This diagram shows the ideal airflow profile for a typical UCV system. Careful design of the airflow distribution and return air grilles on all four AIR FLOW PATTERN
sides enables a controlled airflow pattern to be achieved. Average airflow rate is in accordance with the ACHS guidelines.
An extensive UK MRC-DOH study confirmed the effectiveness of UCV systems in preventing deep sepsis in the joint after total hip or knee replacement. SEPSIS REDUCTION The design of a partial walled Ultra Clean Air system should take into consideration of the entrainment from the room air into the clean zone, air velocity at the operating table and the temperature difference between supply and room air. Wound site air sampling has shown that velocities of around 0.3-0.4 metres/sec. give the best results with downflow systems proving to be between three and eight times more efficient than crossflow systems. DESIGN CONSIDERATIONS
In operating theatres where deep wound surgery takes place, ultra clean air ventilation systems should achieve the following minimum standards: • A maximum of 0.5 bacteria-carrying particles per m3 of air issuing from the final filters, • Less than 10 bacteria-carrying particles per m3 of air within 300mm of the wound, • Less than 20 bacteria-carrying particles per m3 of air in the 2.8m x 2.8m working area at table height (contamination of instruments and material within the sterile field will lead to wound contamination). OPERATING THEATRE MINIMUM VALUES
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