The scientific literature on the relationship between airborne bacteria and wound contamination during different conditions is scares. A study from 1982 (Whyet et al.), demonstrated that the most important and consistent source of contamination of the wound during clean surgery (in this case hip implant surgery) was via air. The study concluded that approximately one third of bacteria in the wound were caused by direct air contamination whereas the remaining number of bacteria were transferred to the wound by indirect routes such as via contaminated instruments.~The present study includes patients undergoing hemiarthroplastic surgery due to hip fracture.~During the surgery active air sampling, for microbial analysis, will be done within 30 cm from the wound.~Passive sampling of instrument tables, to measure number of depositing bacteria on the surface during the procedure, will be performed by placing sterile filters on the table surfaces before initiating the surgical procedure and collecting them at the end.~Skin and wound sampling will be performed with sterile flocked nylon swabs. The method for skin and wound sampling was decided based on a literature review and discussions with the department of Clinical microbiology at Sahlgrenska University hospital. Both aerobe and anaerobe bacteria will be analyzed.~The wound will be measured and number of personnel, door openings and clothing, at each procedure will be recorded.~Patients included in the study will be interviewed after 6 weeks and 1 year, to evaluate incidence rate of SSI.
In the present study we will compare bacteriological findings and the incidence of SSI in relation to laminar airflow (LAF) ventilated ORs, conventional (also called displacement or mixed) ventilated ORs and conventional ventilated ORs with the addition of tables equipped with units providing a local LAF over the surgical instruments.~The hypothesis is that there exist a correlation between number and types of airborne bacteria and bacteria in the surgical wound and on surgical instruments at the time of wound closure.