Asthma Flashcards
Features?
when is cough worse?
when is peak flow worst?
Characterized by recurrent episodes of dyspnoea, cough, and wheeze caused by reversible airways obstruction.
Intermittent dyspnoea Wheeze Cough (worse at night) Chest tightness Diurnal variation – peak flow worse in morning.
Risk Factors
FHx of Atopy - what is it?
- what Ig are these mediated by?
triad of asthma, eczema (atopic dermatitis) and hay fever (allergic rhinitis).
Patients with asthma usually suffer from these other IgE mediated atopic conditions.
: if peak flow is normal on weekends – may be ?
occupational asthma (occurs in 10-15% of adult asthma).
Precipitants
what drugs are contraindicated in asthma ?
Cold air, Exercise
Emotion
Allergens (house dust mite, pollen, fur)
NSAIDs, B-blockers (especially B blocker)
what measurements determine a patients estimated PEFR and estimated FEV1?
how do you measure PEFR?
how do you measure FEV1?
age + sex + height
PEFR = peak flow FEV1 = spirometry
ASTHMA DIAGNOSIS
- all patients aged >17?
- patients aged <5?
All patients aged >17 yrs of age:
should have spirometry* with a bronchodilator reversibility test (BDR) and a FeNO test.
*Do peak expiratory flow if spirometry is unavailable
Patients <5yrs:
Spirometry + BDR test. A FeNO test should be requested if there is normal spirometry
FeNO test
Nitric oxide levels typically correspond to inflammation levels
therefore what is a positive result in children and adults?
- In adults: >40ppb is considered +ve.
- In children: >35 ppb is considered +ve.
BDR Testing: (uses spirometry and bronchodilator)
+ve test is indicated by an improvement in FEV1 of?
and an increase in volume of?
+ve test is indicated by an improvement in FEV1 of 15% or more and increase in volume of 200ml or more.
Typical spirometry results include the following - what is the result in asthmatics?
FEV1
FVC
FEV1% (FEV1/FVC)
- FEV1 significantly reduced
- FVC normal
- FEV1% (FEV1/FVC) <70% = obstructive.
what type of resp failure seen in acute severe asthma
Type 1 resp failure (hypoxaemic - low O2, PO2 <60mmHg )
A patient is admitted with breathlessness - do you do ABG or VBG?
ABG
tells you if Type 1 or Type 2 resp failure
otherwise VBG is fine for anyone that isn’t a resp or cardiac patient
Mx of Acute Attack
O S H I T M E
- Oxygen
- Salbutamol 5mg nebulized with O2
- Hydrocortisone 100mg IV (steroid – reduces inflam).
- Ipratropium – if PEF still <75%, repeat salbutamol every 15 mins with ipratropium.
- T (not used)
- Magnesium sulfate 1.2-2g IV single dose.
- Escalate (ICU) – if not improving
Patients with PEF of what within one hour of initial treatment may be discharged?
otherwise rest must be stable on discharge medication for how long ?
PEF >75%
24 hours
Should know severity of asthma:
- moderate: PEFR ?
- acute severe: RR? and inability to?
- life-threatening: chest action?
Should know severity
moderate:
- >50-75% PEFR
acute severe:
- inability to complete full sentences,
- RR >25
- PEFR 33-50%
life-threatening:
- silent chest or
- cyanosis or
- exhaustion
- PEFR <33%
what drug is contraindicated in asthmatics?
b -blockers