Patent Issued for Zero-Pressure Balloon Catheter and Method for Using the Catheter

By a News Reporter-Staff News Editor at Journal of Engineering -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Kalser, Gary A. (Winter Park, FL); Mayback, Gregory L. (Cooper City, FL); Leone, James (Pittsburgh, PA); Palmer, Matthew A. (Miami, FL), filed on December 13, 2012, was published online on April 14, 2015.

The patent's assignee for patent number 9005165 is Mayser, LLC (Fort Lauderdale, FL).

News editors obtained the following quote from the background information supplied by the inventors: "The present invention relates to a catheter, especially a flexible pressure-limiting or zero-pressure balloon catheter and a method for using the catheter.

"A number of conventional balloon catheters exist in the prior art. Some catheters are used to drain the bladder of a patient during surgical procedure or to treat bladder and/or urethra or prostate conditions, for example. For example, a common balloon catheter made by RUSCH.RTM. and referred to as a Foley catheter is widely used today for treating and draining a patient's bladder. The Foley catheter is shown in FIG. 1 and has a multi-lumen shaft 1 that is disposed in the urethra 10, a balloon portion 3 disposed at the distal end of the shaft 1, a fluid drain section 4 disposed at the distal end of the balloon 3, and a curved, distal guiding tip 5 at the distal-most end of the entire catheter. When placed properly, the proximal-most side of the inflated balloon 3 rests on the interior wall 31 of the bladder 30, entirely blocking off the urethrovesical junction 11 connecting the bladder 30 and the urethra 10. In such a position, the fluid drain section 4 allows continuous drainage of the bladder 30 and the balloon 3 virtually entirely prevents the catheter from slipping out of the bladder. This ideally inserted position is shown in FIG. 1. As used herein, a fluid can be either a liquid or a gas. Exemplary fluids for inflating a balloon 3 are saline, air, or carbon dioxide gas. Exemplary fluids drained by the catheters mentioned herein include urine and blood.

"Basically, the catheter has tube-like body with two lumens passing therethrough. The larger lumen 120 (see FIG. 2) is open to the bladder (distally) and empties into an ex-corporeal bag (proximally) for eventual disposal. A smaller lumen 130 is used to inflate the balloon 3 with water (typically) using a syringe attached to the inflation lumen fitting 260. When inflated in the bladder, for example, the catheter is prevented from sliding out of the urethra in use.

"Over 96 million indwelling catheters are sold worldwide on an annual basis. Twenty four million catheters are sold to hospitals in the U.S. There are numerous complications associated with those catheters that need to be prevented. These complications are responsible for increases in hospital stays, excessive bleeding, mortality, as well as morbidity. They also cause an increased expense and burden on the already-stressed health care system.

"The complications result from several different mechanisms. First, and probably most common, is improper placement of the catheter. Because of the unique anatomy of the male urethra, placing a urethral catheter for urinary drainage can be difficult. A problem arises when the physician, technician, or nurse thinks that the catheter is actually in a proper position when it is not. The proper position for the catheter is with the balloon located in the cavity of the bladder. In this position, the tip distal to the balloon is located in the bladder and is used to drain the bladder cavity.

"For placement of this catheter in the bladder 30 in the ideal position, however, the physician or technician has no visual aid. As shown in FIG. 1, the wall 40 defining the urethrovesical junction 11 is very short in the longitudinal direction of the urethra 10. If the physician inserts the catheter too far into the bladder 30, no damage occurs from balloon inflation; however, there is a possibility of leakage around the balloon 3, which, under normal conditions, helps to lubricate the urethra 10. In such a case, gentle proximal movement will move the proximal side of the balloon 3 against the urethrovesical junction 11. The bladder 30 can then easily expand and stretch to compensate for the balloon 3. A normal bladder capacity is 400 to 500 cc. A normal balloon capacity is approximately 10 to 12 cc although larger balloons are sometimes used. A typical balloon is 5 cc, however, most clinicians put 10 cc of water in the balloon to inflate it. With 5 cc of water in the balloon, the diameter is approximately 2 cm and, with 10 cc, the diameter is approximately 2.5 cm.

"The complication occurs when the technician and/or nurse inflates the balloon when the balloon is not in the bladder. If the technician does not insert the catheter in far enough, then the balloon 3 will be inflated within the urethra 10--a condition that is common and, not only is it to be avoided at all costs, is a frequent cause of bladder infections created during a hospital or clinic visit. Infections arise because inflation of the bladder 3 inside the urethra 10 causes the urethra 10 to stretch too far and tear. Even though the urethra 10 is a flexible tube, it has limits to which it can be safely stretched from within. Almost every balloon catheter has a balloon outer diameter/circumference that well-exceeds the safe stretching limit of the urethra 10. Therefore, if the balloon catheter is not inserted far enough, inflation of the balloon 3 will cause serious injury to the urethra 10. This is especially true with elderly patients who have urethra 10 that are not as elastic as younger patients. Also, just as important is the change in anatomy of older males, in particular, the prostatic portion of the urethra. With age, the prostate becomes larger and, sometimes, the catheter cannot be advanced through the prostatic portion of the urethra. When this occurs, the technician does not insert the catheter all the way into the bladder and inflates the balloon within the urethra, causing severe bleeding and damage.

"The elastomeric balloon of present-day catheter products requires relatively high pressures to initiate inflation and expand to an expected full-diameter shape upon over-inflation. As such, when incorrectly placed in the urethra, the rapid inflation, combined with the high-pressure, causes the balloon to tear the surrounding membrane, called the mucosa. Tearing of the urethra 10 in this way causes bleeding and allows bacteria to enter into the bloodstream at the tear site, thus causing the subsequent bladder infection. Significant bleeding can become life threatening. The urethra can normally dilate several millimeters; however, when the balloon is inflated, this dilation is usually several centimeters. Also, without sufficient and immediate venting of the balloon inflation fluid after placement, an accidental or intentional pull on the catheter externally can and does cause extensive bodily harm to a patient fitted with the device.

"Life threatening bleeds, especially in patients who are anticoagulated, can and do occur. Also when the urine is infected, as in immunocompromised patients and the elderly, the bacteria enter the blood stream and can cause serious infections (e.g., sepsis), which frequently can lead to death. If the patient survives the initial trauma, then long-term complications, such as strictures, can and usually do occur. Strictures are narrowings within the urine channel and usually require additional procedures and surgeries to correct.

"Other mechanisms of catheter-induced injuries are inadvertent manipulation of the tubing or dislodging of the balloon--caused when the catheter is pulled from outside the patient due to a sudden jerk or tension. This commonly happens when the patient is ambulating or traveling from the bed to the commode or bathroom. The tubing may inadvertently become fixed while the patient is still moving, at which time a sudden jerk is imparted upon the balloon and pulls the balloon into the urethra to tear it, causing severe pain and bleeding. Injury caused by the improper, inadvertent, and/or early removal of an inflated balloon catheter is referred to as iatrogenic injury (also referred to as an in-hospital injury). Hundreds of thousands of such iatrogenic injuries occur each year--all of which need to be prevented, not only for patient safety, but also because the cost imposed on the medical health industry for each injury is enormous.

"Yet another scenario occurs when the patient deliberately pulls on the catheter, thereby causing self-induced pain and injury to the urethra. This commonly happens in confused patients, for example, patients in nursing homes who have a disease or cognitive dysfunction problem, such as Alzheimer's disease, or other diseases that make the patient unable to understand the necessity of having a catheter. Confusion occurs when the patient has a spasm causing a strong urge to urinate and pain. During the spasm, the confused patient often tugs and pulls on a catheter, which results in injury. Like iatrogenic injuries, these self-induced injuries must be prevented.

"The injuries mentioned herein are not limited to males and also cause severe damage to the female bladder and urethra. The injuries can also occur post-surgically, which makes the damage even more severe. One common situation where injury is caused is when the patient is medicated with morphine or other analgesics that render the patient confused and unable to make rational decisions. Feeling the foreign body inside the urethra, the confused patient does not know to leave it alone and, instead, gives it the injury-causing tug. These injuries have been well-documented and are not limited to adults. Numerous injuries are documented in pediatric patients.

"Usually, it takes time to make a diagnosis of patient-caused catheter injury. Immediately after diagnosing the injury, a technician needs to deflate the catheter. However, once the urethra is torn, replacing the damaged catheter with another catheter is quite difficult and, in fact, exacerbates the injury. Sometimes, the patient has to be taken to the operating room to replace a urinary drainage tube once the injury occurs. Because catheters and leg bags are now used routinely in certain situations during home health care, this scenario is not limited to hospitals and occurs at nursing homes and patients' homes.

"Most of the recent catheter technology has been focused on reducing urinary tract infections that are caused by catheters, injuries that are usually the most common catheter-related complications.

"In a conventional balloon 3, the balloon 3 has a substantially constant balloon wall thickness. The balloon 3 is fixed to the outer surface of a fluid drainage line (not illustrated in FIG. 1) and is not intended to be removed therefrom or to burst thereon unless an extraordinary amount of inflation occurs. If such an event happens, the material of the balloon will open at a random location based upon the microscopic fractures or weaknesses in the material itself. Such a tearing event is not supposed to occur under any circumstances during use with a patient.

"Prior art catheters are not constructed to prevent tearing of the urethra during a catheter implanting procedure and are not constructed to break in any predefined way. Accordingly, it would be beneficial to provide a balloon catheter that does not inflate past the tearing limit of a urethra and deflates in a desired, predefined way under certain conditions."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "It is accordingly an object of the present invention to provide a very low or zero-inflation pressure balloon catheter and method for using the catheter that overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and that does not inflate when the catheter is placed, for example, in the urethra, and quickly and rapidly deflates if pulled out prior to manual deflation of the balloon.

"With the foregoing and other objects in view, there is provided, in accordance with the invention, a safety catheter includes a shaft. The shaft has a proximal shaft portion having a proximal end and a distal end, a distal tip portion defining a junction with the proximal shaft portion, a fluid drain lumen, and a balloon inflation lumen. The fluid drain lumen defines a distal fluid drain opening at the distal tip portion distal of the junction and a proximal fluid drain opening adjacent the proximal end and fluidically connected to the distal fluid drain opening. A hollow zero-pressure balloon is disposed at the junction and has an interior fluidly connected to the balloon inflation lumen, a distal leg fixedly secured to the distal tip portion, and a proximal leg temporarily secured to the proximal shaft portion.

"In accordance with another feature of the invention, the proximal shaft portion adjacent the junction has a given outer diameter and a portion of the junction adjacent the proximal shaft portion has an outer diameter less than the given outer diameter.

"In accordance with a further feature of the invention, the distal tip portion adjacent the junction has an outer diameter less than the given outer diameter, equal to the given outer diameter, or equal to the outer diameter of the junction.

"In accordance with an added feature of the invention, a proximal portion of the junction adjacent the proximal shaft portion has a given outer diameter and the proximal shaft portion adjacent the proximal portion of the junction has an outer diameter greater than the given outer diameter.

"In accordance with an additional feature of the invention, the distal tip portion adjacent the junction has an outer diameter greater than the given outer diameter, equal to the given outer diameter, or equal to the outer diameter of the junction.

"In accordance with yet another feature of the invention, the shaft has a length sufficient to perform urinary catheterization.

"In accordance with yet a further feature of the invention, the proximal leg of the hollow balloon is relatively inflexible in relation to the distal end of the proximal shaft portion and the distal end of the proximal shaft portion and the proximal leg of the hollow balloon form a removable compression seal therebetween.

"In accordance with yet an added feature of the invention, the removable compression seal has a breakaway point at a pull force of between approximately 1 pound and approximately 15 pounds applied to the proximal shaft portion, between approximately 1 pound and approximately 5 pounds applied to the proximal shaft portion, and/or between approximately 1.5 pounds and approximately 2 pounds applied to the proximal shaft portion.

"In accordance with yet an additional feature of the invention, when the balloon is inflated with a fluid and a pull force of greater than approximately 15 pounds is applied to the proximal shaft portion, the compression seal exceeds a breakaway point and thereby deflates the inflated hollow balloon. The pull force can be greater than approximately 5 pounds or, in particular, greater than approximately 2 pounds.

"In accordance with again another feature of the invention, the proximal leg is temporarily secured to the proximal shaft portion in an inverted orientation.

"In accordance with again a further feature of the invention, the hollow balloon is operable to fold back upon itself when removed from the proximal shaft portion.

"In accordance with again an added feature of the invention, the hollow balloon is operable to inflate with and withstand pressures of between approximately 0.2 atmospheres and 0.5 atmospheres without an appreciable increase in diameter.

"In accordance with again an additional feature of the invention, the shaft has an internal balloon valve operable to selectively open a channel between the fluid drain lumen and the balloon interior.

"In accordance with still another feature of the invention, the internal balloon valve is operable to open the channel when a pressure in the balloon is between approximately 0.3 atmospheres and approximately 1.5 atmospheres.

"In accordance with still a further feature of the invention, the proximal leg of the balloon is temporarily secured at the distal end of the proximal shaft portion.

"In accordance with a concomitant feature of the invention, the distal fluid drain opening is distal of the distal leg of the balloon.

"The zero-pressure balloon catheter of the present invention prevents injury by having the balloon automatically deflate before an injury can occur, for example, when being forced to withdraw from the bladder or being forced to inflate within a urethra. While the catheter of the present invention makes it a safer device for urinary drainage, the present invention can also be used for any procedures in which balloons are used to occlude cavities. Examples of these procedures include coronary artery vessels and peripheral vascular vessels, such as the aorta and extremity vessels. Balloon dilations of other lumens, such as ureters and the esophagus, are also candidates for use of the catheter of the present invention.

"Some of the embodiments of the present invention utilize a valve (e.g., a slit valve) that permits reuse when utilized. With embodiments having no such valve, the invention is a single use after deflation occurs. Although deflation of such a catheter renders it useless, the act of immediate deflation protects the patient from serious harm and cost of replacing a catheter is minimal as compared to the cost of treating catheter-induced injury. Prevention of such injuries is becoming more and more important because the injuries are commonplace. The increase occurs for a number of reasons. First, a greater percentage of the population is aging. Second, there is a current trend to use less-skilled health care personnel to perform more procedures and to be responsible for treatment, both of which save money. The shortage of nursing professionals (R.N.s) exacerbates this trend. The present tendency is to use nursing professionals for more functions, such as administration and delivery of medications. This leaves only the less-skilled technicians with the task of taking vital signs and inserting catheters. Under such circumstances, more injuries are likely. Lastly, catheter-related complications are becoming more severe due to the increased use of anticoagulation medication, such as PLAVIX.RTM., that is frequently prescribed in treating cardiovascular disease.

"Yet another possible complication arising from the standard Foley catheter is that the balloon will not deflate even when the deflation mechanism is activated. This situation can occur, for example, because the wrong fluid is used to inflate the balloon or when a fluid, such as saline, crystallizes, which happens occasionally. Sometimes, the ability to deflate the catheter is interrupted because the drainage channel that is used to deflate the balloon becomes obstructed, which is common if the catheter is left in place too long. Remedy of such a scenario involves an invasive procedure, which includes threading a needle or other sharp object somewhere through the body cavity to puncture the balloon and, thus, dislodge the catheter. Yet another possible complication can occur when there is a stricture evolved. A stricture is scar tissue in the urethra that impedes the passage of the catheter. In such a case, the technician sometimes uses excessive force in trying to push the catheter into the bladder, thereby causing a tear and bleeding.

"With the zero-pressure auto-deflating balloon of the present invention, the technician, nurse, or doctor merely needs to pull on the catheter to cause the catheter to automatically deflate, thus sparing the patient from any additional surgical procedures.

"The added benefit of the present invention is not just for safety, significant financial benefits arise as well. It is believed that catheter-induced injuries are much more common than public documentation suggests. Catheter-related trauma occurs roughly at least once a week in a large metropolitan hospital. Usually, each incident not only increases the patient's hospital stay substantially, but also the expense of the stay. Each incident (which is usually not reimbursed by insurance) can increase the cost to the hospital by thousands, even tens of thousands, of dollars.

"When additional surgery is required to repair the catheter-induced injury, increased expense to the hospital is not only substantial, if litigation occurs as a result of the injury, damages awarded to the patient can run into the millions of dollars. The catheter of the present invention, therefore, provides a safer catheter that has the possibility of saving the medical industry billions of dollars.

"To prevent urethra tearing occurrences due to premature-improper inflation of the balloon and/or due to premature removal of an inflated balloon, an exemplary embodiment of the invention of the instant application provides a balloon safety valve.

"The maximum stress that a typical urethra can take without tearing and/or breaking is known and is referred to as a maximum urethra pressure. It is also possible to calculate how much pressure is exerted upon the exterior of a balloon of a balloon catheter by measuring the pressure required to inflate the balloon. Knowing these two values, it is possible to construct a balloon that breaks rapidly and/or ceases inflation if the maximum urethra pressure is exceeded.

"For example, in a first exemplary embodiment, the balloon, which is typically some kind of rubber, silicone, or plastic, can be made with a breaking point that instantly deflates the balloon if the pressure in the balloon exceeds the maximum urethra pressure. It is acknowledged and accepted that, once the balloon breaks, this catheter is useless and must be discarded because the cost of patient injury far outweighs the cost of the disposable catheter. Also, such a balloon is limited to inflation with a bio-safe fluid to prevent unwanted air/gas from entering the patient. If, however, air or other gas will not injure the patient, the fluid can be air or another gas.

"As an alternative to a one-use breaking safety valve, a multi-use pressure valve can be added to the balloon inflation lumen and can be set to open into the drainage lumen if the maximum urethra pressure exceeded in the balloon or the balloon inflation lumen. Such a valve can be located near or at the balloon inflation port. Any combination of the above embodiments is envisioned as well.

"Another exemplary embodiment of the present invention provides the catheter with a balloon that inflates with virtually no pressure. As used herein, 'virtually no pressure,' 'zero-pressure' and 'low-pressure' are used interchangeably and are defined as a range of pressure between approximately standard atmospheric pressure and 0.3 atmospheres (5 psig). This is in contrast to 'high-pressure,' which is greater than approximately 1.5 atmospheres (22 psig). With such a configuration, the zero-pressure balloon can be deflated with virtually no force. As such, when the clinician attempts to inflate the zero-pressure balloon of the present invention within a urethra, the balloon simply does not inflate. Likewise, when the already inflated balloon within the bladder is forced into the urethra, such deflation needs virtually no pressure to collapse the balloon to fit into the urethra. In both circumstances, injury to the urethra is entirely prevented.

"Although the invention is illustrated and described herein as embodied in a zero-pressure balloon catheter and a method for using the catheter, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. Additionally, well-known elements of exemplary embodiments of the invention will not be described in detail or will be omitted so as not to obscure the relevant details of the invention.

"Other features that are considered as characteristic for the invention are set forth in the appended claims. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward. The figures of the drawings are not drawn to scale.

"Before the present invention is disclosed and described, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. The terms 'a' or 'an', as used herein, are defined as one or more than one. The term 'plurality,' as used herein, is defined as two or more than two. The term 'another,' as used herein, is defined as at least a second or more. The terms 'including' and/or 'having,' as used herein, are defined as comprising (i.e., open language). The term 'coupled,' as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically.

"As used herein, the term 'about' or 'approximately' applies to all numeric values, whether or not explicitly indicated. These terms generally refer to a range of numbers that one of skill in the art would consider equivalent to the recited values (i.e., having the same function or result). In many instances these terms may include numbers that are rounded to the nearest significant figure. In this document, the term 'longitudinal' should be understood to mean in a direction corresponding to an elongated direction of the catheter."

For additional information on this patent, see: Kalser, Gary A.; Mayback, Gregory L.; Leone, James; Palmer, Matthew A.. Zero-Pressure Balloon Catheter and Method for Using the Catheter. U.S. Patent Number 9005165, filed December 13, 2012, and published online on April 14, 2015. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=9005165.PN.&OS=PN/9005165RS=PN/9005165

Keywords for this news article include: Hospital, Mayser LLC, Legal Issues.</p>

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