Asthma and COPD Diagnosis and Management of Acute Exacerbations

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Asthma and COPDDiagnosis and Managementof Acute
Exacerbations
Phillip I Menashe MD Hue Medical College
March 2010
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Asthma and COPD

• COPD
• Airflow limitation that is not fully reversible
• The airflow limitation may be progressive
• Abnormal inflammatory response to noxious gasses
  (Cigarretes)
• Extra-pulmonary effects are common

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Asthma and COPD

• Asthma
• A chronic inflammatory disorder of the airways
• Airways hyper-responsiveness
• Dyspnea, cough, wheezing and chest tightness
• Widespread airflow obstruction
• Reversiblity with time and treatment

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Asthma and COPD

• Acute exacerbation of COPD
• Acute increase in symptoms beyond normal
  day-to-day variation
• Cough increases in frequency and severity
• Sputum production increases in volume and / or
  changes character
• Dyspnea increases.

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Asthma and COPD

• Acute exacerbation of Asthma
• Dyspnea
• Wheezing
• Cough
• Chest tightness
• Mucus production
• Some asthma patients do not perceive symptoms
  until airflow obstruction is severely reduced and
  may experience sudden asthma death. Peak flow
  monitoring may prevent this.

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Asthma and COPD

• Epidemiology of COPD exacerbations
• Infections
• Bacterial (S. pneumoniae, H.influenzae, M
  catarrhalis)
• Viral (Influenza, RSV, coronavirus, adenovirus,
  parainfluenza, rhinovirus)
• Common pollutants
• Nitrogen dioxide
• Particulates
• Sulfur dioxide
• Ozone

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Asthma and COPD

• Epidemiology of asthma exacerbations
• Environmental allergen exposure
• Viral respiratory tract infections
• Airborne irritants
• Emotional stress

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Asthma and COPD

• Acute exacerbation initial evaluation
• History
• Symptoms
• Triggering factors

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Asthma and COPD

• Acute exacerbation initial evaluation
• Examination
• Physical findings
• Severity

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Asthma and COPD

• Acute exacerbation initial evaluation
• Physical findings if severe
• Inability to complete a full sentence
• Tachypnea
• Tachycardia
• Hypoxemia
• Reduced Peak Flow lt 40 in asthma
• Accessory muscle use
• Diaphoresis
• Sitting upright 90 degrees

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Asthma and COPD

• Acute exacerbation initial exacerbation
• Life-threatening attack
• Exhaustion, decreased level of consciousness
• Silent respirations
• Unstable vital signs
• Cyanosis

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Asthma and COPD

• Acute exacerbation initial evaluation
• Laboratory and CXR
• ABG
• Ventilation, PaCO2
• Oxygenation, PaO2, Oxygen saturation
• PH
• CXR
• Primarily to rule out other acute respiratory
  processes.

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Asthma and COPD

• Acute exacerbation initial evaluation
• Baseline pulmonary function can be helpful
• FEV1 in asthma and COPD
• Peak expiratory flow (PEF) in asthma
• Acute asthma PEF lt 40 previous best or lt 200
  L/min indicates severe exacerbation.

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Asthma and COPD

• Initial treatment
• Comfortable sitting position
• Legs down
• Able to bend forward
• Support for upper extremities

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Asthma and COPD

• Initial treatment
• Oxygen
• Nasal cannula or face mask
• Maintain O2 saturation 89 - 92
• Avoid excessive O2 administration in chronic
  hypercarbia as it may exacerbate respiratory
  acidosis.

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Asthma and COPD

• Oxygen induced hypercapnea
• Decreased minute ventilation due suppressed
  hypoxic drive
• Decreased binding affinity of hemoglobin for
  carbon dioxide.
• Worsened ventilation perfusion matching due to
  attenuation of hypoxic pulmonary
  vasoconstriction.

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Asthma and COPD

• Initial treatment
• Beta agonists
• Albuterol nebulized intermittently or
  continuously up to 15mg per hour.
• SQ epinephrine can be used in severe asthma if
  nebulized therapy is unavailable or ineffective.
• Intravenous isoproterenol should be avoided due
  to cardiac toxicity
• Levalbuterol (R-isomer of albuterol) is much more
  expensive and NOT proven to be superior to
  albuterol

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Asthma and COPD

• Initial treatment
• Theophylline
• Generally not recommended for routine use
• Effectiveness may be low and toxicity high
• Initial dose 5mg / Kg infused over 20 minutes
• Maintenance dose 0.2 - 0.7mg / kg / hour
• Titrate to peak serum level 10 -15 mg/L

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Asthma and COPD

• Initial treatment
• Corticosteroids
• A mainstay of therapy in acute exacerbations
• Asthma doses are often very high 125mg - 250mg
  every 6 hours
• COPD doses typically are lower 40mg - 60mg every
  6 hours
• Adverse effect most common is hyperglycemia

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Asthma and COPD

• Initial treatment
• Magnesium sulfate
• Bronchodilator
• Inhibits calcium influx into airway smooth muscle
• May be most effective in severe exacerbations
• Adverse effects are unlikely
• 1 to 2 grams over 20 minutes

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Asthma and COPD

• Initial treatment
• Antibiotics
• Ineffective in acute exacerbations of asthma
• Effective in acute exacerbations requiring
  hospitalization

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Asthma and COPD

• Initial treatment
• Supportive therapy
• Intravenous fluids for dehydration
• H2 blocker / Proton pump inhibitor
• SQ heparin
• Oximetry

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Asthma and COPD

• Noninvasive Positive Pressure Ventilation (NPPV)
• COPD
• Reduces intubation
• Lowers in-hospital mortality
• Lowers length of stay

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Asthma and COPD

• NPPV
• Asthma
• Data is lacking
• Experience suggests use of NPPV may reduce need
  for intubation
• Trial indicated if mechanical ventilation
  imminent

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Asthma and COPD

• Intubation and mechanical ventilation
• Indications
• Physiologic CO2 retention, refractory hypoxemia
• Clinical rapid shallow breathing, fatigue with
  somnolence, unstable vital signs
• The decision to intubate is based on clinical
  judgment that considers the entire clinical
  situation.

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Asthma and COPD

• Intubation and mechanical ventilation
• Intubation may exacerbation airflow obstruction
  due to airway hyper-responsiveness.
• Adequate sedation, IV access, monitoring
• Adequate endotracheal tube size, ? 8mm internal
  diameter
• Expertise in airway management

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Asthma and COPD

• Intubation and mechanical ventilation
• Mode / Settings
• Assist control / volume control
• Initial tidal volume 6-8 cc/kg ideal body weight
• Respiratory rate to attain adequate minute
  ventilation. No need to normalize PaCO2
• FIO2 to maintain O2 saturation ? 89
• PEEP usually not needed but start with 5cm

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Asthma and COPD
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Asthma and COPD

• Intubation and mechanical ventilation
• Dynamic hyperinflation
• Diffuse airway obstruction slows exhalation to
  the point that intra-thoracic pressure does not
  return to atmospheric pressure at the end of
  exhalation of a tidal breath.
• The pressure gradient that remains between thorax
  and atmosphere is called auto-peep or
  intrinsic-peep
• High intra-thoracic pressures can cause
  barotrauma and hemodynamic instability due to
  reduced venous return and inadequate LV diastolic
  filling.

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Asthma and COPD

• Intubation and mechanical ventilation
• Dynamic hyperinflation
• Hemodynamic effects
• Hypotension due to relative volume depletion
• Tachycardia to maintain cardiac output due to
  reduced left ventricular filling.
• Respiratory effects
• Asynchronous breathing with the ventilator
• High peak airway pressures
• Inability to ventilate

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COPD and Asthma
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Asthma and COPD

• Intubation and mechanical ventilation
• Dynamic hyperinflation
• Vigorous intravenous volume replacement for
  hemodynamic instability. Avoid vasopressors
• Increase expiratory time on the ventilator by
  decreasing respiratory rate, lowering tidal
  volume and increasing inspiratory flow rate.
• Continue pharmacologic bronchodilitation
• Do not try to rapidly normalize PaCO2. Permit a
  degree of hypercapnea.

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Asthma and COPD

• Intubation and mechanical ventilation
• Adjunctive therapy
• Sedation
• Versed, propofol, fentanyl
• Paralytics should be avoided
• General anesthesia rarely used
• Preventative measures
• Ventilator associated pneumonia
• Deep vein thrombosis
• Gastrointestinal bleeding
• Supportive Care
• Fluids and Nutrition

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Asthma and COPD

• Intubation and mechanical ventilation
• Liberation from mechanical ventilation
• Resolution of acute component of airflow
  obstruction
• Clinically stable and wakeful off sedation
• Ability to maintain and clear airway.
• Tolerates spontaneous breathing trial

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Asthma and COPD

• Liberation from mechanical ventilation
• Consider extubation to Bi-PAP if parameters for
  liberation are borderline

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Asthma and COPD

• Intubation and mechanical ventilation
• Infrequently required when Bi-PAP widely
  available
• Mortality rates are higher when intubation is
  required
• Intubation may not be appropriate in end stage
  COPD.
• Survivors may have poor long term prognosis
• Close follow-up required following discharge.

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Asthma and COPD

• ER visits and hospitalization
• Common
• Expensive
• Poor long term prognosis if repeated
• Preventable

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