Penetration of water vapour into narrow channels during steam sterilization processes

Doornmalen, J. P.C.M. Van; Verschueren, M.; Kopinga, K.

doi:10.1088/0022-3727/46/6/065201

Cited by 14 publications

(16 citation statements)

References 9 publications

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“…The lack of association between time and effectiveness of sterilization cycles is probably related to failure to achieve the required temperature/pressure parameters. In principle, time (holding period) is clearly linked with the effectiveness of sterilization when the required temperature/pressure of the autoclave is achieved [39] so it is essential that all the parameters required for effective sterilization are reached.…”

Section: Discussionmentioning

confidence: 99%

Effectiveness of steam sterilization of reusable medical devices in primary and secondary care public hospitals in Nepal and factors associated with ineffective sterilization: A nation-wide cross-sectional study

et al. 2019

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BackgroundInadequate sterilization of reusable medical devices can lead to healthcare associated infections (HAIs) through person-to-person or environmental transmission of pathogens. Autoclaving (steam sterilization) is most commonly used for sterilizing medical devices in healthcare facilities. We conducted a nation-wide cross-sectional study to evaluate the effectiveness of steam sterilization practices in primary and secondary care public hospitals in Nepal and to identify factors associated with ineffective sterilization.MethodsUsing a stratified clustered random sampling, 13 primary- and secondary-care public hospitals in Nepal were selected. 189 steam sterilization cycles from these hospitals were evaluated for their effectiveness using self-contained biological indicators, class-5 chemical indicators, autoclave indicator tape and physical parameters. Information about the hospitals and the types of autoclaves being used was also collected. Data were analysed to estimate the proportion of ineffective steam sterilization cycles. Logistic regression was used to identify factors associated with ineffective sterilization.FindingsIn primary and secondary care public hospitals in Nepal, 71.0% (95% CI 46.8% - 87.2%) of the autoclave cycles were ineffective (i.e. showed positive results) when tested with biological indicators and 69.8% (95% CI 44.4% - 87.0%) showed ‘reject’ results with class 5 chemical indicators. There was no statistically significant difference in proportions showing positive or reject results by hospital types for either biological (p = 0.51) or class 5 chemical (p = 0.87) indicators. Autoclave type and pressure achieved during sterilization were statistically significantly associated with steam sterilization failures, adjusted for holding period, evenness of pressure and barrier system used.ConclusionPrimary and secondary care hospitals in Nepal have a high proportion of steam sterilization failure, indicating a risk of person-to-person transmission of pathogens through reusable medical devices. There is an urgent need to improve steam sterilization processes in these hospitals.

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Section: Discussionmentioning

confidence: 99%

Effectiveness of steam sterilization of reusable medical devices in primary and secondary care public hospitals in Nepal and factors associated with ineffective sterilization: A nation-wide cross-sectional study

et al. 2019

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“…If the values of τ −1 of T3 and T5 are significantly lower than their values in the absence of NCGs and τ −1 3 is substantially lower than τ −1 5 , the steam penetration in long hollow channels may be impaired significantly, as has been shown previously. 7 Our model reveals that the basic principle of the ETS, measuring the effect of entrapped air on the heat transfer by condensation on a cooled surface, permits a very sensitive detection of NCGs in harsh environments like water vapor at high temperatures and pressures.…”

Section: Discussionmentioning

confidence: 93%

“…Recently, we have performed model calculations and experiments on a test tube mimicking the channels present in medical instruments. 7 This study revealed that a significant fraction of the commonly used sterilization processes may fail to reduce the amount of NCGs to a level which is sufficiently low for sterilization of the inner part of such instruments. No direct relation has been found between the results of a B&D test and the amount of NCGs in the sterilizer chamber.…”

Section: Introductionmentioning

confidence: 87%

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Measuring non-condensable gases in steam

Doornmalen

Kopinga

2013

Review of Scientific Instruments

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In surgery, medical devices that are used should be sterilized. To obtain surface steam sterilization conditions, not only in the sterilizer chamber itself but also in the loads to be sterilized, the amount of non-condensable gases (NCGs), for instance air, should be very low. Even rather small fractions of NCGs (below 1%) seriously hamper steam penetration in porous materials or devices with hollow channels (e.g., endoscopes). A recently developed instrument which might detect the presence of residual NCGs in a reliable and reproducible way is the 3M(TM) Electronic Test System (ETS). In this paper, a physical model is presented that describes the behavior of this instrument. This model has been validated by experiments in which known fractions of NCGs were introduced in a sterilizer chamber in which an ETS was placed. Despite several approximations made in the model, a good agreement is found between the model predictions and the experimental results. The basic principle of the ETS, measuring the heat transfer by condensation on a cooled surface, permits a very sensitive detection of NCGs in harsh environments like water vapor at high temperatures and pressures. Our model may serve to develop adapted and optimized versions of this instrument for use outside the field of sterilization, e.g., in heat exchangers based on steam condensation.

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“…They verify that the special instrument has been validated for IUSS and the sterilization container also has been validated and cleared by the FDA for IUSS . One of the ophthalmology nurses on the interdisciplinary team has recently reviewed the AORN “Guideline for sterilization,” and she points out that two quasi‐experimental studies found that if phacoemulsification hand pieces are not sterilized in an upright position to allow for free drainage of the channel during sterilization, the necessary parameters for sterilization in the lumen might not be met . The interdisciplinary team verifies that the instrument container currently used for steam sterilization can accommodate phacoemulsification hand pieces in a vertical position.…”

Section: Scenariomentioning

confidence: 99%

Guideline Implementation: Sterilization

Link¹

2019

AORN Journal

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Ensuring that reusable surgical instruments and medical devices have been sterilized is an important factor in preventing surgical site infections. The sterilization method for a particular device is based on the device design, material, packaging, compatibility with the sterilant, load limitations, and safety requirements. Perioperative team members must review the manufacturer's instructions for cleaning, packaging, and sterilizing the device to determine the correct sterilization process. The AORN “Guideline for sterilization” provides guidance for processing reusable medical devices for use in perioperative and procedural settings. This article elaborates on key takeaways from the guideline, including processing a device based on the intended use of the item, protecting sterile items during transport, reprocessing by immediate‐use steam sterilization when certain conditions can be met, and educating personnel who perform sterile processing activities. Perioperative RNs should review the complete guideline for additional information and for guidance when writing and updating policies and procedures.

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Penetration of water vapour into narrow channels during steam sterilization processes

Cited by 14 publications

References 9 publications

Effectiveness of steam sterilization of reusable medical devices in primary and secondary care public hospitals in Nepal and factors associated with ineffective sterilization: A nation-wide cross-sectional study

Effectiveness of steam sterilization of reusable medical devices in primary and secondary care public hospitals in Nepal and factors associated with ineffective sterilization: A nation-wide cross-sectional study

Measuring non-condensable gases in steam

Guideline Implementation: Sterilization

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