Preparation for anaesthesia Flashcards
(22 cards)
Definition of general anaesthesia
An induced, controlled state of unconsciousness accompanied by partial or complete loss of sensation as well as protective reflexes, including the ability to independently maintain an airway and respond purposefully to physical stimulation or verbal command.
Main components of general anaesthesia
Unconciousness
Myorelaxation
Immobility
Antinociception/analgesia
Other features of general anaesthesia
Transient loss of memory
Loss of protective reflexes (e.g. coughing, swallowing)
Inability to ventilate adequately
Potential cardiovascular depression
Impaired thermoregulation
Phases of anaesthesia
Premedication/sedation
Induction of GA
Maintenance of a state of GA
Recovery from anaesthesia
Premedication/sedation
Tranquilisers, sedative agents, and analgesics (acepromazine, a2-adrenoreceptor agonists, opioids).
To tranquillise the animal prior to GA, to allow IV catheterisation.
Induction of GA
Injectable anaesthetic agents (Propofol, Alfaxalone).
Induction of a state of GA (unconsciousness and loss of reflexes) through injection.
Maintenance of a state of GA
Inhalational anaesthetic agents (Isoflurane, Sevoflurane).
Maintenance of patent airways and ventilatory support, monitor physiological variables, CV support if needed.
Recovery from anaesthesia
Tranquilisers in horses, analgesics if it applies (a2-adrenoreceptor agonists, opioids, NSAIDs).
Provision of supportive care and analgesia if applicable, monitoring of physiological parameters until they normalise, risk of peri-anaesthetic death extends to the recovery phase.
Why is planning an anaesthetic important?
Legal protection of the hospital and its personnel
Patient safety
Improved outcome of the anaesthetic
Improved patient flow and effectiveness within the hospital
Legal aspects of anaesthesia
The administration of an anaesthetic drug to effect is an Act of Veterinary Surgery
Knowledge of licensed anaesthetic drugs for specific species and responsible use of cascade
Personnel safety (large animal anaesthesia)
Responsibilities of the anaesthetist
Double check that there is owner consent for GA and for planned clinical procedures
Confirm the animal identity prior to performing any procedure
Minimise the risk of contamination, cross infection and accumulation of pathogens
Things an owner must consent for anaesthesia
The owner gave consent for GA
Gave consent for that specific clinical procedure
Agrees on estimated costs
Anaesthesia basic request form details
Date, time, estimated duration of GA
List of planned clinical procedures
Basic patient details
Etc.
Patient details that should be checked before administration of anaesthesia
Species
Breed
age
Pre-placed IV catheter
Obesity, limb oedema, previous venepunctures
Consent for CPCR
Temperament
Fasting time
Relevant patient clinical history before anaesthesia
Clinical status
Underlying diseases: increased risk
Current therapies/ medications
Clinical exam necessities before anaesthesia (even in emergency)
Thoracic auscultation
Mucous membranes colour, moisture, capillary refill
Pulse quality
Temperature
Is routine pre-anaesthesia screening bloodwork necessary?
Pre-anaesthetic bloodwork reveals abnormalities in only 8% of patients with unremarkable physical exam
The likelihood to change your anaesthetic protocol or to postpone the anaesthetic based on results is 0.2% and 0.8% respectively
If the physical exam reveals abnormalities then this would be different, it is then vets decision whether bloodwork is required.
How to plan an anaesthetic
Anticipate and list the potential complications
Identify a treatment/prevention option for each potential complication
Plan your anaesthetic protocol (drugs, doses and routes of administration)
Plan analgesic approach if needed
Planning of post-operative care (2-12hrs)
Analgesia plan based on procedure and individual animal pain
Airway care and oxygen supplementation (e.g. After airway surgery, brachycephalic)
Post-operative fluids therapy
Support drugs (e.g. antiemetics, vasopressors, antiarrhythmics)
Diagnostic tests (e.g. BG, electrolytes, PCV and TS)
Things to communicate to the owner before anaesthesia
Risk of peri-anaesthetic death
Possible sequels/consequences of GA
Will my animal suffer/feel pain?
Preference for sedation over GA (often the levels of sedation needed with be v high and therefore risk could be higher)
Patient related risk factors for anaesthetic death
Small or young more likely to get hypothermia
Liver dysfunction: bleeding, hypoglycaemia and longer recover
Brachycephalic breeds: respiratory dysfunction/upper airway obstruction and high parasympathetic tone
Procedure related risk factors for anaesthetic death
Arrhythmias during procedures involving heart catheterisation
Moderate to severe bleeding during adrenalectomy/invasive oncologic surgery
Respiratory impairment during thoracotomy
Vagal stimulation during oesophageal foreign body removal
