Asthma Exacerbations**** Flashcards
Severe asthma signs:
Why are the lungs hyper resonant on percussion?
Pulsus paradoxus happens in a severe attack.
- What is it?
- How is it found out?
- Why does it happen?
Due to lungs being hyperinflated with air in COPD, or patients having an acute asthmatic attack.
A BP drop of at least 10 mm Hg with each inspiration.
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This is enough of a difference to cause a noticeable change in the strength of your pulse.
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Hyperinflation puts extra pressure on the veins carrying unoxygenated blood from the heart to the lungs.
As a result, blood backs up in the right ventricle
This causes extra pressure to build up on the right side of the heart, which presses against the left side of the heart.
Difficulty breathing from bronchospasm during acute asthma causes the patient to increase negative pressure in the thorax (hyperinflate) to compensate. The increased effort has an effect similar to that of backward pressure on circulation from the circulatory conditions listed above. Or, it could be seen as similar to the effect of positive pressure ventilation as described.
Signs of life-threatening attack?
Silent chest Confusion Exhaustion Cyanosis Bradycardia
Investigations:
Bedside: Observations are all done!! - What is taken for culture? - What is done to test lung function? - When is an ABG needed?
Bloods:
- What bloods would you do?
Imaging:
- Why do you do a CXR?
Sputum
Peak flow rate (PEFR)
If very severe ======= FBC - baseline U&E - baseline CRP - if infection Blood cultures - if an infection ==== Excludes pneumothorax and infection
Mild and Moderate:
Mild is just increasing symptoms. Under what % is the PEFR which makes it moderate?
Management:
SABA inhaler through spacer:
- How many puffs are done initially?
- How long between each puff?
- How many can be done every 2 minutes?
- How many puffs in total?
- How often can this cycle of using the inhaler be completed if they remain symptomatic?
If PEFR
Every 10-20 minutes
75%
4 puff 30 secs apart
2 (30s apart) every 2 minutes up to 10 puffs
O2 driven SABA nebuliser
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Prednisolone
Assessing the severity of an acute asthma attack:
Severe attack:
- Sign
- Above what RR is classed as severe in adults?
- What about those between 5-12 yrs old?
- What about those <5 yrs old?
- Above what HR is classed as severe?
- What about those between 5-12 yrs old?
- What about those <5 yrs old?
- Under what % is the PEFR, compared to their predicted or best one?
Unable to complete sentences in one breath
RR>25/min = >30 (5-12) = >50 (<5)
HR>110 = >120 (5-12) = >130 (<5)
33-50% of predicted or best
Assessing the severity of an acute asthma attack:
Life-threatening attack:
- Sign - 4
- Under what % is the PEFR, compared to their predicted or best one?
- Cardiac signs - 2
ABG in the life-threatening attack:
- Why is the PaO2 low (<8kPa)?
- Why does the PaCO2 decrease initially?
- Why does the PaCO2 then slowly increase?
During an asthma exacerbation, there is air trapping and ventilation/perfusion mismatch, resulting in hypoxemia (PaO2 or SATS <92).
Silent chest
Poor respiratory effort
Cyanosis
Altered mental state, confusion, coma
<33% of predicted or best
Arrhythmia
Hypotension
During an attack, your airways narrow, making it hard to get air into your lungs. Coughing to clear your lungs uses even more oxygen and can make symptoms worse.
Initially, compensation occurs and hyperventilation causes the PaCO2 to decrease.
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When further air trapping leads to decreased lung compliance and increased work of breathing, the PaCO2 will begin to increase.
Sign on ABG of a near-fatal asthma attack?
High PaCO2 or needing ventilation
Management:
Mneumonic SONSIS - What does it stand for?
How long after initiating Rx should they be reassessed?
Why is ECG monitoring done?
Sit up
Oxygen
Nebulised (S)ABA +/- (I)pratropium
Steroids - takes 4 hrs to take effect so given early
Every 15 minutes
Looking for arrhythmias
Management:
What can be given to those who have no good initial response to therapy? Why?
If they are still not improving:
- Where do they need to be referred to?
- What can be added to medical therapy?
The above can be summarised with the mneumonic MAGAS
A single dose of (mag)nesium sulfate - inhibit smooth muscle contraction, decrease histamine release from mast cells, and inhibit acetylcholine release.
ICU
(A)minophylline IV or IV (S)ABA (salbutamol)
Discharge:
Above what % does the PEFR need to be above before a patient can be discharged?
How long do they need to be on the discharge drugs before they are actually discharged?
What needs to be checked before discharge?
What inhaled med needs to be prescribed?
What needs to be written up?
How long after discharge does a GP appointment need to scheduled for?
How long after discharge does an outpatient appointment need to scheduled for?
> 75%
24 hrs
Inhaler technique
ICS - inhaled corticosteroids
Written management plan + PEF meter
2 days
Within 4 wks
