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Surgical site infection, ultraclean ventilated operating theatres and prosthetic joint surgery: where now?

      Recent years have seen a number of reviews and guidelines on the prevention of surgical site infection (SSI) which focus on pre-, peri- and postoperative factors.
      • Humphreys H.
      Preventing surgical site infection. Where now?.
      National Collaborating Centre for Women's and Children's Health
      Surgical site infection. Prevention and treatment of surgical site infection.
      • Anderson D.J.
      • Kaye K.S.
      • Classen D.
      • et al.
      Strategies to prevent surgical site infections in acute care hospitals.
      However, these guidelines make very little reference to the physical circumstances or conditions under which the surgery takes place. Tradition and practice has been for most general surgical procedures to take place in a plenum ventilated operating theatre with about 20 air changes per hour and for much of prosthetic joint surgery to take place under laminar flow conditions with ultraclean ventilation.
      Over the decades there has been much discussion on the potential role of the environment in the operating theatre and on the justification for physically separating where the actual operation takes place from other areas of the operating theatre suite, e.g. reception, in terms of air pressures. However, the scientific basis for these arrangements and justification for sophisticated ventilation systems is not comprehensive. Whereas air flows have a potential role in minimizing bacterial air counts in the vicinity of the actual surgery, the inanimate environment including floors, walls and furnishing is of little relevance.
      • Ayliffe G.A.J.
      Role of the environment of the operating suite in surgical wound infection.
      One of the most significant studies on the impact of operating theatre ventilation on SSI was a multicentre randomized trial assessing the impact of ultraclean air in operating rooms on deep sepsis after total hip or knee replacement, published in the early 1980s.
      • Lidwell O.M.
      • Lowbury E.J.L.
      • Whyte W.
      • Blowers R.
      • Stanley S.J.
      • Lowe D.
      Effect of ultraclean air in operating rooms on deep sepsis in the joint after total hip or knee replacement: a randomised study.
      However, this study also involved other interventions, namely the use of body-exhaust ventilated suits and prophylactic antibiotics.
      • Lidwell O.M.
      • Lowbury E.J.L.
      • Whyte W.
      • Blowers R.
      • Stanley S.J.
      • Lowe D.
      Effect of ultraclean air in operating rooms on deep sepsis in the joint after total hip or knee replacement: a randomised study.
      Subsequently, the provision of ultraclean laminar flow facilities has been considered the standard by many for prosthetic joint surgery. For example, in a survey of 295 hospitals in the USA, ultraclean ventilated facilities were used for >75% of total knee replacements, especially in centres where larger volumes of surgery were carried out.
      • Miner A.I.
      • Losina E.
      • Katz J.N.
      • Fossel A.H.
      • Platt R.
      Infection control practices to reduce airborne bacteria during total knee replacement: a hospital survey in four states.
      A case could be made for equivalent ventilation for other procedures involving a prosthesis, e.g. the insertion of cerebrospinal fluid shunt or artificial heart valve, given the serious consequences of infection in such patients which include ventriculitis and endocarditis.
      Recent studies have cast some doubt on the efficacy of ultraclean ventilated facilities in reducing SSI in orthopaedic surgery. The ten-year results of the New Zealand Joint Registry indicate that while ultraclean ventilated theatres were used for 44% of all total hip and 38% of all total knee replacements, respectively, there was a significant increase in the requirement for early revision for deep infection in those procedures performed with the use of a space suit and/or operations performed in ultraclean ventilated theatres compared with conventional theatres.
      • Hooper G.J.
      • Rothwell A.G.
      • Frampton C.
      • Wyatt M.C.
      Does the use of laminar flow and space suits reduce early deep infection after total hip and knee replacement?.
      In this issue, P. Gastmeier and colleagues in Germany report on a systematic review of cohort studies of severe SSI following hip and knee prosthetic surgery. No individual study showed a significant benefit for ultraclean ventilated and three studies recorded higher SSI rates following hip prosthesis when the procedure was carried out in ultraclean ventilated theatres.
      • Gastmeier P.
      • Breier A.-C.
      • Brandt C.
      Influence of laminar airflow on prosthetic joint infections: a systematic review.
      It is unclear why the provision of such facilities may have resulted in increased SSI rates but this could relate to other issues such as surgical practice and not be a direct consequence of the ventilation. The use of ultraclean air with laminar air flow does not obviate the need for appropriate professional practice and compliance with other measures believed to be important in preventing SSI. Many of these have been reviewed and, although found not to be backed by much if any scientific evidence, common sense and the importance of highlighting good practice in the operating theatre would seem to justify many of them, e.g. the wearing of face masks by the scrub-team for prosthetic implant operations.
      • Woodhead K.
      • Taylor E.W.
      • Bannister G.
      • Chesworth T.
      • Hoffman P.
      • Humphreys H.
      Working Party Report. Behaviours and rituals in the operating theatre.
      Furthermore, it is important to ensure that instruments in the ultraclean ventilated theatre are not left uncovered outside the ultraclean area as this may increase contamination and may contribute to postoperative infection.
      • Chosky S.A.
      • Modha D.
      • Taylor G.J.S.
      Optimisation of ultraclean air. The role of instrument preparation.
      Finally, surgeons themselves have noticed a deterioration in theatre discipline, e.g. failure to cover the nose with a mask, or allowing the unnecessary entry and exit of personnel through the main door of the operating theatre, and these practices may negate the benefit of either plenum or ultraclean ventilation.
      • Madhavan P.
      • Blom A.
      • Karagkevrakis B.
      • Pradeep M.
      • Huma H.
      • Newman J.H.
      Deterioration of theatre discipline during total joint replacement – have theatre protocols been abandoned?.
      • Mackain-Bremner A.A.
      • Owens K.
      • Wylde V.
      • Bannister G.C.
      • Blom A.W.
      Adherence to recommendations designed to decrease intra-operative wound contamination.
      Considering the expense involved in their construction and maintenance, the finding that ultraclean ventilated theatres may not protect but may indeed increase the rate of SSI is of concern. The reasons for this may relate to air eddies over the operative field due to increased numbers of staff underneath the laminar air flow hood and/or an apparent false sense of security leading to lapses in operating theatre practice. While it is unlikely that randomized controlled trials, along the lines of those carried out in the late 1970s and 1980s, could be repeated, there is an opportunity for national surveillance registries, which collect data on patients prospectively, also to record the conditions under which they are operated on and to record compliance with infection prevention and control measures in the operating theatre.
      • Lidwell O.M.
      • Lowbury E.J.L.
      • Whyte W.
      • Blowers R.
      • Stanley S.J.
      • Lowe D.
      Effect of ultraclean air in operating rooms on deep sepsis in the joint after total hip or knee replacement: a randomised study.
      Although the risk of SSI following prosthetic joint surgery is also related to intrinsic risk factors, e.g. underlying disease such as diabetes mellitus in the patient, and the technique and experience of the surgeon, it may nonetheless be time to review the need for prosthetic joint surgery to be undertaken in ultraclean ventilated conditions both to safeguard patients from any possible increased SSI rate and also to use healthcare resources efficiently and responsibly.

      References

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        Preventing surgical site infection. Where now?.
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        • Kaye K.S.
        • Classen D.
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        Strategies to prevent surgical site infections in acute care hospitals.
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        Role of the environment of the operating suite in surgical wound infection.
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        • Whyte W.
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        • Losina E.
        • Katz J.N.
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