asthma module c. executive committee of national heart, lung and blood institute (nhlbi) national...

Asthma

Module C

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)

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!

Components

Definition of Asthma

• Clinical syndrome characterized by:• Chronic Airway InflammationInflammation• Bronchoconstriction

• Partial or complete reversibility• Airway Hyperresponsiveness

• “Twitchy Airways”

• Hypersecretion of Mucus• Airway Remodeling

Official DefinitionAsthma is a chronic inflammatory disorder chronic inflammatory disorder

of the airwaysof 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 wheezingrecurrent episodes of wheezing, breathlessnessbreathlessness, chest tightnesschest tightness, and coughingcoughing, particularly at nightparticularly at night or in the early morningearly morning.

These episodes are usually associated with widespread but variable airflow obstructionwidespread but variable airflow obstruction that is often reversibleoften reversible either spontaneously or with treatment.

Official Definition

The inflammation also causes an associated increase in the existing bronchial associated increase in the existing bronchial hyper-responsiveness to a variety of stimulihyper-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 inpersistent abnormalities in

lung functionlung function.

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 -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.

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.

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.

Status Asthmaticus

• A severe asthmatic episode that does not respond to correctional therapy.• Less than 5% of adult patients.

• Refractory to 2 agonists and steroids.

• Severe fatigue and respiratory failure.• Mechanical ventilation is often necessary.• Comorbidities include:

• Uncontrolled GERD• Allergic rhinitis• Psychiatric Illness

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.

Etiology

• ExtrinsicExtrinsic• 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.

• IntrinsicIntrinsic• Non-allergic or non-atopic asthma

Extrinsic Asthma

• Caused by external or environmental agents

• Antigen-Antibody reaction

• Antigen’s include• Pollen - Grass & Weeds• Dust - Mites• Animals - Hay• Sulfites - Aspirin

Immunologic Mechanism

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)

Chemical Mediator Effects

• Bronchoconstriction

• Vasodilation

• Tissue Swelling

• Increased mucous production

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

Intrinsic Asthma

• Non-allergic Asthma (Non-atopic Asthma)

• Often occurs later in life (age > 40 years)

• Normal IgE level

• No strong family history of allergy

Clinically difficult to distinguish between intrinsic and extrinsic asthma

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)

Intrinsic Asthma

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 Jamie’s FEV1 is >80% of predicted.

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.

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

Inflammatory Differences Between Asthma and COPD

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

Anatomic Alterations

• Bronchospasm

• Acute and persistent inflammation

• Air trapping and hyperinflation

• Airway remodeling

From EPR-3

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

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

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

Laboratory Findings

• Eosinophils in blood and sputum

• Culture and sensitivity

• CBC• Increased WBC if infection is present

• IgE antibodies elevated in allergic asthma

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

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

Chest X-ray

• Translucent (dark) lung fields (hyperlucent)

• Depressed and flattened diaphragms

• Increased intercostal spaces

• May be normal during symptom free periods

ABG

• Mild Asthma Stage I• Respiratory Alkalosis

PaO2 PaCO2 pH

Normal

ABG

• Moderate Asthma (Stage II)• Respiratory Alkalosis with hypoxemia

PaO2 PaCO2 pH

ABG

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

PaO2 PaCO2 pH

Normal Normal

ABG

• Very Severe Asthma (Stage IV)• Respiratory Failure with hypoxemia

PaO2 PaCO2 pH

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

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

Indicators Suggesting Hospitalization

• Decreased level of consciousness

• Can’t 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

Treatment• Oxygenation• Medications• Immunotherapy• Environmental Control• Hydration• Avoidance of Intubation and Mechanical

Ventilation• Avoid Sedation unless mechanically

ventilated• Monitoring• Influenza Vaccinations

Medications

• Quick Relief – Relievers• Fast acting 2 agonists

• Anticholinergics• Systemic Steroids

• Oral or IV

• Long Term - Controllers• Steroids

• Long Acting 2 agonists

• NSAID• Methylxanthines• Leukotriene Modifiers

IV Steroids

• Methylprednisolone • Solumedrol

• Prednisone

• Prednisolone

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.

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)

Monitor Methylxanthines

• Keep Blood Serum Levels at 5 – 15 g/mL

Monitoring

• Vital Signs

• ABG

• Pulmonary Functions• Peak flowrates and FEV1.0

• Have patient’s keep diary

• Pulse Oximetry

“All That Wheezes is Not Asthma”

• Differential Diagnosis• Rule Out

• Foreign Bodies• Vocal Cord Dysfunction• Tracheal Stenosis• Enlarged lymph nodes/tumors

CLASSFICATION OF ASTHMA SEVERITY AND CONTROL

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 Jamie’s FEV1 is >80% of predicted.

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.

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 patient’s asthma.

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.

Sample Asthma Action Plan

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

Traffic Light

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

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 2 agonist right away. Your asthma may not be under good control. Check with your doctor

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 2 agonists right away. Call your doctor and/or go to the emergency room

Assessing Improvement

• FEV1

• An increase in 12% and 200 mL is a significant response

% Improvement = Post FEV1 – Pre FEV1 x 100

Pre FEV1

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%

Changes in PFT after Bronchodilator

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

Clinical Simulation