GA Accidents and Emergencies Flashcards
What is the CEPSAF enquiry?
a study to estimate the risks of anaesthetic and sedation-related mortality in companion animals in the UK
what is the overall risk of mortality under sedation/GA for dogs?
0.17%
what is the overall risk of mortality under sedation/GA for cats?
0.24%
what is the overall risk of mortality under sedation/GA for rabbits?
1.39%
for what duration did the CEPSAF study look at post-op complications?
48 hours
does sedation or GA carry higher risks?
GA
within what timeframe did 50% of deaths occur?
within 3 hours of recovery
how does ET intubation affect mortality of cats during GA?
increased mortality in cats (not dogs)
what is the risk factor of inhalational anaesthesia?
6 times more likely to die compared to injectable
what is one of the limitation of the of CEPSAF study?
only looked at mortality within 48 hours - some issues take longer to arise
what is a significant patient factor in GA/sedation risk?
poor health - dogs with asa grades 3-5
what types of procedures carry the highest risk for GA/sedation related death?
urgent procedures
how does patient age affect risk of GA/sedation-related death?
older dogs (largest >9 years)
what type of facial conformation carries a higher risk of GA/sedation-related death?
dolichocephalic breeds - 3.7x the risk compared to mesocephalic breeds
why is it thought that dolichocephalic breeds have a higher GA/sedation-related risk?
increased attention/vigilance towards brachycephalic breeds may reduce our concern towards other breeds
possible additional risk pathway that is specific to dolichocephalic dogs that we do not fully understand
what are some of the main factors which contribute to anaesthetic accidents?
unwell patients
equipment failure
inadequate preparation
inadequate monitoring
what is the difference between a complication and an error?
a complication is an event that develops but is not due to human error whereas an error is an avoidable event
give some examples of anaesthetic complications
hypotension
haemorrhage
drug reaction
give an example of an anaesthetic error
APL valve left shut
patient given wrong dose of drug
what are some of the human errors that can occur during anaesthesia?
drug administration errors
incomplete clinical assessment
inadequate knowledge of equipment/protocols
failure to appropriately monitor the patient
closed APL valve
what types of equipment error/failure can occur during anaesthesia?
inability to deliver an appropriate oxygen supply
lack of oxygen in cylinder/source
disconnection of piped oxygen
stuck or missing one way valve
leaks in the machine/breathing system
ventilator failure
what are the benefits of using checklists during anaesthesia?
ensures safety critical steps are performed, as well as improving teamwork and communication
what are the complications that can arise during IV catheterisation?
trauma during insertion
extravascular placement
infection/inflammation
phlebitis
air embolism
pain/discomfort
how can we prevent IV catheter complications?
aseptic technique
start lower down on limb
chose correct catheter type (length/gauge)
prevent patient interference
daily/twice daily observation and dressing change
regularly flush
what are the possible drug administration errors?
incorrect drug/dose/concentration/route used
why do drug administration errors usually occur?
miscommunication
how can we avoid drug administration errors?
double-check all calculations, doses, bottles, route of admin
have an accurate patient weight
always label syringes
understand pharmacology of drug given
check hospital form before and administration
record all drugs given on hospital sheet
what should we do if we spot a drug admin error?
tell the vet immediately
stop giving the drug if not all given
carefully monitor patient
check drug bottle/data sheet for info
contact poison service if necessary
inform owner of mistake
how can we reduce the incidence of drug admin errors?
issues should be discussed regularly at clinical governance meetings
what is the difference between vomiting and regurgutation?
vomiting = active process
regurgitation = passive process, no GI contraction
what is reflux?
regurgitation in an anaesthetised patient
what are the danger periods for vomiting/regurgutation?
induction and recovery
what is GOR?
gastro-oesophageal reflux
what are the risk factors for GOR?
excessive/inadequate pre-op fasting
drug choices
abdominal pressure
abdo surgery/long ops
orthopaedic surgery
why is regurgitation sometimes missed?
some regurgitation is silent
what are the signs in recovery that a patient might have GOR?
may vomit blood-tinged fluid, appear unable to swallow, appear distressedw
name some drugs which might make a patient more likely to have GOR
ACP, diazepam, opioids
why do some opioids make patients at risk of GOR?
Mu agonists relax the oesophageal sphincter
why might GOR be more common in ortho procedures?
usually use a Mu agonist
patient often moved multiple times under GA
how can we lower the risk of GOR?
appropriate pre-op fasting times
identify at-risk patients
pre-op GI protectants?
head up/swift induction
cuffed ET tube
have suction readily available
describe the steps you should take if you notice regurgitation
tell vet, patient head down
suction/swab out pharynx
record on anaesthetic record
which drug might vets give to patients at risk of GOR?
omeprazole IV
why do patients develop corneal ulceration under sedation/GA?
anaesthesia/sedation/opioids reduced tear formation
trauma from external sources can contribute (heat/masks/liquid)
why is it important to prevent corneal ulceration?
corneal ulceration is incredibly painful
how can ocular damage be prevented under GA?
regular use of ophthalmic ointment/lubrication
care with warming devices
careful positioning
be aware of placement of face masks
avoid droplet/liquids around face area
avoid trauma
what should we do if we notice an ulcer forming under GA?
prevent rubbing/scratching
inform vet
potentially start eye ointments to continue at home
try to identify the reason
inform owner
what can hypothermia result in?
cardiac arrhythmias
bradycardia
impaired coagulation and wound healing
shivering –> increased oxygen demand
at what body temperature is atrial fibrillation likely to occur?
30 degrees
at what body temperature is ventricular fibrillation likely to occur?
24-28 degrees
how does hypothermia impact anaesthesia?
drugs have prolonged duration of action
decreased renal plasma flow
decreased oxygen delivery to tissues
lower anaesthetic requirement
how can we prevent hypothermia under GA?
insulate patient
warm from point of premed - don’t leave unsupervised
HME breathing system
care with clip and scrub
use of external heat sources, warm environmental temperature
avoid excessive length of anaesthesia
what is the effect of hyperthermia on BMR?
increased BMR - 13% for every degree above normal
what are the effects of hyperthermia under GA?
increased BMR
increased oxygen requirement
parenchymal cell damage
what occurs at body temperatures >41 degrees?
irreversible brain damage
what occurs at body temperatures >43 degrees?
death
which breeds are at risk of hyperthermia?
brachys
overweight patients
how can we avoid hyperthermia under GA?
close observation of patient warming
identify at-risk animals
provide cooling if required - fan/wet towels/cold water lavage
how can we avoid heat burns under GA?
never leave patient on heat source they are unable to move away from
avoid microwave heat sources - they do not distribute heat evenly
what are possible causes of respiratory failure/restriciton under GA?
depression of respiratory centres in brain
impaired movement of thorax - sandbags, abdo pressure (surgeons hands)
impaired lung movement e.g. pleural effusion
airway obstruction
what are some of the possible signs of respiratory tract obstruction?
increased respiratory effort
paradoxical ventilation
no air movement through nose/mouth
cyanotic mucous membranes
capnography changes
why might we see apnoea/respiratory arrest under GA?
depth i.e. too light (breath-holding) or too deep
unnoticed respiratory tract obstruction
drug-related e.g. fentanyl/NMB/post-induction apnoea
why might we see cyanosis under GA?
may be due to inadequate oxygen supply
may be due to very low cardiac output
what should you do if you notice respiratory tract obstruction and the patient isn’t intubated?
inform surgeon/vet
straighten neck, pull tongue forward, check mouth/pharynx and suction if needed
check equipment, turn on oxygen and intubate
how can we reduce chances os desaturation during intubation?
pre-oxygenate, esp if potentially difficult intubation
what should you do if you notice respiratory tract obstruction and the patient is intubated?
check ET tube isn’t kinked/obstructed/too long/faulty
check breathing system
check oxygen supply
try giving breath and feel for resistance in the bag
what should you do if the patient is apnoeic and cyanotic?
confirm heartbeat
check depth of anaesthesia, check for obstruction/obvious causes
ensure 100% oxygen is given (minute volume)
manual ventilation, check breathing system/tube/chest wall movement
antagonise drugs and turn off volatile agent if necessary
what is cardiac arrest?
cessation of an effective circulation
what can cause cardiac arrest under GA?
pre-existing CVS disease
anaesthetic overdose
hypovolaemia
electrolye/acid-base abnormalities
vagal reflex
undetected respiratory arrest
what improves chances of success for a cardiopulmonary arrest?
earliest detection possible
what should we do if the patient is in cardiac arrest?
call for help - establish team
start cardiac compressions
turn off anaesthetic agent and begin ventilating, check breathing system, tube, confirm chest wall movement
which type of cells in the heart have the ability to contract?
working myocardial cells
which cells in the heart have the ability to generate an impulse?
self-excitatory cells
what is automaticity?
the property of cardiac cells to generate spontaneous action potentials
what heart rate does impulse via the atrioventricular node achieve?
40-60bpm
what heart rate does impulse via the bundle of His achieve?
40-60bpm
what heart rate does impulse via the bundle branches/purkinje fibres achieve?
20-40bpm
what is an arrhythmia?
a change in rate, rhythm or origin that differs from the normal cardiac cycle
what happens in first degree block?
electrical signal is ‘held up’ - struggles to get through each time
what does 1st degree block look like on ECG trace?
prolonged distance between P and R
gap between P and QRS complex is larger than that between QRS and T wave
what are the 2 types of 2nd degree block?
wenckebach and mobitz
what occurs in Wenckeback 2nd degree block?
progressive lengthening of the PR interval until the gap is so large that beats are lost - gradual
what occurs in Mobitz 2nd degree block?
intermittent passage through the AV node, but no progressive development - beats just drop
what is 3rd degree block?
complete heart block - electrical signal cannot get past the AV node
why does 3rd degree block not instantly result in cardiac arrest?
body has safety mechanisms that allow other parts of the heart to generate a beat - these are often weaker and slower
why is the trace in 3rd degree block so irregular?
different induction of beats being given from different parts of the heart at irregular times
what is ventricular tachycardia?
very rapid heart rate caused by abnormal complexes generated by the ventricles
what is the heart rate during ventricular tachycardia?
> 160bpm
what should you do if you notice abnormalities in the ECG trace?
try to get printed/video/screenshot ECG trace
inform vet immediately
