Anesthesia machine overview Flashcards
PISS for Oxygen
2-5
gas/tank color yellow
air
Oxygen cylinder:
liters
pressure
625 L
2000 psi
Gas/tank color brown
Helium
O2 Flush valve
35-75 L/min
O2 delivery directly from source to patient circuit
**use with caution ONLY on exhalation b/c of risk of barotrauma
*only used for machine check and to help fill bellows on expiratory phase
flow meter
- tapered
- pressure of gas forces float up while gas still gets around float
- read ball in middle
- read long float at top
- At low (laminar) flows- viscosity is important
- At high (turbulent) flows- density is important
Cylinder pressure regulator
down regulates pressure from tank to 45 psi
Intermediate pressure system
- pneumatic part of master switch
- pipeline inlets (50 psi, oxygen, nitrous, and air)
- pipeline check valves, pressure regulators and pressure gauges
- oxygen pressure-failure device
- oxygen flush valve
- oxygen second-stage regulator
- flowmeter control valves
Gas/tank color blue
Nitrous oxide
the anesthesia machine
- providdes delivery of medical gases and vapor of volatile anestheics in known concenrations to a common gas outlet
- these gases enter a breathing system
- delivered to the pt via spontaneous or mechanical ventilation
- then exhaled gases are removed (scavenged) from the breathing system
Cylinder pressure gauge
gauge on cylinder.
Full tank is 2,000-2,2000
Pressure sensor shut off
Proportioning type
As the O2 pressure drops, the N2O flow decreases proportionately
PISS for Nitrous oxide
3-5
pneumatic system
uses gas pressure to function
Low pressure system
- flow meter tubes
- hypoxia prevention safety device (proportioning device)
- vaporizers/vaporizer manifold
- check valves
- pressure relief devices (only on newer machines)
- common gas outlet
what are you checking on the complete (daily) check?
- gas line connections
- integrity of seal of system
- flow meter controls
- ventilator
- vaporizer levels
- oxygen analyzer
- low pressure circuit leak test
- circle system test (also between every case)
- workstation self-test
Second stage Regulated
reduces Oxygen pressure to 14 psi and nitrous oxide pressure to 26 psi
(not in all machines)
Gas/tank color black
Nitrogen
Nitrous oxide:
liters
pressure
1590 L
750 psi
DISS
Diameter index safety system
- provides non-interchangeable connections for the medical gas lines
- consists of body, nipple, and nut
- only properly mated parts will fit together and allow the threads to engage
- required on every anesthesia machine.
PISS for heliox
2-4
PISS for CO2
1-6
gas/tank color green
(international white)
Oxygen
High pressure system
- cylinders
- hanger yoke
- yoke block with the check valves
- cylinder pressure gauge
- cylinder pressure regulator
Gas/tank color grey
CO2
Low pressure circuit test
- purpose: check the intergrity of the macine from the flow control valves to the common gas outlet
- components in the low pressure circuit are the most vulnerable to breakage (you also will NOT hear a leak)
- Negative pressure leak test:
- preformed using a scution bulb to the common gas outlet
- bulb is squeezed until fully collapsed, creating a vacuum in the low-pressure circuit
- if bulb remains collapsed for atleast 10 seconds the machine is leak free
- Negative pressure leak test:
Oxygen pressure sensor shut off valve
or
oxygen pressure-failure device
shuts of N20 or proportionally decreases the supply of N20 allowed into the machine if the O2 supply pressure decreases to a pre-determined threshold value
25, 28, or 30, depending on model
**this safety mechanism doesnt actually know how much oxygen is in the mix, it only senses the pressure of the oxygen line.
Air cylinder:
liters
pressure
625 L
1800 psi
Anesthesia machine check
- two checks:
- complete and through daily cehck (every 24 hours)
- circuit (circle system) check is preformed before each new surgical case
Circle system check
- done between every case and with inital check
- purpose: elavulates the integrity of the circle breathing system
- the circle breathing system extends from the common gas outlet to the Y-Piece
- Leak Test - occulde the Y-piece, close the APT valve, flush the circuit with 30cm H20 pressure (O2 flush valve)
* does not assess integrity of unidriectional valves - Flow Test - attach breathing bag to Y-piece, turn on ventilator, and assess integrity of unidirectional valves
oxygen analyzer
- the MOST imporant monitor on your machine for oxygen –> only thing that is making sure we’re delivering the proper precentage of oxygen to the pt
- the ONLY monitor tha detects problems downsream from the flow control valves
- procedure: expose O2 sensor to room air (21%) then hook up to machine and ensure if reads above 90%
PISS for air
1-5
check valves
prevent backflow of gas
Five pathways of oxygen
- flow to the fresh gas flowmeters
- powers the Oxygen flush valve
- activates the fail-safe valve/mechanism
- activates the oxygen supply low-pressure alarm
- compresses the bellows of the ventilator
PISS
Pin Index Safety System
different hole/pin arrangement for each gas type so they cannot accidentally be set up in wrong place.
Pressure sensor shut off
Threshold type
When oxygen pressure becomes lower than threshold (25, 28, or 30), this shut off type completely stops the flow of N20
The anesthesia workstation
integrates most of the components necessary for adminisration of anesthaia into on unit:
gas supply devices
anesthesia machine
vaporizers
ventilator
breathing system
scavenging sytem
respiratory and hemodynamic monitors
suction
