Anesthesia Workstation

Question 1

Government agency

Answer 1

Oversees the machine 2 bodies:
ASTM: in charge and oversees all machines and equipment out on the market since 2000.
ASTM: American Society for Testing and Material
ANSI: all machines prior to year 2000.
ANSI: American National Standards Institute

Question 2

Common manifold

Answer 2

All the flow meters are housed: 
Green = oxygen
Blue = nitrous oxide
Yellow = air
Deliver oxygen alone or other substituents

Question 3

Vaporizers

Answer 3

Oxygen to flow meter

Question 4

Purpose of Oxygen in Anesthesia Machine

Answer 4

1) Flow to the fresh gas flowmeters
2) Powers the oxygen flush valve
3) Activates the fail-safe mechanisms
4) Activates oxygen low pressure alarm
5) Compresses the bellows of the Ventilator

Question 5

Oxygen Flush Valve

Answer 5

Automatically delivers 35-75L directly from the pipeline to the common outlet. Only for anesthesia machine check and circuit or fill the bellow. Delivers that much oxygen = cause barotrauma.

Question 6

Pneumatic System

Answer 6

Air Pressure System

1) High Pressure
2) Intermediate Pressure
3) Low Pressure

Question 7

High Pressure System

Answer 7

The High-pressure circuit consists of those parts which receive gas at cylinder pressure:
o hanger yoke (including filter and unidirectional valve)
o yoke block
o cylinder pressure gauge
o cylinder pressure regulators

Question 8

Intermediate Pressure System

Answer 8

The Intermediate pressure circuit receives gases at low, relatively constant pressures (37-55 psi, which is pipeline pressure, or the pressure downstream of a cylinder regulator):
o pipeline inlets and pressure gauges
o ventilator power inlet
o Pressure regulators
o Oxygen pressure-failure device (fail-safe) and alarm
o flow meter valves
o oxygen and nitrous oxide second-stage regulators
o oxygen flush valve

Question 9

Low Pressure System

Answer 9

The Low-pressure circuit includes components distal to the flowmeter needle
o	valves
o	flow meter tubes
o	vaporizers
o	check valves (if present) = unidirectional valves
o	common gas outlet
o      Hypoxia prevention safety device
o      Pressure relief valves

Question 10

DISS: Diameter Index Safety System

Answer 10

Provides non interchangeable connections for the medical gas lines
Connection consists of body, nipple and nut combination
Only properly mated parts will fit together and allow the threads to engage
Required for every anesthesia machine

Question 11

Oxygen Pressure Failure Device

Answer 11

Only works off as pressure and not FiO2. Still deliver a low oxygen mixture. Yes.

Question 12

Oxygen Flush Valve

Answer 12

Special ring around them and prevent activation. O2 + symbol for the oxygen flush valve

Question 13

Flow Meter Tubes

Answer 13

Hypoxia prevention safety device. Chain that connects oxygen and nitrous so that if you try to deliver oxygen at less than 25% it won’t turn nitrous on
Oxygen and nitrous = chain link
When you try to decrease oxygen and increase nitrous, it won’t allow you to deliver less than 25% while oxygen is on board

Question 14

O2 Pressure Sensor Shut-Off Valve

Answer 14

A safety valve located downstream from the N2O supply source.
Purpose: shuts off N2O or proportionally decrease the supply of N2O allowed into the machine, if O2 supply pressure decreases to a pre-determined threshold value: 25 psi

Question 15

Pressure Sensor Shut-Off

Answer 15

Oxygen enters the machine and flows to pressure-sensor shut off valve and oxygen supply failure alarm system
Pressures sensor: less than 20, pistons start to close.
Oxygen supply greater than > 20 psi = N2O flows
Oxygen supply less than <20 psi = N2O flow stops

Question 16

Oxygen Supply Source

Answer 16

#1 Pipeline Source: 50-55 psi from the wall supply with check valve = goes through second stage regulator. 
#2 Cylinder Supply: 2200 - 2000 psi. Goes through cylinder pressure regulator

Question 17

Cylinder Size

Answer 17

Department of Transportation regulates this.
Pressure from the cylinder needs to be less than pipeline: 45 psi
Cylinder size of G and H: only source of oxygen
Cylinder: back up source and attached to hanger yoke and pin index safety to prevent misconnection

Question 18

PISS

Answer 18

Each gas has their certain configuration
Green = oxygen = PISS: 2, 5
Blue = nitrous oxide = PISS: 3,5
Yellow = air = PISS: 1,5
Each cylinder has 2 pins that correspond

Question 19

Tank Capacity for Oxygen

Answer 19

E cylinder oxygen are considered full at 2000 - 2200 psi and approximately 625 - 700 L of O2.
O2 is used from the cylinder, pressure falls in proportion to the amount of gas left in the tank.

Question 20

Oxygen Pressure

Answer 20

Oxygen pressure on the cylinder gauge reflects volume of contents of the E-sized cylinder O2 stored as GAS

Question 21

Nitrous Oxide

Answer 21

Only way to figure out the amount of nitrous oxide left is to weigh it
Nitrous is stored as liquid

Question 22

Pressure Regulators

Answer 22

Reduce cylinder pressure
O2: 2000-2200 psi
N2O: 745 psi
Second Stage Regulators: not found in all machines will reduce psi to be more compatible with the machines

Question 23

Flow Meters

Answer 23

Measure gas flow to the common gas outlet
Thorpe Tubes vs. Electronic flow sensors:
Gas is specifically color coded
O2 flow knob:
Distinctly fluted
Projects beyond the control knob for other gases
Larger in diameter
Oxygen flow meter positioned downstream from nitrous prevents a hypoxic mixture if leak is present but this not fail proof!
Order: air, nitrous, oxygen and vaporizer
O2 next to vaporizer to prevent back-flow

Question 24

Fail-Safe Mechanism

Answer 24

Oxygen is located downstream position. However, if leak is in O2 flow meter, you can still have hypoxic mixture

Question 25

O2 Flush

Answer 25

``` Flow 35-75 L/min Delivery directly to machine Outlet to patient circuit Use with caution: barotrauma Reasonable use: Aid in machine check Help fill bellow on EXPIRATORY phase of respiration Bellows not filling = don't have mask on face correctly ```

Question 26

Proportional Link System

Answer 26

Second-stage N2O regulator: > 26 psi Second stage O2 regulator: 14 psi Bicycle chain: turn on oxygen no problem Turn on nitrous the chain system is engaged; oxygen automatically turns on

Question 27

Anesthesia Machine Check

Answer 27

Two checks 1) Complete and thorough daily check 2) Circuit check is performed before each new case

Question 28

Monitors

Answer 28

``` EKG Systemic blood pressure Body temperature Arterial hemoglobin saturation with oxygen Carbon Dioxide Anesthetic gas and vapors Alarm system ```

Question 29

Monitors

Answer 29

ETCO2 = capnography is best for revealing a disconnect Oxygen analyzer: most important monitor on the machine. Calibrate at 21% O2 = room air SpO2 = provides ongoing monitoring of exchange

Question 30

Anesthesia Machine Check

Answer 30

``` Gas Line connectors Ventilator check Flow meter controls Vaporizer levels Oxygen analyzer Low pressure circuit leak test Circle system test Workstation Self-tests ```

Question 31

Oxygen Analyzer

Answer 31

The most important monitor on your machine The only monitor that detects problems downstream from the flow control valves General procedure entails exposing O2 sensor to room air (21%) for a given amount of time Detects FiO2 = detects downstream Upstream from O2 analyzer: failure, proportional link and fail safe After the common gas outlet = only downstream regulator

Question 32

Low Pressure Circuit Test

Answer 32

Checks the integrity of the machine from the flow control valves to the common gas outlet Components in the low pressure circuits are most vulnerable to breakage Flow control to common gas outlet

Question 33

Low Pressure Leak Test

Answer 33

Master machine switch, flow control valves and vaporizers to be in OFF position Performed using a suction bulb to the common gas outlet Suction bulb is squeezed several times, fully collapsed, creating a vacuum in the low pressure circuit. If the bulb remains collapsed for at least 10 seconds, the machine is leak free.

Question 34

Circle System Check

Answer 34

Purpose: Evaluates the integrity of the circle breathing system The circle breathing system extends from the common gas outlet to the Y piece. Leak Test: occlude the Y Piece, close APL valve, pressurize the circuit to 30 cm of water using the O2 flush valve. Flow Test: attach breathing bag to Y Piece, turn on ventilator and assess integrity of unidirectional valves

Question 35

Simple Circle System

Answer 35

Expiratory phase Expiratory breathing tube Through the expiratory limb one way valve In and out of the reservoir bag Excess gas is vented out through the pop-off (APL) valve to the scavenger system Inspiratory phase Through the absorber canister flow from top to bottom; where CO2 is removed Back towards the patient Fresh gas enters the circle from the common gas outlet of the anesthetic machine Flows through the inspiratory limb one way valve Then flows through the inspiratory breathing tube