Thinking outside the box: First experiences from the research OR in Weiden with a new surgical ventilation system

Transcription

1 Thinking outside the box: First experiences from the research OR in Weiden with a new surgical ventilation system Prof. Dr. Clemens Bulitta, Chair Institute of Medical Engineering Technical University of Applied Sciences Amberg-Weiden, Germany

2 Agenda Research Environment Problem and Current Situation System Concept and Function Material and Methods Results Conclusions

3 Agenda Research Environment Problem and Current Situation System Concept and Function Material and Methods Results Conclusions

4 Research and Teaching OR Concept: Fully equipped and fully functioning OR allows for testing, developing, demonstrating and training of available technologies (OR, medical and other Equipment, Building Services, etc.) and their integration. The OR as a system can be evaluated in different settings and workflow scenarios allowing for dedicated solutions development, workflow trainings, simulation and process improvement Areas of Research and Teaching: Workflow, Usability and User Centered Design, Training Hygiene, HVAC with innovative solutions and concepts Technology Development and Systems Integration Hospital Planning, Automation and Building Services Videomanagement RFID-Deployment.

5 Implementation

6 Agenda Research Environment Problem and Current Situation System Concept and Function Material and Methods Results Conclusion

7 What is causing deep SSI? The patient undergoing a surgical procedure always taking the risk of become infected by a pathogen causing a deep surgical site infection. The infection could be endogenous or caused by the staff, exogenous, or via nosocomial transmission. The route of the nosocomial transmission could be via the surgical (sterile) instruments and/ or via the ambient air in the OR. Most of the pathogens are released from the staff as airborne skin flakes carrying bacteria's (CFU, Colony Forming Units). Common threshold levels are <100cfu/m 3 or <10cfu/m 3 for general or infectious sensitive surgery respectively.

8 some facts Endogenous Factors: Patient-Flora (skin, GI-tract, existing wounds, ) microbiological colonization within surgical field microbiological colonization outside surgical field Exogenous Factors: OR-staff (surgeon and team): contaminated clothing interference with asepsis wrong hand hygiene Particle and cfu shedding (skinflakes/dander): ca. 5000/min walking (5 to 60 μm) ca /min exercising ca. 5 germs per skin flake/dander Environment and ventilation in the OR Contaminated surfaces, instruments, devices, material,

9 Background: Impact of SSI Anderson DJ, etal. Strategies to prevent surgical site infections in acute care hospitals. Infect Control Hosp Epidemiol 2008;29:S51-S61 for individual references Burden-US ~300,000 SSIs/yr (17% of all HAI; second to UTI) 2%-5% of patients undergoing inpatient surgery Mortality 3 % mortality 2-11 times higher risk of death 75% of deaths among patients with SSI are directly attributable to SSI Morbidity long-term disabilities Length of Hospital Stay ~7-10 additional postoperative hospital days Cost $3000-$29,000/SSI depending on procedure & pathogen Up to $10 billion annually Most estimates are based on inpatient costs at time of index operation and do not account for the additional costs of rehospitalization, post-discharge outpatient expenses

10 Controversial Debate Conclusion: The available evidence shows no benefit for laminar airflow compared with conventional turbulent ventilation of the operating room in reducing the risk of S Sis in total hip and knee arthroplasties, and abdominal surgery. Decision makers, medical and administrative, should not regard laminar airflow as a preventive measure to reduce the risk of SSis. Consequently, this equipment should not be installed in new operating rooms. Lancet Infectious Diseases: Published online February 16,

11 Evidence for CFU and SSI correlation Between 1959 until 1974 Sir John Charnley was able to reduce the SSI after hip prosthesis surgery from 8,5% to 0,7% by reducing the cfu from 600cfu/m 3 down to <1cfu/m 3 (!). This by doing the surgerical procedure in his greenhouse or Charnleybox with ventilated body exhaust suites. He showed a correlation between cfu levels and SSI rate.

12 Evidence for CFU and SSI correlation In a prospective controlled multicenter study with >8 000 patients the results were later confirmed by Lidwell et al in Antibiotic prophylaxis and air cleanliness reduced the SSI independently. In the study ultraclean air was defined as <10cfu/m3 To repeat the studies today with antibiotic prophylaxis as standard treatment will (yet) be difficult or, not to say, impossible due to the low rate of SSI we have today. Comparison of the total germ immission with regard to increasing incision to closure time. Quelle: American Journal of Infection Control xxx (2012) e1-e5, Hirsch et. al Lidwell OM. Sir John Charnley, Surgeon ( ): the control of infection after total joint replacement. J Hosp Inf 1993;23:5-15

13 Different approach in different standards Lack of an EU standard leaves it open for different test methods for different countries: NF S ;2013 SIS-TS 39;2015 DIN ;2008 (currently under revision) HTM 03-01;2007 VCCN RL7; 2014 (only in Dutch) Two major differences between the tests: Measuring protection (degree) from artificial generated particles from the outside into the clean zone (at rest) or measuring the levels of CFU generated by staff inside the clean zone (during surgery) Measurements at rest or in operation state during surgery with a knife time of >45 minutes to reach steady state conditions What will be closest to the real life situation?

14 Agenda Research Environment Problem and Current Situation System Concept and Function Material and Methods Results Conclusions

15 What is the basic thinking and rationale behind Opragon Most surgical procedures have a similar set-up". The patient on the operating table, 3-5 sterile dressed staff around the patient, 1-2 anesthesia staff at the patient's head end and 1-2 other staff elsewhere in the operating room. The majority of the generated cfu s are released very close to the wound and the sterile instruments and must be transported away from there The effect of the convection currents from staff is often neglected.

16 EXTERNAL AIRSHOWER OPRAGON BODY CONVECTION CFU GENERATING STAFF

17 What is needed to break the body convection currents?

18 But Gravity is superior By utilizing air that is 1-1,5 degree below the room temperature at the height of the OR table, combined with special designed extreme low impulse airshowers, the system can create a very powerful and reliable down flow over the OR-table, sterile dressed staff and instrument tables. Temperature or gravity controlled airflow is less sensitive to heat loads and/ or obstacles in the OR area.

19 Thinking outside of the Plenum. OPRAGON EXTERNAL AIRSHOWER

20 And the result is. ULTRACLEAN AIR IN THE WHOLE ROOM

21 How to get low levels of CFU in an operating room? Reduce the "emissions" at the source through dense clothing and/ or the number of staff in the OR. Concentrations of cfu can be reduced through effective ventilation, there are two main principles: Turbulent mixing, diluting principle (Class 1b) Parallel flow, away transporting effect, sweeping action (Class 1a) TAF (Temperature Controlled Air Flow) is a combination of these two principles (Class?) with a high ventilation efficiency as a result, which leads to low cfu levels in the WHOLE operating room.

22 System setups

23 Agenda Research Environment Problem and Current Situation System Concept and Function Material and Methods Results Conclusions

24 Material and Methods: CFD Simulation CAD-Model Research OR OTH

25 CFD Postprocessing Top: Velocity (y-side view: center) Bottom: Protection degree (y-side view: center)

26 CFD Postprocessing Top: Particle load (y-side view: center) Bottom: Coldair-Distribution

27 Validation of CFD-Simulation with smoke

28 Measurements DIN (2008)

29 Measurements SIS-TS 39 (2015) Active Airsampling and Microbiological Assessment

30 Measurements SIS-TS 39 (2015) Active Airsampling and Microbiological Assessment

31 Agenda Research Environment Problem and Current Situation System Concept and Function Material and Methods Results Conclusions

32 CFD Simulation Source: Malin Alsved, Lund University Ulmer Hygienekongress 3/2017

33 Protected area Opragon 22

34 Protected area Opragon 8

35 Protection Degree According to DIN 1946/4

36 Active Airsampling

37 Comparison CFU/m 3 : No Vent TAF TAV TML No Vent CFU/m 3 (cumulated data)

38 Active Airsampling during Surgery Source: Malin Alsved, Lund University Ulmer Hygienekongress 3/2017

39 Survey environmental conditions Source: Malin Alsved, Lund University Ulmer Hygienekongress 3/2017

40 Summary of Results TAF System in compliance with protection degree requirements according to DIN (2008) for class 1a TAF System in compliance with CFU measurements according to SIS-TS 39 (2015) for infection sensitive clean surgery TAF System in Compliance with ISO Class 5 according to ISO (2014) TAF System in Compliance with GMP Class B according to EU-GMP 2008 TAF System controls cfu burden in the entire room TAF system provides comfortable working environment

41 Agenda Research Environment Problem and Current Situation System Concept and Function Material and Methods Results Conclusions

42 Conclusions TAF Sytem fulfills important international hygienic standards for ventilation systems TAF System combines advantages of mixing and unidirectional ventilation systems TAF System significantly reduces microbial and particle burden in Operating Theatres in the ENTIRE room Staff comfort subjectively higher, assessment according to DIN EN ISO 7730 necessary Energy savings based on reduced air volume can be achieved. Further detailed studies are required TAF is a viable and hygienically effective alternative to Laminar Airflow and other ventilation systems

43 Acknowledgements: Avidicare for supporting the research Questions???