Assessment Flashcards
Non-rebreathing Circuit Advantages
Cheap to buy
Soda lime is not required
Low resistance (ideal for smaller patients)
Can change gas levels quickly
Non-rebreathing Circuit Disadvantages
High carrier gas/02 flow therefore more expensive to run
Expired moisture and heat is lost
Different flow requirements for different circuits
Rebreathing Circuit Advantages
Lower fresh gas/02 rates required (cheaper to run)
Expired moisture and heat is conserved
Less pollution than other systems
Rebreathing Circuit Disadvantages
Higher resistance
Expensive to buy
Soda lime must be replaced regularly when exhausted
Humphrey ADE
Can be used as a re-breathing or non re-breathing circuit depending on lever position
Can be run at very low flow rates
Tubing can be used to run as a t-piece, lack, magill or circle (by adding soda lime)
Can be used for IPPV
Anaesthetic Chambers
E.g. Cook’s Chamber
Must be durable and air tight
Needs gas/scavenging outlet
Safety Checks
- Is the circuit assembled correctly?
- Is the APL valve open?
- Are there any kinks/cracks/contamination to the tubing?
- Have you leak tested circuit?
- If using soda lime, have you checked for cracks/exhaustion?
- If using a chamber, are the connections secure and air tight?
Gas Cylinders
Carrier gases stored under pressure
Must be handled carefully
Range of sizes and colour coded
Gas cyinders/piped gases
Pressure Gauge
Shows gas pressure and how much remaining
Pressure Reducing Valve
Safety mechanism
Reduces the pressure of gas coming from cylinder, making it easier to control
Avoids damage to patients respiratory tract
Flowmeters
Shows level of gas flow being supplied to the patient
Graduated glass tube with bobbin (read from the top), or ball (read from the middle)
Vaporisers
2 TYPES: In Circuit (not common) vaporiser is in inspiratory limb and the animals own respiratory efforts control the amount of gas received
Out of Circuit
Glass boyle’s bottle
Tec- Allows controlled amounts of volatile agent to be delivered to the patent
In Circuit Vaporiser
(not common)
vaporiser is in inspiratory limb and the animals own respiratory efforts control the amount of gas received
Out of Circuit Vaporiser
Glass boyle’s bottle
Tec- Allows controlled amounts of volatile agent to be delivered to the patent
Safety Features of Anaesthetic Machinery
Pin-index cylinders
Pipeline connectors
Oxygen alarm
Vaporiser key fillers
Emergency 02 flush
Scavenging
Important to minimise exposure to gases
Passive
- Large tubing from APL valve to outside of building or activated charcoal
Active
- Tubing is connected to a forced ventilation system
- Best method
Passive Scavenger
Large tubing from APL valve to outside of building or activated charcoal
Active Scavenger
Tubing is connected to a forced ventilation system
Best method
Other ways to minimise exposure
All connections must be air tight (masks/ET tubes/circuits etc)
Using key fillers to top up vaporisers
Do not turn on gas until connected
Turn off gas and keep on 02 before disconnecting
Good ventilation
Regularly service equipment
Endo-tracheal Tube Function
Maintains airway
Prevents aspiration pneumonia
Prevents laryngospasm
Reduces environmental pollution
Allows IPPV
Equipment required ET tube
Suitable size ET tube
Tube tie
Mouth gag
Syringe to inflate cuff
Lubricant
Laryngoscope
Intubeaze
ET Tube Types
Red rubber (low volume, high pressure)
PVC (transparent, high volume, low pressure)
Silicone (straight)
Murphy eye (hole in bevelled end near cuff)
ET Tube Checks
Select correct size to minimise dead space
Ensure tube is clean/free from holes/blockages
Ensure cuff is working
Ensure in date
Uncuffed tubes for cats
Checking Placement ET Tubes
Palpate within the trachea
Auscultate lung fields
Observe movement of reservoir bag
Check for air movement (using hair)
ET Tube Disadvantages
Increased airway resistance if tube is too narrow
Kinking/occlusion of tube
Iatrogenic trauma to trachea
Irritation to mucosa if tube not rinsed
Over inflation of cuff can cause tracheal damage
Misplacement
ET tube inserted into oesophagus
Patient light
No movement of bag
Low sp02)
ET tube lodged in bronchus
Sp02 greatly reduced
Unilateral breath sounds
Patient wakes up
Laryngospasm in cats
Use one spray of local anaesthetic
Wait and oxygenate
Use laryngoscope
ET Tube blocked/kinked
Sp02 very low
Little movement of reservoir bag
Cyanosis
Tracheal rupture
Sub cut emphysema
Reduced breath sounds
Extubation
After pharyngeal reflexes have returned
Ensure oropharyngeal area is clear of blood/debris
Wait until swallow returned (dogs)
Extubate before swallowing (cats)
Osophageal Stethoscope
Plastic tubing attached to a stethoscope head piece
Passed into the oesophagus until it lies level with the heart to detect HR/RR
Should be checked it is clean, secure and lubricated before use
Pulse Oximeter
Measure patients arterial oxygen saturation (sp02)- Percentage of oxygen that is bound to haemoglobin in the arterial bloodstream
Useful monitor for cardiovascular/respiratory function
Low readings can indicate tissue hypoxia
Probe is attached to area on non pigmented skin e.g. toes, tongue
Normal range: 95% or above
E.C.G.
Measures electrical activity across cardiac muscle
Provides information regarding HR/rhythm and is good for detecting arrhythmias
Electrodes are attached to the patient via crocodile clips/adhesive pads with surgical spirit or electrode gel
Blood Pressure Monitoring
Direct/ Indirect
Direct Blood Pressure Monitoring
IV catheter placed directly into a peripheral artery
This is connected to a pressure transducer that converts into an electrical signal that can be measured
Requires skill, potential for sepsis at site
Indirect Blood Pressure Monitoring
- Oscillometric (humans)
2. Doppler (cuff attached to manometer that is manually inflated and an ultrasound probe)
Central Venous Pressure
Long IV catheter passed down jugular to lie at thoracic inlet
Catheter attached to pressure manometer
Measures adequacy of venous return to the heart
Requires skill
Capnography
Measures C02 concentration in inspired and expired gases
Allows early detection of respiratory problems
2 types
- Main stream
- Side stream
End tidal carbon dioxide (ETC02) is the C02 breathed out at peak of expiration (35-45mmHg normal range)
Apnoea Monitor
Detects gas movement through ET tube
