1. Clinical Conference: Technology Rounds Biomedical Engineering Evelyn Fan, M.H.Sc., Clinical Engineer Biomedical Engineering November 2, 2005

2. Plan for today Introduction Biomedical Engineering OR Team Fabius GS: “Low Fresh Gas” alarm Fresh gas decoupling You’re on call… What’s wrong with this picture? Summary Conclusion

3. Who are we? BWH Biomedical Engineering Department 27 people 3 teams (OR, ICU, Ambulatory) support the medical equipment used in the entire hospital and outside clinics Responsible for managing and supporting 15,735 medical devices OR team specifically manages all operating room equipment, including CPD, and Anesthesia for outside areas such as Endoscopy, MRT/ MRI, Angio/ Cath lab, etc. 3114 medical devices managed by the OR team 2088 of which have a risk class of ‘Life-Support/ High-Risk/ Normal’, meaning they require scheduled maintenance at least 1x/ yr. 63 anesthesia machines, which require scheduled maintenance 2x/ year.

4. OR Biomed Team Ernst Daniel, Clinical Engineer Evelyn Fan, Clinical Engineer Dr. Jim Philip, Medical Liaison Eddie Holmes, Facilities Technician Claire Cabral, Sr. BMET Garth Meikle, Sr. BMET Ross Jacques, BMET

5. What does biomed do? Vision: It is our goal that no patient is harmed by the application of a medical device within our sphere of influence. Goal: To be a ‘Solutions Department’, providing technology solutions to advance the care and safety of patients and staff. Repairs & Scheduled Maintenance (SM) of clinically used equipment, projects/ installations, on-call/ night-call coverage, incident investigations, capital equipment purchases, etc. Work with many departments including: OR/CSS, anesthesia techs, CPD, Anesthesia, Nursing, Infection control, Perfusion, Environmental Affairs, Risk Management, etc. More details to come in future article for the Anesthesia Record…

6. ‘Fresh Gas Low’ alarm

7. Bellows vs. Piston

8. What is Fresh Gas Decoupling? Water Trap

9. Inhalation I Water trap Inhalation Inspiratory valve Expiratory valve Pressure sensor O2 sensor

10. E Water trap Inspiratory valve Expiratory valve Pressure sensor O2 sensor Exhalation

11. What does the water trap have to do with the ‘Fresh Gas Low’ alarm?

12. During expiration, piston moves down to actively fill with fresh gas  negative pressure created Water in ventilator hose creates ‘occlusion’  higher negative pressure detected by pressure transducer Interpreted electronically by machine as ‘Low Fresh Gas’ alarm. Inspiration Expiration

13. You’re on call.. OR 18, Fabius GS, Anesthesiologist calls you Reports a “Low Fresh Gas” alarm

14. Let’s take a closer look.. Gas monitor exhaust line is unhooked from circuit SAM module is pulling 200mL/min = leak!

15. And the solution is… Gas monitor exhaust line should be attached to expiratory gas sampling port connector Or should be attached to scavenging

16. What is wrong with this picture?

17. What alarm would you see? No alarm message even though reservoir bag is off and machine is pulling in room air

18. Fresh gas decoupling Room air entrainment Piston is electronically driven by the motor No ADS alarms E With no bag present, piston draws in room air

19. Summary Fresh gas decoupling: Good: Motor-driven piston results in minimal tidal volume changes with FGF changes Bad: If bag is empty (ie. low flow) ADS may alarm; if bag is missing can lead to room air entrainment  dilution of [agent] Since the reservoir bag is a part of your circuit, make sure your reservoir bag is attached to the bag arm at all times! What to do when you see a ‘Low Fresh Gas’ alarm Check the water trap Check for a deflated reservoir bag (which may indicated the presence of a leak!) Check the breathing circuit Call biomed (pager # 11055)

20. Conclusion ‘Ask Biomed’ Email: Evelyn Fan (efan1@partners.org)efan1@partners.org Cc: Dr. Jim Philip (jphilip@zeus.bwh.harvard.edu)jphilip@zeus.bwh.harvard.edu Look out for upcoming article in Anesthesia Record about biomedical engineering… Questions?

21. Acknowledgements Special thanks to: Dr. J. Philip, Medical Liaison Garth Meikle, Sr BMET & Ross Jacques, BMET OR Biomedical Engineering team Drager Medical Technical Support

22. Additional Slides

23. What happens to O2% when reservoir bag is removed from circuit?