Asthma Flashcards
Why would you use nebuliser instead of inhaler in acute asthma attack?
not technique dependent, patient doesn’t tire
How can you class the severity of asthma attack?
Moderate, acute severe, life threatening. Only one feature of criteria for this to each classification to be true
Name three features of acute severe asthma
can’t complete sentences in one breath
RR >25
Pulse >110
SpO2 >92%
Name three features of life threatening asthma
SpO2 <92% Silent chest Arrhythmia hypotension Altered mental status, exhaustion cyanosis PaO2 <8
What is a near fatal sign of acute asthma
A rise in PCO2
What is the treatment for acute asthma?
oxygen, salbutamol, ipratropium, steroid (prednisolone)
Define chronic asthma
Episodic, reversible airway obstruction due to
bronchial hyper-reactivity to a variety of stimuli.
Briefly describe the pathophysiology of asthma
Mast cell-Ag interaction → histamine release
Bronchoconstriction, mucus plugs, mucosal swelling
T H 2 cells release IL-3,4,5 → mast cell, eosinophil and
B cell recruitment
Airway remodelling
Two causes of asthma?
Atopy-T1 hypersensitivity to variety of antigens
Stress- cold air, emotion, exercise
Toxins- smoking, pollution, drugs
Name two drugs that causes symptoms of asthma
beta blockers
NSAIDs
Three symptoms indicative of asthma?
Wheeze
Dry cough
Dyspnoea
Diurnal variation
Two associations of asthma in history which would make diagnosis more likely?
Other atopic conditions
Family history
Two investigations for asthma?
- Spirometry with bronchodilator reversibility
- Fractional exhaled nitric oxide
- Peak flow variability- diary
- Direct bronchial challenge test with histamine or metacholine
Describe the drug ladder approach to treatment of asthma. Provide class and a drug example from each
- SABA PRN- salbutamol
- Add Low dose inhaled steroid (ICS)- beclometasone
- Replace SABA with LABA- salmeterol
- If control still poor, trial LAMA- tiotropium, leukotriene receptor antagonist- montelukast, theophylline
- Titrate ICS to high dose.
- Refer to specialist. Consider oral steroids
Name two non-pharmacological approaches to managing asthma
- Yearly asthma review
- Advise exercise
- Smoking/cannibis cessation
- Yearly flu jab
- Individual self-management programme
MOA of ipratropium?
SAMA
acetylcholine antagonist via blockade of muscarinic cholinergic receptors
decreased contraction of the smooth muscles.
Two signs of severe asthma?
PEFR <50%
RR >25
HR >110
Can’t complete sentence in one breath
Two signs of life threatening asthma?
PEFR <33%
SpO 2 <92%, PCO 2 >4.6kPa, PaO 2 <8kPa
Cyanosis
Hypotension
Exhaustion, confusion
Silent chest, poor respiratory effort
Tachy-/brady-/arrhythmias
Two differentials for acute asthma?
pneumothorax
acute exacerbation of COPD
pulmonary oedema
Treatment for acute asthma if moderate?
Sit upright
100% O2 via non-rebreathe mask (aim for 94-98%)
Nebulised salbutamol (5mg) and ipratropium (0.5mg)
Hydrocortisone 100mg IV or pred 50mg PO (or both)
Treatment for severe/life threatening?
Senior help (should really do this from the beginning)
Consider ICU transfer
Aminophylline
IV salbutamol infusion
IV magnesium sulphate (don’t ever do this as a junior…requires you to monitor and deliver continually, very time consuming)
What is the pattern of ABG in acute asthma?
initially respiratory alkalosis
Type 1 resp failure
Then respiratory acidosis- type 2 respiratory failure
How can acute asthma be monitored?
O2 sats RR Peak flow Chest auscultation Respiratory effort
Which electrolyte must be monitored whilst on salbutamol?
potassium- as this causes promotion of potassium absorption into cells
