Chronic Obstructive Pulmonary Disease (COPD)

COPD is a common, preventable, and treatable disease characterized by persistent respiratory symptoms and airflow limitation. It is primarily caused by exposure to harmful particles or gases, such as those from smoking.

The chronic airflow limitation that characterizes COPD is caused by a mixture of small airway disease (chronic bronchiolitis) and destruction of the alveoli and elastic tissue of the lung (emphysema.) These two entities are separate diseases that tend to occur together.

Chronic inflammation from inhaled particles results in the narrowing of the bronchioles (chronic bronchiolitis) and the destruction of tissue that the lung needs to exchange oxygen and expel air effectively (emphysema). Mucociliary dysfunction, another characteristic feature of the disease, is caused by the destruction of the cells that protect the airways and clear foreign particles. 

COPD thus features small airways with limited airflow due to inflammation, fibrosis, scarring, and airway collapse; additionally, the cilia, which normally help move mucus up and out of the airway, no longer function, leading to mucus buildup, which worsens the obstruction.

EMPHYSEMA occurs when the inflammation destroys the alveolar septa (walls). Smaller alveoli coalesce into larger ones, decreasing the surface area available for respiration, leading to difficulties in absorbing oxygen and expelling carbon dioxide.

 

Risk Factors

Many of the risk factors that lead to COPD are preventable. Smoking is the single greatest risk factor and is more significant than all the others combined. Exposure to environmental dust or gases, untreated asthma, and genetics all play a factor in--or increase the risk of--acquiring COPD. Even when other factors are present, acquiring COPD without smoking is rare.

 

Signs and Symptoms

The signs and symptoms of COPD are related to lung obstruction, which leads to reduced oxygen delivery. This leads to dyspnea on exertion, rhonchi, wheezing, cough, and fatigue.

"Pursed-lip breathing" (PLB) is a sign that a patient is trying to pressurize his/her own system because alveoli are drowning. This is a telltale sign of emphysema. Rhonchi are a sign of interstitial lung disease, such as emphysema. (Stridor would be more indicative of bronchitis; and wheezes, asthma.) PLB is a breathing technique that consists of exhaling through tightly pressed (pursed) lips and inhaling through the nose with the mouth closed to create back-pressure inside airways, keeping them open and making moving less work.

COPD is a chronic and progressive disease, but it becomes an EMS-worthy emergency when exacerbated. A "COPD Exacerbation" occurs when infection or other health issues impact the lungs on top of the chronic COPD present. This leads to profoundly increased obstruction, leading to low oxygen levels and increased CO2 in blood.

Identifying COPD Patients:

Blue Bloaters: Typically associated with chronic bronchitis. These patients may present with cyanosis (bluish skin), productive cough, and signs of right-sided heart failure. They often have a stocky build and may exhibit peripheral edema.

Pink Puffers: Typically associated with emphysema. These patients may present with a thin appearance, pursed-lip breathing, and a barrel chest. They often have less cyanosis but exhibit significant dyspnea and use accessory muscles for breathing.

MILD EXACERBATIONS: In mild cases, an exacerbation will usually present with a cough productive of white sputum, increased fatigue, and increased dyspnea from the patient's usual baseline. They may have a fever, increased heart rate, increased respiratory rate, and decreased blood oxygenation (but above 88%).

SEVERE EXACERBATIONS: In severe cases, exacerbations lead to dyspnea at rest and profound fatigue. Mental status changes may also become evident due to increased CO2 retention in the blood. These patients may have dramatically low oxygen saturation. If a patient not on home oxygen has an SPO2 below 88%, it is considered new-onset hypoxemia, an indication for transport.

 

Management of COPD

Day to day management of COPD revolves around smoking cessation, vigilance for developing infections, and monitored exercise. Patients with oxygen saturation below 88% will be on home oxygen.

COPD AND OXYGEN: The body has receptors in the bloodstream that constantly monitor blood levels of oxygen and CO2. Signals from these receptors then signal the brainstem to increase the respiratory rate if CO2 is too high or Oxygen is too low. COPD leads to elevated blood CO2 levels, and this desensitizes the CO2 receptors, meaning the body relies exclusively on oxygen levels to set the respiratory rate! This means giving COPD patients oxygen has the potential to dramatically lower their respiratory rate as the body believes it is doing a good job respiring just because the blood oxygen is high. This can lead to dangerous increases in the accumulation of CO2.

Because of this risk with supplemental oxygen, a PaO2 target saturation (SpO₂) should be between 88-92%.

For comfort, a nasal cannula is superior to a mask and can be adjusted up to 6 L/min. 

A semi-Fowler's or upright position is superior to a supine position to ease the work of breathing.

MILD EXACERBATIONS: A primary care doctor usually manages mild exacerbations in otherwise healthy patients. Patients with an SPO2 below 88% should be placed on oxygen and transported as they are likely to degrade before seeking help outside the emergency room. Those with mild symptoms and no shortness of breath at rest will rarely have EMS called for them in the first place.

Many patients with COPD have co-morbid conditions such as heart disease, diabetes, and cancer. These patients need to be treated with caution as they may decompensate due to interactions between their mild COPD exacerbation and other conditions. Have a low threshold for transporting these patients even if they initially refuse transport.

SEVERE EXACERBATIONS: Severe COPD presenting with significant symptoms as outlined above or low oxygen saturation should be placed on oxygen and transported without delay. IV access is indicated in case resuscitation is required later during transport. Ensure the airway is clear and place the patient in the position which allows them to breathe with the most comfort.

Treatment Tips:

• Oxygen Therapy: Administer oxygen cautiously, as some COPD patients rely on hypoxic drive for respiration. Aim for an SpO2 of 88-92%.
• Bronchodilators: Use short-acting beta-agonists (e.g., albuterol) and anticholinergics (e.g., ipratropium) to relieve bronchospasm.
• Corticosteroids: Consider systemic corticosteroids for acute exacerbations to reduce inflammation.
• Non-invasive Ventilation: Consider CPAP or BiPAP for patients with respiratory distress to improve oxygenation and reduce work of breathing.