Method for the validatable cleaning of semi-critical ultrasound probes

Abstract

The invention relates to a validatable method for cleaning semi-critical ultrasound probes, comprising the following steps: a) removing a protective cover from the ultrasound probe; b) removing the transmission gel adhering to the ultrasound probe using a cloth soaked with an impregnating agent; c) inserting the ultrasound probe into a device for cleaning ultrasound probes, wherein the device for cleaning ultrasound probes contains an elution solution that comes into contact with the ultrasound probe; and d) removing the ultrasound probe from the device for cleaning ultrasound probes and drying the ultrasound probe.

Description

[0001] The present invention relates to a method for the validatable cleaning of semi-critical ultrasound probes, and to a kit-of-parts usable for the validatable cleaning of semi-critical ultrasound probes.

[0002] Experts have long debated whether the legally required validation of the reprocessing of semi-critical medical devices, such as ultrasound probes that come into contact with mucous membranes, can be fully achieved through wipe disinfection. Against this backdrop, it seems odd that while the validation of disinfection for semi-critical medical devices is discussed at length, the cleaning of these devices prior to disinfection is not mentioned at all.

[0003] It should go without saying that semi-critical medical devices are cleaned after use on the patient and only disinfected or sterilized once this cleaning has been successful and meets the relevant requirements. Semi-critical ultrasound probes are typically used with a protective sheath containing a transmission gel. Direct contamination from the patient is therefore rare. However, smear contamination can occur, particularly when removing the sheath after an examination.

[0004] Since ultrasound probes, especially in recesses such as those used for biopsy attachments, are heavily contaminated with transmission gel after examination, insufficient removal of the transmission gel during the cleaning process prior to disinfection impairs the disinfection of the devices. Furthermore, the remaining gel builds up a residue over time that is difficult to remove, leading to contamination and discoloration.

[0005] The gel consists of carbomers, and gel residues can be detected by determining the carbon content per unit area and quantified using TOC (total organic carbon) measurement. DIN EN ISO 15883-5 specifies a warning value of 6 µg carbon / cm², which can be used to assess cleaning effectiveness. In practice, this warning value is often exceeded many times over, as tests of semi-critical ultrasound probes cleaned with wipes have shown. It must therefore be assumed that subsequent disinfection—regardless of the disinfection method—is compromised by the residues and cannot be considered reliable. In other words, inadequate cleaning of the probes, despite subsequent validatable disinfection, means that the entire reprocessing procedure must be considered unvalidated.

[0006] One such prior art, but non-validable, cleaning method for semi-critical ultrasound probes is described, for example, in B. Amann: "Reprocessing of Ultrasound Probes," Zentralsterilisation 3 / 2017, pp. 195-197. Immediately after use, the disposable protective sheath and ultrasound gel are removed, and any adhering contaminants are wiped away with a moist disposable wipe. This is followed by disinfection, which is not described in detail but can be automated or performed by suitable equipment. The disadvantage here is that the cleaning prior to disinfection is performed only by manually wiping the ultrasound gel with a cloth, which does not allow for validation.

[0007] The instructions for "Preparation of Ultrasound Probes for Transvaginal and Abdominal Examinations," published by Dr. Schumacher GmbH in June 2017 ("https: / / www.schumacher-online.com / fileadmin / Docs / Printmedia / Instructions / DrS_Anleitung_Ultraschallsonden_A3_DE_WEB.pdf"), describe how to clean the probes. After removing the protective sheath, the probes should be pre-cleaned with a cloth moistened with water. Following a further cleaning step with another cloth, disinfection is performed by wiping the probe with a cloth, and then the probe is dried. This again describes a cleaning method that cannot be validated by simply wiping the probe with cloths.

[0008] The presentation "Development of instructions for the reprocessing of ultrasound probes using wipe disinfection," DGKH Congress 2016 ("https: / / www.krankenhaushygiene.de / referate / 1d057088c0e892e9c2fd88afed9b6d6f.pd") reveals individual steps for cleaning ultrasound probes, specifically wiping the probe with a water-moistened cloth after removing the protective sheath, manual cleaning with a disinfectant-soaked cloth, and drying the probe. Here, too, the cleaning prior to disinfection is performed solely by wiping the probe with cloths, a process that cannot be validated. Object of the invention

[0009] The object of the present invention is to provide an alternative method for cleaning semi-critical ultrasound probes which preferably overcomes the aforementioned disadvantages known from the prior art and is characterized in particular by objective validation.

[0010] Another object of the present invention is to provide a method for cleaning semi-critical ultrasound probes, after the execution of which the warning value of 6 µg carbon / cm 2< according to DIN EN ISO 15883-5 is undercut on the surface of the cleaned devices.

[0011] In "Reprocessing of Ultrasound Probes with Mucosal Contact," February 1, 2019 (2019-02-01), pages 1-10, XP093124496, accessed online on January 26, 2024 at URL: https: / / vah-online.de / files / download / vah-mitteilungen / VAH_Sonden_HM_1-2_19.pdf, it is described that, for the reprocessing of transvaginal ultrasound probes, gel residue is removed with a dry cloth after removing the protective sheath. Only then is the probe cleaned again with a moist disinfectant wipe. In connection with TEE probes, the insertion of the ultrasound probe into a device for cleaning ultrasound probes, which contains an elution solution that contacts the probe, is described.

[0012] In "Reprocessing of Ultrasound Probes," Recommendation of the Quality Committee (101), June 12, 2017 (2017-06-12), pages 1-3, XP093124452, accessed on January 26, 2024 at URL: https: / / www.dgsv-ev.de / wp-content / uploads / 2016 / 09 / AKQ_d_ZT_3_2017_Aufbereitung-von-Ultraschallsonden.pdf, the cleaning of semi-critical ultrasound probes is described as follows: immediately after use, the disposable protective sleeve and the ultrasound gel must be removed, and any adhering contaminants must be wiped away with a moist disposable wipe. This is followed by disinfection, the details of which are not specified, but which can be automated or performed by suitable equipment.

[0013] In "Disinfection of transvaginal ultrasound probes - a current overview of methods and recommendations" by Möllers et al., Gynaekologe, Springer Verlag, Berlin, Vol. 54, No. 9, July 7, 2021 (2021-07-07), pages 688-693, XP037559193, ISSN:0017-5994, DOI: 10.1007 / S00129-021-04824-2, it is revealed that machine cleaning / disinfection of semi-critical ultrasound probes is preferable to wipe disinfection, as the latter is not validatable.

[0014] WO 2012 / 141672 A2 describes a cleaning container for ultrasound probes used for ophthalmic examinations. The cleaning container is preferably a bag containing cleaning fluid, into which the distal end of the probe is immersed and then the opening is sealed.

[0015] CN 113082241A describes a device and a method for sterilizing transvaginal ultrasound probes. The probes are first pre-disinfected with chlorine dioxide wipes and then sterilized with UV light. General description of the invention

[0016] The invention solves this problem with the features of the claims and in particular with a method for cleaning semi-critical ultrasound probes, comprising or consisting of the following steps: a) Removing a protective cover from the ultrasound probe; b) Removing transmission gel adhering to the ultrasound probe using a cloth soaked with an impregnating agent; c) Inserting the ultrasound probe into an ultrasound probe cleaning device, wherein the ultrasound probe cleaning device contains an elution solution that contacts the ultrasound probe; and d) Removing the ultrasound probe from the ultrasound probe cleaning device and drying the ultrasound probe.

[0017] In current technology, ultrasound probes are often inadequately cleaned by first removing the protective cover from the ultrasound probe with a dry cloth to remove any adhering transmission gel, and then wiping with a moist cloth before disinfecting the probes.

[0018] After this type of cleaning proved to be insufficient, it was surprisingly found that direct cleaning with a damp cloth, i.e., with a non-woven fabric soaked in an impregnating agent, followed by cleaning with an elution solution, not only leads to significantly better, but also to validatable cleaning results.

[0019] Preferably, for the step of removing transmission gel adhering to the ultrasound probe, two wipes soaked with an impregnating agent are used sequentially. These wipes can comprise or consist of, for example, viscose fibers, lyocell fibers, PET fibers, PP fibers, hemp fibers, cellulose fibers, flax fibers, microfibers, cotton fibers, and mixtures thereof. The impregnating agent with which the wipes are treated is preferably a disinfectant or, alternatively, a water-based impregnating agent containing a preservative or microbicide.

[0020] Of course, more than two cloths soaked with an impregnating agent can be used to remove the transmission gel, but this is usually not necessary.

[0021] Within the scope of the present invention, "ultrasound probes" are understood to mean semi-critical ultrasound probes, in particular transvaginal and transrectal ultrasound probes.

[0022] After removing transmission gel adhering to the ultrasound probe using a cloth or two cloths soaked with an impregnating agent, visible residues of transmission gel are preferably removed from depressions or indentations on the surface of the ultrasound probe, such as those present for biopsy tips, where the transmission gel tends to accumulate during use, using an auxiliary tool. A suitable auxiliary tool is particularly rod-shaped and has a soft end, for example, made of fabric, cotton wool, or silicone. A particularly suitable and cost-effective auxiliary tool is a cotton swab, especially a dry and / or double-ended cotton swab.

[0023] Although the step of selectively removing transmission gel residue from the recesses of the ultrasound probes using an auxiliary tool is only optional, its execution is highly preferred, as this significantly improves the cleaning result, as will be described later. However, even without selectively cleaning the recesses with an auxiliary tool, a verifiable cleaning is possible using the method according to the invention.

[0024] After removing the transmission gel using soaked wipes and optionally a cotton swab or a comparable tool, the ultrasound probe is inserted, according to the invention, into a device for cleaning ultrasound probes. The device for cleaning ultrasound probes contains an elution solution that contacts the ultrasound probe, in particular for at least 30 seconds and preferably for 30-60 seconds. During this contact time of the probe with the elution solution, the ultrasound probe and / or the device for cleaning ultrasound probes should preferably be moved so that the elution solution moves within the device, ideally even splashing, which allows the elution solution to penetrate the recesses of the probe particularly well.

[0025] The elution solution is preferably a solution with a pH value in the range of 2-10, particularly preferably an acidic solution with a pH value of 2-5 or 2-4. A volume of just 15 mL of elution solution can be perfectly sufficient for effective cleaning, so that the device used in the inventive method for cleaning ultrasound probes preferably contains 15 mL of acidic elution solution. Particularly suitable elution solutions include a 0.1% peracetic acid solution with a pH of 4 and a solution known under the trade name "Manushield 0.5%", which has a pH of 8 and contains, in addition to water, 10-25 wt% ethoxylated, branched C9-C11 alcohols, 1-5 wt% denatured alcohol, 1-5 wt% C12-C15 Pareth-12, 0.1-1 wt% didecylmethylpoly(oxyethyl)ammonium propionate, 0.1-1 wt% sodium carbonate, 0.1-1 wt% disodium hydroxyethylaminobismethylphosphonate, 0-0.1 wt% glycol and 0-0.1 wt%...-% citric acid content, highlighted.

[0026] In a preferred embodiment of the inventive method for cleaning semi-critical ultrasound probes, the ultrasound probe is inserted into a device for cleaning ultrasound probes, which is a container open at one end, made of or containing plastic, and containing the elution solution. According to a particularly preferred embodiment, the container open at one end, made of or containing plastic, is a bag into which the ultrasound probe is inserted with the ultrasound head first. After insertion of the ultrasound probe, the bag is manually or otherwise sealed around the circumference of the probe and moved or shaken for at least 30 seconds, preferably for 30 to 60 seconds. Shaking, in particular, causes splashing of the elution solution, which is extremely advantageous for cleaning the probe, especially its recesses.

[0027] In an alternative embodiment, a cup, open at one end and made of plastic, is used as a container. Flexible elements are arranged on the inner surface of this cup. The ultrasound probe, with the ultrasound head first, is inserted into the cup and moved manually or otherwise within the cup for at least 30 seconds, preferably for 30 to 60 seconds. The flexible elements can be, for example, bumps (e.g., made of silicone) or bristles (e.g., made of nylon). During the movement of the ultrasound probe within the cup, which can include up-and-down movements as well as rotational movements, the flexible elements, which, together with the elution solution, contact the surface of the probe, ensure thorough cleaning, even in the recesses of the probe.

[0028] In a further alternative embodiment of the method according to the invention, the semi-critical ultrasound probe to be cleaned is inserted into a device for cleaning ultrasound probes, which is a film with absorbent material arranged on it. The absorbent material is soaked with an elution solution, and the film with the absorbent material arranged on it, in contact with the ultrasound probe and is moved on the surface of the ultrasound probe for at least 30 seconds, preferably for 30-60 seconds.

[0029] Regardless of the chosen device for cleaning ultrasound probes, the step of contacting the ultrasound probe with the elution solution is preferably carried out for 30-60 seconds. In embodiments of the inventive method in which, after the removal of transmission gel adhering to the ultrasound probe by means of one or more cloths soaked with an impregnating agent, transmission gel residues are further removed from recesses in the surface of the ultrasound probe using an auxiliary tool, it is sufficient to contact the ultrasound probe with the elution solution for 30 to 35 seconds. However, if this optional step of removing residues from the recesses of the probe with an auxiliary tool is omitted, it is preferred to contact the ultrasound probe with the elution solution for 45 to 60 seconds.

[0030] After contact with the elution solution, the ultrasound probe is removed from the ultrasound probe cleaning device and dried before disinfection. Drying can be done in any way, for example by drying or wiping with a dry cloth, by air drying, or with compressed air.

[0031] Furthermore, the present invention also relates to a kit-of-parts comprising or consisting of the following: a) wipes soaked with an impregnating agent; and b) an eluent-containing device for cleaning semi-critical ultrasonic probes, wherein the device for cleaning ultrasonic probes is selected from a container containing elution solution and a film with absorbent material soaked in elution solution arranged thereon.

[0032] The cloths impregnated with an impregnating agent have the same characteristics as described above with regard to the method according to the invention, in particular with regard to the composition of the impregnating agent and the nonwoven fabric.

[0033] The device containing the elution agent in the kit-of-parts for cleaning ultrasound probes also has the same features as described above with regard to the method according to the invention. Detailed description of the invention

[0034] The invention will now be described in more detail using examples. Example 1: Implementation of the inventive method for the verifiable cleaning of semi-critical ultrasound probes in a first embodiment

[0035] A semi-critical ultrasound probe (transvaginal probe) with a surface area of ​​260 cm² was fitted with a protective sheath and soiled with transmission gel, ensuring that the indentations were completely filled with gel. The sheath was then removed by grasping it with the thumb and forefinger and sliding it distally, thus minimizing the amount of gel remaining on the probe. The probe was then wiped once from proximal to distal with a standard baby wipe ("Hipp Ultrasensitive," wipe 1), and the wipe was subsequently discarded. The gel-covered area of ​​the probe was then wiped again with another wipe of the same type.The probe's indentations were then wiped with a double-ended cotton swab before the ultrasound probe was placed in a foil tube containing 15 mL of Manushield solution (0.1%, pH 8) and shaken for 30-35 seconds. After contact with the elution solution, the ultrasound probe was dried with disposable paper towels.

[0036] The cleaning success of the above-described procedure was verified by means of carbomer quantification or determination of the TOC value.

[0037] This experiment was repeated four times to increase the statistical power of the results, and a further five times in the same manner, but using different conventional baby wipes ("Babydream" wipe 2). The determined TOC values ​​are given in Table 1 below. Table 1: TOC values ​​determined after carrying out the method according to the invention using wet wipe 1 and wet wipe 2 TOC values ​​ / µg C Wet wipe 1 Wet wipe 2 Attempt 1 173,7 100,5 Attempt 2 93,9 300,1 Attempt 3 200,3 253,5 Attempt 4 133,8 180,3 Attempt 5 153,7 286,8

[0038] The determined TOC values, with a maximum TOC value of 300.1 µg C per 260 cm² probe surface, demonstrate that the inventive method leads to excellent and verifiable cleaning results. The warning value of 6 µg carbon / cm², which is regularly exceeded in practice with prior art cleaning methods for semi-critical ultrasonic probes, is significantly and reliably undercut in the inventive method. Based on the cleaning surface of the probe used (260 cm²), the average carbon content after the cleaning described above was between 0.36 and 1.15 µg carbon / cm², indicating only extremely low carbomer residues. Example 2: Implementation of the inventive method for the verifiable cleaning of semi-critical ultrasound probes in a second embodiment

[0039] Following the excellent cleaning results achieved according to Example 1, this example should test a cleaning procedure that uses a different elution solution and does not involve removing the residues of transmission gel from the recesses of the ultrasound probe with an auxiliary tool.

[0040] Analogous to the first embodiment of the method described in Example 1, each step of this method was also carried out as described, except that the wiping of the ultrasonic probe's recesses with the cleaning tool (cotton swab) was omitted, and 15 mL of peracetic acid (0.1%, pH 4) was used as the elution solution instead of 15 mL of Manushield solution (0.1%, pH 8). As a further difference, the treatment with the elution solution was carried out for 50–60 seconds.

[0041] Since the cleaning success with wipe 1, as shown in Example 1, is comparable to the cleaning success with wipe 2, the use of wipe 1 was limited here.

[0042] The experiments were performed five times before the TOC values ​​of the cleaned probes were determined each time. The determined TOC values ​​are given in Table 2 below. Table 2: TOC values ​​determined after carrying out the inventive method using peracetic acid as the elution solution and without cleaning the probe recesses with auxiliary tools TOC values ​​ / µg C Attempt 1 147,1 Attempt 2 153,7 Attempt 3 951,8 Attempt 4 273,5 Attempt 5 246,8

[0043] The determined TOC values, with a maximum TOC value of 951.8 µg C per 260 cm² probe surface, demonstrate that the inventive method also yields validatable cleaning results using peracetic acid as the elution solution and even without cleaning the probe's recesses with an auxiliary tool. Based on the cleaning surface area of ​​the probe used (260 cm²), the carbon content after the cleaning described above was between 0.57 and 3.66 µg carbon / cm² in all cases. While the variation in results is greater than when the recesses are additionally cleaned with an auxiliary tool, the warning value of 6 µg carbon / cm² is reliably undercut even in this embodiment of the inventive method.

[0044] In general, the TOC value of semi-critical ultrasonic probes after carrying out the inventive method is < 4 µg carbon / cm 2< , which proves that the inventive method differs significantly in its cleaning effect from prior art methods which cannot achieve such a low carbon content.

[0045] The features of the invention disclosed in the foregoing description and in the claims can be essential for the realization of the invention in its various embodiments, both individually and in any combination.

Claims

1. Process for the validatable cleaning of semi-critical ultrasound probes, comprising the following steps: a) Removing a protective cover from an ultrasound probe; b) Removing transmission gel adhering to the ultrasound probe using a cloth impregnated with an impregnating agent; c) Inserting the ultrasound probe into a device for cleaning ultrasound probes, wherein the device for cleaning ultrasound probes contains an elution solution that is in contact with the ultrasound probe; and d) Removing the ultrasound probe from the device for cleaning ultrasound probes and drying the ultrasound probe; e) performing a disinfection.

2. Process according to claim 1, characterized in that, for the step of removing transmission gel adhering to the ultrasound probe, two cloths impregnated with an impregnating agent are used successively.

3. Process according to claim 1 or 2, characterized in that, following the step of removing transmission gel adhering to the ultrasound probe using one or more cloths impregnated with an impregnating agent, residues of transmission gel are removed from recesses in the surface of the ultrasound probe using an auxiliary tool.

4. Process according to one of the preceding claims, characterized in that the ultrasound probe is inserted into a device for cleaning ultrasound probes which is a container open on one side, made of or comprising plastic, in which the elution solution is contained.