===== Asthma =====
===Setting & notes:===
  * Viral illness most common precipitant
  * Allergy, drugs (esp aspirin), stress, exercise or other precipitating illness
  * Beware “brittle” asthmatic who may appear “well”. May deteriorate very rapidly
  * more rapid the onset the more likely to respond and less likely to admit.
  * Risk of death:  >3ED visits, >2 admissions, ITU/ ETT in past year, steroid use
=== Presentation ===
  * breathlessness, cough
  * collapse
=== Clinical features ===
  * wheeze, tachypnoea
  * tachycardia, hypertension with paradox

^ Severity      ^ Features      ^ 
| Moderate    | PEF >50% best/predicted\\ • Normal speech. RR<25. HR<110     |
| Acute Severe    | PEF: 33-50%\\ • No sentences. RR>25. HR >110.     | 
| Life Threatening    | PEF <33%. SaO2 <92%\\ • silent chest, cyanosis, weak resp. effort\\ • brady or dysrrhythmia, hypotension\\ • exhaustion. altered consciousness     | 

[[wiki:respiratory:Pneumothorax]]
=== Management ===
  * Oxygen
  * β agonists
          * Neb Salbutamol – 5mg, continuously if sick
          * Neb Adrenaline – 1mg (esp. useful if rapid onset.)
          * IV salbutamol – only if neb's failing
  *anti-cholinergic
        *Neb atropine – 500mcg. (esp for young and COPD type)
  *methylxanthines
        *aminophylline – dangerous in acute asthma. Cardiotoxic, neurotoxic and causes vomiting (do not want when potential airway compromise)
  *steroid
        * give early - IV rather than oral if “sick”
        * Hydrocortisone 200mg IV- reduces inflammation, increases response to β agents
  *Mg SO4
        *20mmol IV over 20min. Aim is to double serum levels.
  *β agonists - β2 - bronchodilator effect
  *adrenaline - β but also α effects which are useful for vasocontriction about the bronchioles, creating 'indirect' bronchodilation.