Anesthesia Machines Flashcards
Who Oversees standards of anesthesia machine?
American Society for Testing and Materials
If the master switch is on….. (2)
Pneumatic and electrical functions
Activates alarms and safety features
If the master switch is off the only things that work are….. (3)
Battery charger
Electrical outlets
The oxygen flush valve is active
Power Failure Indicator
Newer machines have 1 backup source for all components (battery)
Keep machine plugged in- to keep batter charging.
If having to use the backup battery what drains the battery the most?
Ventilator -> hand bag to conserve battery
What is the hospital backup
red outlets
Intended to power ANESTHESIA monitor
Electrical outlets (on machine)
Other appliances should be plugged into……
hospital main
If requirements exceed outlet; circuit breaker will activate
3 parts of pneumatic system
High pressure
Intermediate pressure
Low pressure
Receives gases from cylinders at high variable pressure
High pressure system;
cylinders
pressure release valve
check valves
Purpose of the high pressure system
reduces to lower, more constant pressure suitable for use in machine
Hanger yokes ensure______
Ensures a unidirectional flow
Required to have a least 1 yoke for oxygen and 1 for nitrous
Hanger yoke parts
Body- principal framework
Retaining screw- tightens cylinder (clamp)
Nipple- thru which gas enters machine
Index pins- prevents attaching an incorrect cylinder (PISS)
Washer- forms seal between cylinder and yoke
Check valve assembly- ensures unidirectional flow
Prevents gas from exiting machine when there is no cylinder in yoke
Check valve assembly
check valves assesmbly Prevents gas from being transferred from a cylinder with higher pressure to one with lower pressure if…..
if both are in a yoke and ON
Also called reducing valves
Pressure Regulators
Purpose of the pressure regulators (2)
Reduces high, variable pressure in cylinders to lower constant pressure for machine
Regulator required for each gas supplied by cylinder
Without reducing valves……
provider would have to constantly adjust flowmeter to provide constant flow
If master switch is OFF, intermediate pressure system pressure……..
is 0
Receives gases from the pressure regulator or pipeline
Intermediate pressure system
regulator and pipeline pressure
(45 psi cylinder regulator) (50-55 psi pipeline (wall))—–more than that is too high to deliver to patients. stay below these numbers.
Intermediate pressure system includes…..(6)
Pneumatic part of master switch
Pipeline inlet connections and indicators
Piping
Oxygen pressure failure devices
Oxygen flush valve
Flow control valves
Entry point for gases from pipelines
Pipeline Inlet Connections (in the intermediate pressure system)
Pipeline Inlet connections are fitted with ______
DISS
require oxygen, nitrous and most have air
Pipeline Inlet Connections must contain________
Must contain unidirectional check valve to prevent gas returning to pipeline
Pipeline Pressure Indicators (4)
Indicator required for each gas monitored
Usually found on front of anesthesia machine
Digital or newer machines have LED
Indicator must be on pipeline side….if downstream and cylinder valve open, adequate pressure reading until cylinder is 0
Connects components inside machine in the intermediate pressure system
piping
Piping must be able to……..and leaks must not exceed…….
Must be able to withstand 4x intended pressure (200 PSI)
Leaks must not exceed 25ml/min inside machine
if oxygen pressure is reduced (30 psi)….. (5)
Decreases or discontinues nitrous
Maintains 19% O2 concentration at common gas outlet
Continues until oxygen flow ceases
Simulated in machine check…
oxygen failure alarm will sound within 5 seconds
Receives oxygen from pipeline inlet or cylinder pressure regulator
Oxygen Flush
Sends O2 to common gas outlet
Oxygen Flush must be (5)
Operable with 1 hand
Single purpose
Self-closing
Designed to minimize accidental use
Have flow between 35-75 L/min
Hazards of Oxygen Flush (3)
May stick on
May cause barotrauma
May cause awareness
Regulate flow of oxygen, air, and other gases
Flow Adjustment Control
Oxygen flow knob must be _______
fluted and larger than other gases (looks and feels different)
Downstream of flow control devices
Low Pressure System
flow meters are breaking point
Low pressure system pressures are……and depend on …..
Pressure is slightly above atmospheric and variable
Depends on flow from flowmeters and backpressure from breathing circuit
Low Pressure System includes (5)
Flowmeters
Hypoxia prevention devices
Unidirectional valves
Pressure relief devices
Common gas outlet
Indicate rate that gas is passing through
Flowmeters
Flowmeters design (5)
Thorpe tube- vertical glass tube
Smallest diameter at bottom
Free floating indicator
A stop at top of tube
A flow scale
Flowmeteres empties into______
Empties into a common manifold to deliver gases
Flowmeter Sequence
Normal gas flow bottom-top and left-right
Standard requires oxygen flowmeter to be placed on _____ side
right
Machine manufacturers and sequence
drager; nitrous, air, oxygen
Ohmeda; air, nitrous, oxygen
Mandatory Minimum Oxygen Flow
Minimum of 50-250 ml/min flow (always)
Activated when master switch ON
Minimum Oxygen Ratio
Uses mechanical linkage with nitrous
Link engages when oxygen conc. 25%
cant turn nitrous up anymore without turning up the oxygen
Hypoxia Prevention Devices
Mandatory Minimum Oxygen Flow
Minimum Oxygen Ratio
Unidirectional valves are located…..
Located between vaporizer and common gas outlet
Upstream from oxygen flush valve
Lessens back pressure from flush or breathing circuit
Unidirectional Valves
Opens to atmosphere and vents if preset pressure is exceeded
Pressure Relief Devices
Pressure relief devices are located….
Near common gas outlet
pressure relief devices and jet venilator
Limits ability of machine to provide adequate pressure for jet ventilation- instead to
Receives all gases from machine and delivers mixture circuit
Common Gas Outlet
common gas outlet must be….
Must be difficult to disconnect
Common Gas Outlet should not be used for….
Should not be used for supplemental oxygen
Delay in emergencies
Potential delivery of inhalational agents
Delivers oxygen in case of electronic power failure
Alternative Oxygen Control
Cylinder pressure indicator (4)
Must be present for each gas supplied by cylinders
Increase pressure straightens curve
Falling pressure causes curve to redevelop
Motion is transmitted to gauge
Gauge required to be calibrated in ______
Gauge required to be calibrated in kilopascals (kPa)
may also be PSI
