Patent Application
20130323119
Not applicable.
1. Field
The present disclosure is related to systems and method of disinfecting devices and, in particular, disinfecting medical devices using ultraviolet (UV) radiation.
2. Description of the Related Art
Patients in hospitals are often provided with medical fluids that are administered through an intravenous (IV) infusion using assemblies of tubes and fittings commonly referred to as “IV sets.”
Blood Stream Infections (BSIs) are a dangerous, costly, and persistent problem in healthcare, particularly for long-duration devices that penetrate the skin, such as a CVC. One identified cause of BSI is the contamination of IV access ports leading to intraluminal colonization and infection that may lead to sepsis and death. Maintaining sterile access ports is a challenge since these devices are proximal to patient skin, frequently handled by healthcare workers, and may be touched by visitors or come in contact with contaminated surfaces in the hospital. Episodic cleaning of the external surfaces of access ports immediately prior to connection of an IV line using wipes or cleaning solutions is subjective and it is difficult to maintain high levels of compliance. Furthermore, those solutions may contain materials that interfere with valve operation.
It is desirable to provide a system and method of sterilizing portions of medical devices that may provide an entrance point for microorganisms to enter a patient's bloodstream, particularly IV access ports, without requiring a technique-dependent cleaning activity by the user.
In certain embodiments, an apparatus configured to disinfect an IV access port is disclosed. The apparatus includes at least one sterilizing cap comprising a body configured to removably couple to the access port, and an illuminator coupled to the body. The body and illuminator are configured to expose at least one surface of the access port to a dose of UV light.
In certain embodiments, a method of disinfecting an IV access port is disclosed. The method includes the step of coupling a sterilizing cap to the access port, wherein the sterilizing cap is coupled to a source of UV light and is configured to expose at least one surface of the access port to a dose of the UV light. The method also includes the step of enabling or actuating the UV light source automatically upon completion of the coupling of the sterilizing cap to the access port.
The accompanying drawings, which are included to provide further understanding and are incorporated in and constitute a part of this specification, illustrate disclosed embodiments and together with the description serve to explain the principles of the disclosed embodiments. In the drawings:
The following description discloses embodiments of a sterilizing system and method suitable for sterilizing internal and external surfaces of medical equipment. In certain embodiments, the system is configured to sterilize an access port of an IV set. In certain embodiments, the system includes a main module coupled to a sterilizing connector via a cable. In certain embodiments, the system includes a small module suitable for direct connection to an access port. It will be recognized that access ports are typical of needleless connectors, and descriptions of use of the disclosed system with access ports is considered to cover use with any tube of fluid connector, including male and female needleless connectors, male and female luer connectors, fittings on syringes and other fluid devices, and all other types of connectors used with fluid handling equipment and treatments.
The detailed description set forth below is intended as a description of various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology may be practiced. The appended drawings are incorporated herein and constitute a part of the detailed description. The detailed description includes specific details for the purpose of providing a thorough understanding of the subject technology. However, it will be apparent to those skilled in the art that the subject technology may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring the concepts of the subject technology. Like components are labeled with identical element numbers for ease of understanding.
As used within this disclosure, the terms “optical” and “light” refer to electromagnetic radiation from ultraviolet to infrared, including wavelengths in the range of 10 nanometers (nm) to 1 millimeter (mm) and includes, but is not limited to, light visible to the human eye, which covers the approximate range of 380-760 nm.
As used within this disclosure, the terms “ultraviolet light” and “UV light” refer to light having a wavelength in the approximate range of 10-400 nm.
As used within this disclosure, the term “ultraviolet A,” abbreviated as “UVA,” refers to light having a wavelength in the range of approximately 315-400 nm.
As used within this disclosure, the term “ultraviolet B,” abbreviated as “UVB,” refers to light having a wavelength in the range of 280-315 nm.
As used within this disclosure, the term “ultraviolet C,” abbreviated as “UVC,” refers to light having a wavelength in the range of 100-280 nm.
As used within this disclosure, the terms “sterilized” and “disinfected” mean that the population of DNA-based microorganisms on a surface has been reduced compared to the population present on the same surface prior to the sterilizing or disinfecting treatment. The amount of reduction for a particular application, for example IV products, may be selected by the hospital or industry organization as to achieve sufficient reduction for the application, for example a reduction in BSIs. As the magnitude of the reduction asymptotically approaches but never reaches zero, there will always be some microorganisms present on the sterilized or disinfected surface no matter what duration of treatment is chosen.
As used within this disclosure, the term “eye safe” refers to an intensity of optical radiation that is generally considered to be safe for long-term exposure to the human eye.
Exposure to UVC light kills microorganisms that utilize deoxyribonucleic acid (DNA) at a rate that asymptotically approaches 100% over time. It has been reported (for example, by Von Sonntag, 1986, Disinfection of free radicals and UV-radiation. International Workshop on Water Disinfection, Compagnie Generale des Eaux, Mulhouse) that DNA has absorption peaks at 200 nm, where the DNA absorbs energy in the ‘backbone’ molecules of ribose and phosphate, and at 265 nm, where the DNA absorbs energy mainly in the nucleobases: cytosine, guanine, adenine, and thymine. The absorbed energy breaks the molecular bonds of certain molecules and causes the bonding of other molecules, such as the formation of thymine dimers when two adjacent thymine molecules become fused. This damage prevents the DNA from being able to replicate, effectively killing the cell. UV light can also damage RNA as well as cell proteins and enzymes that further inhibit growth and function of the microorganism.
Table 1 lists representative dosages required to achieve various “kill rates” of certain common organisms when exposed to UV light. The actual dosage depends on the energy distribution of the light emitted by a particular source within the UV band and the particular sensitivity of each organism to various wavelengths of UV light. For example, a source that emits most of its light at 265 nm may be more effective against particular microorganism than another source that emits most of its light at 400 nm.
Legionella pneumophila
Staphylococcus aureus
Listeria monocytogenes
Pseudomonas aeruginosa
Salmonella enteritidis
Bacillus subtilis (spores)
A “dose” is the product of an intensity of the radiation (in units of energy per unit area) multiplied by the duration of exposure (in units of time). For example, the 99.99% kill rate for Listeria monocytogenes, 14 milliwatt-seconds per square centimeter (mW-sec/cm2), can be achieved by exposing a surface to UV light at an intensity of 1 mW/cm2 for 14 seconds, or 2 mW/cm2 for 7 seconds, or 14 mW/cm2 for 1 second.
One generally accepted definition for “sterile” in the medical industry is a “one in a million” probability of a viable microorganism remaining on a surface, which is equivalent to a 99.9999% kill rate. This kill rate will require exposure durations of approximately six times the duration shown for a 90% reduction at the same intensity. The system and method disclosed herein are not limited to a particular level of sterilization, however, and the scope of the present application is limited only by the terms of the appended claims.
Light-emitting diodes (LEDs) that emit light primarily at wavelengths in the UV band are now becoming available at power levels of 1-10 mW. As with previous types of LEDs, it can be expected that the power levels of available UV LEDs will rise while the prices fall as time goes by.
Radiation of any frequency becomes hazardous at some level of exposure. For light, the maximum permissible exposure (MPE) is the highest power or energy density (in W/cm2 or J/cm2) of a light source that is considered safe, i.e. that has a negligible probability for creating damage to a human eye in the worst-case scenario in which the eye lens focuses the light into the smallest possible spot size on the retina for the particular wavelength and the pupil is fully open. The IEC-60825-1 and ANSI Z136.1 standards include methods of calculating MPEs.
In certain embodiments, the access port 34 comprises a UV-transmissive material such that UV light reaches at least one of the interior surfaces of the access port 34. This allows internal features that might otherwise serve as suitable breeding locations for microorganisms to be disinfected. In certain embodiments, the sterilizing cap 104 is configured to direct the UV light into the certain portions of the access port 34 so as to preferentially illuminate one or more interior surfaces.
In certain embodiments, the sterilization system 120 comprises transmissive and/or reflective elements, similar to those shown in
In certain embodiments, the sterilization system 140 is functionally connected to the infusion pump 12 such that the infusion pump 12 will not allow the medical fluid to be delivered to the patient unless a signal has been received from the sterilization system 140 indicating that the access port 34 has been disinfected by use of the system 140. In certain embodiments, the system 140 comprises a visual indicator, for example the indicator light 143, that indicates that the system 140 has recently been activated. In certain embodiments, the visual indicator is provided by the sterilizing cap 104 comprising a fluorescent material that glows for a period of time after exposure to the UV light of the illuminator. In certain embodiments, the sterilizing cap 104 comprises a UV-transmissive material such that a portion of the UV light passes through the body of the sterilizing cap 104, for example to energize a fluorescent coating on the outside of the body of the sterilizing cap 104. In certain embodiments, the access port 34 comprises a fluorescent material.
In certain embodiments, the CVC 30 may be configured to guide a portion of the UV light received from the sterilization port 104 along at least a portion of the tubes 30a and through fittings 30b, for example by a reflective coating (not shown in
Sterilization systems may be configured, in various embodiments, to provide a short high-intensity flash of UV light that is sufficient to achieve the desired kill rate and/or a continuous low-level exposure to UV light that will achieve the desired kill rate over a longer period of time as well as maintain a sterilized surface in a clean condition. For example, the sterilizing system 100 of
In summary, a sterilizing system that generates and distributes UV light, particularly UVC light, to access ports of IV sets and other points of access to a patient's circulatory system is disclosed. Reduction of many pathogen populations by 99% or more can be routinely accomplished in a timeframe of seconds using UV light intensities that are safe for prolonged exposure. Continuous irradiation may provide kill rates of 99.999% or more. One exemplary application is a CVC having multiple access ports, wherein the CVC remains inserted in a patient's vein for an extended period of time. Use of the UV-based sterilizing procedure, either on a periodic basis immediately prior to use or after disconnection of an IV line from an access port at an intensity sufficient to sterilize the access port within seconds, or on a continual basis at a reduced intensity to maintain the access port in a disinfected condition, reduces the likelihood of a BSI. In some embodiments, the UV device is used to cap the hub and bathe it in UV when it is not connected and in-use. The cap serves to protect the surface and can, in certain embodiments, continuously disinfect it. Stand-alone embodiments can be self-powered and attached to hubs. Tethered devices may utilize a central UV source located proximate to the infusion pump that delivers UV light through one or more optical conduit to multiple hubs. It can be appreciated that access ports are but one example of devices with which the disclosed apparatus and methods may be used, and that this apparatus and method can be extended to a variety of potential infection entry points in a hospital setting involving medical apparatus.
It is understood that the specific order or hierarchy of steps or blocks in the processes disclosed is an illustration of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps or blocks in the processes may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.
The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims.
A phrase such as an “aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. A phrase such as an aspect may refer to one or more aspects and vice versa. A phrase such as an “embodiment” does not imply that such embodiment is essential to the subject technology or that such embodiment applies to all configurations of the subject technology. A disclosure relating to an embodiment may apply to all embodiments, or one or more embodiments. A phrase such an embodiment may refer to one or more embodiments and vice versa.
The word “exemplary” is used herein to mean “serving as an example or illustration.” Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs.
Reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more.
To the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as interpreted when employed as a transitional word in a claim.
Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “operation for.”
Although embodiments of the present disclosure have been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the scope of the present invention being limited only by the terms of the appended claims.
