The majority of needlestick injuries are reported by trainee doctors and nurses, so if you are just beginning work in the health care professions, make doubly sure that you receive proper training and that you understand the infection control procedures.

Why accidents happen

A US study of cases of occupational HIV infection amongst health care workers showed that the most common causes of events such as needlestick injuries and other sharps accidents were:

• Sudden or unexpected movement during a procedure.
• Improper disposal of needles or sharps.
• Recapping of needles.

Nearly half of the exposures in one study involved sharps penetrating rubber gloves (Cieselski 1993). But another survey found that the majority of needlestick injuries occurred when the needle and syringe were being prepared for disposal, often when an attempt is being made to re–cap or re–sheath the needle.

Needle type, size and depth of penetration are all determinants of the amount of blood injected; hollow bore needles tend to be the most likely to deliver large quantities of blood, and virtually all the needlestick accidents reported by Cieselski involved this type of needle. Obviously the medical procedure will determine the nature of the needle in use, but these findings may nevertheless serve as a useful rule of thumb to reassure anyone who has sustained a needlestick injury. These injuries are often described as percutaneous injuries.

Sharps injuries commonly occur during the stitching of wounds or whilst cutting tissue. They also occur frequently in situations where surgeons are operating without complete visibility – usually inside a patient (Gerberding).

It has been suggested that some basic changes in surgical practice and instrument design might significantly reduce the frequency of such injuries. These suggestions are discussed in detail in a supplement to the Journal of Infection published in 1991 (Raahave; Sim).

Sharps injuries appear to occur most frequently in gynaecological surgery and in heart surgery.

The frequency of such injuries in other less accident–prone forms of surgical practice is indicated by surveys of the frequency of needlestick and sharps injuries amongst orthopaedic surgeons, who have been identified as less prone than gynaecologists to such injuries. In the UK 49% of orthopaedic surgeons surveyed and in the USA 39% of orthopaedic surgeons had sustained such injuries in the previous month (Panlilio; Tokars).

Two US studies, of health care workers' occupational exposure to blood, showed that the majority of those exposed to blood were nurses – in one study only 19% were doctors and just 7% were laboratory personnel. This may well reflect under–reporting by doctors and medical students however. The rates of exposure amongst doctors and medical students are thought to be much higher.

Avoiding accidents

• Protect existing wounds: don't participate in invasive procedures if you have exposed lesions, cuts, chapped skin or weeping dermatitis.
• In other procedures: cover cuts and sores with waterproof plasters.
• Use disposable gloves and disposable aprons wherever appropriate.
• Wash hands to prevent the spread of infection.
• Take care in disinfection, mopping up blood and disposal of contaminated materials, see below.
• Prevent new wounds.
• Handle sharp instruments with care.
• Dispose of sharps with disposable tongs in puncture proof bins which can be clearly marked and then incinerated.
• Wear protective clothing or devices wherever recommended.
• Don't re–sheath or recap needles: about 40% of needle stick injuries occur as a result of this.

References

British Dental Association . Infection Control in Dentistry. Can be downloaded from http://www.udp.org.uk/resources/bda-cross-infection.pdf

British Medical Association: Bloodborne viruses and Infection Control: A guide for health care professionals. Harwood Academic Publishing, 1998. This is now an interactive CD-ROM costing £190.00, but is the most comprehensive guide around. ISBN 9057024047.

Cieselski C et al: Occupationally Acquired HIV Infection – United States, IX International Conference on AIDS, abstract Ws–C12–1, 1993.

Gerberding JL: AIDS and surgery: Reducing the risk, JAMA 265: 1572–1573, 1991.

Health and Safety Executive. Blood-borne viruses in the workplace: Guidance for employers and employees. Can be downloaded from http://www.hse.gov.uk/pubns/indg342.pdf

Jeffries DJ: Zidovudine after occupational exposure to HIV (editorial), BMJ 302: 1349–1350, 1991.

Panlilio AL et al: Blood contacts during surgical procedures, JAMA 265: 1788–1793, 1991.

Raahave D et al: New operative techniques to reduce surgeons' risk of HIV infection, Journal of Infection 18 Suppl A: 177–183, 1991.

Royal College of Nursing. Wipe it Out: Good Practice in Infection Prevention and Control. Can be downloaded from http://www.rcn.org.uk/resources/mrsa/downloads/Wipe_it_out-Good_practice_in_infection_prevention_and_control.pdf

Sim AJW: Towards safer surgery, Journal of Infection 18 Suppl A: 184–190, 1991.

The Stationery Office. Protection against blood-borne infections in the workplace: HIV and hepatitis.HMSO London: 1995. ISBN 0-11-321953-9. This can be ordered from The Stationery Office, TSO Orders/Post Cash Dept, PO Box 29, Norwich NR3 1GN. Phone: 0870 600 5522, email customer.services@tso.co.uk or order from the website http://www.tsoshop.co.uk/.

Tokars JI et al: Percutaneous injuries during surgical procedures, Seventh International Conference on AIDS, Florence, abstract TH D–108, 1991.

Morgan DR: Missing the point: preventing needlestick injury and exposure to HIV and other bloodborne viruses, Royal Society of Medicine AIDS Letter 42, 1994.