1. Steve Morris Anesthetic Gas Reclamation, LLC Nashville, Tennessee
Dynamic Gas Scavenging System (DGSS®) – The Next Generation of Scavenger Interface
Steve Morris
Anesthetic Gas Reclamation, LLC
Nashville, Tennessee

2. What’s wrong with active scavenging?
Simple, effective, and low maintenance
BUT
Inefficient, costly, and energy-intensive

3. “Active” interface valve
State of the art
for 40 years…

4. An alternative approach
to active scavenging –
the “Dräger box”
No popoff – open design

5. Typical hospital central evacuation pump
50 ft3min-1 (1500 lpm) continuous flow
24 hours a day…

6. PROBLEM
Continuous flow of 50 l/min for each OR requires a large vacuum producer
Capital cost
Ongoing energy requirement
Maintenance/replacement
Risk of overload/fire with older installations

7. SOLUTION Rework scavenging system to be efficient!
Reduce room air entrainment to zero
Reduce equipment and energy costs
Potentially reduce vacuum pump size by 40-60%

8. Dynamic Gas Scavenging System - DGSS®
New scavenging interface for anesthesia machines – first innovation in 30 years
Conserves vacuum from hospital system
Enables collection of undiluted waste anesthetic gas
Replaces current scavenging interface

9. Prototype DGSS®
First tested in Vanderbilt
University OR suite in 2007

10. DGSS history Developed to facilitate WAG recovery
Converts high-flow WAGD to low-flow
FDA 510(k) done – December 2006
Now in full production

11. Current DGSS WAG inlets and evac output configurable in location
and fitting type

12. Installation requirements
12VDC power (500 mA) via external adapter
Specific machine mount
19 or 30mm WAG exhaust (single or dual)
Although approved as external device, the DGSS technology will, in future, be incorporated into existing machine design…

13. DGSS is the first step…
Low-flow WAGD enables anesthetic reclamation through condensation (cold-trap) technology
Recapture efficiencies are ~99% in pilot testing

15. Waste Anesthetic Flows and Concentrations
before and after DGSS installation (GE Aestiva)
FGF (Sevo 2%)
Scavenger
flow (L/min)
Scavenger conc (%)
DGSS flow (L/min)
DGSS
conc (%)
2 lpm
Vent on 36
0.1
8.0
0.5
Vent off
2.0
1.9
5 lpm
0.3
10.8
0.9
5.0
Anesthesia and Analgesia, in press 2011

16. Conclusions
Waste anesthetic gas flows may be dramatically reduced with a modified interface valve
Scavenging ventilator drive gas reduces the efficiency of the system
This modified interface is a necessary first step toward efficient recovery of volatile anesthetics with cryogenic condensation