Pre-emptive and multi-modal analgesia Flashcards
What is allodynia?
Pain from stimuli which are not normally painful. The pain may occur other than in the area stimulated.
What is Multi-modal analgesia?
*Multi-modal analgesia = using drugs from
different drugs groups to provide analgesia,
targeting different parts of the pain pathway.
*Provides more effective analgesia than just
giving one large dose of one drug
*In using smaller doses of drugs, have less side
effects
Which part of the pain pathway do NSAIDs modulate?
Transduction
Which part of the pain pathway do local anaesthetics modulate?
*Transmission
*Block sodium channels, and
thus nerve conductions
*Only true analgesics
Which part of the pain pathway do opiods, ketamine, alpha 2s, nitrous oxide modulate?
Modulation
Which part of the pain pathway do opiods, ketamine, alpha 2s, modulate?
Perception.
What are the side effects of opioids?
*Dysphoria
*Respiratory depression
*Bradycardia
*Nausea
*Sedation
What are the side effects of NSAIDs?
*Renal dysfunction
*Gastro-intestinal disturbances
*Clotting dysfunctions
What are the side effects of alpha 2s?
*Bradydysrrythmias
*Respiratory depression
*Vasoconstriction
*Sedation
*Nausea
What are the side effects of ketamine?
*Hallucinatory effects
*Increased heart rate and blood pressure
*Respiratory depression
What are the side effects of local anaesthetics?
*Cardiotoxicity
*Neurotoxicity
What are the side effects of nitrous oxide?
*>66% inspired fraction will decrease amount
of available oxygen to the patient
*Problems associated with use of nitrous oxide and air filled spaces will occur more quickly if higher percentages are used
What should you try and use during an anaesthetic?
Try and incorporate at least three drug
groups
*Opioid in premed
*NSAID/paracetamol if appropriate
*Local anaesthetic techniques
*+/- Nitrous oxide
*+/- ketamine
*+/- alpha 2 adrenergic agonists
What are the benefits of pre-emptive analgesia?
*Analgesic agents are acting before nociceptive input starts.
*Helps to prevent peripheral and central
sensitisation.
*Should prevent phenomena such as
‘hyperalgesia’ and ‘allodynia’.
*Should make the analgesia more effective and
so should reduce analgesia requirements in post operative period.
What analgesia should animals go home with post dental?
*NSAIDs
*Paracetamol (in dogs)
*Buprenorphine SL (in cats)1
*Tramadol?
*Gabapentin or amantadine if chronic pain suspected
What are the disadvantages of anaesthesia-free dentistry?
*Patient stress and pain
*Injury to patient, staff and equipment
*Risk of aspiration
*Lack of diagnostic capabilities
*Only cleans the visible surfaces of the teeth and therefore lulls the owners into a false sense of security
What are the percentage risks of anaesthesia?
– Dogs [overall] 0.17% [ASA I-II] 0.05% [ASA III-VI] 1.33%
– Cats [overall] 0.24% [ASA I-II] 0.11% [ASA III-VI] 1.4%
What should be involved in a pre-anaesthetic examination?
*Mucous membrane
colour, moistness and
CRT
*Hydration status
*Pulse quality and rate
*Auscultation of all four
heart valves, noting
grade and PMI of any
murmurs.
*Auscultation of the lung fields
*If any irregular rhythm
is auscultated,
concurrent pulse
palpation should be
performed to identify
any pulse deficits.
*Observation of
respiratory rate and
pattern
*Rectal temperature
taking?
What clinical history do you need before an anaesthetic?
*Co-morbidities
*Current medication
*Previous anaesthetics
*Exercise tolerance
*Eating/drinking ok
*Coughing/sneezing
*Vomiting/diarrhoea
*Signs of pre-existing pain
What is the triad of analgesia?
Unconsciousness
Relaxing
Analgesia
What are the best type of endotracheal cuffs?
Square profile, high volume low
pressure cuffs
How much should you inflate a cuff for a cat?
In cats, 1.6 +/- 0.7ml is needed to inflate cuff appropriately.
In cadaver cats, 6ml cuff inflation caused tracheal ruptures in 7/10 cats.
How can you recognise tracheal ruptures?
Immediate signs
– Pneumomediastinum
– Subcutaneous
emphysema
– Pneumothorax
– Pneumopericardium
– Decompensation during GA
Later signs
*Dyspnoea
*Coughing
*Gagging
*Anorexia
*Stridor
*Lethargy
What can be used to for suction during anaesthesia?
*May be used at induction, during anaesthesia
and just before extubation
*Yankauer suction tip
*Urinary catheter
How can volatile agent pollution be countered/reduced?
*Use cuffed endotracheal tubes
*Do not switch on vaporiser until cuff inflated
*Consider TIVA or PIVA
*Ensure high rates of ventilation in work space
*Use low fresh gas flow rates
*At end of procedure, keep patient attached to breathing system until most volatile agent has been exhaled
