Clinical Anaesthetic Machines & Equipment Flashcards
What is the purpose of anaesthetic machines?
to deliver anaesthetic gases/vapours and oxygen to the patient
What does the oxygen flush do?
Pure Oxygen comes out when used, comes through common gas outlet as the anaesthetic agent
- delivers pure oxygen
What is the purpose of the oxygen flush button?
to quickly flush all anaesthetic agent OUT OF THE SYSTEM
What is an oxygen concentrator/generator?
filters air & concentrates air
Creates up to 95% Oxygen through a concentrator
What does a pressure gauge do?
measures pressure of gas in cylinder or pipeline
What is the pipeline pressure?
400-500 kPa (4-5 Bar)
In Europe, how much pressure is in a new cylinder?
137 BAR/13,700 kPa
What does the regulator/reducing valve do?
- reduces pressure of gas in cylinder to a level suitable for the patient
- regulates pressure & keeps it constant
- allows fine and accurate control of gas flow
What does a flowmeter do?
measures gas flow in litres per minute
flowmeters are specifically calibrated for…
the density & viscosity of each gas
Each gas MUST have its own
flowmeter
The bobbin in a flowmeter floats on a
column of gas
What does a vaporiser do?
allows controlled vaporisation of volatile agents
Vaporisers MUST NOT BE…
TILTED! (by greater than 15 degs)
What should you do if you tilt a vaporiser more than 15 degrees?
Flush it properly, do NOT attach to patient!
Each anaesthetic agent vaporiser has a different way of filling so…
you cannot accidentally mix the gases inside the same vaporiser
When do you use the oxygen flush button?
in emergencies only to flush all anaesthetic out of the system
Why do you need to use the oxygen flush button w/ extreme caution?
it will rapidly overinflate the lungs of your patient and cause barotrauma
if you need to push the flush button, what is the proper way of doing it while there is a patient undergoing an anaesthetic procedure?
- disconnect p
- cap end of system
- flush into the scavenging system
- reconnect into system
- turn off anaesthetic agent
- P now only receives O2
Why should you never use the O2 flush to fill the reservoir bag?
Can easily lead to pneumothorax
How fast does the rate of O2 flush through the system?
35 L/min (600 ml/sec)
What is the common gas outlet?
For connection of breathing systems
When attaching to the common gas outlet, what is important to do to secure it?
“Push & Twist” to lock it in so that it does not disconnect from system
What gas(es) come out at the outlet?
Oxygen +/- anaesthetic agent
ETT may be manufactured…
with or without a cuff
Why should you use a cuff on an ETT?
It ensures a good seal between the tube & the tracheal mucosa and is important to preventing regurgitated material from entering the lungs
All ETT have a…
14 mm connector that connects them to the breathing system
The connector on an ETT must be connected to the breathing system by a…
“push and twist” movement to prevent accidental disconnection between the ETT and the breathing system
How do you measure an ETT for an individual patient?
From the end that goes into the trachea, place the tube in a fashion that runs from the thoracic inlet to the tip of the nose.
What is important to remember about the markings on ETT tubes for measuring?
They are the same size no matter what tube you are using
What species should only use ETT tubes without cuffs?
Birds b/c they have complete tracheal rings and the cuff when expanded could rupture the trachea.
Why do we inflate the cuff on an ETT?
- to prevent oral secretions/blood/regurge from entering the lungs
- protects those in the room from inhalant anaesthetics so go straight into the scavenging system
How MUCH should you inflate the cuff on an ETT?
just enough that you no longer hear air escaping around the edges of the tube
What are the potential consequences of overinflating the ETT cuff?
Pressure necrosis or tracheal rupture
What are the advantages of an ETT?
- Protect airway from regurgitation (if cuff inflated)
- Essential in brachycephalic dogs / pigs /wild animals / ruminants
- Less atmospheric pollution from anaesthetic gases of the workplace
- Allows control of ventilation
- Necessary for IPPV
What are potential disadvantages of using an ETT?
- could intubate the oesophagus
- intubation of the main stem bronchus
- kinking of ETT allowing no inhalation or exhalation to occur
- damage to the larynx, trachea, laryngeal spasm
- undiscovered disconnection
What equipment do you require for intubation?
Laryngoscope w/ range of blade sizes
Mouth gag & light source
Lidocaine spray (cats)
KY Jelly/Lube
Swabs/empty syringe/bandage
If you are anticipating a difficult intubation, what instrument could be used to assist you?
A bougie with the ETT railroaded over it
What are the 5 main things to keep in mind when using an ETT?
- ensure cleanliness of the tube
- always check cuff & connector by leak testing
- check length against the patient
- use widest possible
- insert gently
What is the typical dosing of lidocaine in a cat
2 mg/kg
How long does it take for lidocaine to work as a splash block for laryngeal spasm in a cat?
20-30 sec
