Respiritory: Physiology and Function in Obstructive Lung Disease Flashcards
What is an obstructive disorder
Anything that blocks airflow.
Could be inside the airway: mucous, odema
Could be the smooth muscle constricting
Two drugs that can cause dialation of airways?
What receptors do they act on?
What parts of the nervous system does this correspond to?
- Salbutamol - beta 2 agonist - triggers smooth muscle effect of the sympathetic nervous system
- Ipratropium - muscarinic antagonist - blocks the smooth muscle effect of the parasympathetic nervous system
Sympathetic and Parasympathetic transmitters and receptors involved in smooth airway muscle
Sympathetic - adrenaline & noradrenaline - beta 2 receptors
Parasympathetic - acetylcholine - muscarinic
Main differences between asthma and COPD
- Asthma - alergenic and temporary. Bronchoconstriciton, antibodies and inflamation
- COPD - chronic. Mucous hyper secretion, alveolar wall destruction, fibrosis
Simple bedside tool for measuring airflow?
Peak flow.
Quick blow through a tube.
Gives you a quick idea of how reduced airflow is.
If giving someone a peak flow in hospital what are you comparing the peak flow result to?
Their best predicted peak flow.
The useful data is a percentage of peak flow to best predicted peak flow.
If < 50% you would get critical care involved. If < 33% this is considered life threatening
More sophisticated airflow technique?
Spirometry
What is FEV1 and FVC?
FEV1 = air exhaled in 1s
FVC = total air exhaled
General spirometry result that diagnoses obstruction?
FEV1/FVC < 0.7
How can you use brochodialators and spirometry to get a more detailed diagnoses?
You perform a normal spirometry to diagnose obstruction.
Then you give salbutamol and perform another one.
If it improves then it’s asthma.
If not likely COPD. The severity of which is gathered by comparing the FEV1 to predicted
