Chronic Obstructive Pulmonary Disease. Copd

By Author: Ibrahim Machiwala
Total Articles: 463
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Plan of Attack
Definitions
Epidemiology
Goals of Management
Diagnosis
Managing Stable COPD
Managing Acute Exacerbations of COPD

A disease state characterized by airflow limitation that is not fully reversible. Airflow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases. Symptoms, functional abnormalities, and complications of COPD can all be explained on the basis of this underlying inflammation and the resulting pathology.
Definitions
Chronic Bronchitis (clinical)
Sputum production more days than not for at least 3 months a year for at least 2 years
Emphysema (pathologic)
Parenchymal destruction airspace walls distal to terminal bronchioles, without fibrosis
Important: You can have either, but to have COPD you MUST demonstrate obstruction (thus the O in COPD)

Epidemiology
Fourth leading cause of death in U.S.
100,000 American deaths each year
15-20% of chronic smokers develop COPD
2.5% mortality for COPD hospital admissions
...
... COPD with acute respiratory failure:
24% in hospital mortality
59% one year mortality
If you have COPD and PaCO2 > 50mmHg:
67% chance of being alive in 6 months
57% chance of being alive in 12 months

Diagnosis
Symptoms
Dyspnea
Sputum production (especially in the morning)
Recurrent acute chest illnesses
Headache in the morning - possible hypercapnia
Cor pulmonale (Right heart failure)

Goals Of Management
Identifying and ameliorating (if possible) the cause of the acute exacerbation
Optimizing lung function by administering bronchodilators and other pharmacotherapy
Assuring adequate oxygenation and secretion clearance
Averting the need for intubation, if possible
Preventing complications of immobility, such as thromboemboli and deconditioning
Addressing nutritional needs - at the time of the acute illness, most patients are in negative nitrogen balance, which is exacerbated by steroid therapy

Diagnosis:
Signs
Prolonged expiratory time
Expiratory wheezes
Increased AP diameter of chest
Decreased breath sounds (especially upper lung fields)
Distant heart sounds
End stage: accessory muscles, pursed lip breathing, cyanosis, enlarged liver and pedal edema (in case of cor pulmonale).

Diagnosis
Radiology
Chest X-ray
Hyperinflated lung fields more radiolucent
Bullae, often bilateral upper lobes in smokers
Flat diaphragms (best seen on lateral) and retrosternal airspace can indicate air trapping
High Resolution CT of Chest
Most sensitive to detect above changes
No role in routine care of COPD patients
Can be useful for giant bullous disease surgeries or lung volume reduction surgery planning

Diagnosis
Pulmonary Function Testing
Spirometry: Decreased FEV1/FVC
FEV1 percent predicted defines severity
Lung volumes: Increased TLC, RV, RV/TLC
DLCO: Decreased

Gold Staging Criteria
Stage O: Normal spirometry; chronic sx
Stage 1 (Mild):
FEV1/FVC < 70%; FEV1 > 80% predicted
Stage 2 (Moderate):
FEV1/FVC < 70%; FEV1 30-80% predicted
2A: FEV1 50-80% predicted
2B: FEV1 30-50% predicted

Diagnosis
Stage 3 (severe):
FEV1/FVC < 70% AND:
FEV1 < 30% predicted OR:
FEV1 < 50% predicted and clinical evidence of Right heart failure

Diagnosis
American Thoracic Society - Spirometry
Low FEV1/FVC defines obstruction
FEV1%predicted Category
< 35% Very Severe
35-50% Severe
50-60% Moderately Severe
60-70% Moderate
70-80% Mild
80-100% Mild vs. Normal variant
> 100% Normal

Managing Stable COPD
Smoking Cessation Is KEY!
YOUR intervention will make a difference - must address at each visit
Medication
Two therapies ONLY have been shown to improve mortality in stable COPD:
1) Smoking Cessation
2) Oxygen Therapy

Bronchodilator Technique
MDI's get better drug deposition than nebs
Use a spacer device with MDI's
Technique is key - important for patient and doctor
Inadequate dosing can hamper treatment

Sympathomimetics
Beta-2 selectivity is good
Some additive vs. slightly synergistic effects of combining beta-2 agonist and ipratropium (Combivent)
Some data to support decreased H.influenzae pneumonia incidence with Serevent
Anticholinergic Agents (Atrovent, glycopyrrolate)
Similar ability to bronchodilate (in appropriate doses) as beta-agonists
Also reduces sputum volume; no change in viscosity
Usually under dosed
Recommend 2 (36 mcg) puffs qid
glycopyrrolate which is manufactured for IV/IM use for other indications, is available only "off label" for nebulized use in COPD (1 to 2 mg every two to four hours).
Aminophylline and theophylline are not recommended for the management of acute exacerbations of COPD. Randomized controlled trials of intravenous aminophylline in this setting have failed to show efficacy in excess of that afforded by therapy with inhaled bronchodilators and corticosteroids

Mucokinetic agents
There is little evidence supporting the use of mucokinetic (mucolytic) agents, such as N-acetylcysteine or iodide preparations, in acute exacerbations of COPD. In fact, some drugs of this class may worsen bronchospasm.

Oxygen. Yes.
Demonstrated to improve exercise performance, symptom indices and mortality
Goal in hypercapnic patients for SpO2 need not be greater than 88-90%
Always test COPD patients for oxygenation with ambulation if baseline at rest room air SpO2 ok

Systemic Corticosteroids
Never demonstrated to significantly impact mortality or exercise capacity
Slight improvements in symptom indices
Significant side effects
Rarely of benefit, generally of harm to your patient
Occasionally useful in a small subset failing other therapies AND with demonstrated bronchodilator response on PFT's

Inhaled Corticosteroids
Jury still out
Lots of recent research with some favorable data supporting its use
May be part of standard regimens in the future

Vaccines
Pneumovax, annual flu shots
Chronic antibiotic therapy - BAD IDEA
Nutritional status - Important
Pulmonary Rehabilitation
Improved exercise capacity, symptom scores
Lung Volume Reduction Surgery
Transplant

Managing Acute Exacerbations of COPD
Common precipitants:
Infection - esp viral or bacterial
Acute bronchospasm
Sedation

Who To Admit
Countless studies, few definite answers
Worsening hypoxemia and/or hypercapnia
Otherwise, mostly a clinical decision
Key points to consider:
Oxygen
Bronchodilators
Steroids
Antibiotics

Albuterol:
Neb or MDI - neb MAY be better in acute setting, but MDI's have better drug deposition overall
Continuous nebulizer treatments confer no benefit over treatments every 1-2 hours
Generally should avoid subcutaneous beta-agonists
BEWARE: Hypokalemia, tachycardia (occasional)
Levalbuterol still with weak clinical data - few situations where it is clinically indicated

ATROVENT (anticholinergic bronchodilator)
Bronchodilation
May decrease secretions
Few significant side effects
Usually significantly under dosed - emerging data supports much higher doses than usually used currently

Corticosteroids — Parenteral corticosteroids are frequently used in treating acute exacerbations of COPD. Methylprednisolone (60 to 125 mg intravenously, two to four times daily) or the equivalent glucocorticoid dose of other steroid preparations commonly is given.
Corticosteroids Utilization in this setting was initially based upon small randomized trials in which only a minority of patients benefit and the degree of improvement is modest
A randomized, placebo-controlled trial of 271 patients has confirmed the benefits of systemic corticosteroids given for up to 2 weeks to hospitalized patients with COPD exacerbation

Antibiotics
Winnipeg Criteria (give for 2-3 of the following):
Increased cough
Increased purulence
Increased sputum production
Antibiotics accelerate improvement in peak expiratory flow rates and lessen the rate of recrudescence in this setting
Amoxicillin, Doxycycline, TMP/SMX, Azithromycin, Clarithromycin, Levaquin for 10 days

Mucokinetic Agents - JUST SAY NO.
N-acetylcysteine is actually contraindicated in patients with airway obstruction
No significant clinical benefit ever demonstrated
Chest PT, intermittent positive pressure breathing and postural drainage may actually be harmful in the setting of acute obstruction

Methylxanthines (Theophylline, Aminophylline)
Not recommended for acute exacerbations
No significant benefit ever demonstrated in large, prospective trials

Oxygen: YES!
Generally a good thing - cells like that stuff
If requiring a significant increase in FiO2 over baseline requirement, start hunting for something other than just COPD exacerbation
BEWARE of CO2 RETAINERS! (goal SpO2 90%, PaO2 of 60 to 65 mmHg )
1) Altered V/Q relationships
2) Haldane effect (Hgb*O2 holds less CO2 - goes out into plasma)
3) Decreased ventilatory drive (least impt mechanism)

Non-Invasive Positive Pressure Ventilation
BiPAP
Set FiO2, inspiratory (IPAP) and expiratory (EPAP)
Difference between IPAP and EPAP augments tidal volume, therefore improving minute ventilation. CO2 then gets blown off
MORTALITY BENEFIT in patients who will tolerate

Mechanical Ventilation
Respiratory distress
Acidemia that does not correct quickly with therapy
Inability to oxygenate adequately
Often a clinical decision relative to patient's work of breathing