A system for measuring pressure in a biliary tract during endoscopic dilatation of a duodenal papilla

Abstract

The application discloses a system for measuring pressure of a biliary tract in endoscopic duodenal papilla dilation, which comprises a continuously variable diameter biliary tract dilation and pressure measuring catheter structure and a flow rate control module. The continuously variable diameter biliary tract dilation and pressure measuring catheter structure comprises a catheter body and a plurality of balloons, the balloons are sleeved on the catheter body, the catheter body is provided with independent circuit cavities, guide wire cavities and a plurality of water injection cavities, and one end of the water injection cavities is connected with the flow rate control module. The system for measuring pressure of a biliary tract in endoscopic duodenal papilla dilation can realize intraoperative pressure measurement of biliary tract dilation through linkage of the continuously variable diameter biliary tract dilation and pressure measuring catheter structure and the flow rate control module, and can protect the Oddi sphincter from tearing and protect the biliary tract smooth muscle from tearing, thereby realizing targeted dilation of a biliary tract narrow site in the dilation operation and real-time monitoring of the compliance of the biliary tract muscle and the Oddi sphincter.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biliary tract pressure measurement, and particularly relates to a biliary tract pressure measurement system in endoscopic duodenal papilla dilation. BACKGROUND

[0002] Gallstones belong to common clinical diseases, and can be divided into gallbladder stones, common bile duct stones and intrahepatic bile duct stones according to the positions of the stones. The common bile duct stones are more difficult to handle and more harmful. The common bile duct stones are mostly secondary stones which are retained in the common bile duct after the gallbladder stones are discharged into the common bile duct, and a few are primary stones which are mostly formed due to gallbladder infection, bile duct obstruction, and egg factors. Such stones usually can cause abdominal pain, chill and high fever, jaundice, pancreatitis, suppurative cholangitis and other symptoms, and can even endanger life in severe cases.

[0003] Endoscopic sphincterotomy (EST) and endoscopic papillary balloon dilation (EPBD) are common methods for treating common bile duct stones, and have the advantages of small trauma and rapid recovery. However, EST cuts off the Oddi sphincter, resulting in permanent loss of the function of the Oddi sphincter, which can cause reflux cholangitis, recurrence of common bile duct stones and other long-term complications, and is opposed by many domestic scholars. EPBD for treating common bile duct stones not only has a similar success rate of stone removal as EST, but also has a low incidence of intestinal bleeding and intestinal perforation, and causes less damage to the Oddi sphincter than EST, so that EPBD is more and more applied in clinical treatment.

[0004] EPBD uses a small balloon with a diameter of 6-10 mm, which causes less damage to the function of the Oddi sphincter. However, in recent years, there are more and more reports on the use of a large balloon with a diameter of 12-20 mm for EPBD to treat common bile duct stones, which makes it easier to remove stones, reduces the use rate of mechanical stone crushing, shortens the time of intubation and stone removal, and thus reduces the incidence of postoperative pancreatitis. However, with the increase of the diameter of the balloon, the Oddi sphincter can be torn after EPBD, resulting in partial or complete loss of the function of the sphincter.

[0005] The existing technology has the following problems:

[0006] Problem 1: The balloon dilation catheter cannot be continuously changed in diameter, and generally only has three variable diameters, which is clinically referred to as a three-stage expansion balloon.

[0007] Problem 2, at present, the balloon dilatation catheter is applied in surgery, and a small balloon 6-10mm catheter or a large balloon 12-20mm catheter can be selected, and a small balloon and a large balloon cannot be provided in the same catheter. If the balloon is not suitable in surgery, it needs to be replaced, which is time-consuming and laborious.

[0008] Problem 3, there is no pressure measurement evaluation in surgery, and it is unknown that the duodenal papilla can be expanded to how much, and the sphincter is torn and irreversibly damaged if it is expanded too large; but if it is expanded too small, it is not conducive to stone removal.

[0009] Problem 4, there is no integrated catheter of biliary tract pressure measurement and balloon dilatation. SUMMARY

[0010] The main purpose of the present application is to provide a biliary tract pressure measurement system in endoscopic duodenal papilla dilatation, which is linked through a continuously variable diameter biliary tract dilatation pressure measurement catheter structure and a flow rate control module, so as to realize intraoperative pressure measurement of biliary tract dilatation, and protect the Oddi sphincter from tearing and protect the biliary tract smooth muscle from tearing, and then dilate the biliary tract stenosis site in the dilatation surgery, and monitor the compliance of the biliary tract muscle and the Oddi sphincter in real time.

[0011] In order to achieve the above purpose, the present application provides a biliary tract pressure measurement system in endoscopic duodenal papilla dilatation, which comprises a continuously variable diameter biliary tract dilatation pressure measurement catheter structure and a flow rate control module, the continuously variable diameter biliary tract dilatation pressure measurement catheter structure comprises a catheter body and a plurality of balloons, the balloon is sleeved on the distal end of the catheter body, wherein:

[0012] The catheter body is provided with independent circuit cavities, guide wire cavities and a plurality of water injection cavities, one end of the water injection cavity is connected with the flow rate control module;

[0013] Each of the balloons covers a part of the catheter body, and is provided with a group of (strain gauge type) pressure sensors and a pair of electrodes for impedance measurement, and the part is further provided with a water injection port connected with the other end of the internal water injection cavity, so that the corresponding balloon is injected with liquid through the corresponding water injection cavity and water injection port, the expansion degree of the balloon is judged by the volume of the injected liquid; (the liquid can also be a specific electrolyte solution) and the shape change of the balloon when extruded with the inner wall of the biliary tract is analyzed through the measurement of the electrodes.

[0014] As a further preferred technical solution of the above technical solution, the pressure measurement working process of the biliary tract pressure measurement system in endoscopic duodenal papilla dilatation is specifically implemented as follows:

[0015] Step S1: the proximal end of the continuously variable diameter biliary tract dilatation pressure measuring catheter structure is calibrated by pressure measuring instrument, and the catheter body is inserted into the biliary tract through the duodenal papilla with the assistance of a duodenoscope and a guide wire, the pressure changes in the Oddi sphincter and the biliary tract are accurately measured through the pressure sensor on the catheter body, and the balloon is gradually filled with water through the water injection channel, so as to dilate the Oddi sphincter and the narrow biliary tract part;

[0016] Step S2: the flow rate Qx (x is the number of the water injection channel, the same below) of each water injection channel is controlled by the flow rate control module, so that the corresponding balloon is injected through each water injection channel of the catheter body, and the data including the volume Mx of the injected liquid, the pressure sensor reading Px and the impedance information Zx are recorded, and the relevant data of the dilated biliary tract volume V are obtained;

[0017] Step S3: the compliance of the corresponding contact part of the biliary tract is obtained by the expansion of the balloon, and the overall compliance of the biliary tract is evaluated according to the channel compliance obtained by each balloon;

[0018] Step S4: the overall compliance of the biliary tract is applied to the biliary tract dilatation operation.

[0019] As a further preferred technical solution of the above technical solution, for step S2, wherein:

[0020] For the volume Mx of the injected liquid, Mx = ∫Qxdt, the diameter of the balloon is evaluated according to the volume Mx, and considering that the balloon is deformed by the extrusion of the biliary tract, the impedance information Zx is added to correct the calculation of the diameter of the balloon: Dx = D(Mx, Zx), and the specific implementation is:

[0021] When the balloon is not extruded by the biliary tract and freely expands, as the liquid is injected (injection volume: M) into the balloon, the shape of the balloon changes, the effective diameter increases: D0 = f(M), and the impedance value also changes, the impedance value decreases: Z0 = g(M), the subscript 0 represents the free expansion state, the effective diameter D0 and the impedance value Z0 change with the volume increase baseline in the free expansion state, which is obtained in the pressure calibration process of step S1;

[0022] In the formal operation, due to the extrusion of the biliary tract, the balloon will deform and be extruded, the effective diameter D will decrease, and the extrusion will change the impedance value Z (for example, the extrusion limits the transmission path of the carrier, thereby increasing the impedance (Z)), the extrusion coefficient α (α = 0 represents the free state), D = D0*(1-α), and at the same time, the extrusion also changes the impedance value Wherein the function K defines the influence relationship of the extrusion on the impedance, which is obtained by experimental data or calculated according to the model established for the extrusion profile based on the characteristics of the balloon, so D = D0*K -1(Z0 / Z)(Here Z, D, Z0, D0, refer to the value of one of the balloons, the subscript X is omitted);

[0023] For pressure sensor readings Px, the change characteristics of Px are used to determine the interaction between the balloon and the bile duct wall, including:

[0024] I: Identify the starting point of the balloon to start squeezing and expanding the bile duct;

[0025] II: Changes in the compliance of the bile duct sphincter;

[0026] III: Assess the expansion effectiveness by recording the asymmetry of pressure or compliance during expansion and retraction (similar to elastic hysteresis);

[0027] For impedance information Zx, the change value of Zx is used to evaluate the volume of liquid entering the balloon and optimize the calculation of the balloon diameter;

[0028] For bile duct volume V = ∑V x = ∑V(Dx, Mx).

[0029] As a further preferred technical solution of the above technical solution, in step S3:

[0030] The calculation of channel compliance Cx is: Cx = dVx / dRx;

[0031] The calculation of overall compliance C is: C = dV / dP, P = MAX(Px).

[0032] As a further preferred technical solution of the above technical solution, step S4 is implemented as the following steps:

[0033] Step S4.1: Determine whether the overall compliance C is between the upper limit of compliance (C_high) and the lower limit of compliance (C_low) (compliance is too high, worrying about the bile duct expanding too much; compliance is too low, worrying about the bile duct being too rigid), wherein:

[0034] If it is between, determine whether the currently expanded bile duct volume V supports the completion of the expansion operation (i.e. V is greater than or equal to Vtarget), if it supports, then after the operation is completed, the balloon is drained / retracted, the flow rate is Qx', and the relevant data is continuously read until all the balloons are drained, the continuous diameter changeable bile duct expansion pressure catheter structure is pulled out; if it does not support, the flow rate is controlled by the flow rate control module (PID) to increase the balloon volume, thereby increasing the bile duct volume, until the overall compliance C is between the upper limit of compliance and the lower limit of compliance, and the expanded bile duct volume V supports the completion of the expansion operation;

[0035] If it is not between, the volume and pressure of the bile duct are determined respectively, wherein:

[0036] Judge the volume of the dilated bile duct V whether exceeds the volume safety threshold, if yes, directly to the balloon drainage / shrinkage and inform the operator intervention, if not, through the flow rate control module (PID) control flow rate adaptive operation (prompt operator intervention, ensure safety) ;

[0037] Judge the pressure sensor reading Px whether exceeds the pressure safety threshold, if yes, directly to the balloon drainage / shrinkage and inform the operator intervention, if not, through the flow rate control module (PID) control flow rate adaptive operation (prompt operator intervention, ensure safety). BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is the schematic diagram of the continuously variable diameter biliary dilatation pressure measuring catheter structure of the present application.

[0039] Figure 2 is the cross-sectional view of the continuously variable diameter biliary dilatation pressure measuring catheter structure of the present application.

[0040] Figure 3 is the flowchart of the present application.

[0041] Figure 4 is the dilatation operation schematic diagram of the present application.

[0042] Figure 5 is the high-resolution pressure image of the Oddi sphincter and biliary tract of the present application.

[0043] The reference signs include: 1, catheter body; 2, circuit lumen; 3, guide wire lumen; 4, water injection lumen; 5, balloon; 6, pressure sensor; 7, electrode; 8, water injection port; 9, second pressure sensor. DETAILED DESCRIPTION

[0044] The following description is used to disclose the present application so that those skilled in the art can implement the present application. The preferred embodiments in the following description are only as examples, and other obvious modifications can be thought by those skilled in the art. The basic principles of the present application defined in the following description can be applied to other embodiments, modifications, improvements, equivalents and other technical solutions without departing from the spirit and scope of the present application.

[0045] In the preferred embodiments of the present application, those skilled in the art should note that the biliary tract and Oddi sphincter and the like involved in the present application can be regarded as prior art.

[0046] Preferred embodiments.

[0047] As Figures 1-5As shown, the present application discloses a kind of endoscopic duodenal papilla dilation in biliary tract pressure measurement system, including the continuous variable diameter biliary tract dilatation pressure measurement catheter structure and flow rate control module, the continuous variable diameter biliary tract dilatation pressure measurement catheter structure includes catheter body and several balloon 5, the balloon 5 is sleeved in (the distal end of) the catheter body 1, wherein:

[0048] The catheter body 1 is provided with independent circuit cavity 2 (the cavity has circuit connection catheter balloon sensor (pressure and impedance) in it, signal is transmitted back to the front end of catheter structure), guide wire cavity 3 and several water injection cavity 4, one end of water injection cavity 4 is connected with flow rate control module;

[0049] Each balloon 5 covers the part of catheter body 1 and is equipped with a group of (strain gauge type) pressure sensor 6 and a pair of electrode 7 for impedance measurement, and the part is also provided with a water injection port 8 connected with the other end of internal water injection cavity 4, so that the corresponding balloon 5 is injected with liquid through the corresponding water injection cavity 4 and water injection port 8, the expansion degree of balloon 5 is judged by the volume of injected liquid; (the liquid can also be a specific electrolyte solution) and the shape change of balloon when extruded with the inner wall of biliary tract is analyzed by electrode measurement.

[0050] Specifically, the pressure measurement working process of endoscopic duodenal papilla dilation in biliary tract pressure measurement system is specifically implemented as follows:

[0051] Step S1: the proximal end of the continuous variable diameter biliary tract dilatation pressure measurement catheter structure is calibrated by pressure through pressure measuring instrument, and the catheter body is introduced into biliary tract through duodenoscope and the auxiliary (guiding effect) of guide wire, (the guide wire enters biliary tract first, and the guide wire cavity of catheter is sleeved on the guide wire and is introduced into biliary tract), is inserted into biliary tract from duodenal papilla, the pressure change of Oddi sphincter and the inside of biliary tract is accurately measured through pressure sensor on catheter body, and the inside of balloon is gradually injected with water through water injection cavity, so as to dilate Oddi sphincter and narrow biliary tract part;

[0052] Step S2: the flow rate Qx (x is the number of water injection cavity, the same below) of each water injection cavity is controlled through flow rate control module, so that the corresponding balloon is injected with liquid through each water injection cavity of catheter body, and the data including the volume Mx of injected liquid, pressure sensor reading Px and impedance information Zx are recorded, and the related data of dilated biliary tract volume V are obtained;

[0053] Step S3: the compliance of corresponding contact part of biliary tract is obtained through the expansion of balloon, and the overall compliance of biliary tract is evaluated according to the channel compliance obtained by each balloon;

[0054] Step S4: the overall compliance of biliary tract is applied to biliary tract dilation operation.

[0055] More specifically, for step S2, where:

[0056] For the volume of liquid injected Mx, Mx = ∫Qxdt, from which the diameter of the balloon is evaluated, and taking into account the deformation of the balloon due to the compression by the biliary tract, the impedance information Zx is added, correcting the calculation of the diameter of the balloon: Dx = D(Mx, Zx), implemented as:

[0057] When the balloon is free to expand without being compressed by the biliary tract, as the liquid is injected (volume of injection: M) the balloon expands, its shape changes and the effective diameter increases: D0 = f(M), while the impedance value also changes, decreasing: Z0 = g(M), the subscript 0 representing the free expansion condition, the baseline of the variation of the effective diameter D0 and the impedance value Z0 with the volume increase, which will be obtained in the pressure calibration process of step S1;

[0058] In the formal operation, due to the compression of the biliary tract, the balloon deforms, is compressed, and the effective diameter D decreases, the compression causing a change in the impedance value Z (for example, the compression limits the path of the current carriers, thus increasing the impedance (Z)), the compression coefficient a (a = 0 representing the free state), D = D0 * (1 - a), while the compression also changes the impedance value where the function K defines the relationship of the effect of the compression on the impedance, obtained through experimental data or calculated from a model established for the compression profile of the balloon, so D = D0 * K -1 (Z0 / Z) (here Z, D, Z0, D0 refer to the values of one of the balloons, the subscript X is omitted);

[0059] For the pressure sensor reading Px, the change characteristics of Px are used to determine the interaction of the balloon with the inner wall of the biliary tract, including:

[0060] I: Identify the starting point of the balloon to start compressing and expanding the biliary tract;

[0061] II: Changes in the compliance of the sphincter of the biliary tract;

[0062] III: Evaluate the expansion effectiveness by recording the asymmetry of the pressure or compliance in the expansion and retraction processes (similar to elastic hysteresis);

[0063] For the impedance information Zx, the change value of Zx is used to evaluate the volume of liquid entering the balloon and optimize the calculation of the diameter of the balloon;

[0064] For the biliary tract volume V = ∑V x = ∑V(Dx, Mx).

[0065] Further, in step S3:

[0066] The calculation of the channel compliance Cx is: Cx = dVx / dPx;

[0067] The calculation of the overall compliance C is: C = dV / dP, P = MAX(Px).

[0068] Further, step S4 is implemented as the following steps:

[0069] Step S4.1: judging whether the overall compliance C is between the upper limit of compliance (C_high) and the lower limit of compliance (C_low) (compliance is too high, worrying about too large bile duct expansion; compliance is too low, worrying about too rigid bile duct), wherein:

[0070] If between, judging whether the current expanded bile duct volume V supports the completion of the expansion operation (i.e. V is greater than or equal to Vtarget), if yes, then the balloon is drained / retracted after the completion of the operation, the flow rate is Qx’, and the relevant data is continuously read until all the balloons are drained, and the continuous variable diameter biliary tract expansion pressure catheter structure is pulled out; if no, then the flow rate is controlled by the flow rate control module (PID) to increase the balloon volume, thereby increasing the bile duct volume, until the overall compliance C is between the upper limit of compliance and the lower limit of compliance and the expanded bile duct volume V supports the completion of the expansion operation;

[0071] If not between, judging the volume and pressure of the bile duct, respectively, wherein:

[0072] Judging whether the expanded bile duct volume V exceeds the volume safety threshold, if yes, then the balloon is directly drained / retracted and the operator is notified to intervene, if no, then adaptive operation is performed by controlling the flow rate by the flow rate control module (PID) (warning the operator to intervene as appropriate to ensure safety);

[0073] Judging whether the pressure sensor reading Px exceeds the pressure safety threshold, if yes, then the balloon is directly drained / retracted and the operator is notified to intervene, if no, then adaptive operation is performed by controlling the flow rate by the flow rate control module (PID) (warning the operator to intervene as appropriate to ensure safety).

[0074] Preferably, the pressure data of the Oddi sphincter and the biliary tract is obtained according to the pressure sensor reading Px, so that the high-resolution pressure image of the Oddi sphincter and the biliary tract during the operation can be obtained, as shown in Figure 4 .

[0075] Preferably, the other two groups of second pressure sensors 9 are located at the front end of the catheter structure for measuring the basic pressure in the biliary tract, which serves as the reference pressure for the measurement of the expansion treatment pressure in the biliary tract and the Oddi sphincter pressure.

[0076] For the present application:

[0077] The continuously variable diameter biliary dilatation pressure measuring catheter structure, 1. The catheter is a catheter that can contact the mucosa of the digestive tract, and the catheter material can withstand gastric juice and bile environment; 2. The catheter has three cavities inside: a guide wire cavity, a circuit cavity and a group of water injection cavities, and the guide wire cavity can pass through a 0.018 inch zebra guide wire.

[0078] The length of the cylindrical balloon is 10mm, the adjacent balloons are independently spaced by 2mm, and the pressure sensor spacing between each balloon is 12mm. The pressure sensor spacing at the front end of the catheter is 5mm.

[0079] The total length of the catheter structure is 2300mm, the diameter is 3mm, and the catheter structure can pass through the endoscope forceps channel. The proximal end of the catheter structure is connected to a measuring instrument. The proximal end of the catheter structure is provided with a water injection extension tube, and the extension tube is provided with a three-way valve.

[0080] It is worth mentioning that the technical features of the biliary tract and the Oddi sphincter involved in the present patent application should be regarded as prior art. The specific structure, working principle and possible control method and spatial arrangement method of these technical features can be selected by using conventional methods in the art, and should not be regarded as the invention point of the present patent. The present patent will not be further expanded and detailed.

[0081] For those skilled in the art, the technical solutions described in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A bile duct manometry system for endoscopic duodenal papilla dilation, characterized in that, The system includes a continuously variable diameter bile duct dilation and pressure monitoring catheter structure and a flow rate control module. The continuously variable diameter bile duct dilation and pressure monitoring catheter structure includes a catheter body and several balloons, wherein the balloons are fitted onto the catheter body, and: The catheter body has independent circuit channels, guide wire channels and several water injection channels, one end of which is connected to the flow rate control module. Each balloon-encased catheter body is equipped with a set of pressure sensors and a pair of electrodes for impedance measurement. This part also has a water inlet connected to the other end of the internal water inlet channel, so that liquid can be injected into the corresponding balloon through the corresponding water inlet channel and water inlet. The degree of balloon inflation is determined by the volume of injected liquid. Furthermore, the shape change of the balloon when it is compressed against the inner wall of the bile duct is analyzed by the measurement of the electrodes. The specific implementation process of the biliary manometry system during endoscopic duodenal papilla dilation is as follows: Step S1: The proximal end of the continuously variable diameter bile duct dilation and pressure measurement catheter structure is calibrated by a pressure measuring instrument, and the catheter body is inserted into the bile duct through the duodenal papilla with the assistance of a duodenoscope and guidewire. The pressure sensor on the catheter body accurately measures the pressure changes of the sphincter of Oddi and the bile duct. Water is gradually injected into the balloon through the water injection channel to dilate the sphincter of Oddi and the narrowed part of the bile duct. Step S2: Control the flow rate Qx of each water injection channel through the flow rate control module, thereby injecting liquid into the corresponding balloon through each water injection channel of the catheter body, and simultaneously record data including the volume Mx of the injected liquid, the pressure sensor reading Px and the impedance information Zx, and obtain relevant data of the volume V of the dilated bile duct. Step S3: Obtain the compliance of the corresponding contact portion of the bile duct by balloon dilation and evaluate the overall compliance of the bile duct based on the channel compliance obtained by each balloon; Step S4: Apply the overall compliance of the bile duct to the bile duct dilation procedure.

2. The biliary manometry system for endoscopic duodenal papilla dilation according to claim 1, characterized in that, For step S2, where: For the volume Mx of the injected liquid, The balloon diameter is then estimated based on the volume Mx. Considering the balloon's deformation due to bile duct compression, impedance information Zx is incorporated to correct the balloon diameter calculation. The specific implementation is as follows: When the balloon expands freely without being compressed by the bile duct, its shape changes as fluid is injected, and its effective diameter increases. M represents the injection volume, and the impedance value also changes, decreasing as the impedance value decreases: The subscript 0 represents the case of free expansion, in which the effective diameter is... and impedance value The baseline change with increasing volume will be obtained during the pressure calibration process in step S1; During actual operation, the balloon deforms due to compression of the bile duct, reducing its effective diameter D. This compression causes a change in the impedance value Z, and the compression coefficient α... At the same time, compression also changes the resistance value. The function K defines the relationship between compression and impedance, which is obtained through experimental data or calculated by establishing a model based on the characteristics of the balloon to determine the compression profile. ; For the pressure sensor reading Px, the characteristics of Px changes are used to determine the interaction between the balloon and the biliary tract wall, including: I: The starting point of balloon compression and dilation of the bile duct has been identified; II: Changes in the compliance of the bile duct sphincter; III: Assess the effectiveness of expansion by recording the asymmetry of pressure or compliance during the expansion and contraction processes; For the impedance information Zx, the change in Zx value is used to evaluate the volume of liquid entering the balloon and to optimize the calculation of the balloon diameter; For bile duct volume .

3. The biliary manometry system for endoscopic duodenal papilla dilation according to claim 2, characterized in that, In step S3: The channel compliance Cx is calculated as follows: ; The overall compliance C is calculated as follows: .

4. The biliary manometry system for endoscopic duodenal papilla dilation according to claim 3, characterized in that, Step S4 is specifically implemented as follows: Step S4.1: Determine whether the overall compliance C is between the upper and lower limits of compliance, where: If the volume V of the dilated bile duct is within the range of 0-100, it is determined whether the current volume V of the dilated bile duct supports the completion of the dilation procedure. If it does, the balloon is drained / retracted after the procedure is completed at a flow rate of Qx', and relevant data is read until all balloons are drained. The continuously variable diameter bile duct dilation and pressure monitoring catheter structure is then removed. If it does not support the dilation procedure, the flow rate is controlled by the flow rate control module to increase the balloon volume, thereby increasing the bile duct volume, until the overall compliance C is between the upper and lower limits of compliance and the dilated bile duct volume V supports the completion of the dilation procedure. If not, then the volume and pressure of the bile duct are assessed separately, including: Determine whether the volume V of the dilated bile duct exceeds the safe volume threshold. If it does, drain / retract the balloon directly and notify the operator to intervene. If not, control the flow rate through the flow rate control module to perform adaptive operation. Determine if the pressure sensor reading Px exceeds the pressure safety threshold. If it does, drain / retract the balloon and notify the operator to intervene. If not, control the flow rate through the flow rate control module for adaptive operation.

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