|What are the risks of needlestick injuries?|
Within their scope of duties healthcare workers are exposed to a multitude of risks, especially risks of infections caused by needlestick injuries involving contaminated sharp devices. Such blood exposures can lead to the transmission of almost all known pathogens, hepatitis B or C virus (HBV, HCV) and human immunodeficiency virus (HIV) are among the most serious and fatal ones. The risk of contracting hepatitis B virus can be minimized through vaccination, and there is also a relatively efficient postexposure prophylaxis in case of infection with HBV and/or HIV. In contrast, the only possible prophylaxis for hepatitis C virus currently is the prevention of exposure. According to different literature the risk of seroconversion after an exposure to bloodborne pathogens is mostly rated with the well-known “30-3-0,3 rule”, even though the hepatitis B virus may lead to a transmission rate of 100. However, there is the opportunity of an effective vaccination against HBV. Our own research has shown that each employee faces the risk of suffering a needlestick injury approx. every two years, whereas only a low number is reported to the responsible institutions. The majority of these injuries either occurs during the disposal of contaminated needles or is a consequence of incorrect disposal. Also the practice of bi-manual recapping of needles, which has long been forbidden, causes a number of needlestick injuries still to this day.
|How to get an accurate risk assessment?|
As required by Directive 2010/32/EU formal risk assessments need to be carried out for all activities involving medical sharps. An accurate risk assessment takes into account the amount of blood exposure per type of sharps device and the frequency of a needlestick injury. The separation of the minor acceptable risks from the major ones provides useful data for an effective treatment of those risks and finally enables to define proper measures according to the different types of devices.
|What are the main research results?|
The risk of infection is basically a function of the probability that the patients blood is infectious and the probability that enough pathogens are transferred via a needlestick.
Measurements involving blood-filled hollow-bore needles, e.g. winged IV needles or IV catheters, revealed that a typical needlestick injury causes the transmission of approx. 1 µl of blood, whereas the depth of the needlestick influences the blood volume decisively. Furthermore our research has shown that also the needle size influences the transferred volume of blood. Accordingly, large-lumen needles lead to the transmission of a higher volume of blood.1
As shown in the table below, the risk of infection varies between different types of sharps devices or rather the scope of the application. Sharps devices, such as peripheral and central venous catheters, butterfly needles for blood drawing or surgical devices like scalpel blades, reveal a serious or even fatal risk by amount of blood exposure. The risk of injury or infection has to be eliminated or at least reduced as much as possible by implementing safety-engineered sharps devices, improving work practices and providing appropriate training, which furthermore ensure the compliance with the Directive 2010/32/EU.
|Which preventive measures should be taken?|
The data gathered in our study, which is compiled in the risk analysis matrix, finally enables healthcare facilities to take appropriate preventive measures and behavioral rules in order to lower the risk and protect healthcare workers from needlestick injuries.
Effective strategies for controlling injuries and occupational diseases should focus on the following measures (listed in order of preference):
1. Substitution of major hazards for less hazardous materials or processes
2. Technical solutions to minimize the risks
3. Application of engineering controls to separate workers from hazards that remain
4. Administrative controls to reduce the contact uncontrollable by engineering
5. Use of personal protective equipment (last line of defense)
Prof. Dr. Ing. Andreas Wittmann
University of Wuppertal
Faculty of Safety Engineering, Occupational Medicine, Occupational Physiology and Infection Control
1Wittmann, A., Kralj, N., Hofmann, F. (2004): Übertragene Blutvolumina nach Kanülenstichverletzungen – Ein Beitrag zur Risikoabschätzung nach Kanülenstichverletzungen in: Hofmann F., Reschauer G., Stößel U. (Hrsg.): Arbeitsmedizin im Gesundheitsdienst XVII. 188-191. edition FFAS, Freiburg i. Br, 2004