Acute Severe Asthma Flashcards
In a patient you suspect to have acute severe asthma, what are the key points in the history?
Precipitant: infection, travel or exercise?
Usual and recent Rx?
Previous attacks and severity: ICU admissions?
Best PEFR
In pt with acute severe asthma, what are the key investigations?
PEFR
ABG - PaO2 normal or slightly low
PaCO2 low = normal
If PaCO2 elevated, send to ITU for ventilation
Bloods: FBC, U&E, CRP, blood cultures
CXR to rule out pneumothorax/pulmonary oedema
What are the features of severe asthma?
PEFR <50%
RR >25
HR >110
Can’t complete sentences in one breath
What are the features of life threatening asthma
PEFR <33% SpO2 <92%, PaCO2 >4.6kPa, PaO2 <8kPa Cyanosis Hypotension Exhaustion, confusion Silent chest, poor respiratory effort Tachy/brady/arrhythmias
What are the differentials of acute severe asthma
Acute exacerbation of COPD
Pneumothorax
Pulmonary oedema
What are the admission criteria?
Life threatening attack
Features of severe attack persisting despite initial Rx
When could you discharge if admission was not necessary?
May discharge if PEFR >75% 1h after initial Rx
Discharge when
Been stable on discharge meds for 24h
PEFR is >75% with diurnal variability <25%
Discharge plan
TAME pt Checked inhaler technique PO steroids for 5d GP appointment within 1 week Respiratory outpt clinic appointment within 1 month
Management of acute severe asthma - O2, nebs and steroids
Sit up
100% O2 via non-rebreathe mask, aim for sats 94-98%
Nebulised salbutamol 5mg (every 15min or 10mg continuously/ hour) & ipratropium 0.5mg 4-6hrly
Hydrocortisone 100mg IV or prednisolone 40-50mg PO or both
Write “no sedation” on drug chart
Mx of life threatening asthma
Inform ITU
MgSO4 2g IVI over 20mins
Nebulised salbutamol every 15mins
If improving:
Monitor SpO2 - aim 92-94%, PEFR
Continue pred 40-50mg for 5 days OD
Nebulised salbutamol every 4 hours
IV Rx if no improvement within 15-30min
Neb salbutamol every 15 min (monitor ECG) Continue ipratropium 0.5mg 4-6hrly MgSO4 2 IVI over 20min Salbutamol IVI 3-20ug/min Consider aminophylline - load 5mg/kg IVI over 20 min unless already on theophylline Continue 0.5mg/kg/hr Monitor levels ITU transfer for invasive ventilation
Monitoring of acute severe asthma
PEFR every 15-30 min
- pre and post beta-agonist
SpO2: keep >92%
ABG if initial PaCO2 normal or higher