Formative Assessment Flashcards
How long does ACP take to have an effect on the patient and for how long do its effects last?
30-40 mins to effect then
lasts 4-6hrs
Why is ACP contraindicated in shocked animals?
It causes vasodilation which leads to hypotension, this can be disastrous in shocked animals leading to cardiovascular collapse
Which combination of premedicant drugs is suggested as an appropriate for an ASA category 4 canine patient?
Benzodiazepine and opioid
Which category of patients tend to have a higher incidence of concurrent disease and reduced cardiovascular reserve functionality
Geriatrics
At what age is a puppy or kitten assumed to have normal liver function?
12 weeks
Which class of pre-medicant has a significant drug sparing effect?
Alpha 2 agonists
What are the normal expected heart rates in dogs and cats after administration of alpha 2 agonists?
Dog 45-60
Cat 100-115
Which pre-medicants can be used for their anti-convulsive effects?
Diazepam
Midazolam
Which opioids act on the OP3 receptors?
Morphine, methadone, fentanyl, pethidine
How long does buprenorphine take to effect the patient and how long do its effects last?
30-40 mins onset, duration 6 hrs
What effects do opioids have on the cardiovascular system?
Cause bradycardia due to vagal stimulation.
Explain the aims of using an anticholinergic drug such as atropine (note that this is not part of a standard premedication protocol in modern practice)
Reduce salivary and bronchial secretions
To block the effects of impulses in the vagal
nerves (eg, prevent the oculocardiac reflex)
To block the effects of drugs that stimulate the
parasympathetic nervous system, such as opioids
What is the name of the neurotransmitter that is released at the neuromuscular junction?
Acetylcholine
Explain the difference in mode of action between depolarizing and non-depolarizing MBAs
Depolarising – occupies ACh receptors causing an initial contraction.
Non-depolarising – there is no initial stimulation
Explain the use and potential side effects of suxamethonium
Rapid acting, used in intubation of cats.
Side effects include cardiovascular effects, malignant hyperthermia, increases intra ocular pressure
List 2 advantages of using non-depolarising muscle relaxants
They can be topped up
They can be reversed
According to the article which 2 non-depolarising MBAs are widely used in practice?
Atracurium
Vercuronium
List three types of monitoring equipment suggested for use when monitoring a patient under the influence of NBAs
ECG
BP monitor
Pulse oximeter
Capnography
List 3 potential side effects of using a MBA reversal agent such as edrophonium
Increased salivation
Bronchospasm
Bradycardia
Arrhythmias
During recovery from a procedure where MBAs are used, how should the animal be positioned to maximise efficient ventilation?
Sternal recumbency for full inflation of the lungs
General Anaesthesia - Describe, Advantage & Disadvantage
Anaesthesia may be induced and maintained by injectable or inhalational means.
Intramuscular or intravenous are the most commonly used injectable routes of administering general anaesthesia.
Advantages – convenient, rapid loss of consciousness, facilitates surgical field.
Disadvantages – stressful restraint, technical skill required.
Topical Anaesthesia - Describe, Advantage & Disadvantage
Desensitisation is produced only at or near the site of application.
Advantages – little or no cardiovascular depression, inexpensive, easy to do
Disadvantages – used for minor procedures only
Local Anaesthesia - Describe, Advantage & Disadvantage
Produces reversible block of nerve impulse conduction.
Advantages – consciousness retained, good for superficial surgery
Disadvantages – used for minor procedures only, possible wound breakdown
Explain the effects of anaesthesia on the body in each of the following stages of anaesthesia: Stage I
Pulse increased
resp rate increased
possible breath holding may occur depending on agent used.
Pupils dilate.
Hypereflexia.
Patient may vocalise
Salivate
urinate and defaecate.
Explain the effects of anaesthesia on the body in each of the following stages of anaesthesia: Stage III, plane 3
Resp rate decreases
Tidal volume is decreased
a pause appears between inspiration and expiration,
HR and BP decrease
Eye position becomes central
Pupil diameter increased,
Abdo muscles relaxed.
Explain the effects of anaesthesia on the body in each of the following stages of anaesthesia: Stage IV
Progressive respiratory failure leading to respiratory arrest.
Pulse may be rapid then slows becoming inpalpable.
Eye central, pupils dilated and cornea surface dry.
Cyanosis turning grey
CRT increased
ASA Scale I
Physical description & patient example
Physical description- Normal healthy patient
Patient example- Young dog, elective OVH
ASA Scale III
Physical description & patient example
Physical description- A patient with moderate to severe systemic disease
Patient example- Dog with heart murmur resulting in reduced exercise tolerance
ASA Scale IV
Physical description & patient example
Physical description- Patient with severe systemic disease that is a constant threat to life
Patient example- Dog with cardiac arrhythmia resulting in severe circulatory compromise
ASA Scale V
Physical description & patient example
Physical description- A moribund patient – not expected to survive without the procedure
Patient example- Dog with GDV
Explain the purpose of the anaesthetic consent form and describe what is meant by ‘informed owner consent’ (4 marks)
The purpose of the consent form is to record the clients agreement to treatment based on knowledge of what is involved and the likely consequences.
The client may be the owner or someone acting with their authority.
(No one under the age of 16 should sign the form).
Before being asked to sign the client should have the opportunity to read and understand and ask any questions they may have regarding the procedure.
A 2 yr old Labrador is booked in for a routine OVH. Describe the pre-anaesthetic assessment procedures (5)
A full clinical history – status of diagnosed chronic disease if applicable, current meds
Previous anaesthetic history
Temperament of patient, recent changes in food/water consumption
Vaccination status
Clinical examination – CNS, cardiovascular and respiratory status
Pre-op bloods – haematology and biochem
A 2 yr old Labrador is booked in for a routine OVH. Describe the aims of premedication (5)
To calm the patient
Reduce anxiety
Reduce amount of induction agent
Reduce amount of maintenance agent
Provide analgesia
Aid smooth recovery
A 2 yr old Labrador is booked in for a routine OVH.
Describe the induction procedure of general anaesthetic (intravenous) –
include in your answer monitoring procedures immediately post induction (5)
Assist with restraint of patient – i/v catheter in place.
i/v induction – restrain and reassure patient.
Within 20 seconds induction effective.
Assist with endotracheal intubation – connect to anaesthetic machine.
Monitor respiration heart rate CRT and temperature closely
Describe 2 anaesthetic monitoring techniques used to assess cardiovascular system status (you may include items/equipment in your answer) (2)
Observation – colour of mucous membranes, CRT
Palpate pulse- femoral, sublingual, carpal. Auscultate heart.
Equipment – Pulse oximeter, oesophageal stethoscope, ECG
Explain the procedure you would carry out with a patient in respiratory arrest (6)
Inform VS immediately/summon assistance
Turn off anaesthetic vaporiser and flush o2
Patient on 100% O2
Monitor pulse
Manual (or automatic) IPPV
Explain the procedure you would carry out with a tachycardic patient (4)
Establish cause -
inadequate depth of anaesthesia so evaluate in relation to surgery OR may be due to compensatory mechanism/response to hypotension and be critical in preventing hypoxia and hypotension.
Liase with surgeon
Tachycardia may encourage arrhythmias
May require use of drugs to reduce heart rate or increase depth of anaesthesia
List 4 emergency drugs that may be used in an anaesthetic emergency and explain the action of each drug (8)
Adrenaline – cardiac stimulant, increases rate and force of myocardial contractions
Doxapram – respiratory and CNS stimulant
Atipamazole – alpha2 antagonist – used if poor recovery from eg. Medetomidine
Atropine- anticholinergic, used to in excess vagal tone, to treat bradycardia
Diazepam – benzodiazepine used to treat seizures
Frusemide – diuretic, treatment of acute pulmonary oedema
List items of equipment that may be used in an anaesthetic emergency (4)
Defibrillator Ambu bag I/v catheter Laryngoscope Endotracheal tube Suction machine Oxygen supply
Describe the monitoring techniques you would carry out for a patients in recovery from post-orthopaedic surgery (5)
vital signs
pain levels
cranial nerve reflexes
observe – i/v fluids, urination, defaecation, record findings
Describe the monitoring techniques you would carry out for a patient recovering from respiratory arrest (whilst under general anaesthetic) (5)
constant monitoring of respiration
pulse oximetry if possible
concentrate on mm colour, cranial nerve reflexes
vital signs
TPR and record findings
List 5 signs an animal should show on smooth recovery from anaesthesia
Return of cranial nerve reflexes – palpebral, jaw tone, swallowing
TPR – pulse respiration and body temperature returning to normal ranges
No signs of pain
Name any 4 premedicants, stating which drug group they belong to , 1 advantage and 1 disadvantage of each drug.
(1mark for group, 1 mark for advantage and 1 mark for disadvantage)
Make table
Describe the cardiovascular and respiratory effects of propofol post induction
Myocardial depression
Vasodilation and bradycardia
Respiratory depression, may cause apnoea post induction
Describe one advantage and one disadvantage of the inhalational anaesthetic agent sevoflurane
Advantage –
non-irritant,
more rapid induction and recovery
preferred choice for induction by in halaltion method.
pleasant odour - well tolerated for mask induction
Disadvantage –
dose dependent cardiovascular and respiratory depression
unstable in presence of soda lime producing compound A which is nephrotoxic in rats
Describe one advantage and one disadvantage of the inhalational anaesthetic agent Isoflurane
Advantage –
good muscle relaxation
good analgesic
rapid recovery
rapid induction
Disadvantage –
Hypotension
Pungent smell - poorly tolerated for mask induction
Potent respiratory depressant
irritant to the airways
Describe one advantage and one disadvantage of the inhalational anaesthetic agent desflurane
Advantage –
lowest blood gas solubility - allowing rapid alterations in anaesthetic depth and fast recovery
rapidly excreted via lungs
well tolerated for mask induction
Disadvantage –
requires temperature controlled pressured vapouriser (expensive)
irritant to respiratory tract in high concentrations
Name 2 muscle relaxants and state for each one whether they are depolarising or non-depolarising (2)
Suxamethonium (depolarising)
Atracurium, Vecuronium (non-depolarising)
Name 4 opiods
Morphine
Pethidine
Buprenorphine
Butorphanol
Methadone
Name one steroid anaesthetic
Alfaxalone
Describe the correct storage requirements for buprenorphine
stored in locked and permanently secured cabinet – schedule 3
(do not need to keep a register)
Describe the correct storage requirements for butorphanol
stored in cool dry place, shelf at room temperature
Describe the correct storage requirements for propofol
stored in cool dry place, shelf at room temperature
Why might nitrous oxide be administered alongside oxygen as part of an inhalational anaesthetic protocol?
Used to provide analgesia
Has an anaesthetic sparing effect meaning lower doses of volatile agents are generally required.
It is mixed at a 2:1 ratio with oxygen.
Which patients should nitrous oxide be used with caution?
As it accumulates in gas filled spaces it should be used with caution in patients with GDV, intestinal obstruction, pneumothorax, middle ear disease.
Explain the term diffusion hypoxia
N2O has low solubility in blood, at the end of anaesthesia when administration of N2O ceases the N2O present in blood
diffuses back into the alveoli and ‘dilutes’ the alveolar air so less O2 is available.
If the animal is breathing room air hypoxia may occur as a result of this.
This effect is mitigated by ensuring that patients receiving N2O have 10 minutes of pure oxygen after cessation of nitrous administration.
Explain the term Minimum Alveolar Concentration
MAC is a measure of anaesthetic potency
Defined as the quantity of anaesthetic agent required to immobilise 50% of patients when under surgical stimulus.
The lower the MAC value the more potent the anaesthetic.
Explain the term Blood Gas Solubility
Is a measure of how readily the volatile agent dissolves into plasma.
More soluble agents accumulate a reservoir in the blood and slowly move from plasma to the CNS meaning they have a slower onset and recovery time.
Agents with low blood gas solubility e.g. sevoflurane are taken up rapidly from plasma = faster onset and recovery.
