Physiology Flashcards
How does emphysema affect lung capacity
Emphysema increase lung capacity
signs of this include the barrel chest and the hyper-resonance on percussion
Why is there decreased lung perfusion capacity in COPD?
There is reduced SA due to destruction of alveoli
Why is FEV1 reduced in COPD?
The lungs can’t recoil as well so it is harder to get air out
Why may nitrates be used in acute presentations of pulmonary oedema?
Nitrates cause venous dilatation and reduce the preload and strain on the heart
What conditions are associated with atrial fibrillation?
Hypertension (high BP causes damage)
Ischaemic heart disease
Valvular heart disease (esp the mitral valve)
Hyperthyroidism
Old age
Why is hyperthyroidism associated with atrial fibrillation?
Thyroid hormones potentiate the effects of catecholamines
What kind of ABG results would you expect in an anxiety attack?
Respiratory alkalosis
C02 is low (blown off by hyperventilation)
02 remains roughly the same
HC03- stays the same (no compensation as it is an acute process)
What kind of ABG results would you expect in a patient with opiate overdose?
Uncompensated respiratory acidosis
C02 is high (hypoventilation due to respiratory depression causes retention)
HC03- stays the same (no compensation in acute presentations)
What kind of ABG results would you expect in a patient with COPD?
What about when they are having an acute exacerbation?
Respiratory acidosis with metabolic compensation
High C02 due to retention
High HC03- to compensate
In acute exacerbations P02 will be low
What happens to total lung capacity and diffusion in fibrosis?
Both decreased
What ABG results would you expect in a patient with DKA?
Metabolic acidosis
C02 is low as it is being blown off by hyperventilation to try to compensate
P02 will likely be normal
HC03- is low as it is being mopped up by all the excess acid
How do you tell between metabolic and respiratory acidosis?
If pH is low it is acidosis
If C02 is low it is metabolic in cause with compensation
If C02 is high the cause is respiratory
What is hyoscine used for?
Used to reduce excessive secretions as part of end of life care for lung cancer patients
What kind of crackles on auscultation are indicative of fluid build up?
Fine crackles
