FGF, Pre-GA and ASA grading

Question 1

what do you need to know in order to calculate a patient’s FGF?

Answer 1

body weight
resting respiratory rate

Question 2

what are the normal tidal volume values?

Answer 2

cats and small dogs = 15ml/kg
medium dogs = 12ml/kg
large dogs = 10ml/kg

Question 3

how do you calculate FGF for non-rebreathing circuits?

Answer 3

weight x (10-15) = TV
TV x RR = MV
MV x CF = ml/min
ml/min % 1000 = l/min

Question 4

how do you calculate FGF for a circle circuit?

Answer 4

induction rate: 100ml/kg/min
- weight x 100
- for 5-10mins

10ml/kg/min: 10ml/kg/min
- weight x 10

Question 5

how do you calculate FGF for a Humphreys ADE?

Answer 5

Semi-closed mode (<7kg)
- induction rate = 100ml/kg/min (weight x 100)
- maintenance = 70 ml/kg/min (weight x 70)

Recycling Mode (>7kg)
- induction rate = 30ml/kg/min (weight x 30)
- maintenance = 10m;/kg/min (weight x 10)

Minimum Induction Rate = 500ml/min
Minimum Maintenance Rate = 300ml/min
If the calculation is below - use the minimum rate

Question 6

what is involved in a pre-anaesthetic assessment and preparation?

Answer 6

Patient assessment
- temperament - calming drugs given?
- cardiac - pulse, murmurs, arrhythmias - check BP/ECG
- respiratory - rate and effort
- temperature - if day patient don’t do again
- hydration - MM colour
- neurological status - impacts premed - know normal to compare
- pain - acute or chronic
- clinical history - any changes - previous reactions

Question 7

When is a pre-anaesthetic blood test recommended?

Answer 7

geriatric patients may benefit
- good to test organ function
- but expensive so avoid when can

signs a test is needed
- known medical conditions
- sudden changes (weight, eating/drinking, toileting)

Question 8

when on a clinical exam would you suggest an echo is a needed before a GA?

Answer 8

If you have picked up on a murmur or arrythmia

Question 9

Which animals should not be fasted prior to GA?

Answer 9

rabbits
guinea pigs
neonates - dependant
small birds
ferrets

Question 10

how long before surgery should food be withheld?

what are you trying to balance?

Answer 10

neonates: 2-6hours
healthy adult: 3-6 hours

Fasting for too long can cause:
- hypoglycaemia (esp. neonates)
- electrolyte imbalance
- GI issues (not receiving nutrition)
- build-up of acid causing regurgitation

Not fasting for long enough can cause:
- regurgitation and aspiration

Question 11

should we pre-warm patients?

Answer 11

not always found to improve hypothermia
- so patient dependent
- highly stressed will be warmer

but highly recommended for smaller animals (small dogs, cats and rodents) as quickly lose heat

Question 12

should we pre-oxygenate patients?

Answer 12

useful if you know there will be a delayed intubation
- eg. brachycephalic difficulties

useful if the patient has respiratory/cardiac problems

mask may increase stress - especially cats
- so counterintuitive
- flow by has little effect

Question 13

what equipment do you need to prepare for a GA?

Answer 13

oxygen - suitable amount - spare cylinder
flowmeter - spinning - no sticking
vapouriser - full range works - no sticking
scavenging - connected properly - correct weight/exit place
paperwork - all correct, available and ready

Question 14

hoe should you check a breathing system?

Answer 14

visually inspect
close the APL valve for a leak testing
- REOPEN FULLY!!
check soda lime for exhaustion

check inside tubing of coaxial systems

Question 15

when should you use a catheter?
what do you need to consider?

Answer 15

all anaesthetics - give premed first if necessary

use appropriate size
- green (18G) = giant dogs
- pink (20G) = med/large dogs
- blue (22G) = small dogs and cats
- yellow (24G) = rabbits/guinea pigs/ neonates

use appropriate location
- eg not on limb having surgery on

ensure patent before induction

Question 16

how do you prepare yourself for a GA?

Answer 16

know ASA status of patient
- consider comorbidities, breed, age, size etc

all equipment ready and checked

consider procedure
- blood loss, positioning, patient access, cost

consider the patient
- species - anatomy, pathology, pharmacology etc
- breed - any increased risks - eg greyhounds bleeding post-op
- equipment - check familiar with all - if new try out first

solve problems before they happen
- extra drugs/top ups, IVFT ready, warming ready etc

Question 17

what is the ASA grading?
what is its purpose?

Answer 17

a risk assessment score for each patient

assess if procedure is too risky to perform

highlights adjustments that need to be made to ensure safety of patient

Question 18

Describe ASA grade 1

Answer 18

normal healthy animal

no detectable underlying disease

often routine spays/castrates

Question 19

Describe ASA grade 2

Answer 19

slight-mild systemic disease
- but on obvious clinical signs

all neontaes, geriatrics and obese patients
- with no pre-existing health concerns

Question 20

Describe ASA grade 3

Answer 20

mild-moderate systemic disease
- causing clinical signs
- managed

Question 21

Describe ASA grade 4

Answer 21

extreme systemic disease
- a threat to life
- unmanaged

eg GDVs, pyometras, unstable diabetes, sepsis

Question 22

Describe ASA grade 5

Answer 22

dying
not expected to survive 24 hours without surgery

Question 23

what do you need to consider when chosing pre-med drugs?

Answer 23

Patient
- temperament
- ASA grade
- age
- breed

Procedure
- aim
- analgesia level

Question 24

what is needed in a pre-anaesthetic checklist

Answer 24

pre-induction
- check correct patient
- check equipment
- check staffing

pre-procedure - ready in theatre
- communicate safety concerns/likely issues

recovery
- check all procedures completed
- analgesia plan
- ongoing monitoring - blood loss, arrhythmias, obstruction - assign person

Question 25

what are the main considerations when positioning a patient?

Answer 25

well padded
neutral position
- avoid overextension and/or flexion
consider pain
avoid eye trauma
avoid damage to trachea/ ETT obstruction

Question 26

what are the concerns with patients in dorsal recumbency?

Answer 26

added pressure on the diaphragm
- worsened by abdominal distention (eg pregnant)
- so hypoventilation likely

reduces venous return and cardiac output