Anaesthesia nursing Flashcards
(35 cards)
1
Q
what are the 4 types of induction agents (with examples)
A
- Barbituates (e.g Thiopental)
- Steroids (e.g Alfaxalone)
- Cyclohexanones (e.g Ketamine)
- Phenols (e.g Propofol)
2
Q
why do we need a pressure regulator valve? (2 marks)
A
- To keep constant
2. To lower the pressure going into the patient
3
Q
What are the differences between rebreathing and non-rebreathing circuits?
A
Rebreathing:
- Uses sodalime chamber to absorb CO2
- Higher resistance to ventilation
- More economic on gases
- Denitrogenation for first 10 minutes
Non-rebreathing:
- No CO2 absorption
- CO2 cleared by high gas flow rate
- Normally have ‘pop off’ valve
- Low resistance to ventilation
4
Q
What are the differences between rebreathing and non-rebreathing circuits?
A
Rebreathing:
- Uses sodalime chamber to absorb CO2
- Higher resistance to ventilation
- More economic on gases
- Denitrogenation for first 10 minutes
Non-rebreathing:
- No CO2 absorbtion
- Higher flow rate to clear CO2
- Normally have ‘pop off’ valve
- Low resistance to ventilation
5
Q
What is the difference between a vapour and a gas?
A
Vapour: Turns to a liquid when put under pressure and is below is critical temperature
Gas: Does not turn to a liquid under pressure and is above is critical temperature
6
Q
Why is a nitrous oxide cylinder pressure gauge inaccurate most of the time?
A
Nitrous Oxide is a vapour so gauge thinks cylinder is full due to it coming out in a gaseous form
7
Q
What are the advantages and disadvantages of cyclohexanones (Ketamine)
A
Advabtages:
- Provides analgesia
- High therapeutic index so will not cause toxicity
- Little effect on cardiorespiratory depression
- Reflexes still in place
- Multiple administration routes (IV & IM)
- Blood pressure maintained
Disadvantages:
- Confusion in monitoring (dilated eyes, still has reflexes)
- Stormy recovering if given alone
- No muscle relaxation
- Hypersalivation
8
Q
What are the properties of cyclohexanones (Ketamine)
A
- Provides analgesia and amnesia
- If given with alpha-2 agonist must wait 40 minutes before reversing
- Minimal muscle relaxation
- Normally combined with benzodiaepine (midazolam) for muscle relaxation
- Administered IV or IM
- Absorbed through MM’s so care taken when administering
- Metabolised by the liver but contraindicated in patients with liver disease
- Fast onset & lasts 20-40 minutes
9
Q
What are the principles of effective CPR and IPPV?
A
- Reassess patient every 2 minutes
- Change over time maximum of 10 seconds
- Ratio 30:2 of chest compressions:breaths
- Compress chest by 1/3
- Compress chest between 4th and 5th intercostal space
- Patient in right lateral on a hard surface
- Aim for 100-120 compressions a minute
10
Q
Identify the properties of Phenols (Propofol)
A
- Painful if goes perivascularly
- Not water soluble so dissolved in emulsion
- if it doesn’t contain a preservative it must be discarded after 12 hours
- Administered IV
- Given slowly as apnoea is common
- Potent vasodilator so hypotension may occur
- Only provides narcosis and relaxation
- Binds strongly to proteins so care taken if patient hypoalbumnaemia as won’t bind and can cause toxicity
11
Q
What are the properties of sevoflurane?
A
- Very low blood gas solubility (fast onset)
- Not irritant to mucosa
- Licensed for cats and dogs (can be used for other patients on the cascade)
- Normal range 3.3-3.8%
- Expensive
12
Q
What are the properties of Isoflurane?
A
- Licensed for cats, dogs, horses and other equidae, birds, reptiles and small mammals
- Irritant to mucous membranes
- Low blood gas solubility
- Normal range 1.5-2.5%
- Unpleasant smell
- Very little metabolised so non toxic
- HR maintained but vasodilation so hypotension seen
13
Q
What are the properties of halothane?
A
- No longer used (expired 2018)
- Decomposed by UV light so kept in dark bottle
- Contains thymol (preservative) which can build up in vapouriser and effect function
- Poor analgesia
- Moderate muscle relaxation
- Reduces hepatic blood flow so if patient given drugs metabolised by the liver it will reduce effect
14
Q
What are the properties of nitrous oxide?
A
- Insoluble in blood so rapidly enters & leaves blood stream
- Analgesic effects
- Diffuses in gas filled areas so limited use
- Used mainly in orthopaedics for additional analgesia
- Rapid recovery as less volatile agent used
15
Q
What does the pulse oximetry measure?
A
Arterial Oxygen satuation
16
Q
Discuss the use and limitations of using pulse oximetry
A
Use:
- Cheap
- Non-invasive
- Easy to interpret
- Gives pulse rate
- Readings below 95% must be investigated
Limitations:
- Must be on pigmented skin
- Prone to error due to clip
- Calculates using red and inferred light
- Readings below 70% may be inaccurate
17
Q
What are the expected systolic blood pressure ranges for:
- Dogs
- Cats
- Rabbits
A
- 90-140
- 80-140 mmHg (millimetre of Mercury - for all)
- 70-170
18
Q
What is the capnograph used to measure?
A
End Tidal CO2
19
Q
What is the normal range considered to be for capnography?
A
35-45 mmHg
20
Q
What are the properties of a circle circuit?
A
- In common use
- Low flow rate therefore cheaper
- Heat and moisture conservation
- Unidirectional valve
- Suitable for IPPV
- Sodalime removes CO2
- Maintenance flow rate set at 10ml/kg/min
- 2 litre bag
- Patient >10kg
21
Q
What are the properties of the Humphrey ADE circuit?
A
- Low flow rate therefore cheaper
- Can be used on range of weights (0-100kg)
- Semi-closed mode for 0-7kg (without sodalime), Recycling mode for 7-100kg (with sodalime)
- Components:
- APL valve
- Resevoir bag
- Lever to sert mode (upwards = spontaneous & uses bag, downwards = controlled & uses ventilator)
- sodalime canister (patient > 7kg)
- Ventilator port
22
Q
What are the types of pre-medications used in practice?
A
- Alpha-2 adrenoreceptor agonists
- Opiods
- NSAIDS
- Atropine
- ACP
23
Q
What are the properties & side effects of ACP?
A
Properties:
- Sedation
- CNS depression (inhibition of dopamine)
- Altered mood and removal of fear
- Over-sensitivity in some breeds
- -Anti-emetic effect
- Smooth muscle spasmolytic
Side effects:
- Hypotension
- hypothermia
- Cardiac dysrythmia (IV administration)
- Decreased seizure threshold
24
Q
What are the properties and side effects of Alpha-2 adrenoreceptor agonists?
A
Properties:
- Depression of CNS
- Dose dependent sedation, analgesia and muscle relaxation
- Used with Butorphanol
- Effects on CV system
- Animals may appear deeply sedated but react
- RR falls but arterial blood gases maintained
- Can be reversed (IM)
Side effects:
- Decreased RR
- Marked effect on CV system
25
What are the properties of Opiods?
-Stimulation of Mu, Kappa and Delta receptors results in analgesia, respiratory depression miosis, reduced GI motility and euphoria
-Sometimes used in isolation as pre-medication (high risk patients)
Commonly used with ACP (lower doses can be used)
-Provides analgesia, sedation and relaxation
-Can be pure or partial
26
What are the properties & side effects of atropine
Properties:
- Not commonly used now, previously used as sedation
- Used now in specific cases
- Brachycephalic patients
- Reduces salivation and secretions
Side effects:
- Dry mouth
- Tachycardia
- Cardiac arrhythmias
- Confusion
- Mydriasis
27
What are the cranial nerve reflexes and how do you observe them? (12 marks)
1. Palpebral - touch corner of eye
2. Corneal - touch eyeball (usually euthanasia)
3. Eye position - Look at eye, observe VENTROMEDIAL position
4. Pupillary - size, use torch (if very dilated indicates very deep)
5. Jaw tone - pull jaw & feel for resistance
6. Tongue curl - look for positive tongue curl (tongue curl comes back before swallow)
28
What are the 3 methods of measuring blood pressure and how do they work?
1. Doppler - Doppler probe placed over digital artery, inflate cuff proximal to probe & continue to inflate until doppler sound stops. Deflate cuff until first sound from Doppler is audible (Take 6 readings and discard the first, then average)
2. Oscillometric - Cuff is mechanically inflated and deflated and recognises the small change in pressure, usually an ECG reader
3. Direct Arterial - catheter placed into a peripheral artery and connected to a pressure transducer with a saline filled line (more common in EQ)
29
Compare the use of phenols in cats and dogs
Dogs:
- Rapidly metabolised by the liver & lungs so fast recovery
- Can be used in patients with liver disease
- Can be used as maintenance
- Can be used in seizuring dogs
Cats:
- Liver not capable of detoxifying quickly so recovery longer
- Not used in patients with liver disease (put on fluids if not alternative)
30
What drugs may be administered during CPR and why would they be used?
- Adrenaline = Causes vasoconstriction & redirection of blood from the peripheries, increases cardiac contractility, causes bronchodilation (optimises air intake)
- Atropine = Increase HR, used in bradycardic patients
- Lidocaine = Used as antiarrhythmic in cases of ventricular arrhythmia
31
What are the types of compressions that can be performed during CPR and how are they performed?
1. Cardiac pump - head slightly down, arms placed at 4th-5th intercostal space, arms extended & elbows locked, forced applied by bending at the wrist
2. Thoracic pump - medium to large dogs & barrel chested, chest compressed at widest point to increase thoracic pressure, leading to forward blood flow and compression of heart
3. Interposed abdominal compression - abdomen manually compressed during relaxation phase of chest compressions to increase venous return
*Can also place in dorsal recumbency and compress sternum for dogs with wide thorax (eg bulldogs)*
32
What are the properties of steroids induction agents (Alfaxalone)?
- No analgesic properties
- Minimal cardiorespiratory depression
- Apnoea may occur post induction
- No pain on injection
- Good muscle relaxation
- Uneventful recovery
- Rapidly metabolised by liver of cats & dogs
- Suitable as maintenance with top ups or as CRI
- Muscle twitching may be seen after induction or on recovery
33
Name the types of inhalation agents (5 marks)
- Isoflurane
- Sevoflurane
- Halothane
- Nitrous Oxide
- Desflurane
34
Outline how anaesthetic drugs can effect the brain and nervous system (3 marks)
- Drugs must be lipophillic to cross the blood brain barrier
- Combine to a variety of receptors in the CNS
- Depression of CNS causes unconsciousness
35
Outline the difference between respiratory cycle and respiration (4 marks)
- Respiratory cycle has 2 phases (inspiratory and expiratory)
- Respiration is process of gas exchange and has 2 processes (external and internal)
- External is the respiratory cycle
- Internal is the O2 used to release energy & happens at a cellular level
