Theatre design and ventilation

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This ppt is about operation theatre air filteration and asepsis in the OT

Published in: Health & Medicine, Technology

Theatre design and ventilation

  1. 1. THEATRE DESIGN AND VENTILATION DR.LOKESH SHAROFF Orthopaedic surgeon, Mumbai, India
  2. 2. CONCEPT • It was first introduced by SIR JOHN CHARNLEY
  3. 3. ZONES IN THEATRE OUTER ZONE – rest of the hospital outside the theatre complex CLEAN ZONE – theatre complex outside the operating area ASEPTIC ZONE – Operating area DISPOSAL ZONE – Separate exit for contaminated / used linen and instruments
  4. 4. REQUIREMENTS AIR DELIVERY SYSTEM AIR FILTERATION SYSTEM TEMPERATURE CONTROL HUMIDITY CONTROL
  5. 5. TEMPERATURE CONTROL - Ideal working temperature is 19-20 * C – to minimize perspiration - But causes pt. hypothermia - PT. body temp. should be 24-26 * C TO AVOID HYPOTHERMIA
  6. 6. HUMIDITY CONTROL - Should be around 40-60% - Fastest death of organisms occur at 50% humidity
  7. 7. AIRBORNE PARTICLES - Measured as BCP/MM3 – Bacteria carrying particles OR CFU/MM3 – Colony forming units - Each person emits 10k cfu/min at rest and 50k cfu/min with activity - This is reduced in SCRUBS to 140-830 cfu/min with fask mask and caps.
  8. 8. AIRBORNE PARTICLES - CONVENTIONAL AC (well maintained)- gives 50- 500 cfu/mm3 - All particles are not viable – viable : non viable ratio is 1:1000 - Smallest particle in theatre seen in bright light is 12 microns - Smallest particle that can carry bacteria is 4-5 microns
  9. 9. AIR FILTERS- 4 LEVELS - ROUGHING FILTERS removes Large particles and also protects sensitive final filters - PREFILTERS should be 95% efficient - FINAL FILTERS should be 95% efficient with a particle size of 3 microns - HEPA FILTERS should be 99.97% efficient with a particle size of 0.3 microns
  10. 10. HEPA FILTERS - Each hepa filter has a manometer attached to it to measure the amount of resistance to filteration for clogging purposes.
  11. 11. TYPES OF VENTILATION High velocity air flow - high speed jets towards operating table - high speed air at periphery Laminar air flow - horizontal - vertical
  12. 12. CONVENTIONAL WALL DIFFUSER
  13. 13. - Produces plenum - No control of air over operating area - Upto 500 bcp/mm3 – not acceptable for operation theatres
  14. 14. HIGH VELOCITY AIR JET
  15. 15. - Jets increase air turbulence - Flow at 0.6 m/s - Jets may not point at right place and may dessicate the wound
  16. 16. Vertical laminar flow - Room within a room principle - Air is passed through hepa filters from ceiling downwards - Flow at 0.3 m/s - entrainment can happen by moving personnel
  17. 17. Horizontal laminar flow - Forms part of a wall - Easy to install - Movement across it will cause uncontrollable turbulence - adequate clean zone is not possible
  18. 18. PERIPHERAL LAMINAR
  19. 19. CONVENTIONAL LAMINAR
  20. 20. Vertical laminar with canopy and side panels - Canopy – to overcome peripheral entrainment - side panels – extend down to floor to within 20cms from floor - very successful – 10 bcp/m3
  21. 21. Without side panels
  22. 22. - Peripheral entrainment air 0.6 m/s - Higher energy consumption - movement causes deflection of contaminants
  23. 23. EXPONENTIAL AIR FLOW
  24. 24. - Trumpet shaped air flow - Downward and radially outward flow of air - fliteration down to 1 micron - Trays can be positioned even upto ½ m outside the actual canopy
  25. 25. STANDARDS IN AIR FLOW - Direction of air flow shall be under positive control - max. viable organisms should be not more than 1 cfu/mm3 - ULTRA CLEAN ZONE – is less than 10 cfu/mm3
  26. 26. AIR CHANGES - ATLEAST 20-40 AIR CHANGES PER HOUR - Pressure gradient should be 1.3-2.5mm h2O (more pressure causes rapid drying of the wound)
  27. 27. AIR QUALITY CONTROL - Done by CASTELLA SLIT SAMPLER
  28. 28. WATER SUPPLY IN OT - Tanks and pipes – regular inspection for leakages - Bore well water should be avoided as far as possible - tanks and containers should have covers/lids to protect from dust - water sterilised by ultraviolet radiation
  29. 29. ANTIBIOTIC PROPHYLAXIS - CHOICE OF AGENT Active against comon pathogens Take into account drug allergy and sensitivity cefazolin/cefotaxim preferred-long duration clinda/vanco in penicillin allergy pts. Modification for pre-existing cultures if already on abx – then continue same
  30. 30. ANTIBIOTIC PROPHYLAXIS - TIMING Within 15-60 mins prior to incision Vanco should be given 2 hrs before - Infusion should complete before incision
  31. 31. ANTIBIOTIC PROPHYLAXIS - DURATION Further dose efficacy is doubtful Max 24 hrs if only prophylatic intra-op – repeat if length of sx more than half life of drug repeat dose if blood loss >1500ml not to continue abx till drain removal
  32. 32. ANTIBIOTIC PROPHYLAXIS - RISKS - PENICILLIN ALLERGY - ANAPHYLAXIS - ABX ASSOCIATED DIARRHOEA - CLOSTRIDIUM DIFFICLE INFECTION - ABX RESISTANCE - MULTI-RESISTANCE CARRIAGE – SCREENING SHOULD BE DONE IN HIGH RISK CASES
  33. 33. THANK YOU *Pictures taken from journal of orthopedics today

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