Anaesthesia Machine And Monitoring Flashcards
What does the Boyle machine require to function?
Supply of oxygen and nitrogen under pressure
Name a machine that is preferable for usage in the field for anaesthesia. And state why.
Draw over machine
Why: It relies on atmospheric oxygen rather than pure gases under pressure which are usually unavailable in the field
.
State twi main purposes of the Boyle machine
Delivery of gases to the patient
Ability to ventilate the patient: Provide intermittent positive pressure ventilation
Name two types of gases delivered to the patient by the Boyle machine
Anaesthetic gases
Medical gases such as air, oxygen and nitrous oxide
Can the Boyle’s machine work if there is no supply of compressed gases?
Nope, you need those oxygen, nitrous oxide and air
Name two sources of the gases required by the Boyle machine
Wall outlet from the pipeline
Gas cylinder on the machine(Used for backup)
Name two components of the Boyle machine that controls gas flow.
Flowmeter(Rotameter): Has control valve and tubes
Pressure reducing valves or regulators
Name a part of the Boyle machine Used to measure gas flow.
Rotameter: Has tapered tubes that do that
Name 5 safety devices that should be part of the basic anaesthesia machine.
Oxygen flush valvs
Oxygen failure alarms
Pop off valve
Hypoxic guard: Prevent administration of hypoxic mixtures
Optionally non return valve
State two limitations of Mapleson A breathing system.
Requires very high flow gases
Unsuitable for intermittent positive pressure ventilation
Note: Still used in many rural hospitals
What does the Magill’s breathing system best for?
Spontaneous breathing
State the strength and weakness of the Mapleson breathing circuit D(Bain’s system)
S: Good for intermittent positive pressure ventilation
W: Inefficient for spontaneous breathing
What is the Jackson Rees Ayre T piece breathing system preferable for paediatrics?
Has an open ended reservoir bag and has no valves thus have low resistance to air flow
What are the required fresh gas flows (spontaneous ventilation and IPPV) for the Ayre T piece breathing system.
Spontaneous ventilation: 200 ml/kg/min with a minimum of 3L/min (2-3x minute volume)
Intermittent positive pressure ventilation:70 ml/kg/min for normocarbia
What is the most frequently used breathing system for anaesthesia worldwide?
Circle system
Why is the circle system better than other systems?
Use low flows and produce less pollution
Has a soda line that absorbs carbon dioxide and allows for rebreathing of gas
Name a substance found in the canister of the circle system that absorbs carbon dioxide.
Soda lime: Enables rebreathing of the gas
Is the reaction between soda lime and carbon exothermic or endothermic?
Exothermic: Produces water making the gas humidified and warmer
What is the minimum gas flow through the circle system of an ANAESTHESIA machine?
3 ml/kg/min ≈ 200 ml/min for adults: this equates to the basal utilisation
of O2
What is the norm fresh gas flow through a circle system that is hardly reached?
500-1000 ml/min
State 4 signs that show that the soda lime is exhausted.
Colour changes: From white to purple
Cold temperature
Rising baseline PaCO2 seem in capnography
Clinical signs of Hypercarbia(late finding)
Are signs of Hypercarbia the earliest finding that show exhaustion of soda lime?
Nope, the earliest is colour changes.
Is the automatic ventilation provided by the ANAESTHESIA machine essential?
Nope, it can easily be replaced by the Ambubag
Name the mode of intermittent positive pressure ventilation preferred in paediatrics with uncuffed ETT.
Pressure controlled ventilation: Compensate for leaks
