Anesthesia Machine Introduction
Brigham and Women’s Hospital New Residents July 19, 2011
© Copyright 2000-2011, James H Philip, all rights reserved
Anesthesia Machine Introduction
James H. Philip, MEE, MD, CCE Anesthesiologist, Director of Bioengineering
Brigham and Women’s Hospital Associate Professor of Anaesthesia
Harvard Medical School
Patient Anesthetist
ORHospitalWorld
Work-station
observe(senses)
touch
Care Info(lab data, image..)
touchobserve(eyes, ears)
ADS, monitors,PIMS
Inhalant Drugs IV Drugs, Fluids Other
Monitoring
requests
Clinical Care
Interactions
Patient Anesthetist
ORHospitalWorld
Work-station
observe(senses)
touch
Care Info(lab data, image..)
touchobserve(eyesears)
ADS, monitors,PIMS
Inhalant Drugs IV Drugs, Fluids Other
Monitoring
requests
Clinical Care
Interactions
Anesthesia Delivery System
Workstation - Patient InteractionsAirway controlBreathingCirculationDrug delivery for anesthetization
Workstation - Patient InteractionsAirway controlBreathing - safe gasesCirculationDrug delivery for anesthetization
vapors, gases, IVIntravenous Liquid DeliveryMonitoringRecording
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 getWhat you put into the circuit is what the patient gets
Give sufficient 100% oxygen flow to the reservoir bag (not to empty)
Reservoir bag gives 100% oxygen to the breathing bag
The Tidal Volume and Minute Ventilation is determined by the size and frequency of the squeeze of your hand and a perfect seal.
Breathing “circuit”
Manual Resuscitator
One-way valves make sure gas flows to the patient
A special valve allows exhaled gas to be removed
Breathing “circuit”
A bag reservoir lets you see it provides 100% oxygen to the breathing bag by never emptying and never entraining room airBag Reservoir
Partial Rebreathing Circuits are used in Anesthesia
Don’t throw away all the exhaled gasIt contains expensive anesthetic vapors Reuse as much as possible
somehow (learn more later) Remove (Absorb) CO2 and Rebreathe the anesthetic
Partial rebreathing = semi-closed circuitAll ADSs use them
Rebreathing Ventilation
Is not for dummiesRequires knowledge and skillMakes us different from other care providers
EMT, Sedation RN, ED MD, Hospitalist, Others
2000
Better ventilation for difficult patients FGF-independent ventilation Corrects for circuit leaks
More sensitive to water vaporMonitors not integrated
2000 GE Aestiva
At BWH, now in L&D and MOR for HeliOx for ENT Surgery where low density Helium moves through narrow orifices
Anesthesia Machine delivers gases and vapors into a breathing circuit 2001
Provides continuous flow of -Oxygen for LifeAir to safely lower FI O2
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
Oxygen and Gas Delivery
MechanicalPhysical knobs
Rotameters, Digital metersDraeger Fabius
Draeger Apollo
Draeger Fabius
Draeger Apollo
Oxygen and Gas Delivery
ElectronicVirtual knobs
Digital metersGE Avance, Aisys
% Oxygen in FGFNOT inspired - be careful
GE Avance, Aisys
Vaporizer Types
Mechanical Penlon Sigma for isoflurane, sevoflurane GE Tec 3,4,5,7 for isoflurane, sevoflurane GE Tec 6 for desflurane (electro-mechanical) Draeger Vapor 19, 2000 for all agents Direct-reading, temperature-compensated
Electronic GE Aladin for all agents
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
N2 OSERVICE
INLET 55 psi
O2
N2 O
FRESHGAS HOSE
Flush Flow(last)
[Anesthetizinggases flow]
COMMON OUTLET
N2 O
750psi
N2 O
750psi
O2
2000psi
FILTER
WALL
DISSdiameter
indexsafetysystem
CONNEC-TION
O2
N2 O
D S I
SIMPLIFIED ANESTHESIA MACHINE SCHEMATIC DIAGRAM
The Circle-Absorber System
Sampled
ExhaustExpired
CO2
Ab- sorb-ant
200 mL/min
InspiredFresh
Gas Flows
Rebreathed
The Circle-Absorber System
ExhaustExpired
CO2
Ab- sorb-ant
200 mL/min
InspiredFresh
Gas Flows
Rebreathed
The Circle-Absorber System
ExhaustExpired
CO2
Ab- sorb-ant
InspiredFresh
Gas Flows
Rebreathed
To Patient
The Circle-Absorber System
ExhaustExpired
CO2
Ab- sorb-ant
InspiredFresh
Gas Flows
Rebreathed
From Patient
The Circle-Absorber System
Exhaust (APL)Expired
CO2
Ab- sorb-ant
InspiredFresh
Gas Flows
Rebreathed
Spontaneous breathing requires Exhaust Pressure = 0
The Circle-Absorber System
Exhaust (APL)Expired
CO2
Ab- sorb-ant
InspiredFresh
Gas Flows
Rebreathed
Manual ventilation requires Exhaust Pressure > 0
The Circle-Absorber System
Exhaust (APL)Expired
CO2
Ab- sorb-ant
InspiredFresh
Gas Flows
RebreathedGases (O2, N2O, Agent)
The Circle-Absorber System
ExhaustExpired
CO2
Ab- sorb-ant
InspiredFresh
Gas Flows
RebreathedGases
No CO2 rebreathed
The Circle-Absorber System
ExhaustExpired
CO2
Ab- sorb-ant
InspiredFresh
Gas Flows
RebreathedGases
No CO2
No
The Circle-Absorber System
ExhaustExpired
CO2
Ab- sorb-ant
InspiredFresh
Gas Flows
RebreathedGasesNo CO2
Gas is sampled from circuit near patient for I/E measures
Sampled
ExhaustExpired
CO2
Ab- sorb-ant
200 mL/min
InspiredFresh
Gas Flows
VE
Mechanical VentilationSet with a switch (Elec or Mech)Exhaust Valve is out of circiutReservoir bag is
In circuit with Draeger piston Out of circuit with GE bellows
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 shaken or canister is full
Flexible hose kinkedFlexible hose stepped on
Perform Machine-Assisted TestsGE Modulus 2 Plus - noneGE Aestiva - Minor
12 Hour switch off and on Circuit Oxygen Sensor Cal via SmartVent ventilator
GE Aisys - Major Most circuit tests are automated Bellows volume & pressure can feel the circuit and make great ventilation modes
Draeger Fabius - Major Most circuit tests are automated Ventilator Piston can feel the circuit and make great ventilation modes
Draeger Apollo – Major almost everything
CALIBRATE OXYGEN MONITOR
Oxygen Monitor on & sensor in air with hole plugged. Calibrate to 21%. Reconnect sensor in circuitThere is no separate oxygen monitor on Aisys or Apollo
These include integrated gas monitoring including Fi O2 obtained by sampling the gas at the wye (AKA “Y”)
The separate sensor is a Clark ElectrodeThe sampled gas monitor is
Polarographic for the symetrical oxyen molecule and Infra-red absorbsion for all other assymetrical molecules
CO2 , N2 O, Isoflurane, Sevoflurane, Desflurane
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 CIRCUIT FOR INTEGRITY
Attach circuit including reservoir bagOcclude “Y” with thumbFlush and fill bag to 30 cmH2O.Test pressure alarmsOpen relief valve and verify that reservoir bag emptiesObserve scavenger bag fill and empty
CHECK FUNCTION
CHECK VENTILATOR FOR FUNCTIONVentilate Test Bag and observe no volume loss.
CHECK SCAVENGER FOR FUNCTIONCheck that reservoir bag fills and empties. Check valves
not stuck.
This pre-use check is basic
We believe this will keep you and your patient safe for the next few weeks
Following the automated tests on Fabius, Aisys, Apollo will test all the functions of your anesthesia machine
We will have an Anesthesia Machine Workshop next month