The Mölnlycke Health Care blog

Risk assessment of needlestick injuries

By : Andreas Wittmann, July 23 2013Posted in: The Mölnlycke Health Care blog

To avoid danger and to reduce risks, healthcare practitioners must be familiar with the kind of risks involved in needlestick and sharps injuries.

Healthcare workers face a significant risk of serious infections as a result of injuries caused by medical sharps and needlesticks.

Risk of needlestick injuries

The risk of a needlestick injury depends on many factors. Attempts to link certain devices (such as blood collection systems, peripheral venous catheters) with high risk have not been successful in the past. Nevertheless, the risk of sustaining sharps injuries incontestably increases with frequency of use. This is evident from EPINetTM statistics, in which frequently used devices (such as heparin and insulin syringes) are often cited as the reason for an injury.

Risk of infection

Infection risk after a needlestick injury depends on two factors:

  1. The patient must be a carrier of the respective pathogenic agent: it must be present in sufficiently high concentration in his blood or other bodily fluids. The seroprevalence of the harmful agent in the treated patient is critical for the risk to healthcare staff.
  2. The occurrence of an infection depends on the recipient’s immune system and the replicability of the respective pathogen, as well as on the amount of pathogen transferred. For a viral infection, transmission of sufficient fertile pathogens is necessary. Besides the existing viral load in the donor’s blood, the number of pathogenic particles necessary for an infection (infective dose) is also significant. These two factors correlate directly with the amount of blood transferred, which plays a critical role in the seroconversion.

Risk assessment matrix

The science dealing with risk and safety defines risk as the product of probability of occurrence and damage severity. The risk assessment matrix according to Nohl1 is an established tool based on that definition: it shows the probability of an event on the ordinate, and the severity of the injury on the abscissa. The following risk matrix for needlestick injuries is based on this approach.

Risk matrix for needlestick injuries

Risk by amount of blood exposure per device Critical, sufficient for infection e.g. central venous catheter e.g. IV catheter e.g. blood collection e.g. butterfly needles for blood collection
Serious   e.g. IM injection   e.g. scalpel blades
Medium   e.g. port catheters e.g. syringes for subcutanous injections e.g. lancets, heparin syringes
Low e.g. needles for acupuncture     e.g. insulin injection
  Seldom Sometimes Often Frequently
  Frequency of needlestick injuries

 Risk matrix for needlestick injuries, medium seroprevalence for HBV, HCV and HIV in the patient population

The matrix shown is based on the assumption of a representative seroprevalence of the critical agents HBV, HCV and HIV being found in the patient population in German hospitals2, 3, 4.

The area marked in red would be correspondingly larger if the infection risk were to increase due to high seroprevalence levels (e.g. infection ward). The risk matrix shown can help to identify activities and areas with a high, medium and low risk of infection. If action is required, the protection measures should be taken according to the (S)TOP principle, i.e. technical measures such as the use of safety devices have a higher priority than organizational or personnel measures.

1. Nohl, J.: Verfahren zur Sicherheitsanalyse, Wiesbaden: Deutscher Universitäts-Verlag 1989

2. Hofmann F, Michaelis M, Kralj N, Schroebler S: Verlauf der Hepatitis-B-Virus-Seroprävalenz zwischen 1984 und 2001 in zwei großen klinischen Einrichtungen, in: Dokumentationsband über die 44. Jahrestagung der Gesellschaft für Arbeitsmedizin und Umweltmedizin e.V., Rindt-Druck, Fulda 2004: 383 - 385

3. Hofmann F, Michaelis M, Rieger MA. Wilke B: Prävalenz von Hepatitis-Virus-Markern (A, B und C) bei Beschäftigten einer psychiatrischen Einrichtung, in: Dokumentationsband über die 43. Jahrestagung der Gesellschaft für Arbeitsmedizin und Umweltmedizin e.V., Rindt-Druck, Fulda 2003: 619 - 621

4. Schroebler S: Infektionsrisiko durch Nadelstichverletzungen für Beschäftigte im Gesundheitsdienst, in: Dokumentationsband über die 40. Jahrestagung der Gesellschaft für Arbeitsmedizin und Umweltmedizin e.V., Rindt-Druck, Fulda 2000:295-296

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The surgical and wound care environment is always changing. The Mölnlycke Health Care blog addresses topics and trends in surgery and wound care. Among these topics are efficiency, health economy, infection control and patient safety. Read more about this blog and how to comment


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