GP - Acute exacerbation of Asthma Flashcards
What are the different severity of asthma?
Mild acute asthma
Moderate acute asthma
Acute asthma asthma
Life-threatening acute asthma
Near-fatal acute asthma
What is mild acute asthma?
Increasing symptoms
PEFR > 75% best
No features of acute severe asthma
What is moderate acute asthma?
Increasing symptoms
PEFR > 50-75% best
No features of acute severe asthma
What is acute severe asthma?
Difficulty finishing full sentences in one breath
Maybe hypoxic, but SaO2 typically > 92%
RR > 25 breath per minute
HR > 110 bpm
PEFR 33-50 % best
What is life-threatening severe asthma?
PEFR < 33% best
SaO2 < 92%
PO2 < 8 kPa (hypoxic), but PCO2 is normal 4.6-6.0 kPa - Type 1 respiratory failure
Silent chest
Cyanosis
Patients feeling exhausted - reduced respiratory effort
Drowsiness, altered consciousness, or coma
Bradycardia, hypotension
What is near-fatal severe asthma?
Type 2 respiratory failure (low PO2 and high PCO2)
Patient requires immediate mechanical ventilation
What investigations can you do for acute asthma?
- PEFR
- Spirometry shows FEV1/FVC < 70% (obstructive pattern)
- Sputum culture
-
ABG if SaO2 < 92% i.e. in life-threatening acute asthma or near-fatal acute asthma
- Life-threatening acute asthma –> Type 1 respiratory failure –> hyperventilation –> respiratory alkalosis –> hypokalaemia
- Near-fatal acute asthma –> Type 2 respiratory failure –> hypoventilation –> respiratory acidosis –> hyperkalaemia
- CXR to rule out pneumothorax, atelectasis, pneumonia
- ECG - rule out cardiac arrhythmias due to K+ imbalances
What is the management of acute exacerbation of asthma/ asthma attack?
- ABCDE
- Assess severity of attack
- Mild and moderate acute asthma are treated at home or in primary care. Acute severe asthma and life-threatening acute asthma require hospital admission and ICU involvement
- Mnemonic: O SHIT ME
- O2 - aims for a SaO2 of 94-98%
- Nebulised salbutamol - 5 mg
- Oral prednisolone 40 mg STAT and then OD for at least 5 days (or IV hydrocortisone 100 mg every 6 hrs if PO not possible)
- If acute severe asthma (or worse):
- Nebulised ipratropium bromide 500 mcg every 6 hrs
- Reassess patient every 15 minutes
- If PEFR < 75% repeat nebulised salbutamol every 15 munutes
- Monitor ECG for arrhythmias
- If patients with acute severe asthma or life-threatening acute asthma still don’t have a good response to bronchodilators, give IV magnesium sulphate 1.2-2g over 20 minutes
- If life-threatening acute asthma/ near-fatal acute asthma, or if asthma not improving after 15 minutes (e.g. decreased PEFR, worsening hypoxia, hypercapnia, exhaustion, confusion, altered consciousness, etc):
- Urgent ITU or anaesthetic assessment for ventilatory support
- Urgent CXR
- IV aminophylline
- IV salbutamol if nebulised route ineffective
- If asthma improve after 15 minutes:
- Continue nebulised salbutamol every 4-6 hrs (+ nebulised ipratropium if started previously)
- Oral prednisolone 40 mg OD for at least 5 days
- Monitor peak flow and SaO2, aim for 94-98%
- If PEFR > 75% 1 hr after treatment, consider discharge with outpatient follow-up
What is the criteria for asthma discharge after exacerbation?
PEFR > 75%
Stop regular nebulisers for 24 hrs prior to discharge
Asthma nurse review to reassess inhaler technique and adherence
Provide PEFR meter and a personalised written asthma action plan
At least 5 days oral prednisolone
GP follow up within 2 working days
Respiratory clinic follow up within 4 weeks
What is the dose for nebulised salbutamol?
5 mg
What is the dose for oral predisolone in acute asthma?
40 mg STAT and then OD for at least 5 days
What is the dose for IV hydrocortisone if oral prednisolone not available?
100 mg every 6 hrs
What is the dose for nebulised ipratropium bromide?
500 mcg every 6 hrs
What is the dose for IV magnesium sulphate?
1.2 - 2g over 20 minutes
