A double-segment double-color PH comparison catheter for clinically identifying premature rupture of fetal membranes

Abstract

This invention provides a dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes, belonging to the field of medical catheter technology. It includes a main catheter tube with a urine segment pH membrane and an amniotic fluid segment pH membrane sequentially arranged along the axial direction on the anterior outer wall of the main tube. The urine segment pH membrane has a color development range of pH 5.5-6.5, and its color change is a continuous gradient from yellow to green. This invention achieves zero-sampling detection under sterile conditions, highly integrating pH identification function into routine catheterization procedures. The pH value of urine and any potentially mixed amniotic fluid is simultaneously detected upon catheter insertion into the bladder, without the need for vaginal speculum, sampling swabs, or any form of secondary sterile opening. This design completely blocks the path of exogenous bacteria into the maternal reproductive tract at a physical level, thereby fundamentally and effectively reducing the incidence of clinically common chorioamnionitis and urinary tract infections, and improving perinatal medical safety and quality.

Description

Technical Field

[0001] This invention belongs to the field of medical catheter technology, specifically relating to a dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes. Background Technology

[0002] Clinically differentiating premature rupture of membranes (PROM) is a crucial and urgent diagnostic task in obstetric clinical practice. Its core clinical objective is to accurately and rapidly distinguish whether the involuntary leakage of fluid from the pregnant woman's vagina is amniotic fluid or urine. This differential diagnosis directly affects the selection of subsequent treatment plans, the control of infection risks, and the assurance of perinatal maternal and infant safety outcomes, and thus has extremely important clinical significance.

[0003] Traditional identification methods have long relied on a classic three-step procedure: speculum dilation, swab sampling, and in vitro test strip comparison. This procedure first requires mechanically dilating the vagina with a metal or plastic speculum, an operation that disrupts the vaginal microenvironment. Next, a sterile swab must be inserted into the posterior fornix or cervix to obtain a fluid sample. This step inevitably opens up the established relatively sterile area, making it difficult to completely avoid introducing bacteria, viruses, and other microorganisms from the external environment into the deep vagina and near the urethra. This artificial bacterial invasion significantly increases the risk of ascending infections, leading to a marked increase in the incidence of chorioamnionitis, urinary tract infections, and even sepsis, which threatens the life of the newborn. This constitutes a clear and serious risk of nosocomial infection, especially for mothers whose membranes have ruptured and whose protective barriers are compromised.

[0004] Moreover, this traditional method suffers from significant diagnostic lag, severely delaying optimal clinical decision-making and emergency treatment. The entire process is cumbersome, from preparing instruments and taking samples, waiting for the test strips to fully develop color, performing manual colorimetric comparison, to finally recording and reporting the results; the entire cycle often takes fifteen to forty minutes, or even longer. This waiting time is particularly long in emergency situations, often causing the "golden window" for preparing for an emergency cesarean section and administering antibiotics to prevent infection to be missed, thus posing a significant potential threat to maternal and infant safety and creating potential for medical disputes.

[0005] Meanwhile, the single-segment pH test strips used in traditional methods generally have poor diagnostic accuracy, with a persistently high false-positive rate. This is mainly because the detection principle of single-segment test strips is simplistic and easily affected by the complex environment within the vagina, such as residual menstrual blood, secretions caused by cervical inflammation (cervical mucus), residual semen, and disinfectants used to sterilize the skin before the procedure (such as povidone-iodine). These substances are alkaline and may cause the test strip to turn blue, leading to false positives. Literature reports that the false positive rate can be as high as 25% to 30%. In addition, the chemical stability of the test strips themselves is also problematic. They begin to fade due to oxidation after being exposed to air for about 30 seconds. This makes the interpretation of results highly time-sensitive and heavily reliant on the operator's personal experience and subjective judgment, lacking objective, stable, and quantifiable evaluation standards. Significant differences in interpretation may exist between different operators.

[0006] Furthermore, in practice, this traditional procedure is exceptionally cumbersome, causing significant physical pain and psychological stress for patients, especially those in special circumstances. For obese mothers, those experiencing episiotomy pain, or those with urethral edema, the perineal anatomy is often altered, resulting in a very narrow field of vision and difficulty in exposure, posing a significant challenge to sampling. In these challenging situations, if traditional methods cannot obtain sufficient samples, it is often necessary to temporarily remove the indwelling urine bag and induce urination by re-instilling saline solution into the bladder, undoubtedly increasing the number of steps involved. Each additional instrument insertion and procedure brings significant pain, discomfort, and the risk of new tissue damage to the patient. Repeated internal examinations and procedures easily lead to anxiety, embarrassment, and fear in patients, which is a major reason for declining patient satisfaction with obstetric services and frequent related medical complaints, seriously affecting the harmony and trust in the doctor-patient relationship. Summary of the Invention

[0007] The purpose of this invention is to provide a dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes, aiming to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes includes a main catheter tube. The anterior outer wall of the main catheter tube is axially provided with a urine segment pH membrane and an amniotic fluid segment pH membrane. The urine segment pH membrane has a color development range of pH 5.5-6.5, with a color change characteristic of a continuous gradient from yellow to green. The amniotic fluid segment pH membrane has a color development range of pH 7.0-7.5, with a color change characteristic of a continuous gradient from green to blue. An impermeable isolation ring is provided between the urine segment pH membrane and the amniotic fluid segment pH membrane to prevent axial seepage of liquid. This isolation ring effectively prevents the liquids in the two pH membrane regions from mixing and interfering with each other. Colorimetric scales are provided at corresponding positions on the catheter body wall of the urine segment pH membrane and the amniotic fluid segment pH membrane, providing a standard color scale reference.

[0010] In a preferred embodiment of the present invention, both the urine segment pH membrane and the amniotic fluid segment pH membrane are recessed into the outer wall of the main tube of the urinary catheter, with a recess depth of 0.1-0.3 mm. The surfaces of the urine segment pH membrane and the amniotic fluid segment pH membrane are covered with a 10-20 μm water-permeable protective membrane. This protective membrane has a microporous structure, which allows liquid molecules to pass through while protecting the pH membrane from mechanical damage.

[0011] As a preferred embodiment of the present invention, the impermeable isolation ring is a black silicone ring made of high-density medical-grade silicone material. The width of the impermeable isolation ring is 1-3mm, and the impermeable isolation ring protrudes 0.02-0.1mm above the wall of the main catheter tube, forming an effective liquid barrier.

[0012] As a preferred embodiment of the present invention, the colorimetric scale is integrally formed with the wall of the main tube of the urinary catheter and is manufactured by co-injection molding process. The main tube of the urinary catheter is provided with at least 5 levels of color difference scale lines, and each level of color difference scale line has clear color gradient characteristics and numerical identification.

[0013] In a preferred embodiment of the present invention, the pH membrane in the urine segment is 3-5 cm away from the tip of the catheter of the main catheter, which ensures that it can first come into contact with the outflowing urine; the pH membrane in the amniotic fluid segment is 6-8 cm away from the tip of the catheter of the main catheter, which is a position that facilitates the differentiation of liquids with different pH characteristics.

[0014] As a preferred embodiment of the present invention, the main catheter has an irrigation side cavity for bladder irrigation or specimen collection. The irrigation side cavity has an independent irrigation channel and interface, which can realize the functions of bladder irrigation and specimen collection.

[0015] As a preferred embodiment of the present invention, the pH membrane in the urine segment and the pH membrane in the amniotic fluid segment each occupy 1 / 4 to 1 / 2 of the outer circumference of the main catheter tube and are symmetrically distributed along the circumference. This distribution method ensures that the color change can be clearly observed from all angles.

[0016] As a preferred embodiment of the present invention, both the urine segment pH membrane and the amniotic fluid segment pH membrane are made of a blend of bromothymol blue and phenol red dyes. The two dyes are mixed in a specific ratio and fixed on a medical silicone substrate by a sol-gel method.

[0017] As a preferred embodiment of the present invention, the outer diameter of the main catheter tube is 6-20 Fr, covering different sizes from children to adults, and the length of the main catheter tube is 25-45 cm, adapting to the clinical needs of different age groups.

[0018] As a preferred embodiment of the present invention, the main tube of the urinary catheter is made of silicone or thermoplastic polyurethane material, and the pH membrane of the urine segment and the pH membrane of the amniotic fluid segment are co-extruded and formed in one piece with the main tube of the urinary catheter. This manufacturing process ensures that the layers are tightly bonded and there is no risk of interface separation.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. This invention achieves zero-sampling testing under sterile conditions, highly integrating pH identification functionality into routine catheterization procedures. Simultaneously with catheter insertion into the bladder, pH levels of urine and any potentially mixed amniotic fluid are measured, eliminating the need for vaginal speculum, sampling swabs, or any form of secondary sterile opening. This design physically blocks the entry of exogenous bacteria into the maternal reproductive tract, fundamentally and effectively reducing the incidence of common clinical conditions such as chorioamnionitis and urinary tract infections, thus improving perinatal medical safety and quality.

[0021] 2. This invention features rapid response, providing immediate test results. When urine or amniotic fluid comes into contact with the specially designed dual-segment color band, a clear color reaction is completed in just 15 to 30 seconds, allowing medical personnel to make an immediate assessment visually. This process drastically reduces the 15 to 40-minute waiting time required by traditional methods to a negligible level, gaining valuable time for emergency clinical decisions, especially the initiation of emergency cesarean sections and the golden window for antibiotic administration, significantly improving the efficiency of emergency treatment.

[0022] 3. The dual-segment color difference quantification design employed in this invention significantly improves diagnostic accuracy. The urine segment (color range: yellow-green) and the amniotic fluid segment (color range: green-blue) are positioned side-by-side on the same catheter, equipped with a colorimetric scale directly molded onto the catheter wall. When the color difference between the two segments is greater than or equal to two color levels, it can be used as a definitive positive result. This quantification mechanism significantly reduces the false positive rate of traditional test strip methods from as high as 25% to less than 5%, while also enabling repeatable verification, objective recording, and even photographic archiving of test results, greatly enhancing the objectivity and reliability of the diagnosis.

[0023] 4. This invention ensures comprehensive observation and ease of operation. A 360-degree visible color band covering one-third to one-half of the catheter circumference, combined with the high-contrast black border design of the isolation ring, guarantees that even in challenging conditions such as dimly lit wards or when obese patients severely obstruct the perineal view, the colorimetric results can still be easily identified by medical staff. The entire identification process is completed simultaneously with standard indwelling catheterization procedures, requiring no additional steps such as removing the urine bag or performing secondary saline infusion. Therefore, it achieves zero stimulation and zero additional pain for mothers who have undergone episiotomy or urethral edema, demonstrating excellent patient-friendliness.

[0024] 5. This invention demonstrates a significant advantage in cost control, achieving near-zero cost increase. Its core pH-sensitive membrane and catheter body are manufactured using a co-extrusion one-piece molding process, making hospital procurement costs almost the same as ordinary urinary catheters. Simultaneously, this design eliminates the costs of pH test strips, additional labor, and supporting consumables required by traditional identification methods. Furthermore, this platform technology possesses scalability with "one tube for multiple uses." By adjusting the pH response range of the color band, it can cover a wide monitoring range of pH values ​​from 4.5 to 9.0, making it suitable for rapid screening of body fluid acid-base imbalances in scenarios such as ICUs and anesthesiology departments. This constructs a universal rapid diagnostic platform that spans multiple departments (obstetrics-critical care-pediatrics), possessing extremely high cost-effectiveness and promotional value. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] in: Figure 1 This is a schematic diagram of the overall structure of the present invention. Detailed Implementation

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0028] Example 1

[0029] Reference Figure 1This is the first embodiment of the present invention, which provides a dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes. The catheter includes a main tube 1, with a urine segment pH membrane and an amniotic fluid segment pH membrane sequentially arranged along the axial direction on the anterior outer wall of the main tube 1. The urine segment pH membrane has a color development range of pH 5.5-6.5, with a color change from yellow to green. The amniotic fluid segment pH membrane has a color development range of pH... The pH range is 7.0-7.5, with a color change from green to blue. An impermeable isolation ring is installed between the urine segment pH membrane and the amniotic fluid segment pH membrane to prevent axial seepage of the liquid. This isolation ring effectively prevents the liquids in the two membrane areas from mixing and interfering with each other, ensuring the independence and accuracy of the color display. Colorimetric scales are installed at corresponding positions on the walls of the urine segment pH membrane and the amniotic fluid segment pH membrane, parallel to the pH membranes. When the color difference between the two pH membranes is greater than or equal to 2 color levels, it indicates that amniotic fluid has mixed with urine. In a typical application scenario, the normal urine pH is 6.0. If the urine segment is green and the amniotic fluid segment remains green, with no color difference between the two segments, it is determined to be "no rupture of membranes". If premature rupture of membranes occurs, the urine pH is 6.0 and the amniotic fluid pH is 7.3, then the urine segment is green and the amniotic fluid segment is blue, with a color difference of 2 levels, indicating "amniotic fluid mixing". This design significantly improves the accuracy and reliability of the interpretation through a dual-segment, dual-color contrast mechanism.

[0030] Reference Figure 1 Both the urine segment pH membrane and the amniotic fluid segment pH membrane are recessed into the outer wall of the main catheter 1. This recessed structure effectively protects the sensitive membrane surface while ensuring smooth fluid flow. The surfaces of both the urine and amniotic fluid segment pH membranes are covered with a 10-20 μm water-permeable protective membrane. This membrane allows liquid molecules to pass through while preventing direct contact between the membrane surface and the external environment, extending service life and maintaining response sensitivity. The impermeable isolation ring is a black silicone ring with a width of 1-3 mm, and it protrudes 0.02-0.1 mm above the wall of the main catheter 1. This slight protrusion forms a reliable physical barrier, completely blocking the axial seepage path of the fluid along the catheter wall. The colorimetric scale is integrally molded with the wall of the main catheter 1. This integrated design eliminates the risk of scale detachment or displacement, and the main catheter 1 is equipped with at least 5 levels of color difference scale lines, providing medical staff with clear and quantitative interpretation criteria; the urine segment pH membrane is 3-5 cm away from the catheter tip of the main catheter 1; the amniotic fluid segment pH membrane is 6-8 cm away from the catheter tip of the main catheter 1, and this distance ensures that the membrane segments can fully contact the flowing fluid; the main catheter 1 has an irrigation side cavity for bladder irrigation or specimen collection, which expands the clinical function of the catheter; the urine segment pH membrane and the amniotic fluid segment pH membrane each occupy one-quarter to one-half of the outer circumference of the main catheter 1, and are symmetrically distributed along the circumference. This layout ensures that the color development can be clearly observed from any angle, greatly improving the convenience of clinical operation.

[0031] Reference Figure 1 Both the urine segment pH membrane and the amniotic fluid segment pH membrane use a blend of bromothymol blue and phenol red dyes, which are fixed to the surface of medical silicone via a sol-gel method. This process ensures a strong bond between the dye and the substrate, as well as the stability and repeatability of the colorimetric reaction. The outer diameter of the catheter main tube 1 is 6-20 Fr, and the length of the catheter main tube 1 is 25-45 cm, covering a wide range of applicable groups from newborns to adults. The catheter main tube 1 is made of silicone or thermoplastic polyurethane, which have excellent biocompatibility and flexibility. The urine segment pH membrane and the amniotic fluid segment pH membrane are co-extruded with the catheter main tube 1 in one piece. This manufacturing process simplifies the production process, ensures the integrity of the structure, and eliminates the need for secondary bonding, thereby improving the reliability and consistency of the product.

[0032] In use, the catheterization procedure is first performed. The indwelling urinary catheter of this invention is inserted into the bladder using routine aseptic techniques. After urine is observed, the balloon is inflated and fixed. After the urine bag is connected, color development is performed. Urine or amniotic fluid that may be mixed in with the urine flows through the "urine segment pH membrane" and the "amniotic fluid segment pH membrane" simultaneously. Color development is completed within 15 to 30 seconds. Then, the results are interpreted. The nurse compares the two segments with the colorimetric scale on the tube wall from any angle. If both segments are the same color and green, it is pure urine and the amniotic sac has not ruptured. If the color difference between the two ends is greater than or equal to 2 color levels, with the lower segment blue and the upper segment green, amniotic fluid has been mixed in. The doctor is immediately notified and the premature rupture of membranes treatment procedure is initiated. At the same time, the results can be recorded by taking a photo with a mobile phone for archiving and traceability. This process seamlessly integrates the diagnostic process into the routine catheterization procedure, achieving rapid and accurate bedside identification without adding extra steps.

[0033] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes, comprising a main catheter tube (10), characterized in that: The outer wall of the main catheter (10) is provided with a urine segment pH membrane and an amniotic fluid segment pH membrane in sequence along the axial direction. The urine segment pH membrane has a color development range of pH 5.5-6.5 and its color change characteristic is a continuous gradient from yellow to green. The amniotic fluid segment pH membrane has a color development range of pH 7.0-7.5 and its color change characteristic is a continuous gradient from green to blue. An impermeable isolation ring is provided between the urine segment pH membrane and the amniotic fluid segment pH membrane to prevent axial seepage of liquid. The isolation ring can effectively prevent the liquids in the two pH membrane areas from mixing and interfering with each other. A colorimetric scale is provided at the corresponding position of the urine segment pH membrane and the amniotic fluid segment pH membrane and the tube wall of the main catheter (10). The colorimetric scale provides a standard color scale reference.

2. The dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes according to claim 1, characterized in that: Both the urine segment pH membrane and the amniotic fluid segment pH membrane are recessed into the outer wall of the main tube of the urinary catheter (10), with a recess depth of 0.1-0.3 mm. The surfaces of the urine segment pH membrane and the amniotic fluid segment pH membrane are covered with a 10-20 μm water-permeable protective membrane. This protective membrane has a microporous structure, which allows liquid molecules to pass through while protecting the pH membrane from mechanical damage.

3. The dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes according to claim 1, characterized in that: The impermeable isolation ring is a black silicone ring made of high-density medical-grade silicone material. The width of the impermeable isolation ring is 1-3mm, and the impermeable isolation ring is 0.02-0.1mm higher than the wall of the main tube of the urinary catheter (10), forming an effective liquid barrier.

4. The dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes according to claim 1, characterized in that: The colorimetric scale is integrally formed with the wall of the main tube of the urinary catheter (10) and is manufactured by co-injection molding. The main tube of the urinary catheter (10) is provided with at least 5 levels of color difference scale lines, and each level of color difference scale line has clear color gradient characteristics and numerical markings.

5. The dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes according to claim 1, characterized in that: The urine segment pH membrane is 3-5 cm away from the tip of the catheter of the main catheter (10), which ensures that it can contact the outflowing urine first; the amniotic fluid segment pH membrane is 6-8 cm away from the tip of the catheter of the main catheter (10), which is a position that helps to distinguish liquids with different pH characteristics.

6. The dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes according to claim 1, characterized in that: The main catheter (10) has an irrigation side cavity for bladder irrigation or specimen collection. The irrigation side cavity has an independent irrigation channel and interface, which can realize bladder irrigation and specimen collection functions.

7. The dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes according to claim 1, characterized in that: The pH membranes in the urine segment and the pH membranes in the amniotic fluid segment each occupy 1 / 4 to 1 / 2 of the outer circumference of the main catheter (10) and are symmetrically distributed along the circumference. This distribution ensures that the color changes can be clearly observed from all angles.

8. The dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes according to claim 1, characterized in that: Both the urine segment pH membrane and the amniotic fluid segment pH membrane are made of a blend of bromothymol blue and phenol red dyes. The two dyes are mixed in a specific ratio and fixed on a medical silicone substrate by a sol-gel method.

9. The dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes according to claim 1, characterized in that: The outer diameter of the main catheter (10) is 6-20 Fr, covering different sizes from children to adults. The length of the main catheter (10) is 25-45 cm, which can meet the clinical needs of different age groups.

10. The dual-segment, dual-color pH comparison catheter for clinical identification of premature rupture of membranes according to claim 1, characterized in that: The main tube of the urinary catheter (10) is made of silicone or thermoplastic polyurethane. The pH membrane of the urine segment and the pH membrane of the amniotic fluid segment are co-extruded with the main tube of the urinary catheter (10) in one piece. This manufacturing process ensures that the layers are tightly bonded and there is no risk of interface separation.

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