see also:

• paediatric asthma
• asthma
• beta 2 adrenergic agonists
• Mx of the wheezy elderly patient - acute pulmonary oedema versus asthma
• AFTB's lecture notes - Mx of acute asthma
• patient information: Vic Govt asthma management plans in various languages
  • patients should generally go to ED or call 000 for an ambulance and start their asthma “first aid” if either:
    • they don't have access to asthma medications and can't get to a doctor in a timely manner
    • can't speak a full sentence despite using relievers
    • extreme difficulty breathing
    • PEFR < 50% of their best PEFR despite using relievers
    • they feel their asthma is out of control
    • or lips turn blue (or they have a finger oxygen saturation meter showing SaO2 < 92-94% despite using relievers) - does not apply to end stage COPD patients as this may be normal
• Australian Asthma Handbook - Rx level guidelines for adults with asthma
  • level 1: low-dose budesonide–formoterol, taken as needed
  • Level 2: maintenance treatment with a low dose of inhaled steroid-formoterol, plus extra doses from same inhaler taken as needed for relief of symptoms (or salbutamol as reliever)
  • Level 3: maintenance treatment with a medium dose of inhaled steroid-formoterol (or higher number of inhalations using low-dose inhaler), plus extra doses from same inhaler taken as needed for relief of symptoms (or salbutamol as reliever)
  • Level 4: more intensive regimens based on ICS-LABA, sometimes with add-on treatments such as long acting muscarinics (LAMAs) or monoclonal antibody therapies

• the far majority of patients with asthma will not die from their asthma if managed approprately
• of those who do die from asthma:
  • most patients who die from asthma have chronic severe asthma
    • these may fail to act appropriately to call an ambulance when they develop emergency status asthmaticus (see below for more risk factors)
    • they may develop end stage obstructive lung disease with emphysema requiring home oxygen which increases mortality significantly
  • a minority who die from asthma have mild-mod chronic symptoms and develop a sudden severe attack or may have life threatening acute anaphylaxis
  • some have never had asthma and hence no asthma medications or awareness such as those with allergic rhinitis in thunderstorm asthma
  • some die following inappropriate prescribing of sedatives, hypnotics and anxiolytics, beta adrenergic blockers, aspirin (acetylsalicylic acid) or non-steroidal anti-inflammatory drugs (NSAIDs)

• severe asthma:
  • PH near-fatal attack resulting in respiratory acidosis or requiring intubation, or,
  • PH admission for asthma in previous year, or,
  • requiring 3 or more classes of asthma therapy medications, or,
  • heavy use of beta 2 adrenergic agonists, or,
  • repeated attendances to ED for asthma care in past year, or,
  • “brittle” asthma
• AND adverse behavioural patterns such as:
  • non-compliance
  • failure to attend appointments
  • few contacts with GP
  • frequent home visits by GP
  • self-discharge from hospital
  • mental health illness
  • major tranquilliser use
  • denial
  • alcohol or substance abuse
  • obesity
  • learning difficulties
  • employment or financial problems
  • social isolation
  • childhood abuse
  • severe marital, domestic or legal stress

• prioritise therapy in an achievable sequence
• continuous nebulised salbutamol (in oxygen)
• use high flow intranasal oxygen if needed to maintain sats above 92%
• IV hydrocortisone 250mg bolus
• MgSO4 infusion IV (20mmol in 100ml saline over 30-60 minutes)
• nebulised ipratropium bromide (0.5 mg 4-6 hourly) if inadequate response to beta 2 agonists
• consider sub-dissociative bronchodilator doses of IV ketamine at 0.1mg/kg/hr.
• in the agitated patient use IV ketamine 20 to 40mg (0.5mg/kg) to achieve mild dissociation
• if using ketamine, co-administer antiemetic (Ondansetron 8mg)
• prepare for modified rapid sequence induction (RSI) for emergency intubation but temporize with maximal medical therapy in conjunction with trial of bilevel non-invasive ventilation (initial settings iPAP 12, ePAP 5, 80% FiO2)
• the aim is to avoid intubation if at all possible
• if intubation can't be avoided, ketamine is the induction agent of choice
  • pre-oxygenate with high flow intranasal cannula at 60Lm/min
  • give 25% of the total dose over 1 minute, wait a minute for it to circulate
  • give 50% of the total dose, wait a minute for it to circulate
  • then give the remainder of the ketamine dose along with Rocuronium at 1.2mg/kg lean weight
  • after 15 secs, lay patient down and proceed to intubation
  • aim for RR 6, tidal volume 6ml/kg ideal body weight, prolonged exp. time to decrease autoPEEP, and aim for a plateau pressure of < 30mmHg
• be prepared for post-intubation hypotension and look out for hyperinflation of the chest
• titrated crystalloid boluses to offset hypovolaemia
• bedside CXR to exclude other diagnoses or complications if:
  • suspected pneumomediastinum or pneumothorax
  • suspected consolidation
  • failure to respond to treatment satisfactorily
• arterial gases are unnecessary and only cause more distress to the patient
• venous gases are suitable if hypercarbia is suspected

• oxygen to maintain SaO2 94-98% if SaO2 below 92% and not a CO2 retainer (otherwise aim for 90-92%)
• metered-dose-inhaler via spacer device beta 2 adrenergic agonists (or nebulised if unable to use spacer)
  • repeat 6-12 doses every 15-30 minutes initially if still SOB but not needing continuous nebulised Rx
  • stretch out doses as per local policy eg. reduce frequency of doses to hourly then every 2hours, then every 3-4 hours if tolerated
• inhaled steroids with long acting beta agonist (LABA)
  • eg. Symbicort
• consider inhaled long acting muscarinic (LAMA)
• oral corticosteroids
  • steroid tablets are as effective as injected steroids, provided they can be swallowed and retained
  • use oral prednisolone 50mg once daily (equivalent to IV hydrocortisone 100mg qid)

• diagnosis is based on recognition of characteristic pattern of symptoms and signs and the absence of
• inhaled foreign body / aspiration
• acute pulmonary oedema (APO)
• chronic obstructive pulmonary disease (COPD)
• Acute Respiratory Distress Syndrome (ARDS)
• pneumothorax
• pneumonia
• pulmonary embolism (PE)
• pulmonary fibrosis
• bronchiectasis
• sarcoidosis
• strongyloidiasis - in those who have lived in the tropics - Loffler's syndrome (acute onset eosinophilic pneumonitis) can also be caused by Ascaris lumbricoides, and the hookworms Ancylostoma duodenale and Necator americanus.
• large airway stenosis
• hyperventilation

• raised PaCO2 and/or requiring mechanical ventilation with raised inflation pressures

• severe asthma signs plus any one of:
  • altered conscious level
  • exhaustion
  • arrhythmia
  • hypotension
  • cyanosis
  • silent chest
  • poor respiratory effort
  • PEF <33% best or predicted
  • SpO2 <92%
  • PaO2 <8 kPa
  • “normal” PaCO2 (4.6–6.0 kPa)

• any one of:
  • unable to complete a sentence in one breath
  • respiratory rate >= 25
  • heart rate >= 110/min
  • PEF 33-50% best or predicted

• increasing symptoms
• PEF >50-75% best or predicted
• no features of acute severe asthma

• Type 1:
  • wide PEF variability (>40% diurnal variation for >50% of the time over a period >150 days) despite intense therapy
• Type 2:
  • sudden severe attacks on a background of apparently well controlled asthma

• closely monitor for hypoxia, hypercapnoea, exhaustion, drowsiness, confusion, hypokalaemia or complications
• if near-fatal or life threatening attack with inadequate response, consider:
  • *use high flow intranasal oxygen
  • single dose of iv magnesium sulphate (1.2-2 g IV infusion over 20 minutes) should only be used following consultation with senior medical staff, although it does appear to be safe as a single dose and may offer benefit
  • iv aminophylline (5 mg/kg loading dose over 20 minutes unless on maintenance oral therapy, then infusion of 0.5-0.7 mg/kg/hr).
    • measure the serum theophylline concentration if aminophylline is continued for more than 24 hours (aim at a concentration of 10-20mg/l or 55-110 mol/l)
  • trial of BiPAP if underlying chronic obstructive pulmonary disease (COPD) and patient in resus area or ICU
  • rapid sequence induction (RSI) for emergency intubation using iv ketamine
  • transfer to ICU with experienced medical escort capable of intubation
• assess need for antibiotic Rx, although most cases are NOT bacterial and thus do NOT need antibiotics
  • there may be a role for procalcitonin levels to assist in this decision¹⁾
• admit if either:
  • life threatening or near fatal attack
  • any feature of severe attack persisting despite initial Rx
  • PEFR < 75% of expected 1 hour after initial Rx
  • high risk patients such as poor compliance, lives alone, PH brittle asthma, night-time, pregnant, exacerbation despite oral steroids
• discharge:
  • patient should have clinical signs compatible with home management, be on reducing amounts of β2 agonist (preferably no more than four hourly) and be on medical therapy they can continue safely at home
    • NB. patients discharged with PEF <75% best or predicted and with diurnal variability >25% are at greater risk of early relapse and readmission
  • patient should be given a written asthma management plan
  • patient should have 5 days of oral prednisolone 50mg per day

• British Thoracic Society. Scottish Intercollegiate Guidelines Network (SIGN). British guideline on the management of asthma. A national clinical guideline. Published May 2008, revised June 2009. (pdf)