Asthma

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Asthma

• Module C

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• Executive Committee of National Heart, Lung and
  Blood Institute (NHLBI) National Asthma Education
  Prevention Program Expert Panel Report (NAEPP)
• 1991
• 1998
• 2002
• 2007 (link on website)

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NAEPP

• National Asthma Education and Prevention Program
• An expert panel that looked at research related
  to asthma with the intent of designing guidelines
  to improve management.
• First guidelines released in 1991
• REVOLUTIONIZED asthma management!
• Based upon additional research and continued
  improvements in diagnostic techniques and
  therapeutic interventions, subsequent panels have
  provided expert recommendations, the latest of
  which was released in 2007.
• 487 pages in length!

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Components
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Definition of Asthma

• Clinical syndrome characterized by
• Chronic Airway Inflammation
• Bronchoconstriction
• Partial or complete reversibility
• Airway Hyperresponsiveness
• Twitchy Airways
• Hypersecretion of Mucus
• Airway Remodeling

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Official Definition

• Asthma is a chronic inflammatory disorder of the
  airways in which many cells and cellular elements
  play a role, in particular, mast cells,
  eosinophils, T Lymphocytes, macrophages,
  neutrophils, and epithelial cells.
• In susceptible individuals, this inflammation
  causes recurrent episodes of wheezing,
  breathlessness, chest tightness, and coughing,
  particularly at night or in the early morning.
• These episodes are usually associated with
  widespread but variable airflow obstruction that
  is often reversible either spontaneously or with
  treatment.

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Official Definition

• The inflammation also causes an associated
  increase in the existing bronchial
  hyper-responsiveness to a variety of stimuli.
• Moreover, recent evidence indicates that
  subbasement membrane fibrosis may occur in some
  patients with asthma and that these changes
  contribute to persistent abnormalities in
• lung function.

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Goals of Asthma Management

• NAEPP3 recommends the following goals be targeted
  for each patient
• Reduce Impairment
• Prevent chronic and troublesome symptoms.
• Require infrequent use of Short-Acting
  b-agonists.
• Maintain (near) normal PFT.
• Maintain normal activity levels (including
  exercise and other physical activity and
  attendance at work or school).
• Meet patients and family expectations of
  satisfaction
• Reduce Risk
• Prevent exacerbations of asthma minimize the
  need for emergency department visits.
• Prevent progressive loss of lung function for
  children, prevent reduced lung growth.
• Provide optimal pharmacotherapy with minimal or
  no adverse effects.

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Measures of Asthma Assessment and Monitoring

• Severity The intrinsic intensity of the disease
  process.
• Severity is measured most easily and directly in
  a patient not receiving long-term-control therapy
  or by inferring severity from the least amount of
  treatment required to maintain control.
• Control The degree to which the manifestations
  of asthma (symptoms, functional impairments, and
  risks of untoward events) are minimized and the
  goals of therapy are met.
• Responsiveness The ease with which asthma
  control is achieved by therapy.

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Two Domains of Severity and Control

• Impairment An assessment of the frequency and
  intensity of symptoms and functional limitations
  that a patient is experiencing or has recently
  experienced.
• How does asthma affect their life currently.
• Risk An estimate of the likelihood of either
  asthma exacerbations or of progressive loss of
  pulmonary function over time.
• How might asthma affect their life in the future.

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Status Asthmaticus

• A severe asthmatic episode that does not respond
  to correctional therapy.
• Less than 5 of adult patients.
• Refractory to b2 agonists and steroids.
• Severe fatigue and respiratory failure.
• Mechanical ventilation is often necessary.
• Comorbidities include
• Uncontrolled GERD
• Allergic rhinitis
• Psychiatric Illness

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Epidemiology

• 12 Million in US
• From 1982 to 1992, the prevalence of asthma
  increased as did the death rate.
• Five times higher for blacks than for whites.
• Leading cause of hospitalization for children and
  the number one chronic condition causing school
  absenteeism.
• Total cost of asthma care is about 6 billion.

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Etiology

• Extrinsic
• Allergic or Atopic Asthma
• Atopy is the genetic disposition for the
  development of an IgE-mediated response to common
  aeroallergens.
• The strongest identifiable predisposing factor
  for developing asthma.
• Intrinsic
• Non-allergic or non-atopic asthma

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Extrinsic Asthma

• Caused by external or environmental agents
• Antigen-Antibody reaction
• Antigens include
• Pollen - Grass Weeds
• Dust - Mites
• Animals - Hay
• Sulfites - Aspirin

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Immunologic Mechanism
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Chemical Mediators

• Released from mast cell
• Histamine
• Eosinophil chemotactic factor of anaphylaxis
  (ECF-A)
• Neutrophil chemotactic factor (NCF)
• Leukotrienes (formerly known as Slow Reacting
  Substance of Anaphylaxis or SRS-A)
• Prostaglandins
• Platelet activating factor (PAF)

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Chemical Mediator Effects

• Bronchoconstriction
• Vasodilation
• Tissue Swelling
• Increased mucous production

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Response Rate to Chemical Mediators

• Early asthmatic response
• Occurs within minutes of exposure
• Late asthmatic response
• Begins several hours after exposure
• Dual (Biphasic) Response
• Early and late response

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Intrinsic Asthma

• Non-allergic Asthma (Non-atopic Asthma)
• Often occurs later in life (age gt 40 years)
• Normal IgE level
• No strong family history of allergy
• Clinically difficult to distinguish between
  intrinsic and extrinsic asthma

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Causes include

• Infections/Sinusitis
• Exercise/Cold Air
• Industrial Pollutants or Occupational Exposure
• Smoking
• ALL kinds
• Drugs
• Aspirin
• Beta Blockers

• Foods
• Preservatives
• Tartrazine (yellow food coloring)
• Gastroesophageal Reflux (GERD)
• Nocturnal Asthma
• Emotional Stress
• Hormonal
• Pregnancy
• Catamenial (Menses related)

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Intrinsic Asthma
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• Jamie (now age 14), has had three episodes of
  wheezing this week and her parents have brought
  her in for an asthma office visit. When taking
  her history, it is found that Jamie was diagnosed
  with atopic asthma at age 10. Jamie tells the
  physician that she has used her Proventil Inhaler
  once a day, on three separate days this week to
  control her wheezing and shortness of breath. She
  uses no other medications at this time. When
  questioned about her activities, she stated that
  she likes to ride horses and that her parents had
  purchased a horse for her last month (which she
  named Trigger). Although she had been riding
  daily, she has felt too fatigued and short of
  breath to ride this week. She complained of
  waking up at least three times this month with
  shortness of breath and wheezing. A bedside PFT
  was done in the office and the results show that
  Jamies FEV1 is gt80 of predicted.

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Extrinsic vs. Intrinsic

• EPR-3 does not mention these terms.
• Many feel there are multiple variants of asthma
  based upon different phenotypes of the disease.

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Comparison between Asthma and COPD

• Similarities
• Obstructive Diseases
• Hyperinflation and Airtrapping
• Dissimilarities
• Asthma has high inspiratory and expiratory
  resistance COPD only expiratory
• Asthma patients are generally healthier no heart
  failure
• There is a reversible component to asthma

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Inflammatory Differences Between Asthma and COPD
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Anatomic Alterations

• Thickening of the sub-basement membrane.
• Sub-epithelial fibrosis.
• Airway smooth muscle hypertrophy and hyperplasia.
• Mucus gland (goblet cells and bronchial glands)
  hypertrophy and hyperplasia leading to
  hypersecretion of mucous
• Angiogenesis

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Anatomic Alterations

• Bronchospasm
• Acute and persistent inflammation
• Air trapping and hyperinflation
• Airway remodeling

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From EPR-3
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Signs and Symptoms

• Variable from person to person
• Variable from attack to attack
• Intermittent cough
• Intermittent wheeze
• Intermittent dyspnea
• Chest tightness
• Patient may have no symptoms and normal
  spirometry between attacks

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Physical Exam

• Tachypnea
• Tachycardia
• Patient positioning
• Increased A-P diameter of chest
• Hyperinflation
• Pursed lip breathing
• Retractions/Accessory Muscles
• Percussion Note Hyperresonant
• Pulsus Paradoxus of 10 mm Hg or more

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Physical Exam

• Persistent cough
• May be only symptom Cough-Variant Asthma
• 2-3 word sentences
• Low peak flowrate and FEV1
• Wheezing
• Absence is a BAD sign
• Dyspnea
• Chest tightness
• Abdominal paradox

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Laboratory Findings

• Eosinophils in blood and sputum
• Culture and sensitivity
• CBC
• Increased WBC if infection is present
• IgE antibodies elevated in allergic asthma

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Pulmonary Functions

• Decreased Flowrates Severe obstruction
• FEV1 less than 1 liter
• FEV1 predicted less than 70
• Increased RV, FRC, TLC
• During acute exacerbation
• Obstructive Flow Volume Loop
• SVC greater than FVC
• PFT Testing may be normal between episodes

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Pulmonary Function Testing

• Methacholine Challenge Test
• Bronchoprovocation Test
• Decrease in FEV1 by 20 or more from baseline
• Do not order complete PFT when the patient is
  having an acute attack. Monitor peak flowrates
  or bedside spirometry

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Chest X-ray

• Translucent (dark) lung fields (hyperlucent)
• Depressed and flattened diaphragms
• Increased intercostal spaces
• May be normal during symptom free periods

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ABG

• Mild Asthma Stage I
• Respiratory Alkalosis
• PaO2 PaCO2 pH
• Normal ?

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ABG

• Moderate Asthma (Stage II)
• Respiratory Alkalosis with hypoxemia
• PaO2 PaCO2 pH
• ?

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ABG

• Severe Asthma (Stage III)
• Normal acid base balance with hypoxemia
• PaO2 PaCO2 pH
• Normal Normal

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ABG

• Very Severe Asthma (Stage IV)
• Respiratory Failure with hypoxemia
• PaO2 PaCO2 pH
• ?

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Correlate ABG with Flowrates

• Flowrates are a better indicator than ABG in
  assessing airflow obstruction and severity
• Very Severe Asthma attacks may present with
  normal ABG but very low flowrates

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Fatal Asthma

• Respiratory Failure requiring intubation
• Hypoxic seizures
• Changes in Mentation (Obtunded)
• Disregard of asthma symptoms by the patient
• Depression - Low IQ - Drug Abuse
• Fear of Steroids
• Pneumothorax

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Indicators Suggesting Hospitalization

• Decreased level of consciousness
• Cant complete sentences
• Silent Chest
• Pulsus paradoxus
• Cyanosis

• Peak Flowrate of less than 50 of personal best
• FEV1 less than 1 L
• Acidotic pH
• Hyperinflation
• Pneumothorax

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Treatment

• Oxygenation
• Medications
• Immunotherapy
• Environmental Control
• Hydration
• Avoidance of Intubation and Mechanical
  Ventilation
• Avoid Sedation unless mechanically ventilated
• Monitoring
• Influenza Vaccinations

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Medications

• Quick Relief Relievers
• Fast acting b2 agonists
• Anticholinergics
• Systemic Steroids
• Oral or IV

• Long Term - Controllers
• Steroids
• Long Acting b2 agonists
• NSAID
• Methylxanthines
• Leukotriene Modifiers

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IV Steroids

• Methylprednisolone
• Solumedrol
• Prednisone
• Prednisolone

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Use of Magnesium

• Magnesium is a weak bronchodilator
• May prevent respiratory failure in patients
  presenting with severe asthma exacerbations
• May block Calcium from destabilizing mast cell.

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New Interventions for Status Asthmaticus

• Ketamine
• Deep anesthesia with halothane or enflurane in
  combination with propofol or ketamine
• Nitric oxide
• Nebulized lidocaine in combination with albuterol
  or levalbuterol is effective in helping the vocal
  cord dysfunction that may accompany status
  asthmaticus. This is an unpublished observation
  by the author in clinical practice.
• Extracorporeal life support (ECMO)

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Monitor Methylxanthines

• Keep Blood Serum Levels at 5 15 mg/mL

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Monitoring

• Vital Signs
• ABG
• Pulmonary Functions
• Peak flowrates and FEV1.0
• Have patients keep diary
• Pulse Oximetry

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All That Wheezes is Not Asthma

• Differential Diagnosis
• Rule Out
• Foreign Bodies
• Vocal Cord Dysfunction
• Tracheal Stenosis
• Enlarged lymph nodes/tumors

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CLASSFICATION OF ASTHMA SEVERITY AND CONTROL
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• Jamie (now age 14), has had three episodes of
  wheezing this week and her parents have brought
  her in for an asthma office visit. When taking
  her history, it is found that Jamie was diagnosed
  with atopic asthma at age 10. Jamie tells the
  physician that she has used her Proventil Inhaler
  once a day, on three separate days this week to
  control her wheezing and shortness of breath. She
  uses no other medications at this time. When
  questioned about her activities, she stated that
  she likes to ride horses and that her parents had
  purchased a horse for her last month (which she
  named Trigger). Although she had been riding
  daily, she has felt too fatigued and short of
  breath to ride this week. She complained of
  waking up at least three times this month with
  shortness of breath and wheezing. A bedside PFT
  was done in the office and the results show that
  Jamies FEV1 is gt80 of predicted.

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Monitoring Symptoms vs. Peak Flow

• No consensus by EPR-3.
• Self-monitoring is important to effective
  self-management of asthma.
• Both should be elements in a written Asthma
  Action Plan.
• Daily management
• How to deal with worsening symptoms
• Strongly recommended for moderate and severe
  persistent asthmatics.
• Should include a plan for school.

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Asthma Action Plan

• Daily management
• What medications to take daily including the
  specific names of the medications.
• What actions to take to control environmental
  factors that worsen the patients asthma.

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Asthma Action Plan

• How to recognize and handle worsening asthma
• What signs, symptoms, and PEFR measurements (if
  PF is used) indicate worsening asthma.
• What medications to take in response to these
  signs.
• What symptoms and PEFR measurements indicate the
  need for immediate medical attention.
• Emergency telephone numbers for the physician,
  ED, and person or service to transport the
  patient rapidly for medical care.

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Sample Asthma Action Plan
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Peak Flow Monitoring

• Have patient determine their personal best
• Record Peak flowrate for 2-3 weeks when their
  asthma is under control
• Monitor and Record twice/day
• Use traffic light system to correlate symptoms
  with severity

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Traffic Light
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Green Zone

• If your peak flow is more than_____L/min (80 of
  your personal best) you are in the green zone and
  signals good control. Take your medications as
  usual

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Yellow Zone

• If your peak flow is between _____L/min and
  ____L/min, you are in the Yellow Zone (between 50
  80 of your personal best) and this signals
  caution. You must take a short acting b2 agonist
  right away. Your asthma may not be under good
  control. Check with your doctor

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Red Zone

• If your peak flow is below____L/min, you are in
  the danger zone. This represents less than 50
  of your personal best and signals a medical
  alert. Take short acting b2 agonists right away.
  Call your doctor and/or go to the emergency room

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Assessing Improvement

• FEV1
• An increase in 12 and 200 mL is a significant
  response
• Improvement Post FEV1 Pre FEV1 x 100
• Pre FEV1

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Example

• Pre-bronchodilator FEV1 1.2 Liters
• Post-bronchodilator FEV1 1.6 Liters
• Calculate the improvement
• improvement 1.6 - 1.2 x 100
• 1.2
• 33

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Changes in PFT after Bronchodilator
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Complementary and Alternative Medicine Approaches
to the Management of Asthma

• Clinical trial that adequately address safety and
  efficacy are limited, and their scientific basis
  has not been established.
• Includes
• Acupuncture
• Chiropractic Therapy
• Homeopathy and Herbal Medicine
• Breathing Techniques
• Relaxation Techniques
• Yoga

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Clinical Simulation