Liquid Nitrogen / Cryotherapy Guidelines

These guidelines were provided to DermNet New Zealand by ProCare Health Limited, July 2014.

Disclaimer

These guidelines have been written for the use of ProCare member practices. No set of guidelines can cover all the variations required for specific patient circumstances. It is the responsibility of healthcare professionals to use these guidelines to adapt them for safe use within their institutions and for the individual needs of patients.

Definition

Cryotherapy is a minimum invader A procedure that uses an extremely cold liquid or instrument to freeze and destroy abnormal tissue that requires removal. Also known as cryosurgery or cryoablation.

Scope

Registered doctors and nurses who have been trained to perform the procedure.

Treatment of evil one Cryotherapy skin lesions are not covered by this document.

Indications for cryotherapy.

• Viral warts in older children and adults
• Seborrheic keratosis
• Actinic keratosis
• Molluscum contagiosum in adults
• Skin tags *

* Diathermy may be more effective for skin tags / / fibroepithelial polyps

The following skin cancers may be suitable for cryotherapy if performed by a properly trained doctor and where injury has been identified by biopsy:

• Small, thin, typical, superficial. basal cell carcinoma on trunk and limbs
• Small typical intraepithelial scaly Trunk and Limb Cell Carcinoma

Contraindications to cryotherapy

• Undiagnosed skin lesions
• Injury for what tissue pathology it is required
• Injury within a compromised circulation area
• Melanoma
• Previous sensitivity or adverse reaction to cryosurgery
• The patient cannot accept the side effects.
• Patients with poor circulation.
• Unconscious patients
• Small children
• Dark-skinned patients

Precautions when using cryotherapy

• Areas not recommended for the application of liquid nitrogen: corners of the eyes, skin fold between the nose and lips, the skin around the nostrils and the skin that covers nerveseg sides of digits, below the knee in certain groups (eg, diabetics, the elderly)
• The reappearance of a lesion previously treated with cryotherapy should be referred to a doctor for review.
• Recurrent Skin cancers after cryotherapy may be more difficult to treat.
• Take care in patients with a history of slow healing or skin. infection
• Prolonged freezing can cause scarring; light freezing is best and the patient returns to freeze again if response is inadequate
• Cryotherapy leaves permanent white marks that can be very unpleasant, especially in patients with dark skin.
• Cryotherapy can sometimes cause nerve damage and ongoing pain in some dangerous areas where the nerves meet superficially (for example, sides of the fingers)

Cryotherapy checklist

Pre-procedure

• The general practitioner should review any injury where there is uncertainty about the diagnosis or suitability for cryotherapy.
• Obtain informed consent

Prepare team / environment

• Apply goggles and protective gloves.
• Decant liquid nitrogen in the cryospray or if a cotton-tipped applicator is used in apermeable container
• Cotton-tipped applicators have been commonly used, but should only be used for benign injuries due to lower tissue freezing compared to spray techniques

Liquid nitrogen application

• Hand hygiene
• Select the A to D spray tip of the appropriate size for the diameter and thickness of the lesion.
• Apply liquid nitrogen to the lesion for a few seconds, depending on the diameter required and the depth of freezing.
• A margin of 1–2 mm is recommended for benign lesions.
• A disposable plastic ear speculum (trimmed if necessary) can be used to limit the treatment area
• Freezing times range from about five seconds (after the freeze ball appears) for actinic keratoses to 10 or 20 seconds for thicker lesions such as plant warts or seborrheic keratosis
• Two freeze / thaw cycles (with a shorter freeze time) are more effective for thicker lesions such as seborrheic keratosis and warts.
• For warts (especially plantar warts) removal of curb by using a scalpel blade or before keratolytic Treatment (eg salicylic acid) may improve response to subsequent cryotherapy
• Cotton tipped applicators should not be submerged in the flask; new swabs should be used if more liquid nitrogen is required

Post-procedure

• Periodic cleaning and sterilization of cryospray nozzles should be performed in accordance with the manufacturer's recommendations.
• If the mouthpiece comes in contact with the patient's skin, autoclaving is required (see Practice Infection Control politics)
• Clean the flask
• Document the injury and treatment in the patient management system. This includes (but is not limited to)
  • Informed consent obtained
  • Specific instructions from the general practitioner.
  • Injury site
  • Duration of liquid nitrogen application.
  • Follow-up advice

Inform the patient that the treated area:

• Can blister in a few hours (clear, red, or purple)
• Bleeding may occur (although this is not common)
• The blister shrinks to be replaced by a scab in a few days.
• The swelling should settle in a few days.
• Healing depends on where the scab peels off within a week after cryotherapy for facial actinic keratoses, after about three weeks for a similar injury to the hand, and can cause ulceration on the lower leg and it takes three months or more to heal
• A white labelhypopigmentation) or scar can result

If there are signs of infection, the patient should contact the practice **

** For example, by increasing the redness of the surrounding skin, downloadincreasing pain

Complications and side effects.

Acute

• Edema
• Pain
• Headache after facial injury treatment.

Delayed

• Bleeding from the frozen site
• Site infection
• Skin discomfort
• Hyperpigmentation (slowly resolves)

Permanent (rare)

• Altered sensation.
• Hypopigmentation
• Hypertrophic scars
• Hair lost

Security considerations

• Always make sure the work area is adequately ventilated when handling liquid nitrogen
• Personal protective clothing, including leather gloves, safety glasses, and covered footwear, is used when decanting liquid nitrogen from the Dewar storage flask (storage container) to the cryospray or non-permeable container.
• Caution should be exercised when transporting liquid nitrogen
• The Liquid Nitrogen Dewar Flask and Cryospray should be stored in an upright position, in a cool, well-ventilated area, away from high traffic areas. They must be secured to avoid accidental knocks
• To eliminate potential condensation build-up, the liquid nitrogen dewar flask and cryospray should be stored closed according to the manufacturer's instructions
• Dewar flasks used for liquid nitrogen storage must have a loose cap or vent on the cap to avoid pressure build-up and the consequent risk of explosion.

Relevant practice policies and procedures

1. Health and safety policy
2. Informed consent policy
3. Infection control policy
4. Practice Hazard Record
5. Material Data Safety Sheets - Liquid Nitrogen