Clinical Conference:Technology RoundsBiomedical Engineering

Evelyn Fan, M.H.Sc., Clinical Engineer

Biomedical Engineering

November 2, 2005

Plan for todayIntroduction

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

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.

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

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…

‘Fresh Gas Low’ alarm

Bellows vs. Piston

What is Fresh Gas Decoupling?

Water Trap

Inhalation

I

Water trap

Inhalation

Inspiratory valve

Expiratory valve

Pressure sensor

O2 sensor

E

Water trap

Inspiratory valve

Expiratory valve

Pressure sensor

O2 sensor Exhalation

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

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

During expiration, piston moves down to actively fill with fresh gas negative pressure createdWater in ventilator hose creates ‘occlusion’ higher negative pressure detected by pressure transducerInterpreted electronically by machine as ‘Low Fresh Gas’ alarm.

Inspiration

Expiration

You’re on call..OR 18, Fabius GS, Anesthesiologist calls you

Reports a “Low Fresh Gas” alarm

Let’s take a closer look..

•Gas monitor exhaust line is unhooked from circuit

•SAM module is pulling 200mL/min = leak!

And the solution is…

•Gas monitor exhaust line should be attached to expiratory gas sampling port connector

•Or should be attached to scavenging

What is wrong with this picture?

What alarm would you see?

No alarm message even though reservoir bag is off and machine is pulling in room air

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

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)

Conclusion

‘Ask Biomed’ Email: Evelyn Fan (efan1@partners.org) Cc: Dr. Jim Philip (jphilip@zeus.bwh.harvard.edu)

Look out for upcoming article in Anesthesia Record about biomedical engineering…

Questions?

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

Additional Slides

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

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

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