Patent Description:
This application relates to a device and method for monitoring intra-abdominal pressure through the urinary bladder.

Traditionally, physicians relied on visual cues or physical examination to detect increase in intra-abdominal pressure (IAP). More recently <NPL>, showed that IAP measured through the patient's bladder was significantly more accurate than physical examination. That is, it was demonstrated that the clinical abdominal examination was insensitive and inaccurate when compared with urinary bladder pressure measurements.

Various tools for measuring IAP have been developed over the years. Many researchers have documented IAP measurements through almost every natural or manmade orifice in the body. Earlier crude forms of measuring IAP used bladder catheters, nasogastric tubes, and rectal tubes attached to a manometer. The nasogastric or the rectal route was better suited in rare cases of bladder rupture or situations where bladder catheters were contraindicated. However, due to local interferences, the nasogastric and the rectal tube measurements were neither reproducible nor logical as were the bladder catheters.

Thus, measuring of IAP through the bladder became more suitable. In <NPL>, validated the correlation of IAP using a catheter inserted in the bladder. Their study was key in using bladder pressure as the gold standard for measuring IAP. In <NPL>, comparing catheters in various body locations for measuring IAP. They measured IAP from the stomach using a nasogastric tube, from the rectum using a modified rectal tube, from the bladder using a modified bladder catheter, and direct abdominal pressure using a laparoscopic insufflator needle. They found that the bladder catheter had the best measurement of IAP and that the gastric and the rectal catheter measurements were less reliable due to dependence on the position of the catheter. Thus, clinicians generally agreed that the urinary bladder is the best-suited location for measurement of IAP.

The need for measuring IAP has become more important as physicians increasingly realized that organ failure and death were directly related to increase in IAP in certain high-risk patients. High abdominal pressure has been found to cause a decrease in function of the intestines, liver and blood vessels resulting in adverse consequences for the patients. Consequently, accurate measurement of IAP can help decrease patient morbidity and mortality. It has also been more recently discovered that pediatric and neonate population may also have need for IAP measurement to determine specific conditions.

Currently, there are few products available on the market to measure the IAP through the bladder. One device, the Bard IAP device, has a "valve clamp" which diverts urine from the main catheter drainage channel to measure IAP via converting hydrostatic pressure to a readable pressure gauge. This mechanism of IAP measurements is archaic and does not provide continuous pressure measurement when used with the standard <NUM>-channel bladder drainage catheter. Two other manufacturers, Holtech and ConvaTec, also use a column of urine by connecting their kit to an existing bladder catheter. Their systems are cumbersome and the IAP readings are also not continuous. Biometrix has developed an IAP monitoring device which like other manufacturers relies on tapping into the main bladder drainage catheter, using a valve to measure the hydrostatic pressure. In <NPL>, suggested the use of <NUM>-channel bladder drainage catheter so that the smaller channel, which was used for bladder irrigation, could be used to attach a pressure-monitoring device. The use of an extra channel made it possible to have continuous bladder drainage while measuring the bladder pressure. However, this bladder catheter did not provide a continuous pressure read because intermittently the operator needed to add <NUM> of water or saline to the bladder to record the IAP pressure. Thus, the pressure reading at best was intermittent since pressure readings were not performed when fluid was being added to the bladder. Consequently, although this was a step toward increasing the amount of pressure readings/recordings, it still was unable to conduct continuous pressure monitoring. Furthermore, it was still the same cumbersome IAP device set up which required a skilled person to add water before each IAP reading. Control of the amount of water added is critical since adding too much water to the bladder can falsely increase the pressure readings and also increase infection risk, thus further complicating the use.

It has also been recognized that most patients that have a need for measurement of IAP also need to have continuous drainage of the urinary bladder and thus devices need to account for this process.

Consequently, current devices placed in the bladder for measuring pressure require a continuous water column to maintain pressure readings. Thus, they fail to measure IAP continuously but only measure pressure intermittently. They also all rely on tapping into an existing bladder drainage catheter, which adds complications. Furthermore, they do not reduce the complexity of the procedure since they require constant retrograde insertion of a relatively large amount of fluid into the bladder, e.g., 50cc, which increases the ICU workload. Still further, these devices increase the risk of complications and infections associated with fluid injection into the bladder. Fluid injection is also complicated since it needs to be closely monitored since too much fluid in the bladder can give false elevation of IAP readings, causing clinicians to take unnecessary steps in response to what is mistakenly believed is excess IAP.

It would therefore be advantageous to provide a device insertable into the bladder that accurately measures abdominal pressure without requiring adding water to the bladder to obtain such pressure readings. Such device would advantageously avoid the complications and risks associated with such fluid insertion. Furthermore, it would be advantageous if such device could continuously measure bladder pressure without interruption. This would advantageously enable a constant monitoring of IAP so critical time periods are not missed. It would further be advantageous to provide a device that improves the accuracy of the pressure reading in the bladder to more accurately determine IAP so necessary steps can be taken to address IAP only when warranted. Still further, it would be advantageous if such device could satisfy the foregoing needs and provide these enumerated advantages while being simple to use so that so that any of clinical staff with basic knowledge of bladder catheter insertion will be able to insert the device without relying on specially trained staff members.

<CIT> relates to a tamponade balloon assembly which includes an expandable balloon for stanching bleeding from body cavities. <CIT> relates to a catheter for measuring intrauterine pressure and fetal heart rate, an inflated balloon being used as a pressure sensor.

The present invention overcomes the deficiencies and disadvantages of the prior art. The present invention advantageously provides a multi-lumen catheter insertable into the bladder in the same manner as a regular bladder drainage catheter to determine intra-abdominal pressure without requiring insertion of water into the bladder. The catheters of the present invention utilize a gas-charged chamber to measure bladder pressure across a large surface area, and thus, accurately determine intra-abdominal pressure, and enable pressure to be measured continuously without interrupting urine flow and without interruptions to add water to the bladder.

Some embodiments of the catheter of the present invention utilize a stabilizing balloon to help retain the catheter in the bladder during the procedure.

In accordance with the present invention there is provided a multi-lumen catheter for monitoring pressure in a patient, the catheter being as claimed in claim <NUM> and its dependent claims annexed hereto. The catheter comprises an expandable outer balloon at a distal portion of the catheter. An expandable inner balloon is positioned within the outer balloon. A first lumen communicates with the inner balloon and the inner balloon and first lumen form a gas filled chamber to monitor pressure within the bladder. The outer balloon has a circumferential area greater than a circumferential area of the inner balloon, wherein in response to pressure within the bladder exerted on the first outer wall of the expanded outer balloon, the outer balloon deforms and exerts a pressure on the second outer wall of the expanded inner balloon to deform the inner balloon and compress the gas within the inner balloon and the first lumen to provide a finer measurement. A second lumen has a side opening and communicates with the bladder to remove fluid from the bladder. A pressure transducer communicates with the gas filled chamber for measuring bladder pressure based on gas compression caused by deformation of the expanded inner balloon deformed by the expanded outer balloon.

In some embodiments, the gas filled chamber monitors pressure within the bladder to thereby monitor pressure within an abdomen of the patient.

In some embodiments, the pressure transducer measures average pressure continuously throughout insertion of the catheter within the urethra without requiring infusion of water into the bladder.

In some embodiments, the pressure transducer is an external transducer connectable to the catheter. In some embodiments, the pressure transducer is contained within a hub and the hub includes an elongated member extending distally therefrom, and connection of the pressure transducer to a first port of the catheter automatically inserts the elongated member into the first lumen to advance gas into the inner balloon to expand the inner balloon. In some embodiments, the first lumen is not vented to atmosphere when the pressure transducer is connected to the catheter and advances gas to expand the inner balloon.

In some embodiments, the gas within the inner balloon and/lumen is air to provide an air filled chamber.

In some embodiments, the second lumen has a side opening distal of the inner and outer balloons; in other embodiments the side opening is proximal of the inner and outer balloons. The catheter can include a third lumen communicating with the outer balloon to expand the outer balloon. In some embodiments, the hub includes a second elongated member insertable into the third lumen to automatically advance gas into the outer balloon to expand the outer balloon when the hub is connected to the catheter. In some embodiments, the outer balloon is in communication with the first lumen and gas advanced through the first lumen also expands the outer balloon.

In some embodiments, the catheter has a fourth lumen and a temperature sensor positioned within the fourth lumen to measure core body temperature. A wire can extend from the temperature sensor through the fourth lumen and external of the catheter into the hub connected to the catheter. The hub can have a first opening to receive a connector of the wire to automatically connect the temperature sensor to a cable extendable from the hub and connectable to an external temperature monitor.

In some embodiments, connection of the pressure transducer to the catheter a) automatically connects the temperature sensor to a temperature monitor cable; and b) automatically advances air through the first lumen to expand the inner balloon.

In some embodiments, the catheter includes a stabilizing balloon proximal of the outer balloon for stabilizing the catheter, and the catheter includes a fifth lumen communicating with the stabilizing balloon to expand the stabilizing balloon.

In some embodiments, the outer balloon has a circumference engageable with a wall of the bladder at multiple contact regions to provide multiple reference points for calculation of an average pressure of the bladder wall. In some embodiments, the outer balloon has a distal region having a larger transverse cross-section than a proximal region.

Also disclosed herein but falling outside the scope of the present invention is a multi-lumen catheter for monitoring intra-abdominal pressure is provided comprising a distal balloon at a distal portion of the catheter and a first lumen communicating with the distal balloon. The distal balloon and first lumen form a gas filled chamber to monitor pressure within the bladder to thereby monitor pressure within an abdomen of the patient, wherein in response to pressure within the bladder the distal balloon deforms to compress the gas within the distal balloon. The first lumen has a first proximal port communicating with the first lumen. A second lumen communicates with the bladder to remove fluid from the bladder and a temperature sensor is positioned in a third lumen of the catheter and has a wire extending through the third lumen. A hub is connectable to the first port of the catheter and includes a pressure transducer for measuring pressure based on gas compression within the first lumen, wherein connection of the hub to the first port automatically connects the wire to an electrical connector in the hub for connection to a temperature monitor.

Connection of the hub to the first port may automatically advance gas into the distal balloon to expand the distal balloon, the first lumen remaining sealed to outside air during expansion of the distal balloon. The hub can include an elongated member extending distally therefrom and insertable into the first lumen to advance gas into the distal balloon upon connection of the hub to the first port. The hub can include a shroud over the elongated member and the shroud may snap fit over the first port. The first port may have a valve and the elongated member is insertable through the valve when the hub is connected to the catheter. The catheter may includea stabilizing balloon positioned proximal of the distal balloon for stabilizing the catheter.

Also disclosed herein but falling outside the scope of the present invention is a multi-lumen catheter for monitoring intra-abdominal pressure is provided comprising a distal balloon at a distal portion of the catheter and a first lumen communicating with the distal balloon. The distal balloon and first lumen form a gas filled chamber to monitor pressure within the bladder to thereby monitor pressure within an abdomen of the patient, wherein in response to pressure within the bladder the distal balloon deforms to compress the gas within the distal balloon. The first lumen has a first proximal port communicating with the first lumen. A second lumen communicates with the bladder to remove fluid from the bladder. A hub is connectable to the first port of the catheter, the hub including a pressure transducer for measuring pressure based on gas compression with the first lumen. An elongated member extends distally from the hub, wherein connection of the hub to the first port automatically inserts the elongated member into the first lumen to advance gas through the first lumen to expand the distal balloon, the first lumen not vented to atmosphere when the hub is connected to the first port.

A shroud may be positioned over the elongated member and the shroud can be snap fit over the first port or attached in other ways. In some examples, the first port has a valve and the elongated member is insertable through the valve when the hub is connected to the catheter. The catheter can include a stabilizing balloon proximal of the distal balloon for stabilizing the catheter.

Also disclosed herein but falling outside the scope of the present invention is a method for measuring intra-abdominal pressure is provided comprising the steps of:.

The method can further include the step of draining the bladder through the second lumen of the catheter. The step of obtaining pressure readings may obtain average pressure.

The catheter may include an outer balloon positioned over the first balloon and the outer balloon is expandable through a separate lumen of the catheter and deformable based on bladder pressure to deform the first balloon to provide finer measurements of bladder pressure. The step of connecting a pressure transducer may advance an elongated member extending from the hub into the first lumen to advance air into the first balloon. The temperature sensor may be positioned in a lumen of the catheter independent of the first lumen.

Also disclosed herein but falling outside the scope of the invention is a multi-lumen catheter for monitoring intra-abdominal pressure is provided. The catheter includes an elongated body configured and dimensioned for insertion into a bladder of a patient, a first lumen, a second lumen, and a first balloon at a distal portion. The first lumen communicates with the first balloon and the second lumen communicates with the bladder to remove fluid from the bladder. The first balloon is filled with a gas to form along with the first lumen a gas filled chamber to monitor pressure within the bladder to thereby monitor pressure within an abdomen of the patient. A sensor is positioned at the distal portion of the catheter to measure pressure about a circumferential area of the balloon.

Also disclosed herein but falling outside the scope of the invention is, a multi-lumen catheter is provided for monitoring intra-abdominal pressure, the catheter comprising an elongated body configured and dimensioned for insertion into the bladder of a patient, a first lumen, a second lumen, and a first balloon at a distal portion. The first lumen communicates with the first balloon and the second lumen communicates with the bladder to remove fluid from the bladder. The first balloon is filled with a gas to form a gas filled chamber to monitor pressure within the bladder to thereby monitor pressure within an abdomen of the patient. A pressure sensor is positioned at the distal portion of the catheter for continuously measuring pressure of the bladder to provide continuous readings of bladder pressure.

Also disclosed herein but falling outside the scope of the invention is a multi-lumen catheter for monitoring intra-abdominal pressure is provided. The catheter includes an elongated body configured and dimensioned for insertion into a bladder of a patient, a first lumen, a second lumen, a third lumen, a first balloon at a distal portion and a second balloon proximal of the first balloon. The first lumen communicates with the first balloon, the second lumen communicates with the bladder to remove fluid from the bladder, and the third lumen communicates with the second balloon to inflate the second balloon to stabilize the catheter. The first balloon is filled with a gas to form a gas filled chamber to monitor pressure within the bladder to thereby monitor pressure within an abdomen of the patient. A sensor measures pressure within the bladder as the first balloon changes shape in response to changes in pressure in the bladder.

Also disclosed herein but falling outside the scope of the invention is a a multi-lumen catheter is provided for monitoring intra-abdominal pressure, the catheter comprising an elongated body configured and dimensioned for insertion into a bladder of a patient, a first lumen, a second lumen, and a first balloon at a distal portion. The first lumen communicates with the first balloon and the second lumen communicates with the bladder to remove fluid from the bladder, the first balloon filled with a gas to form a gas filled chamber to monitor pressure within the bladder to thereby monitor pressure within an abdomen of the patient. A pressure sensor measures pressure of the bladder and the first lumen extends distally of the first balloon.

Also disclosed herein but falling outside the scope of the invention is a multi-lumen catheter for monitoring intra-abdominal pressure is provided comprising an elongated body configured and dimensioned for insertion into a bladder of a patient, a first lumen, a second lumen and a first balloon at a distal portion. A first side port communicates with the first lumen and the first lumen communicates with the first balloon. The second lumen communicates with the bladder to remove fluid from the bladder. The first balloon is filled with a gas to form a gas filled chamber to monitor pressure within the bladder to thereby monitor pressure within the abdomen. A pressure sensor measures pressure of the bladder and is positioned distal of the first side port for measuring pressure within the bladder resulting in a change of shape of the first balloon in response to changes in pressure in the bladder.

Also disclosed herein but falling outside the scope of the invention is a multi-lumen catheter for monitoring intra-abdominal pressure is provided. The catheter includes an elongated body configured and dimensioned for insertion into a bladder of a patient, a first lumen, a second lumen, and a third lumen, the lumens being independent. A first balloon is positioned at a distal portion and the first lumen communicates with the first balloon. The second lumen communicates with the bladder to remove fluid from the bladder. The first balloon and first lumen are filled with a gas to form a gas filled fully closed chamber to monitor pressure within the bladder to thereby monitor pressure within an abdomen of the patient. A pressure sensor measures pressure within the bladder based on deformation of the first balloon in response to pressure within the bladder exerted on an outer wall of the balloon, the pressure sensor measuring bladder pressure continuously and communicating with an external monitor to visually display pressure readings, the sensor providing continuous pressure measurements throughout its duration of insertion without requiring infusion of water into the bladder.

In accordance with another embodiment of the present invention, a multi-lumen catheter for monitoring intra-abdominal pressure is provided. The catheter includes an elongated body configured and dimensioned for insertion into a bladder of a patient, a first lumen, a second lumen, an outer balloon at a distal portion and an inner balloon within the outer balloon. The first lumen communicates with the inner balloon and the second lumen communicates with the bladder to remove fluid from the bladder. The inner balloon and first lumen are filled with a gas to form a gas filled chamber to monitor pressure within the bladder to thereby monitor pressure within an abdomen of the patient. The outer balloon has a circumferential area greater than a circumferential area of the inner balloon and inflated with a fluid (liquid or a gas, e.g., air) wherein in response to pressure within the bladder exerted on an outer wall of the outer balloon, the outer balloon deforms and exerts a pressure on an outer wall of the inner balloon to deform the inner balloon and compress the gas, e.g., air, within the inner balloon and the first lumen. The pressure sensor measures bladder pressure based on gas compression caused by deformation of the inner balloon. As noted herein, the balloon(s) can be expanded by a gas such as air.

Also disclosed herein but falling outside the scope of the invention is a system for monitoring intra-abdominal pressure is provided comprising a catheter having an elongated body configured and dimensioned for insertion into the bladder of a patient, a first lumen, a second lumen, a third lumen, and a first balloon at a distal portion. The first lumen communicates with the first balloon and the second lumen communicates with the bladder to remove fluid from the bladder. The first balloon and first lumen are filled with a gas to form a gas filled fully closed chamber to monitor pressure within the bladder to thereby monitor pressure within an abdomen of the patient. A pressure sensor measures bladder pressure continuously and communicates with an external monitor to visually display pressure readings, the sensor providing continuous pressure measurements during its insertion without requiring infusion of water into the bladder. An indicator indicates if the measured pressure exceeds a threshold value.

The indicator can be a visual and/or audible indicator.

Also disclosed herein but falling outside the scope of the invention is a method for measuring intra abdominal pressure comprising the steps of a) providing a catheter having first and second lumens and a balloon; b) inserting the catheter into a bladder of a patient; c) injecting gas into the first lumen of the catheter to expand the balloon from a deflated condition to a partially inflated condition; d) obtaining a first pressure reading of the bladder based on deformation of the balloon without injecting fluid into the bladder; e) transmitting the first pressure reading to an external monitor connected to the catheter; f) obtaining a second pressure reading of the bladder based on deformation of the balloon without injecting fluid into the bladder; g) transmitting the second pressure reading to the external monitor connected to the catheter; and h) obtaining consecutive continuous pressure readings of the bladder without injecting fluid into the bladder.

The method can include measuring the temperature of a body of a patient utilizing a temperature sensor within the first lumen.

So that those having ordinary skill in the art to which the subject invention appertains will more readily understand how to make and use the surgical apparatus disclosed herein, preferred embodiments thereof will be described in detail hereinbelow with reference to the drawings, wherein:.

Increased abdominal pressure can cause many adverse conditions including diminishing the function of the intestines, liver, and blood vessels. Simply viewing or feeling the abdomen does not provide sufficient information or reading of health conditions.

It is recognized that urinary bladder pressure directly correlates to the intra-abdominal pressure. Although pressure readings can be determined by access to the esophagus or rectum, the bladder has been found to be the most accurate and the least invasive. In trauma or burn patients for example, time is critical and the less complicated the method for determining bladder pressure the better the clinical results.

The catheters of the present invention measure abdominal pressure via measurement of bladder pressure without filling the bladder with water. This avoids the risks associated with retrograde filling of the bladder with water as such retrograde filling not only increases the complications and workload for the intensive care (IC) staff and can create inaccuracies by providing false elevation of IAP readings, but can adversely affect the patient by increasing the risk of infection. Furthermore, by avoiding refilling of the bladder, bladder pressure can be measured continuously. This is because in devices requiring filling the bladder with water, water needs to be periodically added to the bladder to replace the water drained from the bladder and measurement readings are interrupted during water insertion. Due to these repeated interruptions, pressure cannot be read continuously. Note in some cases, as much as 50cc of fluid needs to be repeatedly added to the bladder.

Thus, the catheters of the present invention efficiently and effectively measure bladder pressure without requiring filling the bladder with water. Also, as will become apparent from the discussion below, the catheters of the present invention provide a more accurate reading of pressure and enable continuous monitoring of the bladder pressure. This is all achieved in an easy to insert device.

It should be noted that the catheters of the present invention can be utilized for measuring other pressure in a patient and are not limited to intra-abdominal pressure.

Furthermore, in some embodiments, the catheter of the pressure invention provides a dual sensor to provide a backup pressure reading. In some embodiments, a dual pressure balloon arrangement is provided. This various embodiments are discussed in more detail below.

Referring now to the drawings and particular examples and embodiments of the present invention wherein like reference numerals identify similar structural features of the devices disclosed herein, there is illustrated in <FIG> a catheter of a first example but falling outside the scope of the present invention. The catheter (device) is designated generally by reference numeral <NUM> and is configured for insertion into and positioning within the bladder of the patient for measuring intra-abdominal pressure. This measurement is to check if the intra-abdominal pressure exceeds a specified threshold since if such threshold is exceeded, there is a risk to the patient as discussed above and steps need to be taken to reduce the pressure such as draining additional fluid from the abdomen, opening the abdomen, etc..

The catheter <NUM> can in some examples and in embodiments of the invention include an alarm or indicator to alert the user if pressure within the bladder, which correlates to pressure within the abdomen, rises to an unacceptable level, i.e., beyond a threshold or predetermined value (pressure). The indicator or alarm can be on the catheter or alternatively on an external device such as the monitor as discussed in more detail below. The alarm can also be connected via wireless connection to a phone or remote device to alert the appropriate personnel. The indicator or alarm can alternatively or in addition be activated if a change in pressure measurement exceeds a specified rate over a specified period of time.

Turning now to details of the catheter <NUM>, which is also referred to herein as the device <NUM>, and with initial reference to <FIG>, <FIG> the catheter <NUM> t has an elongated flexible shaft <NUM> having a lumen (channel) <NUM> extending within the shaft <NUM> and communicating at its distal region with balloon <NUM> to fluidly communicate with balloon <NUM> to inflate the balloon. Balloon <NUM> is utilized for monitoring pressure and is also referred to herein as the "pressure balloon. " A fluid port <NUM> is positioned at a proximal region <NUM> of the catheter <NUM> for communication with an infusion source for infusion of gas, e.g., air, through the lumen <NUM> and into the balloon <NUM>. The catheter <NUM> is shown in <FIG> with balloon <NUM> in the deflated condition (position) and in <FIG> with the balloon <NUM> in the inflated condition (position). The shaft <NUM> also includes a second lumen (channel) <NUM> and third lumen (channel) <NUM> extending therein (see also <FIG>). The second lumen <NUM> may be the largest lumen and is configured for continuous drainage of bodily contents from the bladder and can be connected to a drainage bag for collection of urine. Second lumen <NUM> has a side opening <NUM> at a distal portion, best shown in <FIG>, communicating with the bladder. The third lumen <NUM> terminates at its distal end within balloon <NUM> to fluidly communicate with balloon <NUM> to inflate the balloon <NUM>. The balloon <NUM> is inflatable to stabilize the catheter <NUM> to limit movement of the catheter <NUM> to keep it in place within the bladder and is also referred to herein as "the stabilizing balloon <NUM>. " A fluid port <NUM> is positioned at a proximal region <NUM> of the catheter <NUM> for communication with an infusion source for infusion of fluid through the lumen <NUM> and into the balloon <NUM>. The balloon <NUM> can be filled with fluid, e.g., liquid such as water or saline, or a gas, e.g., air. In <FIG>, the balloon <NUM> is shown in the deflated condition and in <FIG> in the inflated condition.

Note <FIG> is a transverse cross-section of the catheter showing the three lumens of various shapes. These cross-sectional shapes of the lumens are provided by way of example as one or more of the lumens can be circular, oval or other symmetrical or asymmetrical shapes in transverse cross section. This also applies to the cross-sectional views of the other examples and embodiments herein, e.g., <FIG>, <FIG> and <FIG> wherein the lumens can be shapes other than those shown. As noted above, preferably the drainage lumen is the largest lumen but in alternate examples and embodiments one or more of the other lumens could be larger than the drainage lumen.

A sensor <NUM> is positioned within lumen <NUM> adjacent balloon <NUM>. The wire(s) <NUM> are shown extending through lumen <NUM>, the sensor <NUM> and wire(s) <NUM> being of sufficiently small size so as not to interfere with air flow though lumen <NUM>. The sensor <NUM> measures pressure of the bladder. The sensor <NUM> is part of a transducer for converting the variation in pressure to an electrical signal for transmission to an external monitor. The pressure sensor also includes a temperature sensor to measure core temperature of the body as seen inside the bladder. Transmission wire(s) <NUM> of the temperature sensor extend adjacent wire <NUM> through lumen <NUM> and terminate external of the catheter <NUM> for connection to an external monitor. The transducer can be wired directly to the monitor or alternatively wired to a converter external of the catheter for converting the signal received by the transducer and transmitting a signal to the monitor, e.g., a bedside monitor, to display the pressure readings. This is shown schematically in <FIG>. The readings can be displayed in quantitative form, graphical form or other displays to provide an indicator to the clinician of the bladder pressure. The monitor, or a separate monitor, will also display the temperature readings from sensor <NUM>. Alternatively, the sensor/transducer can be connected to the monitor via a Bluetooth wireless connection.

Wires <NUM> and <NUM> can extend though lumen <NUM> and exit side port <NUM> for connection to a converter or monitor or alternatively can be inserted through the lumen <NUM>, piercing the wall to enter the lumen <NUM> distal of the side port.

An alarm system can also be provided wherein the system includes a comparator for comparing the measured pressure (and/or temperature) to a threshold (predetermined) value, and if such threshold is exceeded, an indicator, e.g., an alarm, is triggered to indicate to the hospital personnel the excessive pressure and/or temperature. An alarm system can alternatively or in addition be activated if a change in pressure measurement exceeds a specified rate over a specified period of time. This would alert the staff to an imminent risk of ACS prior to intra-abdominal pressure exceeding a certain value, e.g., <NUM> hg, since due to this link, the relationship between intra-abdominal pressure and abdominal cavity volume is believed to be linear up to an intra-abdominal pressure of <NUM>-<NUM> hg and increasing exponentially thereafter.

The alarm system can be part of the catheter (as shown in <FIG>) or alternatively external to the catheter <NUM>.

The lumen <NUM> and space 16a within balloon <NUM> together form a closed gas, e.g., air, chamber, i.e., the lumen <NUM> forming an air column. With the balloon <NUM> filled with air, pressure on the external wall of the balloon will force the balloon to deform inwardly, thereby compressing the air contained within the balloon space 16a and within the lumen <NUM>. The pressure sensor <NUM> is located in a distal portion of the lumen <NUM> at the region of the balloon <NUM> and thus is positioned at the distal end of the air column. Therefore, the pressure is sensed at the distal region as the sensor <NUM> detects change in air pressure in lumen <NUM> due to balloon deformation. Placement of the sensor <NUM> at a distal location provides a pressure reading closer to the source which advantageously increases the accuracy because it reduces the risk of transmission issues by reducing the amount of interference which could occur due to water, air, clots, tissue, etc. if the transmission is down the air lumen (air column).

Additionally, the pressure measurement occurs about a more circumferential area of the balloon <NUM> providing a pressure reading of a region greater than a point pressure sensor reading. Also, average pressure over an area of the bladder wall can be computed. Thus, the area reading gleans information on pressure over more of the bladder wall. Stated another way, the balloon has a relatively large surface area with multiple reference points to contribute to average pressure readings of the surface around it by the sensor.

The air column is charged by insertion of air through the side port <NUM> which communicates with lumen <NUM>. The side port <NUM> includes a valve to provide a seal to prevent escape of air from a proximal end. The balloon <NUM> can be composed of impermeable material, or in alternative embodiments, a permeable or semi-permeable material with an impermeable coating. This seals the air column at the distal end to prevent escape of air through the distal end, i.e., through the wall of the balloon <NUM>. Thus, with the lumen sealed at the proximal and distal ends, a closed air system is provided, and without the requirement for repeated water insertion, a fully closed unit is provided.

In some examples and embodiments of the invention, when the lumen <NUM> is air charged, the balloon <NUM> is not fully inflated. This improves the accuracy of the balloon <NUM> transmitting pressure from external the balloon to the interior of the balloon and into the lumen, i.e., air column, by ensuring the balloon has sufficient compliancy to prevent the balloon from introducing artifact into the pressure reading which would diminish its accuracy.

In some examples and embodiments, the pressure balloon <NUM> is of a size to receive at least about 3cc (<NUM>) of fluid. However, other sizes/volumes are also contemplated such as about 2cc or about <NUM> cc. Additionally, these volumes represent the maximum volume of fluid for the balloon, however, as noted above, in preferred embodiments, the pressure balloon <NUM> is not fully inflated so it would receive less than the maximum volume. Thus, with a balloon of X volume, the fluid would receive X-Y fluid, with Y representing the amount of desired extra space to achieved desired compliancy of the balloon while still enable sufficient inflation of the balloon to achieve its pressure induced deformation function.

Note in this example, the stabilizing balloon <NUM> is positioned proximal of the pressure balloon <NUM>. Also, the stabilizing balloon <NUM> is larger than the pressure balloon <NUM>. By way of example, the stabilizing balloon <NUM> can have a fully expanded diameter of about <NUM> and the pressure balloon <NUM> can have a fully expanded diameter of about <NUM>, although other dimensions or diameters for these balloons are also contemplated. By way of example, the stabilizing balloon <NUM> can have a capacity of about 10cc (<NUM>) of air, although other sizes/volumes are also contemplated. Note these sizes/volumes for both balloons are provided by way of example and other sizes are also contemplated. Alternatively, the stabilizing balloon can be the same size or smaller than the pressure balloon. Various shapes of the balloons are also contemplated.

Additionally, although the balloon <NUM> is positioned proximal of the balloon <NUM>, it is also contemplated that the balloon <NUM> be positioned distal of balloon <NUM>. The axial spacing of the balloons <NUM>, <NUM> enable the stabilizing balloon <NUM> to engage the bladder wall to provide a sufficient radial force thereon for securing/mounting the catheter within the bladder without interfering with the function of balloon <NUM>.

It should be appreciated that although the stabilizing balloon is shown in the example of <FIG>, it is also contemplated as an alternative that the catheter and system of <FIG> and <FIG> can be utilized without the stabilizing balloon <NUM> as shown for example in <FIG>. Similarly, although the various examples and embodiments (catheter) disclosed herein utilize a stabilizing balloon, it is also contemplated that alternatively the catheter of these various examples and embodiments not include a stabilizing balloon. In the embodiment of <FIG>, catheter <NUM> has two lumens: <NUM>) a lumen for drainage of the bladder which has a side opening at a distal end to communicate with the bladder (similar to lumen <NUM> of <FIG>); and <FIG>) an air lumen filling pressure balloon <NUM> via insertion of air through side port <NUM>. The sensor <NUM> is positioned within the air lumen in the same manner as sensor <NUM> is in lumen <NUM> or in the alternative positions disclosed herein. Thus, the pressure and temperature sensing described in conjunction with <FIG> is fully applicable to the example of <FIG>. Besides the elimination of the stabilizing balloon and its lumen and side port, catheter <NUM> is the same as catheter <NUM>.

Note that although only one sensor is shown in <FIG>, it is also contemplated that multiple sensors can be provided. Also, note that the sensor <NUM> is positioned in lumen <NUM> at a mid-portion of the balloon, i.e., just proximal where the opening in lumen <NUM> communicates with the interior 16a of the balloon <NUM>. It is also contemplated that the sensor can be placed at another portion within the lumen <NUM>, e.g., a more proximal portion, with respect to the lumen opening. Also, the lumen opening need not be at the mid portion of the balloon and can be at other regions of the balloon to communicate with the interior space 16a. Note if multiple sensors are provided, they can be positioned at various locations within the lumen <NUM>.

As shown, the sensor <NUM> and its transmission wires are located in the same lumen <NUM> also used for initial inflation gas, e.g., air, for balloon <NUM> and for the air charged column. This minimizes the overall transverse cross-section (e.g., diameter) of the catheter <NUM> by minimizing the number of lumens since additional lumens require additional wall space of the catheter. However, it is also contemplated in an alternate example and embodiment that the sensor is in a dedicated lumen separate from the inflation lumen <NUM>. This can be useful if a larger sensor or additional wires are utilized which would restrict the air lumen if provided therein. This is also useful if a specific sized lumen for the sensor and wires is desired to be different than the sized lumen for the air column. Provision of a separate lumen is shown in the cross-sectional view of <FIG> wherein in this alternate embodiment catheter <NUM> has four lumens: <NUM>) lumen <NUM> for drainage of the bladder which has a side opening at a distal end to communicate with the bladder (similar to lumen <NUM> of <FIG>); <NUM>) lumen <NUM> for filling pressure balloon <NUM>; <NUM>) lumen <NUM> for filling stabilizing balloon <NUM>; and <NUM>) lumen <NUM> in which sensor <NUM> and its transmission wires <NUM> and temperature sensor wires <NUM> are contained. In all other respects catheter <NUM> is identical to catheter <NUM> and its balloons, air channel, sensor, etc. would perform the same function as catheter <NUM>. Therefore, for brevity, further details of catheter <NUM> are not discussed herein as the discussion of catheter <NUM> and its components and function are fully applicable to the catheter <NUM> of the example of <FIG>. As noted above, the cross-sectional shapes of the lumens can be circular, oval, etc. or other shapes.

Turning now to the use of the catheter <NUM>, the catheter <NUM> is inserted into the bladder. Note catheter <NUM> would be used in the same manner. The balloon <NUM> is inflated to secure the catheter <NUM> in place during the procedure by insertion of a fluid (liquid or gas) through side port <NUM> which is in fluid communication with lumen <NUM>. The system is charged by inflation of the balloon <NUM>, i.e., preferably partial inflation for the reasons discussed above, by insertion of air via a syringe through port <NUM> which is in fluid communication with lumen <NUM>. As discussed above, the catheter <NUM> is a closed system with the balloon <NUM> sealed so that air inserted through lumen <NUM> and into balloon <NUM> cannot escape through balloon <NUM>. Thus, a closed chamber is formed comprising the internal space 16a of the balloon <NUM> and the internal lumen <NUM> communicating with the internal space 16a of balloon <NUM>. With the balloon <NUM> inflated, pressure monitoring can commence. When external pressure is applied to an outer surface 16b of the balloon <NUM>, caused by outward abdominal pressure which applies pressure to the bladder wall and thus against the wall of balloon <NUM>, the gas e.g., air, within the chamber is compressed. The sensor <NUM> at the distal end of lumen <NUM> provides continuous pressure readings, converted to an electrical signal by the transducer within the distal end of lumen <NUM>, and then electrically communicates through wire(s) <NUM> extending through lumen <NUM>, exiting through the proximal side port <NUM> and connected to an external monitor. Note the wire can terminate at the proximal end in a plug in connector which can be connected directly to the monitor or alternatively plugged into a converter to convert the signals from the transducer in the examples and embodiments wherein the converter is interposed between the wires and monitor (see e.g., the system of <FIG>) to provide the aforedescribed graphic display. Although, the system is capable of continuous pressure and temperature monitoring, it can also be adapted if desired for periodic monitoring so the pressure and temperature readings can be taken at intervals or on demand by the clinician.

In the examples and embodiments wherein an indicator is provided, if the measured pressure exceeds a threshold value, and/or a change in pressure measurement exceeds a specific rate over a specific time period, the indicator would alert the clinician, e.g., via a visual indication or an audible indication that the threshold is exceeded. The indicator can include an audible or visual alarm (shown schematically in <FIG>). In the examples and embodiments having an indicator, the indicator can be provided on a proximal end of the catheter which extends out of the patient or the indicator can be part of an external component such as the monitor or a separate alarm system. A visual, audible, or other indicator can likewise be provided in any of the other examples and embodiments disclosed herein to indicate if the measured temperature exceeds a predetermined value, and such indicator can include an alarm and can be part of the catheter or a separate component.

In the example of <FIG>, within the distal end of the air lumen <NUM> is a pressure transducer and pressure sensor <NUM> which also includes a temperature sensor. In the alternate example of <FIG>, the temperature sensor is separate from the pressure sensor. More specifically, catheter <NUM> has an elongated flexible shaft <NUM> having a lumen (channel) <NUM> extending within the shaft <NUM> and fluidly communicating at a distal region with balloon <NUM> to inflate the balloon. Balloon <NUM> (also referred to as the pressure balloon) is utilized for monitoring pressure. A fluid side port <NUM> is positioned at a proximal region <NUM> of the catheter <NUM> for communication with an infusion source for infusion of gas e.g., air, through the lumen <NUM> and into the balloon <NUM>. The catheter <NUM> is shown in <FIG> with balloon <NUM> in the deflated condition (position) and in <FIG> with the balloon <NUM> in the inflated condition (position). The shaft <NUM> also includes a second lumen (channel) <NUM> and third lumen (channel) <NUM> extending therein. The second lumen <NUM> is preferably the largest lumen and is configured for drainage of the bladder. Second lumen <NUM> has a side opening <NUM> at a distal portion communicating with the bladder. The third lumen <NUM> communicates at a distal region with stabilizing balloon <NUM> to fluidly communicate with balloon <NUM> to inflate the balloon. The stabilizing balloon <NUM> is inflatable to stabilize the catheter <NUM> to limit movement of the catheter <NUM> to keep it in place within the bladder. A side fluid port <NUM> is positioned at a proximal region <NUM> of the catheter <NUM> for communication with an infusion source for infusion of fluid through the lumen <NUM> and into the balloon <NUM>.

Sensor <NUM> is positioned in lumen <NUM> for sensing pressure in response to balloon deformation in the same manner as sensor <NUM>. Sensor <NUM> is positioned in lumen <NUM> distal of sensor <NUM> for measuring core temperature. Temperature sensor <NUM> can be a thermocouple, a thermistor or other types of temperature sensors. As shown in <FIG>, the temperature sensor is distal of the balloon <NUM> and its transmission wire(s) <NUM> extend proximally within lumen <NUM>, exiting a proximal end (through side port <NUM>) for communication with a monitor or alternatively a converter which communicates with the monitor. Wire(s) <NUM> of sensor <NUM> also extends through lumen <NUM>, alongside wire <NUM>, exiting through the side port <NUM> or a proximal end wall or a side wall of the lumen. It is also contemplated that alternatively one or both of sensors <NUM> and <NUM>, and their associated wires <NUM>, <NUM>, can be positioned in a separate "fourth" lumen such as in the embodiment of <FIG> so that the "inflation lumen" and the "sensor lumen" are independent.

In use, catheter <NUM> is inserted into the bladder and stabilizing balloon <NUM> is inflated to secure the catheter <NUM> in place. The system is charged by inflation of the balloon <NUM>, i.e., preferably partially inflated for the reasons discussed above, by insertion of gas, e.g., air, through port <NUM> which is in fluid communication with lumen <NUM> in a closed system formed by the internal space 66a of the balloon <NUM> and the internal lumen <NUM> communicating with the internal space 66a of balloon <NUM>. With the balloon <NUM> inflated, pressure monitoring can commence as external pressure applied to an outer surface of the balloon <NUM> compresses the gas within the chamber. The sensor <NUM> at the distal end of lumen <NUM> provides continuous pressure readings, converted to an electrical signal by the transducer within the distal end of lumen, and then electrically communicates through wires <NUM> extending through lumen <NUM> to an external monitor either directly or via a converter. The sensor <NUM> at the distal end of lumen <NUM> provides continuous temperature readings via wires <NUM> communicating directly or indirectly with the monitor, Although, the system is capable of continuous pressure and continuous temperature monitoring, as with the other systems disclosed herein, it can also be adapted if desired for periodic monitoring so the pressure and/or temperature readings can be taken at intervals or on demand by the clinician.

In the alternative example of <FIG>, catheter <NUM> is identical to the catheter <NUM> of <FIG> except that the pressure transducer is positioned external of the catheter rather than in the air (or other gas) lumen. That is, instead of the pressure transducer including the sensor being positioned within the distal end of the air lumen, the pressure sensor <NUM> is positioned within lumen <NUM> at the distal end of the lumen and transmission wire(s) <NUM> connect the sensor <NUM> to the pressure transducer <NUM> positioned outside of the patient at a proximal region of catheter <NUM>. As shown, the pressure transducer <NUM> can be positioned in a side port of catheter <NUM>. In alternate embodiments, it is positioned outside the catheter. The temperature sensor <NUM> is positioned within lumen <NUM> along with transmission wire <NUM> in the same manner as temperature <NUM> and wires <NUM> are positioned in catheter <NUM> described above. The temperature sensor <NUM> can be a separate sensor positioned distal of the pressure sensor <NUM> as shown or alternatively it can be part of sensor <NUM> as in the embodiment of <FIG>. In all other respects, catheter <NUM> is identical to catheter <NUM> and therefore for brevity further discussion is not provided since the structure and function of the balloons, the lumens, the positioning of the sensors in the lumens, the continuous pressure monitoring, etc., as well as the aforedescribed alternative arrangements of catheter <NUM>, are fully applicable to the catheter <NUM>.

In the alternative example of <FIG>, catheter <NUM> is identical to catheter <NUM> of <FIG> except that the pressure transducer and pressure sensor are positioned external of the patient at a proximal region of the catheter rather than in the air lumen. That is, instead of the pressure transducer sensor being positioned within and at the distal end of the air lumen, the transducer and pressure sensor <NUM> are positioned at a side port <NUM> of the catheter <NUM>. In alternative examples and embodiments, they are positioned outside the catheter. In yet other examples and embodiments, the pressure sensor and/or pressure transducer can be positioned within the air (or other gas) lumen at a proximal end of the air lumen. The temperature sensor <NUM> is positioned within lumen <NUM> along with transmission wire(s) <NUM> in the same manner as temperature sensor <NUM> and wire <NUM> are positioned in catheter <NUM> described above. The system is charged by inflation of the balloon <NUM>, i.e., preferably partially inflated for the reasons discussed above, by insertion of air via a syringe or other injection device through the side port <NUM> which is in fluid communication with lumen <NUM>. The catheter <NUM> is a closed system with the balloon <NUM> sealed so that air inserted through lumen <NUM> and into balloon <NUM> cannot escape through balloon <NUM>. Thus, a closed chamber is formed comprising the internal space of the balloon <NUM> and the internal lumen <NUM> communicating with the internal space of balloon <NUM>. With the balloon <NUM> inflated, pressure monitoring can commence. When external pressure is applied to an outer surface of the balloon <NUM>, caused by outward abdominal pressure which applies pressure to the bladder wall and thus against the wall of balloon <NUM>, the gas (e.g., air) within the chamber of the balloon <NUM> is compressed. This compresses the air within the lumen <NUM> creating an air charged column along the lumen <NUM>. The sensor <NUM> at the proximal end of catheter <NUM> measures pressure of the air column at its proximal end and can provide continuous pressure readings, converted to an electrical signal by the transducer at the proximal end or external of the catheter <NUM>, and then electrically communicates through wire(s) to an external monitor. The balloon <NUM>, like balloon <NUM>, balloon <NUM> and the other pressure balloons described herein, is of sufficiently large size to provide a sufficient circumferential area for detection of pressure changes along several parts of the bladder wall, thereby providing an average pressure and enabling more accurate pressure readings. Balloon <NUM> is a stabilizing balloon like balloon <NUM> inflated through a separate lumen.

Note the wire(s) of the sensor <NUM> can terminate at the proximal end in a plug in connector which can be connected directly to the monitor or alternatively plugged into a converter to convert the signals from the transducer in the embodiments where the converter is interposed between the wires and monitor (see e.g. the system of <FIG>) to provide the aforedescribed graphic display. Although, the system is capable of continuous pressure and temperature monitoring, it can also be adapted if desired for periodic monitoring so the pressure and/or temperature readings can be taken at intervals or on demand by the clinician. In all other respects, catheter <NUM> is identical to catheter <NUM> and therefore for brevity further discussion is not provided since the structure and function of the balloons, the continuous pressure monitoring, etc., as well as the aforedescribed alternative arrangements of catheter <NUM>, are fully applicable to the catheter <NUM>.

<FIG> and <FIG> illustrate an alternate example wherein catheter <NUM> includes a pressure sensor within the balloon. More specifically, catheter <NUM> has an elongated flexible shaft <NUM> having a lumen (channel) <NUM> extending within the shaft <NUM> and communicating at its distal region with balloon <NUM> to fluidly communicate with balloon <NUM> to inflate the balloon. Balloon <NUM> (also referred to as the pressure balloon) is utilized for monitoring pressure. A fluid side port <NUM> is positioned at a proximal region <NUM> of the catheter <NUM> for communication with an infusion source for infusion of gas through the lumen <NUM> and into the balloon <NUM>. The shaft <NUM> also includes a second lumen (channel) <NUM> and third lumen (channel) <NUM> extending therein. Second lumen <NUM> has a side opening <NUM> at a distal portion communicating with the bladder. The third lumen <NUM> communicates at a distal region with stabilizing balloon <NUM> to fluidly communicate with balloon <NUM> to inflate the balloon to limit movement of the catheter <NUM> to keep it in place within the bladder for drainage. A fluid port <NUM> is positioned at a proximal region <NUM> of the catheter <NUM> for communication with an infusion source for infusion of fluid through the lumen <NUM> and into the balloon <NUM>.

The pressure sensor <NUM> is carried by catheter <NUM> and positioned within the balloon <NUM> to measure pressure in response to deformation of the balloon in response to pressure exerted on an outer wall of balloon <NUM>. The pressure transducer can include the sensor <NUM> or can be a separate component positioned at a proximal end of the catheter external of the catheter <NUM>. The temperature sensor <NUM> can be positioned within the balloon <NUM>, can be part of sensor <NUM>, or alternatively positioned within lumen <NUM> (as shown in <FIG>), with its transmission wire(s) <NUM> extending within the gas, e.g., air, lumen <NUM> along with the wires of sensor <NUM> in the same manner as in catheter <NUM> described above.

In all other respects, catheter <NUM> is identical to catheter <NUM> and therefore for brevity further discussion is not provided since the structure and function of the balloons, lumens, continuous pressure monitoring, etc. as well as the aforedescribed alternative arrangements of catheter <NUM>, are fully applicable to the catheter <NUM>.

As discussed above, the pressure balloons disclosed herein have a large circumferential area (and large volume) to provide multiple reference points for pressure readings and to provide an average pressure to enable more accurate readings. Thus, the pressure balloon provides for gross measurement. In an embodiment of the present invention shown in <FIG>, the pressure balloon for detecting pressure, designated by reference numeral <NUM>, forms an outer balloon of catheter <NUM>. Contained within the outer balloon <NUM> is an inner balloon <NUM>. The inner balloon <NUM> provides a smaller diameter balloon and a smaller circumference (and volume) than the outer balloon <NUM>. The inner balloon <NUM> together with the lumen <NUM> forms a smaller gas, e.g., air, column than in the embodiments discussed above where the larger balloon internal space communicates directly with the air lumen. This provides finer measurements. Thus, the compliant outer balloon <NUM> compresses the compliant inner balloon <NUM> which compresses the air within air lumen <NUM>. The closed system is thereby formed by the internal space of the inner balloon <NUM> and the lumen <NUM>. In certain instances, the smaller balloon air column can provide a more accurate reading from the average pressure determined by the larger outer balloon <NUM>.

The inner balloon <NUM> and outer balloon <NUM> can be separately/independently inflated and closed with respect to each other so there is no communication, e.g. passage of gas or liquid, between the inner and outer balloons <NUM>, <NUM>. The outer balloon in the embodiments having an inner balloon within the outer balloon can be filled with a gas like the inner balloon or alternatively filled with a liquid such as saline.

The pressure transducer and pressure sensor <NUM> can be positioned within the lumen <NUM> in the same manner as sensor <NUM> of <FIG> and can function in the same manner. Alternatively, the pressure transducer can be at a proximal end of the catheter <NUM> as in the embodiment of <FIG> or external of the catheter. A temperature sensor can be part of sensor <NUM> as in the example of <FIG> or alternatively it can be a separate component which can be positioned for example distal of the pressure sensor within the gas, i.e., air, lumen as in the example of <FIG>. The transmission wires of the pressure sensor <NUM> and the temperature sensor extend through lumen <NUM>.

The catheter <NUM> can optionally include a stabilizing balloon <NUM> similar to balloon <NUM> of <FIG>. The catheter <NUM> would have a lumen, e.g., lumen <NUM>, to inflate the stabilizing balloon <NUM>. Lumen <NUM> with side opening <NUM> provides for drainage of the bladder. Lumen <NUM> which is used to inflate the inner balloon <NUM> and create the gas column has an opening at a distal region to communicate with inner balloon <NUM>. A separate lumen <NUM> has an opening at a distal region to communicate with the outer balloon <NUM> to fill the outer balloon <NUM>.

In use, catheter <NUM> is inserted into the bladder and stabilizing balloon <NUM> is inflated to secure the catheter <NUM> in place. The system is charged by inflation of the inner balloon <NUM>, i.e., preferably partially inflated for the reasons discussed above, by insertion of air through a side port which is in fluid communication with lumen <NUM> in a closed system formed by the internal space 143a of the inner balloon <NUM> and the internal lumen <NUM> communicating with the internal space of inner balloon <NUM>. Outer balloon <NUM> is filled, i.e., preferably partially inflated for the reasons discussed above, via injection of air through a separate lumen. With the outer balloon <NUM> inflated, pressure monitoring can commence as external pressure applied to the larger circumferential outer surface of the outer balloon <NUM> compresses and deforms the outer balloon <NUM> which compresses the inner balloon <NUM>. As the inner balloon <NUM> is compressed and deformed in response to compression/deformation of the outer balloon <NUM> based on changes to bladder pressure, the sensor <NUM> at the distal end of lumen <NUM> provides continuous pressure readings, converted to an electrical signal by the transducer within the distal end of lumen <NUM>, and then electrically communicates through wires <NUM> extending through lumen <NUM> to an external monitor either directly or via a converter. Although, the system is capable of continuous pressure and continuous temperature monitoring, as in the other embodiments disclosed herein it can also be adapted if desired for periodic monitoring so the pressure and/or temperature readings can be taken at intervals or on demand by the clinician.

Note that although separate lumens are provided for the inflation of inner balloon <NUM> and outer balloon <NUM>, in an alternate embodiment, a single lumen can be utilized to inflate both balloons <NUM> and <NUM>.

<FIG> illustrates an alternate embodiment of catheter <NUM>, designated by reference numeral <NUM>'. Catheter <NUM>' is identical to catheter <NUM> except a larger outer balloon <NUM>' is provided to cover more surface area for pressure readings. In all other respects, catheter <NUM>' is identical to catheter <NUM> and for brevity further discussion is not provided since the features and functions of catheter <NUM>, and its alternatives such as single or two lumens for inner and outer balloon inflation, are fully applicable to catheter <NUM>'. For ease of understanding, the components of catheter <NUM>' which are identical to catheter <NUM> are given the same reference numerals as catheter <NUM>.

Note that the larger balloon <NUM>' can be used with the catheters of any of the embodiments described herein. Thus, a pressure balloon of the larger size balloon <NUM>' can be used instead of the smaller pressure balloons illustrated in the drawings. Note the size of the balloons is provided by way of example and are not necessarily drawn to scale comparatively to the other components.

<FIG> illustrates an alternate embodiment of catheter <NUM>, designated by reference numeral <NUM>". Catheter <NUM>" is identical to catheter <NUM> except a pear shaped larger outer balloon <NUM>" is provided. The larger balloon <NUM>" covers more surface area for pressure readings. The pear shape could in certain applications decrease the risk of obstructing the ureter and provide more tactile continuity of the balloon to the bladder wall giving a better transmission of abdominal pressure to the internal sensor. In all other respects, catheter <NUM>" is identical to catheter <NUM> and for brevity further discussion is not provided since the features and functions of catheter <NUM>, and its alternatives such as single or two lumens for inner and outer balloon inflation, are fully applicable to catheter <NUM>". For ease of understanding, the components of catheter <NUM>" which are identical to catheter <NUM> are given the same reference numerals as catheter <NUM>. <FIG> illustrates a catheter identical to catheter <NUM>" with identical balloons, the only difference being that the side opening <NUM>' is positioned proximal of the balloon <NUM> rather than distal of the balloon as in <FIG>. That is, opening <NUM>', in communication with the catheter lumen <NUM>' for drainage of the bladder, is positioned between the stabilizing balloon <NUM> and the inner and outer pressure (and inner) pressure balloon <NUM>" (and <NUM>). Thus, it is distal of the stabilizing balloon <NUM> and proximal of the outer balloon <NUM>".

Note that the positioning of the side opening for drainage of <FIG>, which communicates with the drainage lumen of the catheter, can be utilized with any of the catheters disclosed herein. Thus, in the catheters disclosed in the various embodiments herein, instead of the drainage opening positioned distal of the pressure balloon(s), it can be proximal of the pressure balloon and distal of the stabilizing balloon so it is between the two balloons.

Note that the pear shaped balloon <NUM>" can be used with the catheters of any of the embodiments described herein. Thus, a pressure balloon of the pear shape of balloon <NUM>", and of larger size if desirable, can be used instead of the pressure balloons illustrated in the drawings.

<FIG> illustrate an alternate embodiment of the catheter of the present invention. The pressure balloon for detecting pressure, designated by reference numeral <NUM>, forms an outer balloon of catheter <NUM>. Contained within the outer balloon <NUM> is an inner balloon <NUM>. The inner balloon <NUM> provides a smaller diameter balloon and a smaller circumference (and volume) than the outer balloon <NUM>. The inner balloon <NUM> together with the lumen <NUM>, which communicates with the inner balloon <NUM> for inflation thereof, forms a smaller gas, e.g., air, column as in the embodiments of <FIG>. This provides finer measurements. Thus, the compliant outer balloon <NUM> compresses the outer wall <NUM> of the compliant inner balloon <NUM> which compresses the air (or other gas) within air lumen <NUM>. The closed system is thereby formed by the internal space 204a of the inner balloon <NUM> and the lumen <NUM>. The smaller balloon air column can in certain instances provide a more accurate reading from the average pressure determined by the larger outer balloon <NUM>.

The pressure transducer and pressure sensor are external to catheter <NUM> and mounted to port <NUM> at the proximal end <NUM> of catheter <NUM>. More specifically, a transducer hub or housing, designated generally by reference numeral <NUM>, contains the pressure transducer and sensor and is mounted to the angled side port <NUM>. In the embodiment of <FIG>, the hub <NUM> is mounted over the port <NUM> and can be locked or secured thereto such as by a friction fit, snap fit, threaded attachment, a latch, etc., maintaining an airtight seal so the air is contained within the lumen <NUM> and balloon <NUM>. The hub <NUM> has an elongated (rod-like) member or nose <NUM> extending distally therefrom (<FIG>) dimensioned to be inserted through the proximal opening in port <NUM> and into air lumen <NUM>. (Note the air lumen <NUM> as in the other lumens extend into their respective angled side ports). The elongated member <NUM> also has a channel <NUM> extending therethrough to allow the pressure wave to travel through to the pressure sensor. Although in preferred embodiments no additional air needs to be injected into inner balloon <NUM> via lumen <NUM> after attachment of hub <NUM>, it is also contemplated that a port or opening can be provided in hub <NUM> to receive an injection device for injection of additional air. Such additional air can communicate with and flow through channel <NUM> of elongated member <NUM>, into lumen <NUM> and into inner balloon <NUM> for inflation, or alternatively, a side port or opening in angled port downstream of the elongated member <NUM> could be provided.

To charge the system, when the hub <NUM> is mounted to the side port <NUM>, the elongated member <NUM> extends into lumen <NUM> to advance air through the air lumen <NUM> into inner balloon <NUM> to expand inner balloon <NUM>. In some embodiments,. 2cc of air can be displaced/advanced by the member <NUM>, although other volumes are also contemplated. Thus, as can be appreciated, mounting of the hub <NUM> to the catheter <NUM> automatically pressurizes the air lumen/chamber and expands the inner balloon <NUM>. Note the inner balloon <NUM> can be partially or fully inflated (expanded), dependent on the amount of air advanced into the inner balloon <NUM>. Further note that the lumen <NUM> is not vented to atmosphere when the transducer hub <NUM> is attached and air is advanced through the air lumen. The port <NUM> can include a closable seal through which the elongated member <NUM> is inserted but maintains the seal when the elongated member <NUM> remains in the lumen <NUM>.

Lumen <NUM> which is used to inflate the inner balloon <NUM> and create the air column has an opening at a distal region to communicate with the interior of inner balloon <NUM>. Lumen <NUM> of catheter has an opening at a distal region to communicate with the outer balloon <NUM> to fill the outer balloon <NUM>. Angled port (extension) <NUM> at the proximal end of catheter <NUM> receives an inflation device to inflate, either fully or partially, the outer balloon <NUM>.

Note as in the other embodiments disclosed herein, air is described as the preferred gas for creating the column and expanding the balloon, however, other gasses are also contemplated, for each of the embodiments herein.

The outer balloon <NUM> can be shaped such that a distal region 207a (<FIG>) has an outer transverse cross-sectional dimension, e.g., diameter, greater than an outer transverse cross-sectional dimension, e.g., diameter, of the proximal region 207b. A smooth transition (taper) can be provided between the distal region 207a and proximal region 207b. Note the balloon <NUM> can be pear shaped as shown in <FIG> although other configurations are also contemplated. This pear shape in some applications is designed to conform to the shape of the bladder.

The inner and outer balloons <NUM>, <NUM> can by way of example be made of urethane, although other materials are also contemplated such as silicone or EVA.

A temperature sensor <NUM> (<FIG>), such as a thermocouple, is positioned within the catheter <NUM> at a distal end to measure core body temperature. The sensor <NUM> is shown positioned in a lumen <NUM> separate from the lumens <NUM> and <NUM>. One or more wires <NUM> extend from the sensor <NUM> through the lumen <NUM>, exiting the lumen <NUM> and catheter <NUM> at a proximal end between the angled extensions/ports of the catheter <NUM>, e.g., between the port <NUM> for the inner balloon <NUM> and the port <NUM> for the outer balloon <NUM>. A connector <NUM>, e.g., a male connector, is at the proximal terminal end of the wire <NUM> as shown in <FIG>. The transducer hub <NUM> includes a connector <NUM> with openings <NUM> (<FIG>) which receive the connector <NUM> of the wire <NUM>. When the hub <NUM> is mounted to port <NUM> of catheter <NUM>, the connector <NUM> of the wire is automatically connected to a connector carried by or within the hub <NUM> which is in communication with a temperature monitor. Note the connector, e.g., female connector, within or carried by the hub <NUM> can already be mounted to an external temperature monitor via a cable when the hub <NUM> is mounted to catheter <NUM> or alternatively the hub <NUM> can first be mounted to port <NUM> of the catheter <NUM> and then a cable is connected between the temperature monitor and catheter <NUM>. In the illustrated embodiment of <FIG>, the wire connector <NUM> can plug into the openings <NUM> of connector <NUM> positioned on the hub <NUM>. Note the connector <NUM> can also be internal of the hub <NUM> with an opening in the wall of the hub to enable access for the wire connector. Also note that alternatively the wire can include a female connector and the hub can have a male connector. Other types of connectors/connections are also contemplated.

As can be appreciated, connection of the transducer hub <NUM> to the catheter <NUM> (port <NUM>) a) automatically connects the temperature sensor <NUM> to a connector for communication with a temperature monitor cable; and b) automatically advances air through the first lumen <NUM> to expand the inner balloon <NUM>.

The catheter <NUM> can optionally include a stabilizing balloon <NUM> similar to balloon <NUM> of <FIG>. The stabilizing balloon <NUM> can be made of silicone, although other materials are also contemplated. If provided, the catheter <NUM> would have a lumen, e.g., lumen <NUM>, to inflate the stabilizing balloon <NUM>. Angled side port <NUM> can be provided in communication with lumen <NUM> for injection of a liquid or gas to expand the stabilizing balloon <NUM>. The foregoing description of the stabilizing balloons in connection with other embodiments is fully applicable to balloon <NUM>. Catheter <NUM> also includes a lumen <NUM> with a distal side opening 211a (<FIG>) to provide for drainage of the bladder as in the aforedescribed embodiments. In the illustrated embodiment, the side opening 211a is distal of outer balloon <NUM> and inner balloon <NUM> and distal of the stabilizing balloon <NUM> which as shown is proximal of outer balloon <NUM> and inner balloon <NUM>. In alternate embodiments, the stabilizing balloon <NUM> can be distal of the outer balloon <NUM>.

Thus, in the embodiment of <FIG>, catheter <NUM> has five lumens: <NUM>) lumen <NUM> communicating with inner balloon <NUM> to inflate the inner balloon <NUM> and forming the air filled chamber; <NUM>) lumen <NUM> communicating with outer balloon <NUM> for inflating outer balloon <NUM>; <NUM>) lumen <NUM> communicating with the stabilizing balloon <NUM> to inflate stabilizing balloon <NUM>; <NUM>) drainage lumen <NUM> having a side opening 211a at a distal end for drainage of the bladder; and <NUM>) lumen <NUM> for the temperature sensor wire(s) <NUM>. Catheter <NUM> also has three angled extensions/ports at its proximal end <NUM>: <NUM>) port <NUM> for access to lumen <NUM> to inflate the inner balloon <NUM>; <NUM>) port <NUM> for access to lumen <NUM> to inflate outer balloon <NUM>; and <NUM>) port <NUM> for access to lumen <NUM> to inflate stabilizing balloon <NUM>. Drainage lumen <NUM> extends linearly terminating at region <NUM>. Lumen <NUM> terminates proximally at the region of the angled ports <NUM>, <NUM> through which wire <NUM> can exit from the catheter <NUM> for connection to a temperature monitor via hub <NUM>. Note the location of the ports can vary from that illustrated in <FIG>. Also, location of the lumens and the cross-sectional dimension and size of the lumen can vary from that shown in <FIG> as <FIG> provides just one example of the location and size, e.g., diameter, of the lumens as well as the shape/cross-sectional configuration and location. The catheter <NUM>, as in the foregoing embodiments, can have an atraumatic tip <NUM>.

In use, catheter <NUM> is inserted into the bladder and stabilizing balloon <NUM> is inflated to secure the catheter <NUM> in place. The system is charged by inflation of the inner balloon <NUM>, i.e., preferably partially inflated for the reasons discussed above, by advancement of air through lumen <NUM> upon attachment of the pressure transducer <NUM> to the port <NUM> of catheter <NUM>. Such attachment moves elongated member <NUM> into lumen <NUM> to displace the air (or other gas) already in the lumen <NUM> to expand the inner balloon <NUM>. A closed system is formed by the internal space 204a of the inner balloon <NUM> and the internal lumen <NUM> communicating with the internal space 204a of inner balloon <NUM>. In a preferred embodiment, additional air does not need to be added to the balloon <NUM>/lumen <NUM>. Outer balloon <NUM> is filled, i.e., preferably partially inflated for the reasons discussed above, via injection of air through the separate port <NUM> which communicates with lumen <NUM> of catheter <NUM>. With the outer balloon <NUM> inflated, pressure monitoring can commence as external pressure applied to the larger circumferential outer surface of the outer balloon <NUM> compresses and deforms the outer balloon <NUM> which exerts a force on the outer wall of inner balloon <NUM> and compresses the inner balloon <NUM>. As the inner balloon <NUM> is compressed and deformed in response to compression/deformation of the outer balloon <NUM> based on changes to bladder pressure, the pressure sensor within the external hub <NUM> attached at the proximal end of the catheter <NUM> provides continuous pressure readings, converted to an electrical signal by the transducer within the hub <NUM>, and then electrically communicates through a connector, e.g. cable <NUM>, to an external monitor either directly or via a converter to display pressure readings. Although, the system is capable of continuous pressure and continuous temperature monitoring, it can also be adapted if desired for periodic monitoring so the pressure and/or temperature readings can be taken at intervals or on demand by the clinician. Temperature readings are also taken during the procedure as temperature sensor <NUM> is connected to a temperature monitor via wire <NUM> connected to a connector of hub <NUM> which is connected to the temperature monitor to display temperatures. The temperature monitor can be separate from the pressure display monitor or alternatively integrated into one monitor. Cable <NUM> can connect to the temperature monitor as well (directly or via a converter) or a separate cable extending from the hub <NUM> could be provided for connection to the temperature monitor.

Note that although separate lumens are provided for the inflation of inner balloon <NUM> and outer balloon <NUM>, in an alternate embodiment, a single lumen can be utilized to inflate both balloons <NUM> and <NUM>. In such embodiment, catheter <NUM> can have one less angled port and one less lumen since inflation of the outer balloon <NUM> would be through port <NUM> and lumen <NUM>.

The proximal and distal end of the inner balloon <NUM> in the illustrated embodiment are within the confines of the outer balloon <NUM>, i.e., the proximal end of the inner balloon <NUM> is distal of the proximal end of the outer balloon <NUM> and the distal end of the inner balloon <NUM> is proximal of the distal end of the outer balloon <NUM>. Thus, in this illustrated embodiment, the inner balloon <NUM> is fully encapsulated within the outer balloon <NUM>.

With this inner/outer balloon arrangement, the larger outer surface of the outer balloon <NUM> takes gross measurements and then the forces are concentrated on the smaller inner balloon <NUM> to amplify/concentrate pressure on the small area of the inner balloon so small changes can be detected and waves transmitted to the pressure transducer (via the length of the lumen to a proximal transducer, e.g. an external pressure transducer).

As noted above, preferably no additional air needs to be added after mounting of hub <NUM>. However, it is also contemplated that in alternate embodiments a port can be provided in communication with hub <NUM> to enable subsequent injection of air though lumen <NUM> and into inner balloon <NUM>. Additionally, outer balloon <NUM> can in some embodiments receive additional fluid injection via port <NUM> during the procedure.

<FIG> illustrates an alternate example of the pressure transducer hub. Hub <NUM> has a shroud <NUM> (shown schematically) positioned over elongated member <NUM>. This helps protect/shield the elongated member <NUM>. When the transducer <NUM> is mounted to the port <NUM> of the catheter, the shroud <NUM> fits over cover <NUM> of port <NUM> and is retained by a snap fit or by other methods of securement.

In the aforedescribed embodiments, mounting of the transducer hub a) automatically connects the temperature sensor to a connector for communication with a temperature monitor cable; and b) automatically advances air through the first lumen to expand the inner balloon. In the embodiment of <FIG>, the pressure transducer hub <NUM> has a second elongated member <NUM> extending therefrom. When transducer hub <NUM> is mounted to the catheter, e.g., port <NUM>, elongated member <NUM> enters the air lumen in the same manner as elongated member <NUM> of <FIG>. Additionally, elongated member <NUM> automatically enters the lumen <NUM> at port <NUM> which communicates with the outer balloon <NUM>. Therefore, in this embodiment, mounting of the transducer hub <NUM> a) automatically connects the temperature sensor to a connector for communication with temperature monitor cable as in the embodiment of <FIG>; b) automatically advances air through the first lumen to expand the inner balloon as in the embodiment of <FIG>; and c) automatically advances air through lumen <NUM> communicating with the outer balloon <NUM> to inflate (expand) the outer balloon <NUM>. The catheter of <FIG>) is otherwise identical to catheter <NUM> of <FIG> so for brevity further discussion is not provided since the description of the function and elements of catheter <NUM> are fully applicable to the catheter of <FIG> (and to the catheter of <FIG>).

<FIG> show an alternate example of the hub/connector for use with a catheter according to the invention. The pressure transducer is external to catheter <NUM> and mounted to port <NUM> at the proximal end <NUM> of catheter <NUM> via connector (housing) <NUM>. Catheter <NUM> is identical to catheter <NUM> of <FIG> except for the connector and transducer hub temperature sensor connection.

More specifically, transducer hub or housing, designated generally by reference numeral <NUM>, contains the pressure transducer and sensor <NUM> and is mounted to the angled side port <NUM>. In the embodiment of <FIG>, the hub <NUM> is mounted to the catheter <NUM> by connection to housing <NUM>. Housing <NUM> is connected to port <NUM> via a barbed fitting <NUM> providing an interference fit with the port <NUM>. The hub <NUM> is locked or secured to connector <NUM> such as by a snap fit provided by the latch arms discussed below, although other attachments are also contemplated such as a friction fit, threaded attachment, other form of latch, etc., as well as other types of snap fits to provide an attachment that maintains an airtight seal so the air is contained within the air lumen and balloon <NUM> of the catheter <NUM>. (As noted above catheter <NUM> is identical to catheter <NUM> except for its connector so catheter <NUM> includes (not shown) the inner and outer pressure balloons, stabilizing balloon, temperature sensor, etc..

The housing <NUM> attached to catheter <NUM> has a proximal opening <NUM> and a channel (lumen) <NUM> to receive an elongated (rod-like) member or nose <NUM> extending distally from transducer hub <NUM>. As shown channel <NUM> has a first diameter region 296a to match with the lumen <NUM> of the port <NUM>, a second larger diameter region 296b proximal of region 296a to receive the male rod <NUM> of the hub <NUM>, and a still larger diameter region 296c proximal of region 296b to receive the valve <NUM> and valve <NUM> and allow expansion thereof. As shown, valve <NUM> is dome shaped and is distal of valve <NUM>. Conical cap <NUM>, proximal of valve <NUM>, provides a lead in to the valve <NUM> for the rod <NUM>. Thermistor pins <NUM> receive thermistor connectors <NUM>. Note valves <NUM>, <NUM> are one example of valves that can be provided as other valves to provide an airtight seal are also contemplated. A single valve is also contemplated.

Hub <NUM> is mounted to connector <NUM> and includes a housing <NUM> from which a pair of distally extending snap fit connector arms <NUM> extend. The latch arms <NUM> are sufficiently flexible to enable attachment and have an enlarged distal portion <NUM>, illustratively shown as arrow shaped although other enlarged shapes could be provided. The elongated member <NUM> extends between the latch arms <NUM>. When the hub <NUM> is mounted to the connector <NUM>, the elongated member <NUM> extends into the channel <NUM> to advance air to inflate the inner balloon. The enlarged ends <NUM> of latch arms <NUM> enter recesses <NUM> and engage shoulders 291a to retain the hub <NUM>. Note to release (disconnect) the hub <NUM>, the ends <NUM> are pressed radially inwardly to disengage from shoulder 291a and the hub <NUM> is pulled proximally. Note that alternatively a different number of latch arms could be provided.

The housing (connector) <NUM> has a lumen <NUM> for communication with the lumen <NUM> in the side port <NUM> of catheter <NUM> which communicates with the air lumen and inner balloon of the catheter <NUM>. As noted above, the lumen <NUM> is dimensioned to receive the elongated rod <NUM> of transducer hub <NUM>. The wire for the sensor extends in housing <NUM>. When transducer hub <NUM> is attached to connector <NUM>, such attachment inserts the elongated rod <NUM> into lumen <NUM> to advance air though the air lumen in the catheter and into the balloon <NUM>. (Note the air lumen extends into its angled side port <NUM>). The elongated member <NUM> also has a channel or lumen <NUM> extending therethrough to allow the pressure wave to travel through to the pressure sensor. Although in preferred embodiments no additional air needs to be injected into balloon <NUM> after attachment of hub <NUM>, it is also contemplated that a port or opening can be provided in hub <NUM> to receive an injection device for injection of additional air. Such additional air can communicate with and flow through channel <NUM> of elongated member <NUM>, into the air lumen and balloon <NUM> for inflation, or alternatively, a side port or opening in the angled port downstream (distal) of the elongated member <NUM> could be provided. Attachment of hub <NUM> to housing <NUM> also automatically connects thermistor connectors <NUM> to thermistor pins <NUM> to automatically connect the temperature sensor to the hub <NUM> for communication via a cable to a temperature monitor.

To charge the system, when the hub <NUM> is mounted to the side port <NUM> via attachment to connector <NUM>, the elongated member <NUM> extends into lumen <NUM> to advance air through the air lumen into balloon <NUM> (or the pressure balloon in the embodiments with a single pressure balloon) to expand the balloon <NUM>. That is, connection of the transducer hub <NUM> to the catheter <NUM> (port <NUM>) automatically advances air through the connector lumen <NUM>, the port lumen <NUM> and the first lumen <NUM> to expand the balloon <NUM>. (Such connection also automatically connects the temperature sensor to the hub <NUM>). In some embodiments,. 2cc of air can be displaced/advanced by the member <NUM>, although other volumes are also contemplated. Thus, as can be appreciated, mounting of the hub <NUM> to the catheter <NUM> automatically pressurizes the air lumen/chamber and expands the balloon. Note the balloon can be partially or fully inflated (expanded), dependent on the amount of air advanced into the balloon. Further note that preferably the lumen is not vented to atmosphere when the transducer hub <NUM> is attached and air is advanced through the air lumen. The port <NUM> includes a closable seal, e.g., valves <NUM> and <NUM>, through which the elongated member <NUM> is inserted but maintains the seal when the elongated member <NUM> remains in the lumen <NUM>. Note that catheter <NUM> is identical in all other respects to catheter <NUM> so that the description of catheter <NUM> and its components and function (and alternatives) are fully applicable to catheter <NUM>, the difference being the connector <NUM> of catheter <NUM> to receive transducer hub <NUM>. The transducer hub is also different, e.g., has latch arms and a different configuration.

In <FIG>, the latch arms are reversed so that they are located on the connector rather than on the transducer hub as in <FIG>. More specifically, transducer hub (housing), designated by reference numeral <NUM>, has an elongated member <NUM> with a channel <NUM> and is identical to elongated member <NUM> of <FIG> for advancing air through the lumen and into the pressure balloon. Pressure transducer <NUM> is contained within the housing <NUM>. Recesses <NUM> are dimensioned to receive the latch arms <NUM> of the connector or housing <NUM> which is connected to the side port <NUM> of catheter <NUM>. (Catheter <NUM> is the same as catheter <NUM> of <FIG> except for connector <NUM>). Extending proximally from housing <NUM> are two latch arms <NUM> with enlarged region <NUM> which engage the shoulders <NUM> formed by recesses <NUM> in hub <NUM> in a similar manner as latch arms <NUM> of <FIG> engage in recesses <NUM> and shoulder 291a. Connectors <NUM> in hub <NUM> engage thermistor pins <NUM> of connector <NUM> for connection of the temperature sensor. Connection of the hub <NUM>, like hub <NUM>, automatically advances air to inflate the pressure balloon and automatically connects the temperature sensor.

To disconnect (release) the hub <NUM>, ends <NUM> of latch arms <NUM> are pressed radially inwardly to disengage from shoulder <NUM> so hub <NUM> can be pulled proximally out of connector <NUM>.

Note the lumen which is used to inflate the pressure balloon <NUM> and create the air column has an opening at a distal region to communicate with the interior of the pressure balloon. If an outer balloon is provided, an additional lumen can be provided in the catheter to communicate with the outer balloon to fill the outer balloon and an additional angled port (extension) at the proximal end of the catheter would receive an inflation device to inflate, either fully or partially, the outer balloon.

Note in each of the embodiments disclosed herein, air is described as the preferred gas for creating the column and expanding the balloon, however, other gasses are also contemplated for each of the embodiments.

The pressure balloons of the embodiments herein can be symmetrically shaped as shown or alternatively shaped such that a distal region has an outer transverse cross-sectional dimension, e.g., diameter, greater than an outer transverse cross-sectional dimension, e.g., diameter, of the proximal region. A smooth transition (taper) can be provided between the distal region and proximal region, although other configurations are also contemplated. The inner (and outer) balloon can by way of example be made of urethane, although other materials are also contemplated.

The wire connector of the foregoing embodiments can plug into the openings of a connector positioned on or in the hub. The wire connector can be internal of the hub with an opening in the wall of the hub to enable access for the wire connector. Also note that alternatively the wire can include a female connector and the hub can have a male connector. Other types of connectors/connections are also contemplated.

In alternate embodiments, any of the catheters disclosed here can include a pulse oximetry sensor to measure oxygen saturation in the urethral or bladder tissue. The sensor can be located either proximal or distal to the pressure balloon and/or stabilizing balloon. It could also alternatively be mounted within one of the balloons.

It is also contemplated that in some embodiments a backup system be provided to determine pressure. The backup system can provide a double check of pressure readings to enhance accuracy. Such backup system can be used with any of the examples and embodiments disclosed herein to provide a second pressure reading system. One example of such backup system is disclosed in <FIG>. In this example, catheter <NUM> has the pressure transducer/pressure sensor <NUM> like sensor <NUM> of <FIG> within the air (or other gas) lumen <NUM> communicating with pressure balloon <NUM>, forming a "first system", plus a pressure transducer/pressure sensor <NUM> at a proximal end of the catheter as in <FIG> or external of the catheter forming a "second system". Thus, the pressure sensor <NUM> is at a distal end of the air charged lumen <NUM> and pressure sensor <NUM> is at proximal end of the air charged lumen <NUM>. Both sensors <NUM> and <NUM> are electrically connected to a monitor which provides a graphic display of pressure readings. Catheter <NUM> also includes a temperature sensor either as part of the sensor <NUM> or a separate component that can be positioned for example in the lumen <NUM> distal of sensor <NUM> as in the embodiment of <FIG>. A stabilizing balloon <NUM> and an inflation lumen to inflate balloon <NUM> can also be provided. Lumen <NUM>, having a side opening <NUM> at its distal end, is configured to drain the bladder similar to lumen <NUM> and side opening <NUM> of the example of <FIG>.

In use, catheter <NUM> is inserted into the bladder and stabilizing balloon <NUM> is inflated to secure the catheter <NUM> in place. The system is charged by inflation of the balloon <NUM>, i.e., preferably partially inflated for the reasons discussed above, by insertion of air through side port <NUM> which is in fluid communication with the air lumen in a closed system formed by the internal space of the balloon <NUM> and the internal lumen <NUM> communicating with the internal space of balloon <NUM>. With the balloon <NUM> inflated, pressure monitoring can commence as external pressure applied to an outer surface of the balloon <NUM> compresses the air (or other gas) within the chamber. The sensor <NUM> at the distal end of lumen <NUM> provides continuous pressure readings, converted to an electrical signal by the transducer within the distal end of lumen, and then electrically communicates through its transmission wires extending through the air lumen to an external monitor either directly or via a converter. Additionally, pressure within the air charged column is measured at a proximal region by sensor <NUM> within side port <NUM> of catheter <NUM>. The sensor <NUM> at the distal end of lumen <NUM> provides continuous pressure readings, and such pressure readings can be confirmed by the proximal sensor. Such pressure readings can be performed continuously (along with continuous temperature monitoring) or alternatively can also be adapted if desired for periodic monitoring so the pressure and/or temperature readings can be taken at intervals or on demand by the clinician. Thus, air pressure readings at a proximal end plus microtip pressure readings at the distal end are provided. The sensors <NUM> and <NUM> can electrically communicate with an external monitor to display both pressure readings from sensors <NUM>, <NUM>, or alternatively, if the pressure readings are different, they can be averaged to display a single measurement. Clearly, other displays of information can be provided to display the information from the two sensors <NUM>, <NUM>.

The sensors disclosed herein can be microtip sensors within the air (or other gas) lumen or balloon. In alternative embodiments, fiber optic sensors within the air (or other gas) lumen or balloon can by utilized to transmit circumferential/area pressure. The pressure transducers can be housed within the catheter or alternatively external to the catheter. Additionally, core temperature sensors can be part of the pressure sensor or a separate axially spaced component.

The multi-lumen catheters disclosed herein provide an air (or other gas) charged balloon giving precise readings of intra-abdominal pressure and core temperature and the systems are charged via insertion of air through a side port. The multi-lumen catheters are easily inserted into the bladder in the same manner as standard bladder drainage catheters and enable continuous drainage of urine while continuously recording IAP without interrupting urine flow and without requiring retrograde filling of the bladder with water. Thus, these catheters provide a closed system. The catheters also have a balloon providing a large reservoir (large capacity) and large circumferential area/interface for obtaining more information from the bladder over multiple reference points (rather than a single point sensor) that provides an average pressure to provide a more accurate assessment of the surrounding environment as pressure measurement is not limited to one side of the bladder but can determine measurements on the opposing side as well.

As noted above the catheters in some embodiments can be connected to a bedside monitor through either a wire or blue-tooth wireless connection. The system can also in some embodiments include an indicator or alarm system to alert the staff at the site as well as remote staff through wired or wireless connections to external apparatus, e.g., hand held phones or remote monitors.

As noted above, an alarm or indicator can be provided in some embodiments to alert the staff. The indicator can be a visual indicator such as a light, LED, color change, etc. Alternatively, or additionally, the indicator can be an audible indicator which emits some type of sound or alarm to alert the staff. The indicator can be at the proximal region of the catheter or at other portions of the catheter, e.g., at a distal end portion, where known imaging techniques would enable the user to discern when the indicator is turned on. It is also contemplated that in addition to providing an alert to the user in some embodiments, the pressure monitoring system can be tied into a system to directly reduce abdominal pressure so that if the pressure exceeds a threshold level (value), the abdominal pressure can automatically be reduced. In such systems, an indicator can be provided on the proximal portion of the catheter, e.g., at a proximal end outside the patient's body, or separate from the catheter. The sensor can be in communication with the indicator, either via connecting wires extending through a lumen of the catheter or a wireless connection. The sensor can be part of a system that includes a comparator so that a comparison of the measured pressure to a predetermined threshold pressure value is performed and a signal is sent to the indicator to activate (actuate) the indicator if the measured pressure exceeds the threshold pressure to alert the clinician or staff that pressure within the abdomen is too high and a signal is also sent to a device or system to automatically actuate the device or system to reduce the abdominal pressure. If the measured temperature is below the threshold, the indicator is not activated. A similar system can be used for temperature measurement and indication.

It is also contemplated that a micro-air charged sensor could be provided in the retention (stabilizing) balloon.

It is also contemplated that microtip sensors and/or fiber optic sensors can be utilized to measure pressure, and these sensors can be utilized instead of or in addition to the air pressure readings utilizing the aforedescribed balloon(s) for measuring pressure.

Pulse oximeters for measuring oxygen levels (oxygen saturation) in the urethral and/or bladder tissue could also be provided. In some embodiments, the pulse oximetry sensors can be positioned on the catheter proximal to the retention balloon. Alternatively, the sensors can be positioned within the retention balloon, on the catheter distal to the pressure balloon or on other regions of the catheter. Another channel in the catheter can be provided for the sensor and its connector to external devices, e.g. readers.

The catheters disclosed herein are designed for insertion into the bladder. However, it is also contemplated that they can be adapted for insertion into the rectum, colostomy pouch, stomach, supra-pubic bladder drain, or other orifice directly connected with the abdominal cavity.

Claim 1:
A multi-lumen catheter (<NUM>) insertable into a patient for monitoring bladder pressure, the catheter comprising:
a shaft having at least a first lumen (<NUM>) and a second lumen (<NUM>);
an expandable outer balloon (<NUM>) at a distal portion of the catheter, the outer balloon having a first outer wall and being partially inflated in use;
an expandable inner balloon (<NUM>) positioned within the outer balloon, the inner balloon having a second outer wall, the inner balloon measuring pressure after the outer balloon is partially inflated;
the first lumen (<NUM>) communicating with the inner balloon, the inner balloon and first lumen forming a gas filled chamber to monitor pressure within the bladder, wherein the outer balloon has a circumferential area greater than a circumferential area of the inner balloon, wherein in response to pressure within the bladder exerted on the first outer wall of the expanded partially inflated outer balloon, the outer balloon deforms and exerts a pressure on the second outer wall of the expanded inner balloon to deform the inner balloon and compress the gas within the inner balloon and the first lumen to provide a finer measurement; and
the second lumen (<NUM>) adapted to communicate with the bladder to remove fluid from the bladder; and
a pressure sensor (<NUM>) communicating with the gas filled chamber for measuring bladder pressure based on compression of gas caused by deformation of the expanded inner balloon deformed by the expanded outer balloon, characterized in that the first and second lumens extend within the shaft and the second lumen has a side opening (<NUM>).