Anesthesia Machine Intro

Anesthesia Machine Intro

New Residents July 5, 2007

© Copyright 2000-2007, James H Philip, all rights reserved

ADS1 Ready JHP

Anesthesia Machine Intro

James H. Philip, MEE, MD, CCEAnesthesiologist, Director of (Anesthesia) Bioengineering, Brigham and Women’s Hospital

Medical Liaison, Department of Biomedical Engineering, Partners HealthCare SystemAssociate Professor of Anaesthesia, Harvard Medical School

Patient Anesthetist

ORHospitalWorld

Work-station

observe(senses)

touch

Care Info(lab data, image..)

touchobserve(eyesears)

ADS, monitors,?computer

Inhalant Drugs IV Drugs, Fluids Other

Monitoring

requests

ClincalCare

Interactions

Patient Anesthetist

ORHospitalWorld

Work-station

observe(senses)

touch

Care Info(lab data, image..)

touchobserve(eyesears)

ADS, monitors,?computer

Inhalant Drugs IV Drugs, Fluids Other

Monitoring

requests

ClincalCare

Interactions

Anesthesia Delivery System

Workstation-Patient Interactions

Life Support with oxygen & breathingInhalant Drug (Gas & Vapor) DeliveryIntravenous Drug DeliveryIntravenous Liquid DeliveryMonitoringRecording

Life Support (Oxygen)Inhalant Delivery

OtherIntravenous Drug DeliveryFluid DeliveryMonitoringRecording

Anesthesia Machine

Anesthesia Machine Evolution

1846 Morton Ether Inhaler

Inhaler had limitations

1850 improvement

This 1850 version worked horizontal

with no hands required

Open Circuit Inhaler

Open Circuit = Non-rebreathingPatient breathes in the ether vapor, breathes ether out (and it is discarded)Breathes in new ether vaporBreathes it out again (discarded)

Manual Resuscitator

Open Circuit = non-rebreathing Circuit = what you set is what you get

Give sufficient oxygen to the reservoir bag (not to empty)

Reservoir bag gives 100% oxygen to the breathing bag

The Tidal Volume is determined by the close of your hand and a perfect seal.

Manual Resuscitators

Bag Reservoir Hose Reservoir

Needs a bag reservoirso you can see it provide 100% oxygen to the breathing bag by never emptying

Bag Reservoir

Partial Rebreathing Circuits used in Anesthesia

Don’t throw all the exhaled vapor awayReuse as much as possibleSomehow (learn when you are ready) Remove (Absorb) CO2 and Rebreathe the Anesthetic

Partial rebreathing = semi-closed circuitAll USA ADSs use them

1890 added a

Breathing Circuit

1950added a work

surface

Then, Drawers,

Temperature-compensated

vaporizers,Circuit,

Absorber, Common

gasoutlet

1990 Integrated

Monitorsand

DataRecording

Datex-Ohmeda

Central Display

(CD)ADS

2000

Better ventilation for difficult patientsFGF-independent ventilationCorrects for circuit leaks

More sensitive to water vaporMonitors no longer integrated

GE Aestiva

Draeger Fabius

Gas & Flow Monitor integratedCV Monitor not integrated

GE - Aisys

Basics of the Anesthesia Delivery System

Anesthesia Delivery System - ADS

Anesthesia MachineBreathing CircuitWorkspaceControl

Anesthesia Machine delivers gases and vaporsinto a breathing circuit 2001

Provides continuous flow of -Oxygen for LifeAir to safely lower FIO2

Nitrous Oxide for partial anesthesiaAgent vapor for complete or partial anesthesia

N O2 O2Air

(Continuous Flow) Anesthesia Machine

Vaporizer

1 2 3..

5

21

34

6789

21

34

6789

55

21

34

6789

mL/mL/mL/mL/m

300

200100

400

50

600900

000

IsofluraneSevofluraneDesflurane FGF

(FreshGasFlow)

CommonOutlet

Flow Tubes

Sevo Iso Des

Direct-reading temperature-compensated

Vaporizers

Agent-specificFiller Port

Dial ReleaseAttachment

LeverDial

Direct Reading

Vaporizer

ExclusionInterlock

Dial Setting

2

3

4

5

1

2 4

1

2

3

4

5

6

06 8 10

Flow rate (L/min O2)

% is

oflu

rane

0

Performance curve, Tec 4(Isotec 5%)

Anesthesia Machine

Anesthesia Machine

Schematic

O2

2000psi

O2 SERVICE

INLET55psi

35 psi

35 psi

50 or 250ml/min

NEEDLEVALVE

FAILSAFEVALVE

CALIBRATEDVAPORIZERS

Fresh Gas Flow (FGF)

OXYGEN FLUSHVALVE[first]

ON/OFFSWITCH

CHECKVALVE PRESSURE

REGULATOR

N2OSERVICE

INLET 55 psi

O2

N2O

FRESHGAS HOSE

Flush Flow(last)

[Anesthetizinggases flow]

COMMON OUTLET

N2O

750psi

N2O

750psi

O2

2000psi

FILTER

WALL

DISSdiameter

indexsafetysystem

CONNEC-TION

O2

N2O

D S I

SIMPLIFIED ANESTHESIA MACHINE SCHEMATIC DIAGRAM

Patient Breathing Circuit

Allows cyclic flowTo and from the patient

(AKA Breathing)

Circle absorption anesthetic breathing circuit

flipped

The Circle-Absorber System

Sampled

ExhaustExpired

CO2

Ab-sorb-ant

200 mL/min

InspiredFresh

Gas Flows

Rebreathed

The Circle-Absorber System

Sampled

ExhaustExpired

CO2

Ab-sorb-ant

200 mL/min

InspiredFresh

Gas Flows

Rebreathed

The Circle-Absorber System

Sampled

ExhaustExpired

CO2

Ab-sorb-ant

200 mL/min

InspiredFresh

Gas Flows

Rebreathed

The Circle-Absorber System

Sampled

ExhaustExpired

CO2

Ab-sorb-ant

200 mL/min

InspiredFresh

Gas Flows

Rebreathed

To Patient

The Circle-Absorber System

Sampled

ExhaustExpired

CO2

Ab-sorb-ant

200 mL/min

InspiredFresh

Gas Flows

Rebreathed

From Patient

The Circle-Absorber System

Sampled

Exhaust (APL)Expired

CO2

Ab-sorb-ant

200 mL/min

InspiredFresh

Gas Flows

Rebreathed

The Circle-Absorber System

Sampled

Exhaust (APL)Expired

CO2

Ab-sorb-ant

200 mL/min

InspiredFresh

Gas Flows

RebreathedGases (O2, N2O, Agent)

The Circle-Absorber System

Sampled

ExhaustExpired

CO2

Ab-sorb-ant

200 mL/min

InspiredFresh

Gas Flows

RebreathedGases

No CO2 rebreathed

The Circle-Absorber System

Sampled

ExhaustExpired

CO2

Ab-sorb-ant

200 mL/min

InspiredFresh

Gas Flows

RebreathedGases

No CO2

No

The Circle-Absorber System

Sampled

ExhaustExpired

CO2

Ab-sorb-ant

200 mL/min

InspiredFresh

Gas Flows

RebreathedGasesNo CO2

The Circle-Absorber System

Sampled

ExhaustExpired

CO2

Ab-sorb-ant

200 mL/min

InspiredFFGF , CDEL

FE FI

FE , CE

FI , CI

Gas Flows,Concentrations

~=

F = Flow C = Concentration

The Circle-Absorber System

Sampled

ExhaustExpired

CO2

Ab-sorb-ant

200 mL/min

InspiredFFGF , CDEL

FE , CE

FI , CI

FE FI~=

CI~=

FFGF x CDEL

+FFGF x CDEL FE x CE

Inspired Concentration =Flow-weighted average ofFresh Gas and Expired GasConcentrations

Low FGF

More rebreathingInspired more dependent on ExpiredInspired less dependent on Vaporizer

View the Breathing CircuitThe Circle-Absorber System

Absorber opened - w gas channels shown

Absorber opened - w gas channels shown

Exp

Insp

Absorber Assembly Top CoverOhmeda GMS 1985-2000-present

The Anesthesia Workspace

BWH Anesthesia Workspace

Don’t clutter ADS with Airway EquipmentMy view

MRSMAIDWorkspace Setup

MachineRoomSuctionMonitorsAirwayI V Drugs

MRSMAIDWorkspace Setup

MachineRoomSuctionMonitorsAirwayI V Drugs

MRSMAIDMachineRoomSuctionMonitorsAirwayI V Drugs

Workspace Setup

Suction off if:DISS hose unscrewedWall switch offHose disconnect from CanisterCanister switch off Insert seated incorrectlyAny hole openFlap valve closed

because unit was shakenor canister is full

Flexible hose kinkedFlexible hose stepped on

Workshop this afternoon

Evelyn Fan, OR Clinical EngineerErnst Daniel, OR Clinical EngineerBMETs (Biomedical Equipment Technicians)

BWH Biomedical Engineering OR Team

Ernst Daniel CE

Evelyn Fan CE

James Philip MD

Clair Cabral

Jeremy Essex

Ed Holmes

Rossiny Jacques

M Anthony Johnson

C Trevor Roberts

Frantz Teleau

WorkshopADS Safety Check

Day Check Case Check

Anesthesia MonitorsZero/CalibrateAttaching trodesControlling monitor measurementsObserving results

Numerals nowNumeric TrendDigital Trend

These are in your Goals for Week 1, Week 2, Life !

BWH July 2007 Abbreviated Pre-Use Check

Perform Machine-Assisted TestsGE Modulus 2 Plus - noneGE Aestiva - Minor

12 Hour switch off and onCircuit Oxygen Sensor Cal via SmartVent

GE Aisys - MajorMost circuit tests are automatedBellows volume & pressure can feel the circuitand make great ventilation modes

Draeger Fabius - MajorMost circuit tests are automatedVentilator Piston can feel the circuitand make great ventilation modes

Calibrate Oxygen Monitor

Oxygen Monitor ON & sensor in air with hole plugged. Calibrate to 21%. Reconnect sensor in circuit

Check Machine for Gas Delivery

Machine OnOxygen flows smoothlyDisconnect oxygen hoseOxygen alarm soundsSwitch ON oxygen tank. Verify P > 1000 psi and Alarm

silences.Tank off with wrenchTurn oxygen flow upAlarm sounds oxygen failureConnect oxygen hose to silence alarm.Turn up nitrous and observe alarm and/or control.Negative Pressure Test - later

Check Breathing Circuit for Integrity

Attach circuit including reservoir bagOcclude “Y” with thumbFlush and fill bag to 30 cmH2O.Test pressure alarms

NAD - Continuing pressure alarm, high pressure alarmOhmeda - High pressure relief

Open relief valve and verify that reservoir bag emptiesObserve scavenger bag fill and empty

Check Function - Ventilator, Suction

CHECK VENTILATOR FOR FUNCTIONVentilate reservoir bag and observe no volume loss.

CHECK SCAVENGER FOR FUNCTIONCheck that reservoir bag fills and empties. Check valves

not stuck.

Thank you

James H. Philip, MEE, MD, CCE

Office Neville House NH 2-24E617 732-7330 Page 11615jphilip@partners.org

http://local.bwh.harvard.edu/intranet

End