Laminar Air Flow in the Operating Room to Prevent Hip and Knee Arthroplasty Infections

PICHON RIVIERE, A.; AUGUSTOVSKI, F.; GARCIA MARTI, S.; GLUJOVSKY, D.; ALCARAZ, A.; LOPEZ, A.; BARDACH, A.; CIAPPONI, A; REY-ARES, L.

Documento de Evaluación de Tecnologías Sanitarias

IECS

Año: 2012 p. 1 - 30

1668-2793

Deep infections after a prosthesis replacement surgery are a rare complication, but serious, since they increase mortality, prolong hospital stay and increase costs. Several measures have been evaluated in order to prevent them, some aim at increasing the host´s resistance and others at reducing wound contamination. Among the latter, laminar flow use is proposed in order to reduce the number of present microorganism in the operating room air, thus potentially reducing the number of infections. Although it has been used in some operating rooms where orthopedic surgeries are performed, its use is controversial.TechnologyLaminar air flow consists of an equipment that releases previously-filtered air flow that travels at a uniform speed along parallel streams and with minimum disruption. This flow removes all the macroparticles present in the air, to which microorganisms are attached to. These systems are more efficient to remove small particles of up to 0.3 mm.PurposeTo assess the available evidence on the efficacy, safety and use coverage policy related aspects of operating rooms with laminar air flow for the prevention of infections in patients with hip and knee arthroplasties.MethodsA bibliographic search was carried out on the main databases: DARE, NHS EED, on Internet general search engines, in health technology evaluation agencies and health sponsors. Priority was given to the inclusion of systematic reviews; controlled, randomized clinical trials (RCTs); health technology assessments and economic evaluations; clinical practice guidelines and coverage policies of other health systems.ResultsA systematic review (SR) with meta-analysis (MA), one RCT, four recommendations for infection control, and two health technology assessment were found.The SR with MA published in 2012 included four observational studies which used data from the infection surveillance systems in Germany, United States and New Zealand and one study carried out in a hospital in the United Kingdom. It included a total of 75,064 knee replacements and 121,755 hip replacements in 400 hospitals. In the individual studies none, except for the one conducted in the United Kingdom, showed benefits for the patients operated on in operating rooms with laminar flow. The MA showed an increase in the risk of severe infection associated to laminar flow in patients with knee replacement with a relative risk (RR) of 1.36 (95%CI 1.06-1.74) as well as in patients with hip replacement with a RR of 1.71 (95%CI 1.21-2.41). The limitations of this MA are that the studies included use different definitions for severe infections of the surgical site, the fact that using surveillance data may bring about a potential risk of bias and that the sites included in the study had different severe infection rates of the surgical site.The RCT conducted in the 80s found a decrease in the number of infections in patients operated under laminar flow. However, these results present a high bias risk since the most effective measure to prevent surgical site infections, the use of antibiotic prophylaxis, was not used in 30% of the patients.In 2003, the Center for Disease Control and Prevention (CDC) refrained from giving recommendations on the use of operating rooms with laminar flow for orthopedic surgeries. The regulations set forth by the Ministry of Health in France consider that the efficacy of laminar flow has not been demonstrated and the Infection Control Committee from the Health Department in Hong Kong, considers the ventilation systems with laminar flow are not necessary to decrease the risk of infection, if proper hygiene measure are taken and antibiotic prophylaxis is administered.The technology assessments found consider this type of ventilation does not lead to a lower incidence of infections, which in the context of routine antibiotic prophylaxis, its contributions to prevent them would be only marginal and that could even increase them.ConclusionsThe evidence found is of moderate quality.Laminar flow is not beneficial with respect to reducing surgical site infections and the data grouped from several infection surveillance systems show an increase in the number of infections in the patients who undergo surgery in the operating rooms that use this technology.Implementing ventilation systems with laminar flow in order to reduce surgical site infections in orthopedic surgeries is not supported by scientific evidence which demonstrates a clinical benefit.