1.1.2: Breathlessness Flashcards
How to manage a cat/dog with respiratory distress
- Calm, stress-free environment
- Remove collars
- Oxygen: flow-by or mask, oxygen cage, nasal catheters
- Obtain IV access to allow anaesthesia and intubation if required
What is your diagnosis?
Left-sided congestive heart failure
What is furosemide and how does it work?
Furosemide
* Loop diuretic
* Inhibits the reabsorption of sodium and chloride (and therefore water) in the thick ascending loop of Henle
What are your immediate next steps for this case?
- Stabilise with oxygen
- Reduce preload with vasodilators and diuretics (e.g. furosemide)
- Reduce afterload with arteriodilators
- Provide positive ionotropic support (oral pimobendan)
- Treat any complications e.g. arrhythmias, cardiac cachexia
- Thoracocentesis/abdominocentesis if required to remove fluid
You diagnosed a dog with left-sided congestive heart failure, and treated it appropriately when it presented with acute respiratory distress. What might you suggest to the owner for long-term monitoring and treatment of this disease?
- Book in for ultrasonography/radiography to stage the heart disease (and consider appropriate drugs for each stage)
- Consider sodium-restricted diet
What elements of your physical exam could you use to localise disease to a specific area of the respiratory tract?
- Auscultate lung fields and thoracic inlet
- Assess inspiratory vs expiratory noise
- Dyspnoea ± abdominal effort
- Observe respiratory rate and pattern
- Posture: head elevated? Standing vs lying down?
- Mucous membrane colour
In the normal animal, which phase of respiration is longer than the other? How might this change depending on the location of the respiratory disease?
- Normal: inspiratory phase is longer than expiratory phase
- This is often reversed in lower airway disease
An animal presents with a slow respiratory rate, exaggerated inspiratory effort (long inspiratory phase), and elevated inspiratory effort. Where will you localise this to?
a) URT
b) Lower respiratory tract
c) Pleural space disease
d) Non-CRS condition
a) URT
An animal presents with fast, shallow breaths. Both phases of breathing are altered. There is an increase in inspiratory effort, but is no marked increase in expiratory effort. Where do you localise this to?
a) URT
b) Lower respiratory tract: pulmonary parenchymal disease
c) Pleural space disease
d) Non-CRS condition
b) LRT: pulmonary parenchymal disease
* e.g. Idiopathic pulmonary fibrosis
* There is increased inspiratory effort
* Increased expiratory effort is not possible in this case due to reduced lung compliance
An animal presents with fast, shallow breaths. Both phases of breathing are altered. There is marked increase in both inspiratory and expiratory effort. Where do you localised this to?
a) URT
b) LRT (pulmonary parenchymal disease)
c) Pleural space disease
d) Non-CRS condition
c) Pleural space disease
e.g. pleural effusion
* Loss of pleural adhesion increases the effort required to breathe
* Both inspiratory and expiratory effort are increased
Tachypnoea
Increased respiratory rate
Hyperpnoea
Increased respiratory effort
Orthopnoea
Dyspnoea in any position other than standing or erect sitting; usually due to bilateral pulmonary oedema
Trepopnoea
Dyspnoea in one lateral recumbency but not the other
* Unilateral lung or pleural disease, or unilateral airway obstruction
* Often seen when patients are hospitalised and put into lateral
* Deterioration can be rapid -> be vigilant!
Rhonchi
- Low-pitched wheezes or coarse crackles
- Non-repetitive and non-musical
- Low-pitched sounds produced during early inspiration and expiration
- Signs of turbulent airflow through secretions in large airways
Moist crackles heard on auscultation might suggest…
CHF
* Most prominent on inspiration
* Usually seen with some respiratory distress
Which are the higher pitched of these two sounds:
a) Rhonchi
b) Wheezes
b) Wheezes
What do wheezes/ronchi indicate?
- Narrowing of large airways (bronchi/trachea)
- Most commonly heard on expiration; may also hear on inspiration
How could you use percussion to identify a pleural effusion?
- Percussion - tapping the chest and listening to determine whether tympanic sound created by chest wall is normal/ increased/ decreased
- With a pleural effusion, sounds will be dull below the fluid line and normal above it
- There are many possible causes of increased/decreased sounds on percussion
Respiratory difficulty is associated with disease in one of four areas:
- URT
- Pleural space
- Lung itself: alveolar or interstitial
- Non CRS conditions e.g. metabolic/physiologic
The lungs have 4 components:
1. Airway
2. Interstitial disease
3. Alveoli
4. Blood vessels
Disease in which area will result in coughing? What about breathlessness?
- Airway - disease results in cough
- Interstitial disease - disease results in breathlessness
- Alveoli - disease results in breathlessness
- Blood vessels - relevant in heart failure (pulmonary veins), parasites e.g. heartworm, thromboembolism
Disease of the upper respiratory tract where there is difficulty breathing will be characterised by:
- Inspiratory difficulty
- Audible noise
- Mostly surgical intervention
- May require emergency tracheostomy
Disease of the pleural space will be characterised by:
- May have characteristic respiratory pattern
- Muffled heart and lung sounds
- -> Ultrasound the thorax to check for this and remove fluid
Disease of the lung itself could be caused by:
- Anything in the alveoli: blood, pus, parasites
- Anything in the interstitium e.g. SOL, fibrosis
Non-CRS conditions are often characterised by/present with:
- Rapid, shallow breathing
- Open-mouthed breathing/panting
- Examples: hyperthermia, obesity, pain, fear, excitement, anaemia, acidosis, parturition, hyperthyroidism and many others
How might a patient with a pulmonary thromboembolism present? Would they have any comorbidities?
- Acute onset dyspnoea
- Few radiographic signs
- Might be in a hypercoagulable state e.g. after trauma/surgery, in sepsis/DIC, HAC/endogenous corticosteroids, hypoT4, IMHA, glomerulonephropathies
Describe a basic approach to a dog or cat presenting with respiratory distress
- Giving oxygen/putting somewhere stress-free is never going to be wrong
- Identify the principle problem and localise it: URT, pleural space, lung: alveolar or interstitial, or non-CRS?
- Establish differentials for the principle problem
- Make a plan - you can make decisions without having a diagnosis
