Patent Application
20070228085
The present application relates to a dispenser for delivering selectively either a foam or a mist and more particularly such a dispenser useful in delivering foams and mists for pretreatment of instruments prior to a washing and sterilization process.
Medical instruments after use are typically contaminated with blood and other body matter as well as potentially contaminated with infectious microorganisms. Before being reused in a future medical procedure these instruments must be washed and sterilized. The process of washing and sterilization becomes complicated when blood and other matter are allowed to dry onto the instruments. Blood in particular becomes much more difficult to remove once it has dried.
It has been suggested that after use instruments be placed into a liquid filled container to maintain moisture and prevent foreign matter thereon from drying and becoming more difficult to remove. However, such containers can be quite heavy and difficult to move-and the liquid therein can become contaminated and it is not desirable to spill this liquid. One solution that has been proposed is an enzymatic foam which is prayed onto instruments after use and prior to eventual sterilization. The foam weighs less than a liquid and purports to enhance cleaning by initiating some degree of cleaning at the early stage when the foam is placed upon the instrument. Such foams provide little or no antimicrobial activity.
A dispenser, according to the present invention, provides for dispensing a mist or a foam. It comprises a solution in the dispenser, a foaming nozzle on the dispenser for dispensing the foam from the solution and a misting nozzle on the dispenser for dispensing the mist from the solution.
Preferably, the solution comprises hydrogen peroxide, preferably in a range of from 0.1% to 15% by weight, more preferably 2% to 10% by weight and most preferably 3% to 8% by weight. It can also comprise peracetic acid.
Preferably, instructions are including instructing a user to foam the solution onto a contaminated surface of a medical instrument prior to cleaning of the instrument and to maintain the foam in contact with the surface until such time as the instrument is cleaned. Further preferable instructions include instructions to apply the mist into a lumen of the instrument prior to cleaning of the instrument.
In one aspect of the invention, the dispenser includes a propellant therein for dispensing the foam and mist under pressure of the propellant. This includes typical aerosol propellants such as chlorofluorocarbons (CFCs) and more preferably more environmentally acceptable propellants such as volatile hydrocarbons (i.e. propane, n-butane and isobutane, dimethyl ether, methylethyl ether, nitrous oxide and hydrofluoroalkanes (HFA).
In one aspect of the invention, each of the foaming nozzle and misting nozzle are of a manually pumping type.
The solution further preferably comprises a surfactant, a foam booster, a thickening agent and a pH adjustor.
An accessory spray tube is preferably provided which is adapted to the nozzle for spraying mist into smaller opening or area.
During a medical procedure, one or more medical instruments may be employed. These instruments become contaminated with blood, tissue and potentially contaminating microorganisms. Typically the instruments are set aside after use to await washing and sterilization. This waiting period can be several hours or much longer. During this waiting period blood and other matter which dries upon the instrument becomes much more difficult to remove during the subsequent cleaning procedure. This can be a particular problem when a procedure lasts many hours and uses many different instruments or when due to limited personnel time, it is difficult to process the instruments in a timely fashion.
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One method of dispensing the hydrogen peroxide foam 14 would be to spray the foam 14 from a foaming aerosol spray can 16. Such cans employing a propellant are well known to those of skill in the art. Also, the container 12 preferably includes an insert or tray 18 having a plurality of apertures therethrough to allow easy rinsing of the instruments 10 and for efficient diffusion of vapor sterilants into contact with the instruments 10 when the container 12 is used in a sterilization procedure. A lid 20 is also preferably provided.
Instruments 10 are placed into the container 12 as they are finished being used in a procedure. A quantity of foam 14 is sprayed over the instruments 10 to keep them moist and inhibit drying of blood thereon, to start dissolving the blood thereon and to disinfect the instruments. The foam 14 preferably contains between 1 to 15 percent hydrogen peroxide by weight and more preferably between about 3 to 8 percent. Such concentration may not achieve a level of sterilization sufficient for immediate reuse on a patient, but will substantially reduce the load of microorganisms on the instrument surfaces so as to minimize the chances that personal handling the instruments, especially during cleaning, will get infected from them. The lid 20 is preferably placed on the container 12 prior to transporting the instruments from the location of the procedure, such as an operating room, to the location of the washing. When the instruments 10 are ready for washing, the insert 18 can be lifted out and the foam 14 rinsed off while the instruments 10 are still in the insert 18. Normal washing and sterilization may then occur. Washing may comprise treatment with enzymatic cleansers, detergents or other cleaning agents, preferably in combination with mechanical scrubbing or agitation, including optionally treatment with water jets, ultrasonic vibration or the like. Following washing the instrument should be sterilized, preferably in the container 12, such as by chemical vapor or steam autoclaving.
It is particularly convenient if the container 12 with the insert 18 is adapted for use in the terminal sterilization such as a STERRAD® hydrogen peroxide/gas plasma system or a steam system. Suitable materials, such as liquid crystal polymers, and construction details for such containers, especially containers adaptable to either steam or hydrogen peroxide, are shown in US Patent Nos. 6,379,631 and 6,692,693 to Wu incorporated herein by reference. Such containers are typically wrapped with CSR wrap or incorporate semi-permeable membrane filters to allow sterilization of instruments therein with vapor sterilants while protecting the against ingress of potentially contaminating microorganisms after sterilization.
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Formulation 4
Formulation 5
Final pH = 6.1
Final pH = 6.0
Final pH = 5.6
(A) Test with fresh blood
A drop of fresh blood, approximately four millimeters in diameter was applied to a Petri dish. One was left untreated and the other treated with a peroxide foam of formulation 7 generated with Airspray F2-L11 Finger Pump Foamer. Within ten minutes the untreated blood had dried whereas the treated blood had reacted and dissolved in the peroxide foam.
(B) Tests with dried blood
A drop of dried blood was treated with room temperature tap water for ten minutes and another drop of dried blood was treated with a 3% hydrogen peroxide foam of formulation 7 generated with Airspray F2-L11 Finger Pump Foamer. The drop of dried blood treated with tap water remained after ten minutes. After ten minutes, the drop of dried blood treated with the hydrogen peroxide foam had dissolved.
An additional test was conducted comparing a commercially available enzyme foam, Prepzyme XF enzyme foam, available from Ruhof Corporation of Mineola, N.Y. A drop of dried blood was treated with the Prepzyme XF and another drop of dried blood was treated with a 6% hydrogen peroxide foam of formulation 6. After ten minutes the blood treated with the Prepzyme XF remained whereas the blood treated with the hydrogen peroxide foam was dissolved within five minutes.
(C) Foam stability test
A foam prepared according to formulation 9 was placed into a Petri dish of dimensions 150 mm diameter and 15 mm deep. Prepzyme XF was placed into a similar Petri dish. The foams were allowed to rest for one hour whereupon they were inspected. The foam of formulation 9 maintained substantially all of its volume over the period of one hour. The Prepzyme foam had fallen to the extent that a portion of the lower surface of the Petri dish was no longer covered by foam. After four hours the foam of formulation 9 still covered the bottom surface of the Petri dish.
(D) Tests against microorganisms
Tests of efficacy in killing microorganisms were conducted comparing both a 3% hydrogen peroxide foam prepared according to formulation 7 and 6% hydrogen peroxide foam prepared according to formulation 6 against the Prepzyme XF enzymatic foam using the following test procedure:
Efficacy Results with Duplicated Samples:
The invention has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
