Physiology Flashcards
What happens to the FEV1/FVC% in someone with COPD (obstructive lung disease)
The FEV1 is decreased, the FCV is normal and the ratio is decreased.
A ratio of 70% or less is needed for a COPD diagnosis
What happens to pulmonary compliance in emphysema?
It is increased because the elastic tissue is lost so it’s easier for the lung to expand but difficult for it to recoil
What happens to gas exchange in emphysema?
It is affected due to destruction of alveoli and reduced surface area for gas exchange
What happens to the total lung volume in emphysema?
It is increased as the lungs are hyper-inflated
When is dynamic airway compression likely to occur in a patient with COPD?
During active expiration
What are the physiological changes in a patient with breathlessness due to anxiety?
Increased central and autonomic arousal
What happens to pulmonary compliance and gas diffusion in pulmonary fibrosis?
Reduced pulmonary compliance and impaired gas diffusion
What does a dry cough, increasing shortness of breath on exertion and crackles at the bases of the lungs indicate?
Pulmonary fibrosis
What happens to the airways and surface area in COPD?
Fixed airway obstruction and decreased surface area for gas exchange
What happens to the FEV1/FVC% in someone with restrictive lung disease (eg pulmonary fiborisis)
The ratio will not be affected (more than 70%)- both FEV1 and FVC will be low
What happens to pulmonary compliance and gas diffusion in a patient with lung oedema (eg in left ventricular failure)?
Reduced pulmonary compliance and impaired gas diffusion
At what PO2 does the oxygen saturation start to drop below 90% (think about the oxygen dissociation curve)
8 kPa
What is the main effect of pulmonary fibrosis?
It effects the thickness of the membrane which affects the diffusion of gases
Why in fibrosis is O2 levels affected more than CO2?
CO2 diffuses more easily, so the PCO2 will stay similar during exertion while PO2 will drop more significantly
In metabolic acidosis, what happens to the PCO2?
It is low as the patient is blowing off CO2 to try and compensate
In metabolic acidosis, what happens to the HCO3?
It decreases
How much is the functional residual capacity in a young adult man?
Approximately about 2.2 litres
What is the functional residual capacity?
The volume of air present in the lungs at the end of passive expiration
What is the tidal volume?
The lung volume representing the normal volume of air displaced between normal inhalation and exhalation when extra effort is not applied
What is the inspiratory reserve volume?
The maximal amount of additional air that can be drawn into the lungs by determined effort after normal inspiration
What is the inspiratory capacity?
The amount of air that can be inhaled after the end of a normal expiration
What is the expiratory reserve volume?
Additional amount of air that can be expired from the lungs by determined effort after normal expiration
What is the residual volume?
The amount of air that remains in a person’s lungs after fully exhaling
What is the vital capacity?
The greatest volume of air that can be expelled from the lungs after taking the deepest possible breath
What is the total lung capacity?
Total amount of air in the lungs after taking the deepest breath possible
Does a low PO2 cause vasoconstriction or vasodilation?
Vasoconstriction
What happens to a patient’s blood pressure in tension pneumothorax?
Hypotension due to the increased pressure in the lungs which decreases the pressure gradient that maintains venous return
What happens to the intra-pleural pressure in tension penumothorax?
It increases
What happens to oxygen saturations and PO2 in anaemia?
They both remain normal - the PO2 remains normal as there is no issue with the resp or cardiac systems and the saturation remains normal as there is less haemoglobin but what little is present will be fully saturated
What is the PO2?
The amount of oxygen dissolved in the blood
What happens to the total lung capacity and lung diffusion capacity in COPD?
Total lung capacity is increased (due to lung hyperinflation) but lung diffusion capacity is decreased
What medications would you give to someone presenting with acute decompensated heart failure?
IV furosemide and nitrate infusion
What is the most common arrhythmia associated with hyperthyroidism?
AF
In oedema what sort of crepitations do you hear?
Fine crackles
