FAQs on Covid-19: How to disinfect and sterilize medical devices

— By Dr KK Aggarwal

532: What is Medical equipment: Disinfection and sterilization ?

The type of cleaning, disinfection, and sterilization required depends on the type of medical equipment.

533: What is a Noncritical equipment ?

Medical equipment that comes into contact with intact skin but not mucous membranes (eg, stethoscopes, blood pressure cuffs, patient care area surfaces)

534: What are Semi-critical equipment ?

Medical equipment that comes into contact with non-intact skin or mucous membranes (eg, thermometers, endoscopes)

535: What are Critical medical equipment ?

Medical equipment that comes into contact with sterile tissue or the vascular system (eg, implants, catheters, surgical instruments)

536: How to clean Noncritical medical equipment ?

They should be cleaned using a disinfectant that kills most bacteria and some viruses and fungi; cleaning these items with an alcohol wipe between uses is often sufficient.

Mobile communication devices such as pagers and cell phones may also become contaminated with bacteria; these devices should be disinfected similarly.

537: How to clean semi-critical medical equipments ?

They should be free from all vegetative microorganisms, but small numbers of bacterial spores are permissible since non-intact skin and mucous membranes are generally resistant to infection by spores.

538: How to clean critical medical equipment ?

They must be sterile because any microbial contamination could transmit disease. These items should be purchased as sterile or be sterilized between uses.

539: Can bleach be harmful ?

Before you start using bleach everywhere, it’s important to know that bleach is caustic and can emit potentially lethal fumes.1 That’s why it’s important to dilute your bleach and ensure that it’s not used at full-strength and not mix it with other solutions and chemicals.

The Centers for Disease Control (CDC) recommends using different amounts of bleach and water depending on what is being cleaned. Be sure to follow these steps exactly to make a safe and effective bleach solution that meets your needs.

540: Can I mix Ammonia with bleach ?

A: Mixed with bleach converts the chlorine in bleach to chloramine gas. Breathing in the fumes can cause coughing, shortness of breath, and pneumonia.

541: Can we mix acidic compounds such as vinegar or window cleaner create chlorine gas in bleach ?

No: When mixed with bleach, excessive exposure can cause chest pain, vomiting, and even death.

542: can we add alcohol in bleach ?

No. Alcohol converts to chloroform when mixed with bleach. Breathing in chloroform can cause fatigue, dizziness, and fainting.

543: How long fresh bleach solution last ?

Chlorine bleach solution begins to lose its disinfectant power quickly when exposed to heat, sunlight, and evaporation. To ensure the strength of your solution, mix a fresh batch each day and discard whatever is leftover. Keep out of the reach of children.

544: What is the bleach concentration to clean hard surfaces such as plates and counter tops ?

Mix 1 cup (240 milliliters) of bleach with 5 gallons (18.9 liters) of water.

545: What is the bleach concentration to clean disinfect healthcare facilities ?

To make a 1:10 solution to disinfect healthcare facilities that may have been tainted by contagions, you’ll need 1 part bleach for every 9 parts water.

545: What to do if bleach [powder gets poured on the skin ?

If you do get any bleach on your skin, wipe it off immediately with a damp cloth.

546: Do I still need to use soap and water ?

You can wash the surface with soap and hot, clean water before using the bleach. After applying the beach let the surface you are cleaning air dry.

547: How do I prepare 1% chlorine solution ?

Guidelines for Preparation of 1% sodium hypochlorite solution
Product Available chlorine 1percent Sodium hypochlorite
liquid bleach 3.5% 1 part bleach to 2.5 parts water
Sodium hypochlorite liquid 5% 1 part bleach to 4 parts water
NaDCC (sodium dichloroisocyanurate)
powder 60% 17 grams to 1 litre water
NaDCC (1.5 g/ tablet) – tablets 60% 11 tablets to 1 litre water
Chloramine – powder 25% 80 g to 1 litre water
Bleaching powder 70% 7g to 1 litre water

Approach to disinfection and sterilization of medical devices

EPA: Environmental Protection Agency.

* 2% glutaraldehyde-based products, 6% stabilized hydrogen peroxide, chlorine, peracetic acid.
¶ 2% glutaraldehyde-based products, 6% stabilized hydrogen peroxide, peracetic acid.
Modified with permission from: Rutala WA. APIC guideline for selection and use of disinfectants. Am J Infect Control 1996; 24:313. Copyright © 1996 Mosby, Inc.

((The writer is President, CMAAO, HCFI and Past national President IMA))