Small animal anesthesia Flashcards
What are the steps to preforming small animal anesthesia
Preanesthetic evaluation and patient prep
Pre anesthetic medication
Anesthetic induction
Maintenance and monitoring
Recovery
What are the steps to the preanesthtic exam
Full physical examination
Age
Temperament (Pre-hospital: gabapentin, trazodone,…)
Breed
Medical history
Past problems, previous adverse drug responses
Anaesthetic events
Present problems – medication
Basic hematology (PCV, TP, BUN, Gluc)
Diagnostic tests? Older – sick patients
CBC, serum chemistry, urinalysis advisable
Older or ill patients
On the basis of the physical exam and history
Radiograph thorax (trauma, resp problems)
ECG, echocardiography (murmurs, arrhythmias)
Delay anesthesia until
Further assessment if performed
Patient stabilised
Anesthetic risk established
What should you communicate to a client about anesthesia
Anesthetic risk
Set expectations
Patient prep starts at home
Prehospital anxiety rugs (PO, 2 hours prior to drop off)
Trazodone
Gabapentin
What are the ASA physical status classifications
ASA 1 normal healthy patient
ASA 2 mild systemic disease – no functional limitation
ASA 3 severe systemic disease – definite functional limitation
ASA 4 severe systemic disease that is a constant threat to life
ASA 5 Moribund, not expected to survive without operation
How long shoudl you fast from food and water and why
Allow free access to water
Care with old animals and animals with increased fluid requirements
Recommended fasting before anesthesia
Young animals: requires shorter fasting times (hypoglycemia)
6-16 weeks: 4 hours
Older than 16 weeks: 6-8 hours
Make sure to give patients with PUPD water to before premed
What are the aims of premed
Sedation and anxiolysis (fear free)
Facilitate animal handling
Balanced anaesthetic technique
Analgesia
Smooth and quiet recovery
What are the steps to making an anaesthetic protocol
Physical exam
Age
Temperament
Surgical procedure
Clinical setting
Premedicatio: sedative + opioid
Induction
Maintenance: inhalant +/- opioid +/- local anaesthetic
Postoperative pain management: NSAID,opioid
What are the common premeds used
Opioids
- Hydromorphone
- Methadone
- Butorphanol
- Buprenorphine
Sedatives
- Acepromazine
- Dexmedetomidine
- Midazolam
Maybe some anticholinergics
- Atropine
- Glycopyrrolate
DON’T CO ADMINISTER AN ANTICHOLINERGIC WITH DEXMEDETOMIDINE
- Simultaneously increase and decrease heart which can cause negative effects especially in older animals
What are the common premeds used for a calm dog
Acepromazine: 0.01-0.05 mg/kg
Hydromorphone: 0.1 mg/kg
OR
Dexmedetomidine: 1-5 micro gram/kg
Hydromorphone: 0.1 mg/kg
What is the common protocol for agitated dogs
Acepromazine: 0.01-0.02 mg/kg
Dexmedetomidine: 1-10 μg/kg
Hydromorphone: 0.1 mg/kg
Plus Ketamine 1-10mg/kg for aggressive dogs
What is the standard protocol for cat premed
Dexmedetomidine: 8-30 μg/kg
Hydromorphone: 0.1 mg/kg
What is used as a more reliable sedative in cats
For more reliable sedation use a ketamine-based protocol
Provides General anesthesia for invasive short procedures
Monitor patient!
Provide life support
DEXMEDETOMIDINE (10-25μg/kg)
- Ketamine (2-10 mg/kg)
- Butorphanol (0.4 mg/kg)
DEXMEDETOMIDINE (5-15μg/kg)
- Midazolam (0.2 mg/kg)
- Butorphanol (0.4 mg/kg)
ALFAXALONE 2 mg/kg
- Butorphanol (0.4 mg/kg)
- Midazolam (0.2 mg/kg)
Acepromazine is not a good sedative in cats
What should you check before performing anesthesia on our machines
Ensure ET tubes/intubation aids are readily available
Monitoring equipment
Anesthesia machine
Select appropriate breathing system
Perform leak test
Check: oxygen, inhalant, CO2 absorbent, waste scavenging
Ensure ET tubes and intubation aids are readily available
How should you prep the patient for anesthesia
Venous access - catheter placement
Stabilize hemodynamically unstable patients
Check HR, RR and pulse quality
Connect monitoring equipment (appropriate for disease condition)
Pre oxygenation: reduces risk of hypoxemia
Quiet environment
What meds are used as induction agents
Administer to effect
Propofol
Diazepam
Ketamine
Alfaxalone
Mask induction
Iso
Sevo
Not stress free so last resort
What meds are used for cat induction
Propofol
Diazepam
Ketamine
Alfaxalone
mask/chamber induction
Sevo
Iso
Administer to effect
What are the ABCs of anesthetic induction
Airway
Breathing
Circulation
Depth and drugs
Equipment
Fluids
What does it mean when you say airway for induciton
Intubation
Secure tube
Inflate cuff
Confirmation of endotracheal intubation
How do you check breathing when induction
Auscultation for bilate lung sounds while manually ventilating
Check for spontaneous ventilation
What should you do for intubation after induction
Prior to use check
Endotracheal tube for patency
Cuff for leaks
Have multiple ETT sizes available
Laryngoscope, cling, cuff syringe
Pre measure ET tube length (incisor teeth to thoracic inlet)
What is the technique to intubating a dog
Can be performed in sternal, lateral or dorsal
Apply slight coating of lube (improves cuffs ability to seal)
Open dogs mouth, pull tongue forward gently
Open the dogs mouth, pull tongue forward gently
Straighten head and neck, extend tongue
Put tip of laryngoscope blade on base of tongue, NOT on epiglottis
Insert endotracheal tube under visualization
Inflate cuff and check for leaks
Secure tube
Avoid over-inflation of the ET tube cuff
How do you intubate cats
More difficult than dog:
Small oropharynx
Prone to laryngospasm
Local anesthetic (lidocaine) useful to prevent laryngospasm
Lidocaine spray: metered dose 12mg
Lidocaine neat 2% (2mg per 0.1ml)
How do you confirm ETT placement
Direct visualisation (use laryngoscope)
Rebreathing bag
Chest excursions
Palpate one trachea below the larynx
Capnograph
Gold standard
Auscultation of both sides of the animals chest during manual ventilation
How do you check depth of drugs during anesthesia
Check depth of anesthesia
Eye position
Palpebral reflex
Jaw tone
Base on your patients depth → turn on vaporizer
How do you check equipment for anesthesia
Apply monitoring equipment
Doppler first: audible signal
Monitor BP
Assess patient
Adjust vaporizer setting
Why do you give fluids during surgery
Correction of normal ongoing fluid losses
Support of cardiovascular function
Countering of potential negative physiologic effects
Maintaining patient IV catheter
Paradigm of 10ml/kh/hr is NOT evidence based
New fluid guidelines during anaesthesia
Cats: 3ml/kg/hr
Dogs: 5ml/kg/hr
When do you extubate SA
After dental surgery check oral cavity for fluid,…
Don’t untie tube until patient has reached final recovery spot
ET-tube cuff should not be deflated until just before extubation
Dogs: Extubation on return of swallowing reflex
Cats: need to be extubated sooner
On return of good palpebral reflex, ear flick reflex
Prone to laryngospasm or laryngeal edema
What is the optimal recovery time
Optimal recovery time: within 10-30 min of end of anesthesia
What are common complications of recovery
Emergence delirium - caused by inhalant
Dysphoria - caused by opiods
Pain
Delayed recovery
Patients should be closely observed until they are alert, normothermia and ambulatory
How do you insure patient comfort during recovery
Enviro stress (noise, bright lights)
Hypothermia
Urinary bladder distension
Pain assessment and adequate pain management
What supportive care should you provide during recovery
O2
Fluids
Heating
Eye ointment
