Ex2 Anesthesia Gas Machine Flashcards
Most fragile part of anesthesia gas machine
Flowtubes
What are flowtubes susceptible to?
Breakage, leakage, inaccuracy d/t dirt, static electricity
Flowmeters - Shape
Variable orifice flowmeter
Tapered - narrow at bottom; wide at top
Annular opening around float is larger at higher flows
Why is oxygen always added last in path of flow?
Chance of producing hypoxic mixture is lessened
Only cylinder safety relief valve that melts at temperature
Fusible plug made of Woods metal
Melts at temperature 157-220 F
Most fragile part of cylinder
Cylinder valve
Only monitor to accurately detect hypoxic mixture
O2 analyzer
O2 Flush valve
Average delivery 50L/min
35-75 L/min
Fail safe is based on
Pressure (Oxygen)
Fail-safe Datex-Ohmeda
Pressure sensor shutoff valve
Flow of all other gases shut off when O2 supply pressure < 20 psi
Drager - Fail safe
Oxygen failure protection device (OFPD)
Reduces supply of other gases proportionally as O2 supply pressure decreases. Shuts off all flow of N2O/air when O2 pressure < 12psi
Second stage regulators are which machine
Datex-Ohmeda
Rod and diagram proportioning system
Drager - oxygen ratio monitor controller
Drager maintains
25% O2
Proportioning systems are based on
FLOW (not pressure)
- which also means concentration
- 25%
Second stage regulators trigger
O2 14 psi
N2O 26 psi
Most dangerous situation regarding hypoxic guard system
Inert gas administration (3rd gas such as Helium) should detect with O2 analyzer
-able to bypass hypoxic guard system w/ Drager
Location of proportioning devices
*ratiometers
Between the O2 and N2O flowmeters
*between fail safe/flowmeters
Fail safe devices rely on oxygen
Pressure
Proportioning devices rely on oxygen
Flow
Reasons for increased inspired CO2
- Exhaustion of absorbent granules
OR - Faulty unidirectional valves
Inspiration occurs on ETCO2 waveform
EA
AB
DE
NOT just D
Components of high pressure system
Hanger yoke
Yoke block + check valves
Cylinder pressure gauge
Cylinder pressure regulators (ENDS here)
Intermediate pressure system
Exposed to pipeline pressure
50 psi
High pressure system
Exposed to cylinder pressure
Components of intermediate pressure
Pipeline inlets, check valves, pressure gauges O2 pressure-failure devices Flush valve O2 second stage regulator (if present) Flowmeter valve *ENDS here
Dividing point between intermediate - low pressure systems
Flowmeter valve
*intermediate system
Low pressure system
Distal to flowmeter valves
Low pressure system components
Ventilator power inlet Flowmeter tubes Vaporizers Check valves (if present) Common fresh gas outlet** ENDS here
How to check low pressure system
Attach bulb syringe to common gas outlet
Safety relief valves dependent on cylinder pressure
Frangible disk
Spring-loaded
Plum Bob
Read at the top of float
Rotating ball
Read in the center of float
Drager has what type of indicator float?
Rotating ball
Dates-Ohmeda has what type of indicator float?
Plumb bob
Hypoxic guard is also known as
Proportioning systems
Purpose of proportioning systems
Link O2/N20 so that final breathing mix = 25%+/-4% O2
Dated Ohmeda hypoxic guard
Link 25 system (chain/teeth)
Bellows should be looked at during
Expiration
Ascending — better detects loss of pressure
T/F safe to keep cylinder upright without support
False
T/F may leave empty cylinder on machine
F
T/F maintain plastic cover on port while installing cylinder
False - do not leave plastic on
T/F cylinders are color coded for sole identification
False - they are color coded but ALWAYS read label
T/F oiling valves will maintain use
False. - do not oil valves
T/F once cylinder is removed, do not place yoke plug
False - yoke plug ALWAYS needs to be placed - backup for check valve
