Ian Samson, EMEA Regional Training Specialist for DuPont, offers his guidance on personal protection when working with cytostatics

According to the World Health Organisation, between now and 2020, the cancer rate will rise by 50%, producing 15 million new cases a year worldwide. As the number of cancer patients rises, so does the use of chemotherapy treatments using cytostatic drugs. While effective in treating disease, these drugs are also potentially hazardous for the oncology nurses, pharmacists and other healthcare professionals who handle them.

There are a wide range of potential effects on those exposed to cytostatic drugs. The toxicity affects not only tumour cells but also healthy cells; therefore cytostatic drugs pose a quite specific occupational risk to health care workers. Yet research indicates that insufficient care is being taken with cytostatic agents. Studies report a widespread, low-level contamination of areas where cytostatic drugs are used. Traces of cytostatic drugs have been found on work benches, floors, vials and exterior surfaces. In some cases, traces have been found on the floor outside preparation rooms which poses a contamination risk to supposedly ‘safe’ areas. 

Protecting the worker and the process

Precaution must be taken to prevent the formation of cytostatic aerosols and dust and to avoid cytostatic contamination during production, preparation, disposal, storage and transportation of these substances. At the same time, it is important to protect the process from human contamination, including hair, shedding skin and clothing fibres. If there is any risk of contact, the use of suitable personal protection equipment (PPE) is mandatory to ensure effective full-scale protection. These protective measures apply to all staff that come into contact with cytostatics, including cleaning, maintenance and shipping staff. One of the most effective ways of protecting both the worker and the process is through the use of disposable coveralls. But with so many on the market it can be difficult knowing which one is right for you, so understanding what to look for is key.

Particle emission barrier

Barrier efficiency against migrating particles, such as those from clothing or human skin, is a critical performance feature when working with cytostatics. Protective coveralls are tested for barrier efficiency against migrating particles and fibres through two different test methods; the Helmke Drum and Body Box tests.

The Helmke Drum test method simulates particle shedding of clothing through movement and is a good indication of the quantity of fibre that a coverall, both inside and out, will shed during normal working practices. The garment is tumbled in a rotating drum to release particles from the surface of the garment whilst an automatic particle counter is used to sample the air. The sample is then used to determine the average particle concentration in the air during the initial ten minutes of the test.

To ascertain the contamination of a cleanroom by simulating the particle filtration of clothing and the particle release of the person under real wear conditions the BodyBox test is used. During the test, a test person performs a series of defined movements ranging from still to walking, knee bends and arm movements in a cleanroom test cabin. Particle counters determine the quantity of particles generated by the wearer and garment that are emitted into the chamber. One of the benefits of this method is that it is able to test what is commonly known as the ‘bellows effect’, where air can be created within the garment through movement. Through further movement the air and any fibres or skin that has been shed is pushed forcefully into the room through the cuffs and ankles of the coverall. Due to the high variation in particle generation between individuals no performance classification exists and there is no limit value for emission, but choosing the lowest possible filtration rate is always recommended.

Protection from particle intrusion

When determining the level of protection from particle intrusion it is important to look at the Type 5 test results. The Type 5 test specifies the minimum requirements for chemical protective clothing resistant to penetration by airborne solid particles.

To test particle intrusion, the Type 5 test method uses sodium chloride particles at 0.6 micron sizes suspended in a fine spray in a test chamber. The 9 minute test (3 minutes standing, 3 minutes walking and 3 minutes squatting) is repeated on 10 suits. To pass the test 8 out of the 10 suits tested must have on average less than 15% inward leakage into the suits. This means that coveralls that have passed the Type 5 test offer a certain level of protection against fine particulates. It is important to choose a coverall that offers the lowest level of inward leakage for the best possible protection when working with cytostatic drugs.

The importance of material

While most coveralls look similar, the material used makes a difference in determining the end protection level. There are three common types of material; MPF (Microporous Film), SMS (Spun Bond - Melt Blown -Spun Bond) and Tyvek®. When tested against BS 6909 these materials perform very differently. MPF (sometimes known as LMPF) is made using a spunbond polypropylene and a film of polyethylene. Due to the structure of the material it is not breathable and has a high particle shed count. SMS is a breathable material but has poor liquid repellency. Due to the short fibres in the material it sheds fibres quickly so is unsuitable for cleanroom environments. Tyvek®, manufactured only by DuPont, is made up of ultrafine endless high density polyethylene fibres using specific spinning and bonding technology. Because of the endless fibres it has a very low particle shed count.

Comfort is key

Whilst protecting both the worker and the process is crucial, a further, important issue is having coveralls that are comfortable. Comfort is closely linked to protection – after all, if workers are comfortable they are more willing to wear the protective garments and thus protection is heightened. Therefore the garments should ideally be  designed to be durable enough to allow for a range of movement and flexibility, without compromising safety through ripped seams. At the same time, the fabric should offer sufficiently high levels of permeability to both air and water vapour to allow it to “breathe”.

A range of solutions

When choosing protective coveralls to protect both the worker and the process it is always advisable to carry out a detailed analysis of the hazardous substance and of the working environment to ensure the right level of protection for the task. Tyvek® and Tychem® protective clothing offer a superior level of protection and exceed requirements for migrating particle efficiency and particle hold out, as well as offering comfortable, flexible protection. To offer the right protection where needed, protective clothing from DuPont is available in a range of models, such as a suit with a hood or collar, integrated socks, sewn or covered seams and thumb loops. Where additional protection is required, for example where certain parts of the body may be more frequently or heavily exposed to the hazardous substance, accessories are available. This includes sleeves, overboots, overshoes, lab gowns, aprons and back-fastening gowns that are compatible with other products.

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