Anaesthesia machine Flashcards
State two main functions of the anaesthesia machine.
Delivery of medical and anaesthetic gases
Provide a means to manually ventilate the patient under positive pressure
Name two types of ventilation that can be providing anaesthesia.
Automatic mechanical ventilation
Manual ventilation with an Ambubag
List 5 basic parts of the Boyle machine
Gas supplies under pressure
Gas flow controls
Vaporisers
The breathing circuit
Ventilation systems
Name two ways in gas is supplied to the anaesthesia machine.
From the central tanks through the pipeline and wall outlet
Gas cylinders found on the machine(backup)
What is the colour for the piping and wall outlets of the following gases: Nitrous oxide, oxygen and air
Nitrous oxide: Blue
Oxygen: White
Air: Black but wall outlet is grey
What is the colour of oxygen cylinders?
Black with a white shoulder
Is oxygen stored in a gaseous form in the central tanks?
Nope, as a liquid but converted into gas before entering the central pipelines
What is the commonest usage of nitrous oxide in anaesthesia
Used as a carrier gas to augment anaesthesia
In what form is nitrous oxide stored?
Gaseous form: It cannot be stored as a liquid
Note: The hospital keeps a central manifold large N2O cylinders which are piped to the theatre complex
What is the colour of the cylinder and piping of nitrous oxide?
Blue
How is administration of a wrong gas prevented in anaesthesia?
The wall outlets are colour coded and each has a specific shape for a certain gas
Can Nitrous oxide be increased alone in the anaesthesia machine?
Nope, when it increases oxygen increases as well
What is the function of the valporiser?
Convert volatiles from a liquid into a gas which is then delivered into the gas mixture given to the patient
Which part of the anaesthesia machine prevents the incorrect filling of volatiles?
Vaporiser fillers with a specific shape
Note: it is colour coded the same as the agent and only fits on that gas vaporiser only. It may be metal, plastic keyed fillers(top) or funnel filler adapters(bottom)
What is the colour code of sevoflurane, desflurane and Isoflurane respectively?
Isoflurane: Purple
Sevoflurane: Yellow
Desflurane: Blue
What is the breathing circuit system used in modern anaesthesia machine?
The circle system
Describe the circle breathing circuit.
It consists of piping(tubing) with unidirectional valves. Gas flows from the machine into the inspiratory limb of the patient and the patient exhales via the expiratory limb. It also contains soda lime that absorbs carbon dioxide.
What is the role of soda lime in the Boyle’s machine
It reacts with carbon dioxide forming heat and moisture which prevents the patient’s airway from drying out.
Note:Allows for low flows of gas to be used which is economically favourable
What is an indicator that soda lime is exhausted?
Changes colour from white to purple
Name a breathing circuit ideal for induction in paediatrics
Ayre T piece(Jackson Rees circuit)
What is the disadvantage of the Jackson Rees circuit
It has no carbon dioxide absorber so it requires a minimum gas flow to wash out carbon dioxide.
What is the minimum gas flow to wash out carbon dioxide when using a Jackson Rees circuit.
At least 2-3x patients minute ventilation if breathing spontaneously
And 2x minute volume for controlled manual ventilation
State one specific feature of the Ayre T piece that differentiates it from the circle system.
It is valve free and the reservoir bag is open
Note: It can be occluded for controlled manual ventilation
