Cardiorespiratory Flashcards
define dyspnoea
difficult or labored breathing
define tachypnoea
increased rate of of respiration
define orthopnoea
upright position with extended neck
what is normal respiratory rate when resting?
<35 brpm
what is normal respiratory rate when sleeping?
<25 brpm
what are the main causes of tachypnoea/dyspnoea?
physiological
hypoxaemia
hypercapnia
respiratory disease
cardiac disease
what are the physiological causes of tachypnoea/dyspnoea?
stress
pain
excitement
exercise
what is hypoxaemia?
not enough oxygen in the blood
what makes up the upper airway?
nasal passages
pharynx
larynx
trachea
what type of dyspnoea is associated with upper airway issues?
inspiratory dyspnoea
what is inspiratory dyspnoea?
hard for the patient to breathe in
what sounds may be heard with inspiratory dyspnoea?
stertor
stridor
what is stertor?
snoring
what is stridor?
harsh, high pitched breathing sounds on inspiration
what conditions are stertor and stridor commonly seen with?
stertor - BOAS
stridor - laryngeal paralysis
what are the upper airway causes of dyspnoea?
laryngeal paralysis
BOAS
neoplasia
polyps
FB
inflammation
tracheal collapse
how should upper airway causes of dyspnoea be treated?
if obstructed: anaesthesia and intubation
decompensation may be rapid
what makes up the lower airway?
bronchi
bronchioli
what respiratory pattern is seen with lower airway dyspnoea?
quick short inspiration
prolonged expiration
what may be heard on lung auscultation of lower airway dyspnoea patients?
harsh lung sounds (wheezing, crackles)
what are harsh lung sound on auscultation caused by?
bronchoconstriction
secretions blocking airways causing crackles as air forced past
what are the lower airway causes of dyspnoea?
asthma
bronchitis
smoke inhalation
bronchopneumonia
COPD
what dyspnoea type is seen with lung parenchyma disease?
inspiratory and expiratory
what are the lung parenchymal causes of dyspnoea?
pulmonary oedema (cardiac or non cardiac)
pneumonia
haemorrhage
contusion
neoplasia
thromboembolism
parasites
what are the cardiac causes of pulmonary oedema?
CHF
what are the non-cardiac causes of pulmonary oedema?
electrocution
strangling
what breathing pattern is seen with pleural space diseases?
restrictive pattern
increased rate but reduced depth
why is restrictive dyspnoea seen with pleural space diseases
lungs cannot expand due to fluid/air leading to shallower breaths
what are the pleural space causes of dyspnoea?
pneumothorax
pleural effusion
masses
diaphragmatic hernia
what are the causes of pleural effusions?
haemorrhage
infection (pyothorax)
neoplasia
heart failure
chylothorax
what are the auscultation findings in patients with effusions?
if standing: muffled heart and lung sounds ventrally (fluid settling)
normal dorsally
what are the auscultation findings in patients with pneumothorax?
muffed heart and lung sounds dorsally as air rises
what is involved in initial assessment of respiratory emergencies?
oxygen is crucial
targeted physical exam
check for URT signs
RR rate and effort
MM
heart rate
any arrhythmias
murmurs
check peripheral pulses (defecits)
what is the goal of oxygen supplementation?
increase oxygen content in arterial blood and delivery to tissue
what are the determinants of oxygen delivery?
haemoglobin concentration
blood oxygenation
cardiac output
how does haemoglobin concentration determine oxygen delivery?
oxygen carrying capcity reduced if haemaglobin reduced (e.g. anaemia)
how does cardiac output determine oxygen delivery?
reduced leads to reduced oxygen delivery to tissues
what are the main methods of oxygen supplementation?
flow by
mask
nasal prongs
oxygen catheter
collar (not ideal)
oxygen cage
intubation
ventilation
how is pleural effusion / pneumothorax diagnosed?
physical exam
thoracic xray
ultrasound
what are the benefits of ultrasound for respiratory patients?
less stressful
no need to be in lateral
what can be used to stabilise pleural effusion/pneumothorax patients?
thoracocentesis
what is involved in thoracocentesis?
sedate animal
prep area
use catheter to drain chest
collect samples for cytology, culture and biochem
what catheters may be used for thoracocentesis?
catheters for dogs
butterfly needle for cats
what are the main considerations for oxygen administration?
is supplementation indicated
awareness of O2 toxicity
rate of delivery needed (not too much or too little)
what are the aims of oxygen supplementation?
resolution of life threatening hypoxaemia
relief of respiratory distress
what are the lungs vulnerable to when patients are on high FiO2?
oxygen toxicity
what influences oxygen toxicity?
FiO2 and duration
when are patients only likely to receive 100% FiO2?
intubated or ventilated
how what FiO2 should patients be on if on long term oxygen?
<60%
what can be done to avoid oxygen toxicity?
administer to lowest level the patient will tolerate
what are the main patient monitoring methods available for dyspnoeic patients?
physical exam
ABG
pulse ox
what is the downside of monitoring patients through physical exam?
insensitive
what should be monitored on a clinical exam of respiratory patients?
RR and effort
MM
heart rate
peripheral pulses
anxiety levels
what may be indicated by mm colour?
dehydration
hypovolaemia
hypotension
vasoconstriction
why may respiratory patients be hypotensive/vasoconstricted?
cardiac output reduced
are mucous membranes necessarily a good indicator of respiratory patient status?
could be normal
what is measured by ABG?
PaO2
what is the gold standard method of evaluation of arterial oxygenation?
ABG
where are ABG samples taken from?
dorsal metatarsal artery
femoral artery
what is needed for ABG?
specific syringe
blood gas analyser
what is crucial about ABG samples to ensure PaO2 is measured accurately?
airtight
analysed straight away
what is normal PaO2 on ABG at room air?
100 mmHg
what is normal PaO2 on ABG at 100% O2?
500mmHg
what does PaO2 depend on?
FiO2
barometric pressure
what PaO2 suggests hypoxaemia?
<80 mmHg on room air
what O2 saturation suggests hypoxaemia?
<95%
what PaO2 is indicated by SpO2 of <90%?
<60 mmHg
how much does PaO2 increase by on 100% FiO2?
~5x room air
why are venous PaO2 readings less useful?
venous PaO2 around 40mmHg once O2 has been delivered to tissues
on room air what PaO2 should you aim for?
80-120 mmHg
on room air what SpO2 should you aim for?
95-100%
what does pulse oximetry measure?
peripheral oxygen saturation
what is calculated by a pulse ox?
haemaglobin oxygen saturation
is the reationship between PaO2 and SpO2 linear?
no
what is the issue with thoracic radiographs?
dangerous if patient is unstable
requires lateral recumbancy
could lead to rapid decompensation
what is congestive heart failure caused by?
increased pressure in the heart leading to increased pressure in veins returning to the heart
this creates increased pressure in the capillaries which prevents fluid from being reabsorbed from the tissues
what types of CHF are seen in dogs?
left sided
right sided
congenital
what signs are seen with left sided CHF?
pulmonary veins
pulmonary oedema
what can lead to left sided CHF in small dogs?
myxomatous mitral valve disease
what can lead to left sided CHF in large dogs?
DCM
what happens to the heart muscle during DCM?
muscle becomes weakened
what part of the cardiac cycle is affected by DCM?
systolic failure - heart not strong enough to pump
what signs are seen with right sided CHF?
systemic veins affected
effusions / ascites seen
what can right sided CHF lead to?
pericardial effusion
what are the sings of CHF in cats?
both left and right sided can be seen
what side of the heart is commonly more affected in cats?
left
what is the most common heart disease in cats?
hypertrophic cardiomyopathy
what is the effect of hypertrophic cardiomyopathy on the cardiac cycle?
diastolic dysfunction due to thickening of heart muscle - heart cannot fill
what are the two types of backward CHF?
left sided
right sided
what organ is most affected by left sided CHF?
lungs
what are the signs seen in the lungs of left sided CHF?
pulmonary oedema
tachypnoea
dyspnoea
cough
how does left sided CHF lead to cough?
cough receptors are in large airways and so unlikely affected by pulmonary oedema
more likely that enlarged heart is triggering receptors
what area is most affected by right sided CHF?
body
what signs are seen with right sided CHF?
distended peripheral veins
ascites
pleural effusion
what are the respiratory effects seen as a result of pleural effusion / ascites?
tachypnoea / dyspnoea due to restriction of breathing
what is forward CHF?
reduction in cardiac output
when is forward CHF often seen?
endstage disease - especially DCM
what side of the heart can be affected by forward failure?
left or right
what are the signs of forward CHF?
weak peripheral pulses
tachycardia
why does forward CHF lead to weak peripheral pulses and tachycardia?
reduction in stroke volume leads to increased heart rate in an attempt to increase cardiac output
how do patients with left sided CHF present?
heart murmur
tachypnoea
dyspnoea
tachycardia
pale
prolonged capillary refill time
arrhythmias
weak peripheral pulses
pulse defecits
are heart murmurs always seen with left sided CHF?
most but not all
can have murmur and no CHF but can have CHF with no murmur
what sort of heart failure are pale mm more commonly seen with?
forward failure
what is involved in initial assessment of left sided CHF patients?
history
targeted physical exam
stabilisation before diagnostic testing
why must CHF patients be stabilised before diagnostic tests are performed?
patients often fragile and may decompensate
how can left sided CHF patients be stabilised?
minimise stress
consider mild sedation
O2
what may CHF patients be given for mild sedation?
butorphanol - reduce RR and calm
what drugs may be given to stabilise left sided CHF patients?
furosemide IV
pimobendan PO or IV
what is the purpose of furosemide?
reduces circulating volume and so work of the heart
what can furosemide reduce in LHS CHF patients?
pulmonary oedema
what is the rol of pimobendan in the stabilisation of left sided CHF patients?
improve myocardial contractility to increase stroke volume and cardiac output
via what route should pimobendan be given?
PO if possible and safe, if not IV
what are the main diagnostic tests used for left sided CHF?
echocardiography
thoracic xray
ECG
BP
blood tests
what is the role of echocardiography in left sided congestive heart failure?
diagnosis
assessment of severity
what is the role of thoracic xray in left sided congestive heart failure?
assess for pulmonary oedema or other potential causes of respiratory distress
is thoracic xray always indicated?
not if in resp distress due to risk of decompensation
may be used later once more stable
what is the role of ECG in left sided congestive heart failure?
detection of arrhythmia
what is the role of BP measurement in left sided congestive heart failure?
assess for hypotension
what is the role of blood tests in left sided congestive heart failure?
check electrolytes and renal function (due to diuretics)
what may be seen on xray of a patient in left sided CHF?
pulmonary oedema - lungs compressed ‘floating’ on fluid
enlarged heart
what is normal sleeping RR?
<25 brpm
what is normal resting RR?
<30 brpm
what should be monitored about a left sided CHF patient?
RR and effort
BP
HR and pulse quality
ECG
how can patient improvement when stabilising in left sided CHF be shown?
RR and HR decrease
what is the RR goal for patients in left sided CHF?
<40 brpm
when should you be concerned about left sided CHF patients BP?
systolic <80 mmHg
what should you do if arrhythmias are detected on ECG?
telemetry
when may thoracic radiographs be used in an unstable CHF patient?
if patient isnt improving as rapidly as expected
how should left sided CHF patients be treated once stabilised?
optimise therapy
start feeding ASAP
book revisits for blood tests, echo etc
what must be explained to owners about managing left sided CHF?
therapy is life long
why should CHF patients be fed as soon as possible?
cardiac cachexia leading to loss of muscle mass and body weight
how often may blood tests be needed for CHF patients?
~3 monthly
what are the causes of right sided CHF?
pulmonic stenosis
tricuspid dysplasia
pericardial effusion
how is right sided CHF diagnosed?
history and physical exam
clip neck
echocardiography
thoracic xray
ECG
CT
why should the neck be clipped on all suspected right sided CHF patients?
look for jugular pulsation
what may be found on auscultation of right sided CHF patients?
muffled heart sounds due to effusion
what is the role of echocardiography in right sided congestive heart failure?
diagnosis
detection of neoplasia
what is the role of thoracic xray in right sided congestive heart failure?
assess heart size
what is the disadvantage of using thoracic xray to assess heart size?
pericardial effusion may appear like an enlarged heart
what is the role of ECG in right sided congestive heart failure?
arrythmia
what is the role of CT in right sided congestive heart failure?
neoplasia detection - primary or metastasis
what is a pericardial effusion?
increased fluid in the pericardium
what is cardiac tamponade?
right atrium is lowest pressure chamber and so collapses due to the increased external pressure from the effusion - this impairs filling of the right side of the heart and in trun decreases cardiac output
what is the effect of pericardial effusion?
due to increased fluid and collapse of the right atrium filling of the right side of the heart is impaired leading to decreased cardiac output and reduced left sided heart filling
what are the causes of pericardial effusion?
idiopathic
neoplastic
what animals mainly present with pericardial effusion?
large breed adult dogs
how is pericardial effusion treated?
stabilisation through pericardiocentesis and IVFT
why is IVFT indicated for pericardial effusion?
pressure in heart is reduced as is venous return
IVFT can increase systemic volume and so increase pressure in heart and hopefully cardiac output
what drugs are not indicated for pericardial effusion?
diuretics due to risk of reducing venous return even more
what is the only heart failure condition that IVFT is indicated for?
pericardial effusion
how does fluid drained from the pericardium typically appear?
looks like blood
how can you check fluid drained from the pericardium is actually not being drained from the heart itself?
pericardial fluid will not clot - blood will - plain serum tube to watch for clotting
ECG to check for arrhythmia if heart is being prodded
what should be seen following pericardiocentesis?
visible improvement in HR, pulse strength and demenour
how long should patients be hospitalised for following pericardial effusion?
12-24 hours
what should be monitored for following pericardial effusion and pericardiocentesis?
arrhythmias
recurrence
what should owners be warned about following pericardial effusion?
signs to look out for
that it may recur
what is the most common cause of feline cardiac emergencies?
hypertrophic cardiomyopathy
what can heart failure in cats be precipitated by?
stress
anaesthesia
IVFT
how do cats in heart failure commonly present?
murmur
gallop sounds
tachypnoea
dyspnoea
open-mouth breathing
tachy or brady cardia
weak peripheral pulses
hypothermia
what signs indicate a cat is more sick with CHF?
gallop sounds
bradycardia
what is a significant feline cardiac emergency?
arterial thromboembolism
where does the thrombus develop from in feline arterial thromboembolism?
L atrium
what are the signs of arterial thromboembolism?
sudden onset hindlimb paresis / paralysis
pain
pallor/cyanosis of pads and nail beds
pulselessness
cold leg
what are the 5 Ps of arterial thromboembolism?
pain
pallor
paresis/paralysis
pulselessness
poikilothermy
why does paralysis/paresis, poikilothermy and pulselessness result from arterial thromboembolism?
blockage of distal aorta
what is the initial approach to feline cardiac emergancies?
history
physical exam
stabilisation
further tests once stable as cats are so fragile
how should feline cardiac patients be stabilised?
AVOID STRESS
O2
furosemide
drain pleural effusion
gentle warming
analgesia and soft bedding if arterial thromboembolism
how can feline cardiac emergencies be diagnosed?
echocardiagraphy for diagnosis
thoracic xrays (avoid if possible)
ECG - arrhythmia
BP measurement - hypotension
blood tests - electrolytes and renal parameters
how should feline patients be managed once stabilised?
adjust drug therapy to lowest effective dose
life long treatment
warm soft bedding
physio if ATE
Home ASAP
encourage eating
minimise stress including vet visits
revisit for bloods and echo
what must owners be informed about cats with cardiac issues?
monitor sleeping resp rate and respiratory effort for signs of worsening CHF
look for signs of ATE (5 Ps)
warn them that cats may die suddenly
what is the normal heart rate of a dog?
60-160 bpm
what is the normal heart rate of a cat?
160-220 bpm
what is classed as a brady arrhythmia in a dog?
<60 bpm
what is classed as a brady arrhythmia in a cat?
<120 bpm
what is classed as a tachy arrhythmia in a dog?
> 160 bpm
what is classed as a tachy arrhythmia in a cat?
> 240 bpm
how may patients with arrhythmias present?
syncope/ collapse
weakness
exercise intolerance
signs of CHF
abnormal heart rhythm (irregular/brady/tachy)
weak peripheral pulses
pulse defecits
how can arrhythmia be diagnosed?
ECG
what is a severe type of brady arrhythmia?
3rd degree AV block
what HR is associated with 3rd degree AV block?
40 bpm
what is occuring during 3rd degree AV block?
AV node not functioning
impulse from SA node not transmitted
ventricular rhythm with atrial tachycardia
what is seen on ECG with 3rd degree AV block?
P and QRS complexes are not associated as SA node not triggering ventricular depolarisation
describe this cardiac rhythm
3rd degree AV block - P unrelated to QRS
what HR is associated with ventricular tachycardia?
300 bpm
how does ventricular tachycardia appear on ECG?
wide and bizarre complexes
what cardiac rhythm is this?
ventricular tachycardia
where does fluid collect in left sided CHF?
lungs - pulmonary oedema
where does fluid collect in right sided CHF?
body - ascites, pleural effusion, jugular pulsation
how should all cardiac patients be managed?
with care
low stress
very fragile
what is echocardiography used to diagnose?
cardiac disease
what is thoracic xray used to diagnose?
heart failure
what are ECGs used to diagnose?
arrhythmias
what are the signs of respiratory distress in cats?
tachypnoea
orthopnoea
dyspnoea
open mouth breathing
when triaging a patient what is crucial?
assess the most life threatening concerns even if distracting wounds/fractures
what body systems are assessed as a priority during triage?
respiratory
CVS
neuro (head trauma etc)
what is key when managing respiratory patients?
fragile!
low stress environment
O2
when examining a respiratory patient what areas should you look at?
observe rate, effort and pattern
auscultate
purcussion
check cranial rib spring
assess oxygenation
what is cranial rib spring?
palpation of cranial ribs to assess for potential masses
ribs should compress slightly and spring back
what is indicted by inspiratory dyspnoea?
extrathoracic upper airway obstruction
what is indicted by expiratory dyspnoea?
intrathoracic upper airway obstruction
lower airway disease
what is indicated by rapid shallow breathing or slow laboured breathing?
pleural space disease
parenchymal disease
what are adventitious lung sounds?
abnormal respiratory noises
what sort of adventitious lung sounds may be heard on auscultation?
wheezes
crackles
how else can the chest be assessed during examinaton aside from auscultation?
palpation (cranial rib spring)
percussion
what is a valuable tool for monitoring oxygen delivery?
pulse ox
what are the 4 main causes of dyspnoea?
URT obstruction
LRT disease
pleural space disease
parenchymal disease
what are the common URT causes of dyspnoea?
FB
nasopharyngeal polyps
tumours
what are the common LRT causes of dyspnoea?
feline asthma
bronchitis
what are the common pleural space causes of dyspnoea?
pneumothorax
pleural effusion
haemothorax
diaphragmatic rupture
what are the common parenchymal causes of dyspnoea?
pulmonary oedema
haemorrhage
infection
neoplasia
fibrosis
what is indicated by inspiratory noise and dyspnoea?
URT disease
what area of the URT may be affected if stridor is heard?
larynx
what are the potential causes of laryngeal disease?
neoplasia
oedema
FB
spasm
paralysis
abscess
granuloma
what must be done if a URT patient is unable to breathe effectively?
intubation
may need ucath
what is indicted by expiratory dyspnoea with no URT noise?
lower airway disease
what may indicate chronic lower airway disease on auscultation?
expiratory wheezes
increased resonance
what are the common causes of feline lower airway disease?
asthma
chronic bronchitis
bacterial infection
lungworm
FB
neoplasia
what is feline asthma caused by?
type 1 hypersensitivity response to an allergen
what is caused by hypersensitivity in feline asthma?
airway hyper-responsiveness
reversible bronchoconstriction
secondary inflammatin
what is seen with chronic bronchitis?
airway inflammation
excess mucus production
airway narrowing
what can be developed secondary to feline asthma and chronic bronchitis?
pneumothorax
how should feline lower airway disease be treated?
stress free
O2
bronchodilators
what bronchodilators may be used to treat feline lower airway disease?
terbutaline
salbutamol
how is terbutaline administered?
IM/sC
q4
how is salbutamol administered?
1-2 puffs of inhaler for effect
what may be seen on xray of a patient with chronic bronchitis?
lungs over expanded due to ongoing inflammation
what disease types are indicated by rapid shallow breathing with no URT noise?
parenchymal disease
pleural space disease
what disease types are indicated by rapid shallow breathing with no URT noise and no muffling of heart or lung sounds?
parenchymal disease
what are the main causes of parenchymal disease?
haemorrhage
pneumonia
oedema (cardiogenic or non-cardiogenic)
neoplasia
fibrosis
how should cardiogenic pulmonary oedema be treated?
cage rest
oxygen
sedation with butorphanol if necessary
furosemide I/M if needed
what disease types are indicated by inspiratory dyspnoes, rapid shallow breathing with no URT noise and muffling of heart or lung sounds?
pleural space disease
what is seen on chest percussion with pleural space diseases?
dullness
what are the main causes of pleural space diseases?
pleural effusion
pneumothorax
neoplasia
diaphragmatic rupture
what is heard on auscultation and percussion of patients with pneumothorax?
hyper-resonance dorsally
reduced lung sounds
what should be done if pleural effusion seen/suspected?
drain
sample
what types of fluid may be seen in pleural effusion?
transudate
modified transudate
exudate
what is indicated by pleural effusion of transudate?
hypoalbuminaemia
what is indicated by pleural effusion of modified transudate?
CHF
neoplasia
what is indicated by pleural effusion of septic exudate?
pyothorax
what is indicated by pleural effusion of non-septic exudate?
neoplasia
FIP
what is indicated by pleural effusion of chyle exudate?
CHF
trauma
idiopathic
what is indicated by pleural effusion of blood exudate?
trauma
coagulopathy
neoplasia
what equipment is needed for thoracocentesis?
clippers
sterile prep
gloves
catheter
3 way tap
EDTA
plain tube
20ml syringe
where should the needle be placed for thoracocentesis?
7th to 8th intercostal space
whereabouts in relation to the rib should thoracocentesis needles be placed?
cranial - nerves and blood vessels run along caudal boarder
what tubes are needed for thoracocentesis sampling?
EDTA for cytology
plain for biochem, culture and sensitivity
what should the patient be started on following thoracocentesis?
IV antibiotics pending culture results
what are the main considerations for emergency care of respiratory patients?
stress free
sedation if needed
O2
equipment needed for thoracocentesis, intubation and tracheostomy
U/S preferred
xray if safe
meds
what are the main bronchodilators used?
terbutaline IM
salbutamol inhaler
what are the main emergency drugs used for respiratory patients?
bronchodilators
glucocorticoids
furosemide (IV or IM)
what glucocorticoids may be used in respiratory patients?
dexamethasone IV or IM
fluticasone inhaler
when will furosemide be given to patients?
if CHF expected
what is the common management for URT disease?
intubate
what is the common management for LRT disease?
bronchodilators
what is the common management for CHF?
frusemide
what is the common management for pleural space disease?
thoracocentesis