Approach to the collapsed patient- anaesthesia workshop

Question 1

What is safter GA or sedation

Answer 1

general anaesthetic- as ensures airway (ET tube and oxygen), monitoring and control

Question 2

What drugs affect the cardiovascular system more

Answer 2

isoflurane and sevoflurane
try to minimise these to minimise their effects

Question 3

List 8 things to improve anaesthesia in sick patients

Answer 3

reduce stress and anxiety
titrate/ calculate drug dose depending on case
enrich oxygen supply
ET intubation
careful monitoring
judicious (careful amount) IVFT
close monitoring
pain relief

Question 4

why is stress bad when anaesthetising patients

Answer 4

increases catecholamines and adrenaline- this increases oxygen demand

Question 5

why is pain relief important in anaesthesia

Answer 5

can cause ECG dysrhythmias

Question 6

A young bulldog (with known BOAS stage 3) presents to the practice on a hot summer day, he collapsed after walking into garden. The dog is panting and gasping for breath. The pulse is regular and rapid 132 bpm. The mucous membranes are mauve/pink. CRT is 2.5 seconds. Based on this limited history, where is the problem in the tree of life?
1. Mitochondrial function
2. Heart rate
3. Microcirculatory flow
4. Haemoglobin saturation

Answer 6

Haemoglobin saturation- not enough O2 into the blood stream

Question 7

define hypoxemia

Answer 7

is low oxygen levels in the blood

Question 8

define hypoxia

Answer 8

is low oxygen levels in the tissue

Question 9

define hypoxic hypoxia

Answer 9

not enough oxygen avaliable to lungs e.g. BOAS dogs

Question 10

define anaemic hypoxia

Answer 10

Reduced haemoglobin content
e.g. IMHA, haemorrhage

Question 11

define circulatory hypoxia

Answer 11

cardiovascular impairment
e.g. hypovolaemic, septic shock

Question 12

define histotoxic hypoxia

Answer 12

cells can’t use the oxygen
e.g. mitochondrial problem, cyanide

Question 13

describe when we give oxygen supplementation

Answer 13

Rule of thumb oxygen saturation below 93% and an arterial partial pressure of oxygen below 70 mmHg should prompt oxygen supplementation

Question 14

list 2 things that can help with diagnosis of hypoxemia

Answer 14

Pulse oximeter, & or blood gas analyser
Visual observation of mucous membrane colour (not very accurate)

Question 15

List 4 ways to provide a dog with oxygen

Answer 15

by flow by
via a mask
oxygen cage
nasal lines

Question 16

list 2 disadvantages of providing oxygen by flow by

Answer 16

often not well tolerated
can further contribute to anxiety

Question 17

list 2 disadvantages of providing oxygen via a mask

Answer 17

may not be tolerated in anxious patients
Rebreathing of carbon dioxide can occur with tightly fitting masks, and periodically switching out the mask is recommended

Question 18

List 3 advantages of an oxygen cage

Answer 18

Physical separation of the clinical team from the patient
Reduces anxiety
can provide humidified air

Question 19

list 2 disadvantages of oxygen cages

Answer 19

Disadvantage is this approach may ‘miss’ changes - as not constant monitoring
Expensive

Question 20

what is FiO2

Answer 20

fraction of inspired oxygen
the concentration of oxygen in the gas mixture

Question 21

what flow rate should you use 1 or 2 nasal lines

Answer 21

1= 50-100ml/kg/min
2= 100ml/kg/min through both - used in very hypoxic dogs

Question 22

list 6 things that cannula choice depends on

Answer 22

species/ breed
visible veins
fragility of veins
length of time needed
solution to be infused
blood sampling

Question 23

as animals become more compromised list 3 drugs families that should be avoided

Answer 23

-NSAIDs
-high dose Alpha 2 agonists- bad effects on CV (low dose does not have these effects)
-Acepromazine

Question 24

what pain relief can you give to very sick animals

Answer 24

opioids e.g. methadone (IM or slow IV)
OR
lidocaine as constant rate infusion - provides whole body analgesia- mostly used in dogs

Question 25

when giving lidocaine as constant rate infusion what do you need to make it doesn’t also contain

Answer 25

adrenaline

Question 26

what do you need to consider when inducing a compromised animal

Answer 26

Administer drugs slowly as ‘vein to brain’ time has increased with low cardiac outputs- otherwise could overdose the animal

Question 27

what could you give with induction drugs to reduce the amount used

Answer 27

benzodiazepine (midazolam)
give some propofol/ alfaxalone then midazolam then more propofol/alfaxalone

Question 28

why can ketamine be a good induction agent in compromised animals

Answer 28

keeps HR normal
doesn’t vasodilate

Question 29

list 3 ways to reduce the use of isoflurane/ sevoflurane in compromised patients

Answer 29

give increments of ketamine
constant rate infusion
local blocks

Question 30

if SPO2% is dropping what should you do

Answer 30

THINK
- is the resp system ok?
- is oxygen supply and delivery ok?

Question 31

list 4 things that the capnograph informs you about

Answer 31

ventilation
metabolism
cardiac output
equipment/ airway

Question 32

what is the normal range of a capnograph

Answer 32

35-45mmHg

Question 33

Why can cat capnographs not look like big normal ‘squares’

Answer 33

Often on T piece- and oxygen on high rate it is diluting the CO2 breathed out

Question 34

list 3 ways to measure blood pressure

Answer 34

non-invasive blood pressure
doppler
direct/invasive

Question 35

Hypotension occurs at BP of

Answer 35

systolic <80-90mm Hg
mean <60-70 mm Hg
diastolic < 40mm Hg

Question 36

What can you do if your patient gets hypotension during anaesthesia

Answer 36

switch down volatile agent and consider PIVA
try IV bolus of crystalloid
if animal is bradycardic to?= administer anticholinergic
then consider inotrope or vasoconstrictor