Session 12 - Group Work Flashcards
What is unusual about the sympathetic receptors in bronchial smooth muscle and from this, what constitutes the main sympathetic control signal for bronchodilation?
They promote relaxation rather than constriction; sympathetic system will usually cause the upregulation of things but in this case it does not because you need more air to get in.
Adrenaline as a hormone from the adrenal gland is activating the b2 receptors in the lungs. Therefore, they’re not coming through the sympathetic system or nerves, it is dictated by the systemic adrenaline made in the adrenal medulla.
Anticholinergic muscarinic receptor antagonists are also not in ‘first line’ use for asthma. Why is this, and what does their mode of action make them better suited for?
They are slower action - they take a while to work/kick in. The maximum response occurs at 30-60 mins and last about 3 hours. Therefore you are better off to use a beta agonist as this is much quicker acting.
They are best used for COPD because it is not an inflammatory condition.
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
a) What is your diagnoses?
Acute severe asthma
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
b) What are your first treatment priorities?
- Oxygen, high flow - aim to keep O1 94-98% sat (hypoxic pts)
- Nebulised salbutamol - continuous if necessary, oxygen driven
- Oral prednisolone ~40 mg daily for 10-14 days
- can be stopped without tailing down (hydrocortisone IV if can’t swallow; prednisolone can’t be IV) - If moderate exacerbation not responding, or acute severe/life threatening, add nebulised ipratropium bromide
- Consider IV aminophylline if no improvement and life threatening features not responding to above treatment (BEWARE if taking oral theophylline ).
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
c) By what route should the steroid be delivered if possible?
Orally (prednisolone)
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
d) What clinical benefit does evidence suggest early steroid therapy will achieve?
Steroids work after a few hours so are there for the long-term effect. Therefore, by the time it works, it will prevent reinflammation.
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
e) Describe how ipratropium affords relief of symptoms in this patient, but why the therapeutic effect is limited.
Bronchodilation develops more slowly and less intense
than adrenergic agonists
It is a long-acting anti-cholinergic so it reduces the parasympathetic response of bronchoconstriction of M3. However, it also has effect on M2 receptors and cholinergic neurons, we can get increased vagal tone, so it’s not as effective as you might think.
Try and treat B2
Cannot be taken orally.
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
f) Why does it have limited systemic side effects? What route related side effect is common?
If inhaled it is not going to cross the lungs etc. so there are limited systemic side effects.
Dry mouth route-related side effect common because it is not reaching systemically.
Oral route would lead to related side effect of dry mouth
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
g) On discharge what should you make sure the patient and doctor have discussed?
- Inhaler technique
- Self-management
- Compliance
- Step up/step down
- When to go in for review.
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
h) Which class of antihypertensive agents are contraindicated in asthmatic patients and why?
Beta blockers - if you’re blocking the B2 receptors you’re doing the opposite of the effect you want, bc you cause bronchoconstriction and that will exacerbate the condition.
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
i) What properties of a new long acting beta agonist would you consider important if you were able to advise a pharmaceutical chemist? Think about the dosing and side effects of current agents.
- We want selectivity to the B2 receptors to minimise side effects
- You want something that can be nebulised, i.e. spray, so that it can be taken at home, ideally once a day
- Cheap to make so it is accessible to all
- Don’t want it to taste bitter to increase pt compliance (but also not too nice for OD)
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
j) What considered risk needs to be made when prescribing inhaled corticosteroids (ICS) in patients with COPD?
Risk of infection due to downregulation of inflammatory cytokine tx
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
k) What is remarkable about stage two of Guedel’s signs of anaesthesia?
Stage 2: unconscious, breathing erratic but delirium could occur, leading to an excitement phase.
As they continue to breathe, as the volatile partitions from the lungs into the brain, or in the case of IV agent, they then go into paradoxical phase of excitement. Muscle tone can a bit more physically see. Breathing becomes slightly erratic, so effectively they’re in that phase.
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
l) What affect does nitrous oxide have on the delivery of inhalation anaesthetics?
Reduces the MAC so reduces the amount of primary anaesthetic needed required. You use this because it also acts as an analgesic and has a low side effect profile so it’s more favourable to use this rather than the primary in higher doses.
1) A 27-year-old asthmatic male student is admitted with 4 days progressive wheezing, a non-productive cough and increased breathlessness. He has been attempting to self-manage disrupted sleep (coughing and slight wheeze) over the last few weeks with his reliever inhaler. On examination, HR 95 bpm, respiratory rate 28, BP 130/80 mmHg, sats 93% on air, peak flow 250L/min (predicted 510 L/min) struggling to complete sentences in one breath.
m) In exacerbations of COPD, steroids may be prescribed typically for 7-14 days. Using your knowledge of the inflammatory process associated with asthma and COPD, explain why there is greater urgency to administer steroids in asthma exacerbation compared to COPD.
Asthma is usually an acute inflammatory condition, so steroids will affect it quicker …
Asthma - hypersensitivity reaction so mediated by eosinophils - quicker - 18 hrs response.
COPD usually exacerbates an infection, there primary immune response so mediation is neutrophils which lasts long (5-90 hrs).
