Asthma in Emergency

Asthma in Emergency

Most asthma deaths occur outside hospital and are:

  • In patients with chronic severe disease
  • In those receiving inadequate medical treatment
  • In those who have been symptomatically deteriorating, and may have already sought medical help
  • Associated with adverse behavioural and psychological factors

Asthma Assessment

Remember Assess severity and start bronchodilators!

Mild-Moderate (maybe admitted to hospital or more likely may improve and go home)

  • SaO2 >95% room air
  • Tachypnea <25
  • Able to talk in sentences or phrases
  • No accessory muscle use
  • Alert
  • Skin Colour: Normal
  • Chest auscultation: Normal or Wheeze

Severe (admitted to hospital)

  • SaO2 90- 95% room air
  • Tachypnea >25bmp
  • Mild to moderate tachycardia for age
  • Can only speak a few words in one breath
  • Mild-moderate use of accessory muscle
  • Skin colour: Pallor
  • Chest auscultation: Wheeze

Life-Threatening (Admitted to hospital possible transferred to a higher level faculty)

  • SaO2 <90% room air
  • Tachypnea >30
  • Tachycardia or Bradycardia
  • Able to talk in words or unable to speak or cry
  • Moderate to severe accessory muscle use
  • Agitation, drowsy or confused
  • Skin colour: Cyanosis
  • Chest auscultation: Silent chest or reduced air entry
Think Take note if person can talk in whole sentences, phrases, words or can't talk at all!
Screen Shot 2016-10-13 at 11.35.55 AM

Image from Australian asthma handbook 

Mild/Moderate Asthma

Remember Assess severity and start bronchodilators!

Mild (maybe admitted to hospital or more likely may improve and go home)

  • SaO2 >95% room air
  • Able to talk in sentences
  • No accessory muscle use
  • Alert

Management:

  • Short-acting Beta2 receptor agonist (ie. Salbutamol with spacer)
    • Reassess, Repeat bronchodilator, Reassess, Repeat
  • +/- Anticholinergic - Ipratobium bromide (if bronchodilator alone has poor response)
    • Reassess, Repeat Ipatropium bromide, Reassess, Repeat
  • Oral prednisolone
    • Reassess at 1 hour after starting bronchodilator, monitor and continue discharge
  • Continue to severe management if not improving
Remember If not responding to any treatment during the 1 hour after bronchodilator, immediate transfer to high level care → move to life-threatening management

Discharge

  • Discharge summary
  • Discharge medication (+spacer)
  • Educate
  • Asthma action plan
  • Follow up with GP

Acute Severe Asthma

Severe asthma defined as:

  • PEFR 33-55% predicated or best
  • RR >25
  • HR >110
  • SaO2 90- 95% room air
  • Can only speak a few words in one breath
  • Mild-moderate use of accessory muscle
  • Skin colour: Pallor
  • Chest auscultation: Wheeze

Management

  • Oxygen
  • Short-acting Beta2 receptor agonist (ie. Salbutamol with spacer)
    • Reassess, Repeat bronchodilator, Reassess, Repeat
  • +/- Anticholinergic - Ipratobium bromide (if bronchodilator alone has poor response)
    • Reassess, Repeat Ipatropium bromide, Reassess, Repeat
  • Oral prednisolone (the earlier given in an attack, the better the outcome) - or IV hydrocortisone if unable to tolerate oral
    • Reassess at 1 hour after starting bronchodilator
    • Monitor
    • Discharge
  • +/- IV salbutamol
  • +/- IV magnesium sulphate immediately if very severe
  • +/- IV aminophylline some patients may respond, give if poor response to initial therapy
  • IV fluids - patients are often dehydrated
  • Antibiotics - if evidence of infection
Indications for invasive ventilation in asthma
Coma
Respiratory arrest
Exhaustion
Deteriorating ABG
Screen Shot 2016-10-13 at 11.35.18 AM

Image from Australian asthma handbook

Life-threatening Asthma

Life-threatening asthma any one of:

  • PEFR <33%
  • SaO2 <90%
  • Silent chest (soft/absent breath sounds)
  • Cyanosis
  • Bradycardia/arrythmia/hypotension
  • Exhaustion
  • Confusion
  • Coma
Remember Mneumonic CHEST for life-threatening asthma: Cynosis, Hypotension and Hypoxia (pO2 <90%), Exhaustion, Silent chest, Tachycardia and Threatening PEF < 33% best or predicted (in those >5yrs old)

Management

  • β-agonist (Salbutamol via continous nebulisation)
  • Anticholinergic - Ippatropium Bromide
  • Steroids (the earlier given in an attack, the better the outcome)
  • IV salbutamol
  • IV magnesium sulphate immediated if very severe
  • IV aminophylline some patients may respons, give if poor response to intitial therapy
  • +/- Intubation and ventilation
  • IV fluids patients are often dehydrated
  • Antibiotics only if an infection caused exacerbation
Indications for assisted ventilation in asthma
Coma
Respiratory arrest
Exhaustion
Deteriorating ABG
Remember Mneumonic O-SHIT-MI for the management of Severe/Life-threatening asthma: Oxygen, Salbutamol, Hydrocortisone (Prednisolone), Ippatropium bromide, Theophylline, Magnesium sulphate, Intubation and ventilation
Screen Shot 2016-10-13 at 11.35.34 AM

Image from Australian asthma handbook

Pathogenesis Asthma Exacerbations

Airway obstruction occurs due to a combination of:

  • Inflammatory cell infiltration
  • Mucus hypersecretion with mucus plug formation
  • Smooth muscle contraction

Long-term uncontrolled asthma can lead to air trapping and asthma exacerbations through what is called dynamic hyperinflation.

  • Airflow obstruction → Slow expiratory airflow and incomplete gas exhalation dynamic hyperinflation → Patient takes next breath → Gas becomes trapped in alveoli
  • Gas becomes trapped in alveoli until the alveoli can not hold any more gas and exhaled volume = inhaled volume → Equilibrium

Mild asthma

  • Only most severely obstructed airways collapse
  • Collapsed airways with air trapping results in:
    • Decreased expiratory reserve volume
    • Increased residual volume

As asthma gets more severe

  • Expiratory reserve diminishes and this results in profound dyspnoea

Complications of Asthma exacerbations

  • Cardiac arrest
  • Respiratory failure/arrest
  • Hypoxaemia with CNS injury
  • Pneumothorax
  • Toxicity with medications
  • Aspiration/pneumonia
  • Nosocomial infection