chronic obstructive pulmonary disease (copd). copd is characterized by : **chronic airflow...
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Chronic Obstructive Pulmonary Disease (COPD)
• COPD is characterized by :**Chronic airflow obstruction & accelerated loss of lung function which is progressive & NOT
fully reversible.** COPD is preventable & treatable but NOT curable.**In COPD, airway obstruction is fixed & irreversible
w/ different degrees of reversibility according to patients.
• COPD is assoc. w/ abnormal response to noxious chemicals or gases.
• Most common risk factor for COPD is SMOKING• COPD pts. experience: -productive cough
-dyspnea
**See table2 p.920 for comparative table b/w asthma & COPD
• General Goals of Management of COPD:1) Prevent or slow disease progression.2) Relieve symptoms.3) Improve exercise tolerance.4) Improve overall health status.5) Prevent & treat complications.6) Prevent & treat exacerbations.7) Decrease mortality.
• 2 Major Forms of COPD:1) Chronic Bronchitis (C.B.)2) Emphysema1) Chronic Bronchitis (C.B.):
Defined clinically as chronic excessive secretion into bronchial tree occurring most days during a period of @ least 3 months /yr for @ least 2 consecutive yrs.
2) Emphysema:Defined anatomically as abnormal permanent enlargement of the alveoli distal to terminal bronchioles accompanied by destruction of their walls without fibrosis.
• Both C.B.& emphysema are :1) Indistinguishable. 2) Have different risk factors.3) Have similar management strategies.
** Although Asthma & COPD are both characterized by airflow obstruction, their pathophysiologic features & response to treatment are different.
• Etiology:*Smoking is major risk factor for COPD.• About 80-90% of COPD pts. have a history of current or past
smoking although only 15-20% of smokers develop COPD due to genetic variation.
• Other R.F. include:1. Environmental factors(pollution&occupational)2. Recurrent pulm. infections in childhood.3. α₁ antitrypsin deficiency: Rare & inherited (<1% of
emphysema cases)
• Exacerbations of COPD typically have an infectious etiology, either viral or bacterial.
• During an exacerbation, there is:1) Increased S/S 2) Increased mucus production3) Worsening of gas exchange4) Worsening of airway obstruction assoc. w/ an
increased risk of resp. failure.
• Clinical Presentation & Diagnosis:• Clinical assessment of COPD pts. includes:
1) Medical history2) Physical examination
• Diagnosis of COPD is considered w/complaints of:*Chronic cough
*Dyspnea*Sputum production* + History of risk factors
• Signs & Symptoms:• Pathophysiologic changes progress over yrs. & clinical symptoms occur later.• By time pt. seeks med. help, disease is far advanced.• Sig. overlap b/w clinical presentation of C.B. & Emphysema.* Productive cough is assoc. more w/ C.B.• Dyspnea is more assoc. w/ Emphysema.• Obesity is assoc. w/ C.B. (Blue bloaters)• Wt. loss is assoc. w/ Emphysema (Pink puffers)• Gold standard for COPD diagnosis is spirometry: FEV1/FVC < 70% • When SABA is administered & spirometry is repeated in 15-30 min.:
-COPD is typically characterized by < 12% improvement in FEV1 (or <200ml in pts w/ very low lung volumes).- A large increase in FEV1 is more consistent w/ asthma.
• COPD progression may develop acute & chronic complications, i.e.:
1)Pulm. HTN2)Cor Pulmonale & Rt. CHF ( Blue Bloaters )3)Polycythemia4)Hypoxemia & resp. acidosis 5)Emphysematous (Pink Puffers)
• An individualized approach to therapy should be: 1) Appropriate
2) Based on the severity classification3) Patient’s risk factors
• Important initial intervention: to reduce or eliminate exposure to risk factors.
• Smoking cessation: the only treatment strategy proven to slow the chronic progressive loss of lung function.
• Approaches to Treatment:• Pharmacotherapy:• None of the currently available therapies is shown
to prevent or slow progressive loss of lung function.
• 1⁰ role : symptomatic relief• 1⁰ strategy: using bronchodilators.• Response to meds. : Different among pts. • Assessment of response & S/Es (table35.8 p.926)
• Reversibility of airflow limitation through spirometry (FEV1) : Not shown in many pts.
• Dyspnea : Major debilitating symptoms for advanced dz. pts.
• Inhaled route of adm.(MDI, DPI, Neb.): -Pref. because > effective, faster onset & safer than oral.
-All inhaled mechanisms are equally effective in chronic management.
-MDI & DPI: > convenient-Nebulizer: initial treatment in exacerbation.
*Bronchodilator combination used for additive benefits & reduced S/Es.
1) Bronchodilaters:A. Beta-2 Agonists:
-SABA-LABA
B. Anticholinergics:-SA Ach-LA Ach
C. Methylxanthines
I. Bronchodilators:A) Beta-2 Agonists:Examples of SABA:-Albuterol-Pirbterol-Terbutaline
*Albuterol:- Most commonly used inhaled SABA.- < 5 min OA-Relativ. short DA ( 4hrs.w/chronic use) ̴�
*In COPD, SABA: -Relieves symptoms -Improves exercise tolerance -No sig. lung function improvement
Examples of LABA: ( DA 12hrs) ̴�-Formoterol (OA 5min., pk. 30min.) Difference NOT ̴� ̴�-Salmeterol ( OA 15min., pk. 1-2 hrs.) important ̴� ̴�
clinically*Sig. advantage of LABA over SABA*Considered for those NOT controlled w/ SABA• For more frequent or chronic symptoms, long acting
bronchodilators (LABA, LA Ach.) are more effective in:1. Improving lung function2. Improving exercise tolerance3. Improving quality of life4. Reducing frequency of exacerbations
B) Anticholinergics:1) Short Acting:Ipratropium Br.: (by inhalation)* ≥ bronchodilation than SABA @usual doses.*Little systemic absorption.*OA within 15 min., DA 4-6 hrs.*@ max. doses bronchodilation by beta-2 agonists maybe = to that of ipratropium in COPD but S/Es are more common w/SABA. *Due to slower OA, SABA may be preferred for acute bronchospasm w/ ipratropium used on scheduled basis.*Given as 2 inhalations QID increased to 6 inh. if needed.
2) Long Acting:Tiotropium:*Once daily dosing regimen.*Comparing Tiotropium w/Ipratropium in COPD:1.Tiotrop. used QD, Ipratrop. used QID.2. < Multiple exacerbations w/ Tiotrop.3. Sig. longer time to 1st exacerbation w/Tiotrop.4. For most outcomes, Tiotrop.> effective than
Ipratrop. but > expensive.
• Studies did NOT show significant clinical difference between LABA & Tiotropium in COPD management.
• Short- acting bronchodilators (Albuterol + Ipratropium) combination increase effectiveness & as per treatment guidelines are commonly used in the management of Mild-Mod. COPD.
• Limited data are available on the use of Long-Acting Bronchodilators combination, however,(LABA + Tiotropium) combinations are used for severe COPD patients.
C) Methylxanthines:
• Theophylline is currently considered a 3rd- line agent in the management of COPD due to the availability of safer & more potent therapies & its risk of toxicities.
• Issues to be considered with the use of Theoph.:1) Different dosage forms &salts of theoph. are
available.(SR QD or BID are most appropriate)2) Significant variability in bioavail. between different
products & patients.3) Recommended therapeutic range for COPD 8-12ug/ml.4) Smoking , other drugs, & disease factors interact w/
theoph. Careful monitoring of serum theoph. conc. is important.
5) Sig. S/E profile involves: GI, CNS, CV.
• Summary of Bronchodilator Therapy:1) Bronchodilators are the mainstay of therapy for chronic COPD
management.2) Inhaled form preferred over systemic.3) Short-acting agents are used initially.4) If symptoms continue, LA agents are >effective & convenient:
Different trials showed long-acting bronchodilators (LABA & LA Ach) provided > benefit in improving different outcome measures than Short-Acting agents(SABA & SA Ach).
5) Bronchodilator combinations are commonly used with added benefit & reduced S/Es from higher doses of a single agent.
6) Oral theoph. Is an option reserved for those NOT responding to inhaled regimens or refuse to use inhaled meds.
II. Corticosteroids:• Did NOT result in dramatic response (unlike in
asthma) which may be due to neutrophilic nature of COPD.
• Systemic corticosteroid should be avoided in chronic COPD due to its lack of benefit & serious toxicity.
• ICS has superior safety over systemic.
• Current Guidelines suggest:Trial of ICS therapy warranted in patients: 1) whose FEV1 < 50%.
& 2) who experience frequent exacerbations.
*Newer ICS agents i.e.: -budesonide -fluticasone
-mometasone May have less of a risk of S/Es.
• Combination of LABA & ICS:-For convenience & ease of use.-Showed greatest FEV1 response w/ No difference in the exacerbation rate.
*Mucolytic/Expectorant agents:- Showed NO clinical benefit in COPD.
*Respiratory stimulants:-Not recommended due to short-lived effect + potential risk.
• α₁-Antitrypsin Replacement Therapy:
- Only used for the rare inherited form of emphysema.
- Requires weekly or twice weekly infusions.
- Not indicated for other forms of emphysema.
• Non-pharmacologic Approaches:1) Tobacco Cessation2) Pulmonary Rehabilitation3) Nutritional Therapy4) Keeping Immunization Current5) Supplemental O₂ Therapy
1) Tobacco Cessation:* Difficult to achieve & maintain.• The most important intervention in the
prevention & treatment of COPD.• Slows the rate of loss of lung function• Most important & beneficial intervention• Associated w/ immediate & sustained health
benefit.
2) Pulmonary Rehabilitation:a. Patient Education ( Dz., technique, ̴�
adherence, self management skills).b. Exercise Training.c. Psychological Support & intervention
(for anxiety & depression).d. Nutritional Therapy.
3) Nutritional therapy in COPD was shown to be valuable in: 1. Relieving symptoms
2. Improving exercise tolerance 3. Improving overall health status
• Poor nutrition has sig. impact on COPD.• Pulm. Rehab.: 1. Less beneficial in preventing complications &
exacerbations. 2. No effect in reducing mortality or slowing dz.
progression.
4) Keeping Immunization Current:
a. The inactivated IM Influenza virus vaccine should be used because it has been shown to reduce serious illness & death in COPD pts.
b. Pneumococcal vaccine is recommended to be given SQ or IM because it provides prophylaxis against most common strains of Strep. Pneumiae.
5) Supplemental O₂ Therapy: (Long-Term Therapy)-Improves survival in COPD pts. w/ chronic hypoxemia.-Benefit seen if:
- pO₂<55mmHgor -pO₂<60mmHg w/ evidence of end- organ effect
of COPD, i.e.:*Cor pulmonale *Polycythemia *Cognitive impairment
• Greatest benefit shown in those who used O₂for @ least 15hrs/d.
• Nasal Cannula: The most common & convenient method of O₂ supplementation.
• ABGs & Pulse Oximetry: The 1⁰ methods for determining O₂ saturation.
• Goal of Therapy: Maintain O₂ saturation ≥ 90%.• Most are managed @ flow rates of 1-4L/min.
• Surgical Management:• For those who can NOT be managed medically.1. Bullectomy: -Removing bullea (large air spaces in
lungs)not participating in gas exchange2. Lung Volume Reduction Surgery (LVRS):
-More common-More comprehensive procedure in removing non-functional segments of lung tissue.
3. Lung Transplantation:-Used in advanced COPD
• Managing Exacerbations:• Associated w/ increased morbidity & mortality.• Acute worsening in patient’s baseline, i.e.:
-worsening dyspnea-increased cough-change in volume & appearance of sputum
beyond the day-to-day variations.• Severity: Levels 1-3
-Level 1: Managed as outpatient (E.R.)-Level 2: Requires hospitalization-Level 3: Complicated by respiratory failure
• General Management:1) Supplemental O₂ if warranted.2) Intensification of bronchodilation therapy.3) Systemic corticosteroid therapy.4) Antibiotics in most cases.5) Ventilatory support if respiratory failure is
present.
1) Level 1:• Commonly treated w/ intensification of
bronchodilator therapy: -Increase dose of SA bronchodilators (comb. SABA + Ipratropium) by MDI or Neb.-Less evidence to the role of LA
bronchodilators: Guidelines recommend LA bronchodilators to be
continued or added if pt’s condition warrants.
• Level 1 therapy involves use of Short Course of Systemic Corticosteroid:
-improves lung function. & -reduces relapse rate. **Prednisone 0.5-1 mg/kg/d X 10-14 d* Insufficient data on ICS use in COPD
exacerbation
• Antibiotics are commonly used in COPD exacerbations:
* S.Pneumoniae, M.Catarrhalis, H.Influenzae were found in pts. w/ stable COPD or exacerbation representing either colonization or infection.
*The presence of 2 of 3 of the following is an indicator for antibiotic use:
1. Increased dyspnea2. Increased sputum 3. Increased sputum purulance
**Traditional antibiotics are as effective as newer ones** Duration of antibiotic therapy= 7-10 days
2) Level 2:• Frequently treated as inpatients.• Treatment approach similar to level 1.• Oral antibiotics & corticosteroid if possible
(as effective as parenteral)• Consider extended-spectrum antibiotics
esp. if Ps. Auroginosa is suspected.
3) Level 3:• May require ventilatory support. • Aggressive bronchodilator therapy.• Corticosteroid therapy.• Broad-spectrum antibiotics may be warranted
initially.• Follow-up w/in 1 month of hospitalization.
* Theophylline oral or IV has minimum benefit in acute exacerbations of COPD.
** Prophylactic Antibiotics to reduce exacerbations is NOT proven effective & increases the risk of resistance.
** Very Important Tables:1) Table 35.11 p.935: General Principles for
Pharmacotherapy of COPD
2) Table 35.12 p. 936