurements are less disturbed than in the prior art.

[0008] To achieve this objective, the invention proposes an apparatus for monitoring perfusion of a rectal mucosa as defined in the claims.

[0009] Advantageously, the apparatus according to the invention makes it possible to associate data from a perfusion sensor with those from a muscular activity sensor in order to obtain monitoring of the perfusion taking into account muscular activity, in particular periods of contractions of the rectum to expel a plug upstream of the device.

[0010] More particularly, the processing unit receives as input perfusion measurement data and muscle activity data, and allows the muscle activity data to be taken into account for monitoring tissue perfusion. Preferably, the measurement data is invalidated during periods of muscle activity.

[0011] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures, in which: there figure 1 is a diagram of an apparatus according to the invention, inserted into a rectum; the figure 2 is an apparatus according to a first embodiment of the invention; and the figure 3 is an apparatus according to a second embodiment of the invention.

[0012] The present invention relates to apparatus for monitoring perfusion of a rectal mucosa and comprises a device 1 for monitoring perfusion of a rectal mucosa. In particular, the device 1 comprises a probe in the form of a catheter. Preferably, the body 1a of the catheter is not rigid.

[0013] Such a device 1 comprises a perfusion sensor 2 configured to detect perfusion of the tissue. The perfusion sensor 2 is a sensor using photoplethysmography technology, namely a photoplethysmographic sensor. This type of sensor 2 associated with such a device 1 and the associated perfusion measurement have been presented in detail in particular in applications WO2013127819 and WO2015044336, relating to measurements in a particular tissue, namely a duodenal mucosa.

[0014] For a photoplethysmography sensor to provide a reliable perfusion indication over time, the photon path between the transmitter and receiver must be constant in a given application. In particular, it is important firstly that the sensor is pressed against the wall, secondly that the interface between the sensor and the mucosal wall is always the same, and thirdly, that the composition of the tissue remains unchanged.

[0015] In the case of a rectal measurement as for a duodenal measurement, the first point is resolved by an approach of the same type as for a duodenal probe described in the applications mentioned above, in particular a balloon or a stent allowing the sensor to be pressed against the wall.

[0016] Regarding the second point, in the context of a measurement in another particular tissue such as a rectal mucosa 3, stools can come to be placed between the perfusion sensor 2 and the wall and disturb the measurements.

[0017] Regarding the third point, it does not pose any particular problem except in the case where the muscles surrounding the rectal ampulla contract in order to expel the stool. In this case, the mucosa is crushed between the muscles and the contents of the rectal ampulla, which results in a densification of the blood network without increasing the total flow. This densification can disrupt perfusion measurements.

[0018] A first solution is to block the arrival of stool upstream of the measurement point in order to eliminate corruption of the measurement due to stool getting between sensor 2 and the mucosa. For example, a plug can be used.

[0019] Unfortunately, this solution is problematic in that stool will accumulate above the plug. Beyond a certain amount of stool, the pressure of the stool on the mucosa will exceed a threshold, estimated at 3 kPa, which will trigger the expulsion reflex.

[0020] This expulsion reflex will modify the density of the capillary network, resulting in an erroneous value of the calculated perfusion indicator in the sense that it will no longer be comparable to the previous values.

[0021] It is particularly important to know the onset of muscle activity in order to take it into account for perfusion measurements. This is especially important because muscle activity can begin well before actual expulsion.

[0022] To overcome these drawbacks, the device according to the invention further comprises at least one activity sensor 4 configured to detect muscular activity of the organ, said at least one activity sensor being arranged close to the perfusion sensor 2. The perfusion sensor 2 and the activity sensor 4 are configured to be associated with a processing unit 5.

[0023] More particularly, the processing unit 5 receives as input perfusion measurement data and muscle activity data, and makes it possible to take into account the muscle activity data for monitoring the perfusion of the tissue. Preferably, the perfusion measurement data are invalidated during periods of muscle activity.

[0024] According to the invention, the monitoring device 1 comprises an occlusion section 6 comprising the activity sensor 4, and a perfusion measurement section 7 comprising the perfusion sensor 4. In particular, the occlusion section 6 is arranged upstream of the perfusion measurement section 7 with reference to the direction of transit.

[0025] Advantageously, the occlusion section 6 is part of the device, and makes it possible to avoid a stopper which would be difficult to remove after use.

[0026] In particular, the occlusion section 6 is configured to achieve a “semi-occlusion”, i.e. it partially blocks either solid stools and liquid stools, or only solid stools; and it is expelleable by the muscles of the rectum 3.

[0027] Advantageously, the occlusion section 6 makes it possible to have a measurement space around the measurement section 7 without disturbance of the measurements by stools coming between the sensor and the mucous membrane of the rectum 3.

[0028] According to the invention, the occlusion section 6 is movable between a folded position in which it has a small size in a radial direction and a deployed position in which it has a large size in the radial direction.

[0029] Advantageously, the occlusion section 6 can take a first configuration allowing easy insertion, namely the folded position, and a second configuration allowing good semi-occlusion of the rectum, namely the deployed position.

[0030] The occlusion section 6 may be inflatable. For example, it comprises a balloon. Advantageously, an inflatable occlusion section allows for simplified configuration change by simply inflating / deflating the occlusion section.

[0031] The occlusion section 6 may comprise a stent. Advantageously, a stent allows for a rigid deployed position.

[0032] The occlusion section 6 may comprise a shape memory material such as a shape memory plastic.

[0033] According to the invention, the perfusion measuring section 7 is preferably inflatable, and is movable between a folded position in which it has a small size in a radial direction and a deployed position in which it has a large size in the radial direction.

[0034] The advantages of the deployable occlusion section 6 are applicable mutatis mutandis to the deployable perfusion section 7.

[0035] According to a variant, the activity sensor 4 is a force sensor 4a arranged on the occlusion section 6. In particular, the force sensor 4a is arranged between the occlusion section 6 and the mucosa of the rectum 3. The force sensor 4a measures the mechanical pressure of the mucosa on the occlusion section 6. Advantageously, a force sensor 4a makes it possible to locally measure the muscular activity of the mucosa.

[0036] According to one variant, the activity sensor 4 is a local pressure sensor 4b. In particular, the local pressure sensor 4b is arranged in the occlusion section 6. The local pressure sensor 4b measures the pneumatic pressure in the occlusion section 6. Advantageously, a local pressure sensor 4b makes it possible to locally measure the muscular activity of the mucosa by means of the measurement of the pneumatic pressure.

[0037] According to a variant, the perfusion measuring section 7 comprises a second activity sensor 4 which may be one of the activity sensors described above. Preferably, the second activity sensor 4 is an external pneumatic pressure measuring device 4c. In particular, this device 4c is arranged on a section not introduced into the rectum 3.

[0038] According to a first embodiment, the occlusion section 6 comprises a balloon 8 which may be ovoid. This variant is in particular illustrated in the figure 2 .

[0039] The balloon 8 may include a force sensor 4a around the circumference. Alternatively or in combination, the balloon may include a pressure sensor 4b inside.

[0040] Preferably, the balloon 8 is associated with an external pressure measuring device 4c for measuring the pneumatic pressure of the balloon 8.

[0041] The preferred variant of the first embodiment comprises: a blocking balloon 8 with a diameter greater than 2 cm and less than 6 cm corresponding to a maximum dilation of the rectal ampulla; a measuring balloon on the measuring section 7, with a size of approximately 3 cm configured to be arranged close to the blocking balloon 8, for example at approximately 2 cm. This measuring balloon is equipped with a photoplethysmography sensor. In particular, the sensor is inside the balloon but faces the wall. a preferably hollow catheter body 1a; and an acquisition and processing unit which analyzes the pressure variations to signal the rectal activity.

[0042] The hollow body 1a of the catheter allows the passage of: cables 2a of the perfusion sensor 2; an air inlet channel for inflating the measuring balloon (7). This same air inlet is connected to a pressure sensor 4c; and a second air inlet channel for inflating the semi-occlusive balloon 8. This same air inlet is connected to a pressure sensor 4c.

[0043] According to a second embodiment, the occlusion section 6 comprises a receptacle 9 and an evacuation channel 10. This variant is in particular illustrated in the figure 3 . Thus, according to a second embodiment, the occlusion section has a receptacle shape such as a cone shape extending by said evacuation channel 10. Advantageously, the evacuation channel allows the evacuation of liquid stools and can thus limit the pressure of the stools on the occlusion section 6.

[0044] The receptacle 9 may be brought into the deployed position by means of a stent, by an inflatable device such as a balloon or by a shape memory device such as a shape memory plastic.

[0045] The receptacle 9 preferably comprises a force sensor 4a on its surface, in particular on the stent or on the shape memory device. Alternatively or in combination, the receptacle may comprise a pressure sensor inside the balloon if applicable. In this case, the balloon may be a toric balloon.

[0046] The preferred variant of the second embodiment comprises: a multi-lipped shape memory funnel 9, with a maximum diameter greater than 3cm and less than 4cm. The larger diameter portion is equipped with a force sensor 4a for axial strain measurement. a measuring balloon on the measuring section 7, with a size of approximately 3cm configured to be arranged in proximity, for example 2cm from the smallest portion of the funnel 9. This measuring balloon (7) is equipped with a photoplethysmography sensor 2. In particular, the sensor is inside the balloon but faces the wall. a preferably hollow catheter body 1a; and an acquisition and processing unit 5 which analyzes pressure variations to signal rectal activity.

[0047] The body 1a of the hollow catheter allows the passage of: 2a cables of the photoplethysmography sensor; 4d cables of the effort sensor; an air inlet channel for inflating the measuring balloon. This same air inlet is connected to a pressure sensor 4c.

[0048] The invention relates to an apparatus for monitoring perfusion of a rectal mucosa, comprising a device 1 as described previously and a processing unit 5 associated with said sensors 2, 4.

[0049] The measurement data is tracked over time. Experimental details such as perfusion or effort measurement units and instrument calibration are known per se to those skilled in the art or are set forth in the international applications cited above.

Claims

1. Apparatus (1) for monitoring perfusion of a rectal mucosa comprising a device for monitoring perfusion of a rectal mucosa, comprising: - a perfusion measuring portion (7) which is movable between a folded position in which it has a small size in a radial direction and a deployed position in which it has a large size in the radial direction, - a photoplethysmographic perfusion sensor (2) designed to detect a perfusion of the rectal mucosa, the perfusion sensor (2) being mounted on the measuring portion (7) so as to be pressed against the rectal mucosa when the measuring portion (7) is deployed in a rectum, - an occlusion portion (6) movable between a folded position in which it has a small size in a radial direction and a deployed position in which it has a large size in the radial direction in order to perform a semi-occlusion of the rectum, - at least one activity sensor (4) designed to detect a muscular activity of the rectal mucosa, said at least one activity sensor (4) being arranged on or in the occlusion portion (6) in the vicinity of the perfusion sensor (2), the monitoring apparatus further comprising a processing unit (5) designed to process the data from the perfusion sensor (2) taking into account the data from the activity sensor (4).

2. Monitoring apparatus (1) according to claim 1, wherein the occlusion portion (6) comprises a balloon, a stent or a shape-memory material, designed to move the occlusion portion (6) between the folded position and the deployed position.

3. Monitoring apparatus (1) according to either claim 1 or claim 2, wherein the perfusion measuring portion (7) is inflatable.

4. Monitoring apparatus (1) according to any of claims 1 to 3, wherein the activity sensor (4) is a pressure sensor, a stress sensor and / or a pneumatic pressure measuring device.

5. Monitoring apparatus (1) according to any of claims 1 to 4, wherein the perfusion measurement portion (7) comprises a second muscle activity sensor (4c).

6. Monitoring apparatus (1) according to any of claims 1 to 5, wherein the occlusion portion (6) comprises a receptacle (9) and an evacuation channel (10).

7. Monitoring apparatus (1) according to any of claims 1 to 6, wherein the occlusion portion (6) is arranged upstream of the perfusion measurement portion (7) referring to the transit direction.