Dynamic Gas Scavenging System Dynamic Gas Scavenging System (DGSS(DGSS®®) – The Next Generation of ) – The Next Generation of

Scavenger InterfaceScavenger Interface

Steve Morris

Anesthetic Gas Reclamation, LLC

Nashville, Tennessee

WhatWhat’’s wrong with active s wrong with active scavenging?scavenging?

• Simple, effective, and low maintenance

–BUT

• Inefficient, costly, and energy-intensive

“Active” interface valve

State of the art for 40 years…

An alternative approach to active scavenging –

the “Dräger box”

No popoff – open design

Typical hospital central evacuation pump

50 ft3min-1 (1500 lpm) continuous flow

24 hours a day…

PROBLEMPROBLEM

• 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

• http://www.beaconmedaes.com/PDFs/library/WAGD.pdf

SOLUTIONSOLUTION

• 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%

Dynamic Gas Scavenging Dynamic Gas Scavenging System - DGSSSystem - 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

Prototype DGSS®

-First tested in Vanderbilt University OR suite in 2007

DGSS historyDGSS history

• Developed to facilitate WAG recovery

• Converts high-flow WAGD to low-flow

• FDA 510(k) done – December 2006

• Now in full production

Current DGSS Current DGSS

WAG inlets and evac outputconfigurable in location and fitting type

Installation requirementsInstallation 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…

DGSS is the first step…DGSS is the first step…

• Low-flow WAGD enables anesthetic reclamation through condensation (cold-trap) technology

• Recapture efficiencies are ~99% in pilot testing

FGF (Sevo 2%)

Scavengerflow (L/min)

Scavenger conc (%)

DGSS flow (L/min)

DGSSconc (%)

2 lpm

Vent on 36 0.1 8.0 0.5

Vent off 36 0.1 2.0 1.9

5 lpm

Vent on 36 0.3 10.8 0.9

Vent off 36 0.3 5.0 1.9

Waste Anesthetic Flows and Concentrations before and after DGSS installation (GE Aestiva)

Anesthesia and Analgesia, in press 2011

ConclusionsConclusions

• 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