Nurses undertaking application of cryotherapy for clinically diagnosed external genital warts and molluscum contagiosum virus (MCV) must be accredited; see Delegation of clinical practice.
Use of self-administered topical applications for treatment of diagnosed external genital warts and MCV is considered prior to use of cryotherapy.
Services have liquid nitrogen or compressed carbon dioxide safe handling processes in place according to local requirements.
Proceed in accordance with the following policy directives.
NSW Health. Infection prevention and control policy. Sydney: NSW Health; 2017. Available at: http://www1.health.nsw.gov.au/pds/ActivePDSDocuments/PD2017_013.pdf
NSW Health. Injury management and return to work. Sydney: NSW Health; 2013. Available at: http://www1.health.nsw.gov.au/pds/ActivePDSDocuments/PD2013_006.pdf
NSW Health. Work health and safety: better practice procedures. Sydney: NSW Health; 2013. Available at: https://intranet.nnswlhd.health.nsw.gov.au/docs/PD2013_050-work-health-and-safety-better-practice-procedures-v-001.pdf
Safe handlingAny person handling liquid nitrogen or compressed carbon dioxide must be aware of the potential occupational health hazards, risks involved in use, controls to minimise these risks, spill control, emergency response and incident reporting procedures. Any person handling liquid nitrogen or a compressed carbon dioxide unit must be fully oriented to the safety techniques in order to safely and competently perform their duties. Orientation and accreditation of clinical staff who will use these substances and devices is the responsibility of the appropriate line manager.When transferring liquid nitrogen or compressed carbon dioxide, safety precautions must be maintained at all times.
Personal protective equipment, including thick gloves and safety glasses, should be used when handling liquid nitrogen or compressed carbon dioxide. Avoid confined areas and ensure adequate ventilation.
Figure 4.6: Example of material data safety sheet for liquid nitrogen
ApplicationCryotherapy destroys the wart tissue by freezing and thawing. It is suitable for external dry or moist warts and can be used in pregnancy.Proceed as follows:
- Identify lesion to be treated.
- Prepare equipment as available; this may include:
- canister of liquid nitrogen with cryotip
- compressed carbon dioxide and acetone decanted into a single-use metal pot with loosely wound cotton on wooden applicator
- personal protective equipment.
- Position patient for comfort and accessibility to areas being treated.
- Freeze full thickness of the wart or MCV lesion until there is whitening of the surrounding skin area for 2 mm. Use a freeze, thaw, freeze technique with lesions held frozen for 10–30 seconds.
- Allow to thaw and repeat up to three cycles depending on size and number of warts or MCV lesions. Treatment of large warts or areas at one time can create wound care problems.
- Repeat treatment fortnightly until the warts or lesions have resolved.
- Reassess after six treatments or earlier if not responding.
Use of topical anaesthetic cream or gel to reduce pain may facilitate cryotherapy.
Aftercare instructions for clientAdvise as follows:
- Blisters may form on the treated area.
- Pain and necrosis are common and bathing with salt water, preferably twice daily (2 handfuls of salt per bath or 2 tablespoons in a large bowl) may promote skin healing and reduce irritation.
- Keep skin clean and dry.
- Adverse effects include possible balanoposthitis, irritation, local oedema, necrosis, ulceration and pain, especially when the area thaws. Both hyper- and hypopigmentation can occur and are usually temporary.
- Genital warts may recur.
- Avoid sexual contact or wear condoms after treatment until lesions have resolved.
- Condoms may reduce risk of transmission.
All treatments given, immediate effects and verbal aftercare instructions are to be documented in the medical record.
References and further reading
- British Association for Sexual Health and HIV. Standards for the management of sexually transmitted infections (STIs). London: Medical Foundation for AIDS & Sexual Health; 2014. Available at: http://www.medfash.org.uk/uploads/files/p18dtqli8116261rv19i61rh9n2k4.pdf
- NSW Health. Infection prevention and control policy. Sydney: NSW Health; 2017. Available at: http://www1.health.nsw.gov.au/pds/ActivePDSDocuments/PD2017_013.pdf
- SafeWork NSW. Codes of practice. Sydney: SafeWork NSW. Available at: http://www.safework.nsw.gov.au/law-and-policy/legislation-and-codes/codes-of-practice
- University of Sydney Department of Pharmacy. Safe work procedure: use of cryogenics. October 2016. Available at: http://sydney.edu.au/pharmacy/about/whs/risk-assessment/swp-working-with-cryogenics.pdf
- WorkCover NSW. Preparation of safety data sheets for hazardous chemicals code of practice. Sydney: WorkCover NSW; 2011. Available at: http://www.safework.nsw.gov.au/__data/assets/pdf_file/0017/50084/preparation-safety-data-sheets-haz-chemicals-code-practice-3564.pdf