Issues with Chemical Disinfectants

Manual disinfection risk

Manual soak (soaking bulk liquid disinfectants) and chemical impregnated wipes risk.

  • Threat to the safety of patients as steps in the cleaning and disinfection process can be missed, lack of compliance and digital traceability systems.
  • Manual wiping cannot reassure reproducible between operators or single operator every time.
  • Risk of exposure to dangerous chemicals.
  • Global disinfection guidelines are favouring automation
  • Manufacturer’s instructions are beginning to move away from manual HLD as an option.1-2

There have been numerous cases of cross infection risks to patients due to manual ultrasound probe reprocessing:

  • Patient contacting hepatitis C virus after transrectal prostate biopsy as part of an individual screening for prostate cancer.
  • Patient contracting hepatitis B linked to improper ultrasound transducer disinfection that led to a fatality.3-7

Probe Handle and cable cross-infection risk

Common short falls in manual chemical ultrasound probe reprocessing

  • Only the distal tip of the probe and shaft are HLD?

Recent Studies show that the handle and cable section are exposed to cross-infection risk during a clinical examination in women’s clinics and in acute care medical departments.

  • more than 80% of handles which are not immersed during chemical soaking disinfection are contaminated.8-11
  • 61% of samples tested positive for blood contamination
  • 48% tested positive for microbiological contamination.
  • 57% transducers showed blood contamination
  • 88% transducer cables are in direct patient contact,
  • 62% transducer leads and 46% transducers showed microbial contamination.12

Healthcare facilities need to review policies to ensure that the handle, cable and probe are adequately disinfected? 8-1

Low Level Disinfection Wipes Effectiveness

There are several studies that show Low Level Disinfection (LLD) wipes are not as effective as automated High Level Disinfection methods.

  • A recent study in a clinical setting confirmed that the LLD procedure alone is unsafe compared to using a HLD method such as UV-C that can reliably inactivate pathogens (HPV). The study stated that automated HLD method is strongly recommended to ensure patient safety.6
  • A meta-analysis found procedures using LLD wipes, contamination remained up to 12.9% for pathogenic bacteria and 1% for pathogenic viruses on endocavitary probes. Stating the probability of infection transmission of viral pathogens to patients from these procedures was estimated to be 1-6%.7
  • High Risk of infection following Low Level Disinfection. In a study conducted at the Gynecology Department of the Lyon University Hospital from July to October, 216 samples were collected before the ultrasound examination, after Low Level Disinfection applied. The results showed:
    • 2% (63/216) vaginal probes are detected to be contaminated with Human DNA
    • 8% (6/216) vaginal probes are detected to be contaminated with Human papillomavirus HPV and 4/6 with High Risk HPV
    • The study concluded that in all hospitals, where LLD is performed, the endovaginal ultrasound procedure must therefore be considered a source for nosocomial High Risk HPV infections. Recommending stringent use of high-level disinfectants.21
  • Various global guidelines recommend High Level disinfection for endocavity ultrasound probes that are classified as semi-critical/semi-invasive.
  • Some institutions and medical teams proceed to Low Level Disinfection (LLD) and may not be fully aware of the cross-infection risks after use of an ultrasound probe. However, LLD has been proven to be insufficient, as demonstrated by the results of a retrospective cohort study using linked national datasets from Scotland.20

Skin and respiratory problems

A substantial number of studies have shown that Ortho-phthalaldehyde (OPA) and glutaraldehyde (GTA) anaphylaxis, can pose severe health and safety risks for patients and clinical staff.

Exposure to these chemicals can cause skin reactivity, dermatitis, respiratory problems, and systemic antibody production. It now appears that the health issues of OPA exposed to health care workers are comparable to that of glutaraldehyde, suggesting that it may not be a safe alternative.13-19

  1. Ofstead CL, Wetzler HP, Doyle EM, Rocco CK, Visrodia KH, Baron TH and Tosh PK. (2015). Persistent contamination on colonoscopes and gastroscopes detected by biologic cultures and rapid indicators despite reprocessing performed in accordance with guidelines. Am J Infect Control, 43:794-801.
  2. Weber DJ, Rutala WA. Assessing the risk of disease transmission to patients when there is a failure to follow recommended disinfection and sterilization guidelines. Am J Infect Control. 2013;41(5 Suppl):S67-71.
  3.  Leroy S. Infectious risk of endovaginal and transrectal ultrasonography: systematic review and meta-analysis. The Journal of hospital infection. 2013;83(2):99-106. NAN0046.
  4.  Ferhi K, Roupret M, Mozer P, Ploussard G, Haertig A, de La Taille A. Hepatitis C transmission after prostate biopsy. Case Rep Urol. 2013;2013:797248.
  5.  Medicines and Healthcare products Regulatory Agency (UK), Medical Device Alert Ref: MDA/2012/037.
  6.  Maxime Pichon, Karine Lebail-Carval, Geneviève Billaud, Bruno Lina, Pascal Gaucherand and Yahia Mekki (2019) Decontamination of Intravaginal Probes Infected by Human Papillomavirus (HPV) Using UV-C Decontamination System. J. Clin. Med, 8, 1776; doi:10.3390/jcm8111776.
  7.  Leroy, S., et al. (2014). “Impact of vaginal-rectal ultrasound examinations with covered and low-level disinfected transducers on infectious transmissions in France.” Infect Control Hosp Epidemiol 35(12): 1497-1504.
  8.  Alfa MJ. Intra-cavitary ultrasound probes: cleaning and high-level disinfection are necessary for both the probe head and handle to reduce the risk of infection transmission. Infect Control Hosp Epidemiol. 2015;36(5):585-6.
  9.  Ngu A, McNally G, Patel D, Gorgis V, Leroy S, Burdach J. Reducing Transmission Risk Through High-Level Disinfection of Transvaginal Ultrasound Transducer Handles. Infect Control Hosp Epidemiol. 2015;36(5):581-4.
  10.  Westerway SC, Basseal JM, Brockway A, et al. Potential Infection Control Risks Associated with Ultrasound Equipment – A Bacterial Perspective. Ultrasound Med Biol. 2017;43(2):421-6.
  11.  Leroy S. Infectious risk of endovaginal and transrectal ultrasonography: systematic review and meta-analysis. Journal of Hospital Infection (2012),
  12.  Keys M, Sim BZ, Thom Ogilvie, et al. Efforts to Attenuate the Spread of Infection (EASI): a prospective, observational multicentre survey of ultrasound equipment in Australian emergency departments and intensive care units. Crit Care Resusc. 2015;17(1): 43-46.
  13.  Anderson SE, Umbright C, Sellamuthu R, Fluharty K, Kashon M, Franko J, et al.(2010) Irritancy and allergic responses induced by topical application of ortho-phthalaldehyde. Toxicol Sci;115(2):435-43.
  14.  Hasegawa G, Morinaga T, Ishihara Y. (2009) ortho-Phthalaldehyde enhances allergen-specific IgE production without allergen-specific IgG in ovalbumin-sensitized mice. Toxicol LettFeb 25; 185(1):45-50.
  15.  Cooper DE, White AA, Werkema AN, Auge BK. Anaphylaxis following cystoscopy with equipment sterilized with Cidex OPA (ortho-phthalaldehyde): a review of two cases. J Endourol. 2008;22(9):2181-4.
  16.  Suzukawa M, Komiya A, Koketsu R, Kawakami A, Kimura M, Nito T, et al. Three cases of ortho-phthalaldehyde-induced anaphylaxis after laryngoscopy: detection of specific IgE in serum. Allergol Int. 2007;56(3):313-6.
  17.  Suzukawa M, Yamaguchi M, Komiya A, Kimura M, Nito T, Yamamoto K. Ortho-phthalaldehyde-induced anaphylaxis after laryngoscopy. J Allergy Clin Immunol. 2006;117(6):1500-1.
  18. Fujita, M. Ogawa, and Y. Endo. A case of occupational bronchial asthma and contact dermatitis caused by ortho-phthalaldehyde exposure in a medical worker,” J Occupational Health, vol. 48, pp. 413–416, 2006.
  19. N. Sokol. Nine episodes of anaphylaxis following cystoscopy caused by Cidex OPA (orthophthalaldehyde) high level disinfectant in 4 patients after cytoscopy. J Allergy and Clinical Immunology, vol. 114, pp. 392–397, 2004.
  20. Health Protection Scotland (HPS), NHS National Services Scotland (2017). NHS Scotland Risk Based Recommendations
    for the Decontamination of SemiInvasive Ultrasound Probes: Risk of infection following semi-invasive ultrasound procedures in
    Scotland, 2010 to 2016. Version 1.0.
  21. Casalegno and et al. High Risk HPV Contamination of Endocavity Vaginal Ultrasound Probes: An Underestimated Route of Nosocomial Infection?  PLOS ONE | 2012

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