General Precautons

• The body's defence systems
• Sterilisation, disinfection and cleansing
• Gloves and hand hygiene
• Disinfectants and skin prep

The body's defence systems

The body defends itself from harm by a number of means including:

The Skin
The skin is primarily a barrier between the inside of the body and the outside world. It is covered with micro-organisms, which themselves help to protect the body from invading bacteria which have the potential to cause harm. Sebum and sweat, which is secreted onto the skin from pores in the skin's surface, have a mild anti-bacterial action.

The mouth and nose:
The mouth and nose are protected by "friendly bactera" found in the saliva. However, this friendly bacteria is not so friendly if it manages to enter other areas of the body where it is not normally found (for example, a human bite which breaks the skin). The nost also helpts to filter the air being inhaled for micro-organisms which may be harmful to the body.

The airways and lungs
The airways and lungs are lined with mucous membranes whic produce thick, sticky mucous, This mucous "captures" any micro-organisms whic henter the lungs through inhalation. These memebreanes also have "micro-villi" which sweep in an upward motion to move the mucous and the micro-organisms trapped in it up and out of the lungs and into the throat where it is swallowed.

The gastro-intestinal tract (stomach and bowels):
The GI tract is protected firstly by a strong acid in the stomach (gastric acid). The stomach contents are so acidic that most micro-organisms are destroyed there. The bowels are also protected by "friendly bacteria" which has the potential to be not so friendly in other areas of the body, for example, Escheria Coli is commonly found in the bowel but is capable of causing quite serious urine infections if it gets into the bladder. High standards of hygiene are an important consdieration when using urinary catheters and sounds because of the potential for contamination of the bladder with micro-organisms found in th bowel.

The bladder:
The bladder is considered a sterile area of the body and is normally free from micro-organisms ("friendly" or otherwise.) The continual flow of ureine (which is considered sterile until it leave the urethra) fromt he kidneys into the bladder and out through the urethra flushes the system portecting the urinary tract from infection.

The immune system:
Works in a number of ways to identify and kill invading micro-organisms.

Some micro-organisms, particularly viruses, have the ability to evade some or all of these defences, Some of them may survive in or on the body without causing the body to react to them for hours, days, weeks, months and sometimes years. People who are carrying these micro-organisms may do so without knowing.

It is important to consider these points when taking part in invasive procedures and the following precautiosn can be used to minimise the risks posed to both patient and klinician.

lili (July 2008)