Diagnostic approach to the dyspnoeic patients

Question 1

Discuss the common causes of dyspnoea in dogs and cats

Answer 1

pleural effusion
pulmonary oedema from forward heart failure
Asthma in cats
Non-cardiogenic pulmonary oedema in puppies
Trauma, causing pulmonary contusions and rib fractures impairing mechanical respiration and oxygen transfer
Laryngeal paralysis

Question 2

Explain how to differentiate conditions according to the anatomical division of the respiratory tract affected

Answer 2

Upper airway disease can often present as a prolonged inspiration? Like an obstruction in upper airway?
Laryngeal paralysis - inspiratory stridor?
Lower airway disease can be more effort on expiration
Often lower airway disease is mixed respiratory effort

Cravioventral with pneumonia
Perihilar in some cases of LSh failure
Harsh dorsal lung sounds with pleural effusion
Harsh CV sounds with pneumothorax
Harsh everywhere with feline asthma

Question 3

Identify and differentiate pleural space disease, bronchointerstitial disease and alveolar disease

Answer 3

Pleural space disease
Bronchointersitial disease
Alveolar disease

Inspiratory dysnpnoea - UAO (stertor or stridor) , or severe chronic pleural effusion. Spend much longer trying to breathe in, they can only manage a small inspiratory tidal volume so expiration is usually short. Noise ass with inspiration unless very severe

Inspiratory dys with an expiratoyr push - fixed UAO

No upper airway noise? Severe chronic, pleural effusion. Due to large volume pleural space disease.

Where expiration is worse than inspiration -> expiratory dyspnoea, usually mixed though. Feline asthma

Short, shallow pattern, -> pleural space disease, but a lot of other things can cause this pattern.

Respiratory pattern, effort, rate (almost always inc as worsens, but with a lot of work to breathe like with really stiff lungs, so rr can fall, this is very serious and impending arrest) , noise
Moderate, severe or critical (no mild!)

Collapsing trachea - inspiration is fine, snaps shut when breathing out = goose honk cough

Abdominal movement -
Abdominal effort - push on expiration
Paradoxical abdo movement - UAO, stiff lungs, diaphragm hole or not working, severe chronic pleural effusion -> lungs cant expand, so diaphragm is pulled cranially, and abdo is sucked inwards

Question 4

Describe the methods of stabilisation used depending upon the anatomical site affected

Answer 4

Regardless of the anatomical site, in a dyspnoeic patient the first treatment is oxygen therapy. This is to improve oxygenation to the cells and help stabilise the patient.
If an upper airway obstruction is suspected then sedation and examination of the upper airway is undertaken, being prepared to insert a tracheostomy tube if retrieval is unsuccessful.
If laryngeal paralysis is suspected, then injection of steroid to reduce inflammation is indicated.
Flow by’ - next to nothing, better than nothing
Mask, - stressful for some patients, could get close to 60-80%, easy and cheap, requires restraint
E collar and cling film - can get inspired o2 30-60%, fewer leaks - higher inspired o2, but also higher himidyt , co2 and temp which makes dyspnea worse
Nasal catheters - insp o2 conc of 30-60% , estimate tidal volume (10ml/kg) at 40 breaths/min = minute volume of 400ml/kg so 20kg dog gets 8L/min, a flow rate >2l/min per nostril =- drying and damage of nasal mucosa, cant do high flow rates longer (2l/min/nostril = max), risky in head trauma patients as can cause them to sneeze etc.

Trancheal cannuluation
O2 cage
intubation/ventilation

Question 5

Describe the subsequent diagnostic evaluation of the patient with respiratory distress

Question 6

Differentiate the causes of pleural effusions on the basis of the clinicopathological characteristics of the fluid.