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Management of Acute Asthmatic Exacerbation in Adult

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Management of Acute Asthmatic Exacerbation in Adult

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									    Management of Acute
Asthmatic Exacerbation in Adult
            Jia-Horng Wang
   Department of Respiratory Therapy
    Taipei Veterans General Hospital

                                參
 Definition of Exacerbation
Synonym
– Asthma attacks
– Acute asthma
Definition
– Episodes of progressive increase in
    shortness of breath
    Cough
    Wheezing or
     chest tightness or
    some combination of these symptoms
          Acute Exacerbation
Respiratory distress : common
Decreases in expiratory airflow
–   Quantified by measurement of lung function
–   PEF or FEV1
–   More reliable indicators of the severity of airflow
    limitation
Symptoms
– More sensitive measure of the onset of an
  exacerbation
– Precede the deterioration in peak flow rate
 Severe Acute Exacerbation
Potentially life threatening
Treatment requires close supervision
Seek medical help promptly
Proceed to the nearest clinic or hospital
that provides emergency access for
patients with acute asthma
Close objective monitoring (PEF) of the
response to therapy is essential
Primary Therapies for Exacerbation

 Depending on severity
 – Repetitive administration of rapid-acting
   inhaled bronchodilators
 – Early introduction of systemic
   glucocorticosteroids
 – Oxygen supplementation
   Aims of Treatment
Relieve airflow obstruction
Relieve hypoxemia
Plan of prevention of future
relapses
          Patients at High Risk
        of Asthma-Related Death
History of near-fatal asthma requiring intubation and
mechanical ventilation
Hospitalization or emergency care visit for asthma in
the past year
Currently using or have recently stopped using oral
glucocorticosteroids
Not currently using inhaled glucocorticosteroids
Over-dependent on rapid-acting inhaled 2-agonists
History of psychiatric disease or psychosocial
problems
Non-compliance with an asthma medication plan
     Response to Treatment
Response to treatment in acute exacerbation
may take time
Patients should be closely monitored using
clinical as well as objective measurements
The increased treatment should continue until
measurements of lung function return to their
previous best (ideal) or plateau within the first
two hours
– Admission
– discharge
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            Severity of Asthma Exacerbation
               Mild           Moderate         Severe             Respiratory arrest
                                                                  imminent
Breathless     Walking        Talking          At rest
               Can lie down   Prefer sitting   Hunched forward

Talks in       Sentences      Phrases          Words


Alertness      May be         Usually          Usually agitated   Drowsy or confused
               agitated       agitated

Respiratory    Increased      Increased        Often > 30/min
rate
Accessory      Usually not    Usually          Usually            Paradoxical thoraco-
muscles and                                                       abdominal
suprasternal                                                      movement
retraction
Wheeze         Moderate, often Loud            Usually loud       Absence of wheeze
               only end
               expiratory
            Severity of Asthma Exacerbation
                 Mild         Moderate         Severe                Respiratory arrest
                                                                     imminent
Pulse/min        <100         100-120          >120                  Bradycardia



Pulsus           Absent       May be present   Often present         Absence suggests
paradoxus        <10 mm Hg    10-25 mm Hg      >25 mm Hg             respiratory muscle
                                                                     fatigue

PEF after        Over 80%     Approximately    < 60%
initial                       60-80%           (<100 L/min adults)
baronchodilat                                  Response lasts <2
or                                             hrs
% predicted or
personal best
PaO2 (on air)    Normal       >60 mm Hg        < 60 mm Hg
And/or                                         Possible cyanosis
                 < 45 mm Hg   < 45 mm Hg       >45 mm Hg
PaCO2
                                               Possible
                                               respiratory failure


SaO2 (0n air)    > 95%        91-95%           < 90%
Management of Acute Exacerbation

 Severe asthma exacerbations
 – treated in an acute care facility where
   monitoring is possible
     Objective measurement of airflow
     obstruction
     Oxygen saturation
     Cardiac function
Management of Acute Exacerbation
  Milder exacerbations can usually be treated
  in a community setting
   –   A reduction in peak expiratory flow of less than 20%
   –   Nocturnal awakening
   –   Increased use of short acting 2-agonists
   –   Good response to the increase in inhaled
       bronchodilator treatment after the first few doses
         Referral to an acute care facility is not required
  Patient education and review of maintenance
  therapy should also be undertaken
 Treatment-- Bronchodilators
For mild to moderate exacerbations
– repeated administration of rapid-acting inhaled 2-
  agonists (2-4 puffs every 20 minutes for the first hour)
  -- the best and most cost-effective method of
     achieving rapid reversal of airflow limitation
– After the first hour, the dose of 2-agonists required
  will depend on the severity of the exacerbation
     Mild : 2 to 4 puffs every 3-4 hours
     Moderate: 6-10 puffs every 1 or 2 hours
– Individualized titration according to patient’s response
– Lack of response – refer to an acute care facility
 Treatment-- Bronchodilators
Monitor PEF after the initiation of
increased bronchodilator therapy
– Delivered via a metered dose inhaler, ideally
  with a spacer -- the most effective method
    produces at least an equivalent improvement in
    lung function as the same dose delivered via
    nebulizer
– No additional medication is necessary if
    rapid-acting inhaled 2-agonist produces a
    complete response
    the response lasts for 3 to 4 hours
     Stepping Up Treatment
 in response to Loss of Control
Rapid-onset, short-acting or long-acting
  2-agnonist bronchodilators
Inhaled glucocorticosteroids
Combination of inhaled
glucocorticosteroids and rapid and long-
acting 2-agnonist bronchodilator for
combined relief and control
Treatment -- Glucocorticosteroids

  Oral glucocorticosteroids
   – 0.5-1.0 mg of prednisolone/kg or
     equivalent during a 24-hour
     period should be used to treat
     exacerbations
      after instituting the other short-term
      treatment options recommended
      for loss of control
Management - Acute Care Settings

 Severe exacerbations of asthma are
 life-threatening medical emergencies
 Treatment is often most safely
 undertaken in an emergency
 department
      Assessment --History
A brief history and physical examination pertinent
to the exacerbation should be conducted
concurrently with the prompt initiation of therapy
History
– severity and duration of symptoms -- exercise
  limitation and sleep disturbance
– all current medications -- dose (and device) prescribed,
  dose usually taken, dose taken in response to the
  deterioration, and the patient’s response (or lack
  thereof)
– time of onset and cause of the present exacerbation
– risk factors for asthma-related death
Assessment– Physical Examination
 Assess exacerbation severity by evaluating
 –   the patient’s ability to complete a sentence
 –   pulse rate
 –   respiratory rate
 –   use of accessory muscles
 –   others
 Any complicating factors should be identified
 –   pneumonia
 –   atelectasis
 –   pneumothorax or pneumo-mediastinum
    Functional Assessment
PEF or FEV1 and arterial oxygen
saturation measurements are strongly
recommended
– A baseline PEF or FEV1 measurement should
  be made before treatment is initiated without
  unduly delaying treatment
– Oxygen saturation should be closely
  monitored, preferably by pulse oximetry
            Chest X-Ray
Is not routinely required
Should be carried out if
– a complicating cardiopulmonary process is
  suspected
– patients requiring hospitalization
– Patients not responding to treatment where a
  pneumothorax may be difficult to diagnose
  clinically
– Physical signs suggestive of parenchymal
  disease
Arterial Blood Gas Measurements
Not routinely required
Should be completed in patients
 –   with a PEF of 30-50% predicted
 –   do not respond to initial treatment
 –   when there is concern regarding deterioration
The patient should continue supplemental
oxygen while the measurement is made
Respiratory failure
 – PaO2 < 60 mm Hg (8 pKa)
 – A normal or increased PaCO2 (especially > 45 mm Hg,
   6 pKa)
        Treatment - Oxygen
To achieve arterial oxygen saturation of > 90%,
oxygen should be administered by nasal
cannulae, by mask
PaCO2 may worsen in some patients on 100 %
oxygen
– especially those with more severe airflow limitation
Oxygen therapy -- titrated against pulse oximetry
to maintain a satisfactory oxygen saturation
           Treatment-
Rapid-acting inhaled 2-agonists
Rapid-acting inhaled 2-agonists should
be administered at regular intervals
Initial use of continuous therapy, followed
by intermittent on-demand therapy for
hospitalized patients
No evidence to support the routine use of
intravenous 2-agonists in patients with
severe asthma exacerbations
   Treatment- Epinephrine
A subcutaneous or intramuscular
injection of epinephrine may be
indicated for acute treatment of
anaphylaxis and angioedema
Not routinely indicated during asthma
exacerbations
Treatment– Ipratropium bromide
 A combination of nebulized 2-agonist
 with an anticholinergic may produce better
 bronchodilatation than either drug alone
 Should be administered before
 methylxanthines are considered
 Combination 2-agonist/anticholinergic
 therapy is associated with lower
 hospitalization rates and greater
 improvement in PEF and FEV1
   Treatment- Theophylline
Has a minimal role in the management of
acute asthma
Its use is associated with severe and
potential side fatal side effects
Their bronchodilator effect is less than that
of 2-agonists
The benefit as add-on treatment in adults
with severe asthma exacerbations has not
been demonstrated
          Treatment-
 Systemic Glucocortocosteroids
Speed resolution of exacerbation
Utilized in the all but the mildest
exacerbations , especially if
– The initial rapid-acting inhaled 2-agonist
  therapy fails to achieve lasting improvement
– The exacerbation develops even though the
  patient was already taking oral
  glucocorticosteroids
– Previous exacerbations required oral
  glucocorticostoids
         Treatment –
 Systemic Glucocorticosteroids
Oral glucocorticosteroids -- as effective as those
administered intravenously
– preferred -- less invasive and less expensive
Oral glucocorticosteroids
– requires at least 4 hours to produce clinical
  improvement
Daily doses of systemic glucocorticosteroids for
hospitalized patients
– equivalent to 60-80 mg methylprednisolone as a
  single dose, or
– 300-400 mg hydrocortisone in divided doses
         Treatment –
 Systemic Glucocorticosteroids
40 mg methylprednisolone or 200 mg
hydrocortisone -- adequate in most cases
A 7-day course in adults has been found
to be as effective as 14-day course
No benefit to tapering dose of oral
glucocorticosteroids , either in the short-
term or over several weeks
           Treatment –
   Inhaled Glucocorticosteroids
Inhaled glucocorticosteroids are effective as part
of therapy for asthma exacerbations
Combination of high-dose inhaled
glucocorticosteroids and salbutamol in acute
asthma
– provided greater broncodilatation than salmutamol
  alone
– conferred greater benefit than the addition of systemic
  glucocorticosteroids across all parameters, including
  hospitalizations
          Treatment –
  Inhaled Glucocorticosteroids
Inhaled glucocorticosteroids can be as
effective as oral glucocorticosteroids at
preventing relapses
A high-dose inhaled glucocorticosteroids
(2.4 mg budesonide daily in four divided
doses) achieve a relapse rate similar to 40
mg oral prednisone daily
    Treatment - Magnesium
Intravenous magnesium sulphate (usually given
as a single 2 g infusion over 20 minutes) is not
recommended for routine use in asthma
exacerbations
Can help reduce hospital admission rates in
certain patients, including
– Adults with FEV1 25-30% predicted at presentation
– Adults and children who fail to respond to initial
  treatment
– Children whose FEV1 fails to improve above 60 %
  predicted after 1 hour of care
    Treatment - Magnesium
Nebulized salbutamol administered in
isotonic magnesium sulphate provides
greater benefit than if it is delivered in
normal saline
      Treatment-
Helium Oxygen Therapy
There is no routine role of this
intervention
It might be considered for
patients who do not respond to
standard therapy
Treatment- Leukotriene Modifiers

     There is little data to suggest
     a role for leukotriene
     modifiers in acute asthma
  Criteria for Hospitalization

A pre-treatment FEV1 or PEF < 25%
predicted or personal best
A post-treatment FEV1 or PEF < 40%
predicted or personal best
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        流量 (PEF)
    力              (FEV1)
        度




        療
        療            度 90%

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                       流量
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                            度
度
                                 :
    流量: 60-80%
                                 流量 < 60%
    : 度 狀
                                 :  狀     度   狀
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                                    硫
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1-2                                                   1                   不
              良            1-2               不                :
      療                          :
                                                             : 度 狀,               , 亂
          :                          : 度    度 狀
                                                             流量 < 30%
          流量 >70%                    流量 < 60%
                                                      PaCO2 > 45 mmHg
          度 90% (   95%)             度
                                                      PaO2< 60 mmHg



                                     療                            療
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                                         硫
                                             流量                       刺
      療                               度        數                          茶




          流量 >60%
                                                          六                   見
   Criteria for Discharge from
    Emergency Department
Patients with post-treatment lung function
of 40-60% predicted
– adequate follow-up available in the
  community
– assured compliance
Patients with post-treatment lung function
  60% predicted
       Discharge Planning
A 7-day course of oral glucocorticosteroids
As-needed inhaled bronchodilator
Inhaled glucocorticosteroids
Education of inhaler technique
Use of peak flow meter to monitor therapy
Identifying precipitating factors and
providing strategies for future avoidance
Providing action plan and written guidance
!
    !
    惡                         理(I)
                          度
        流量連   兩       < 80%
>70%

臨   狀:




                      療



    良             不              不
      惡                  理(II)
                     療



                良
               度惡
          流量 > 80%
              刺
3-4                      刺   24-48



                  連
                 便
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             不
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    流量 60-80%
類

                    刺



                連
        便
惡                      理 (IV)
               療



          不良
         度惡
    流量 < 60%
類
                       刺

                   車

								
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