BEYOND THE BASICS: COPD

     Chronic obstructive pulmonary disease (COPD) is said to significantly affect one in four adults and is an extremely common complaint seen by EMS personnel in the field. Despite the prevalence of this disease, there are both misconceptions and misinformation about the diseases that are included within the definition of COPD. This failure to understand the disease concepts reduces our ability to identify and treat COPD patients effectively.

     The diseases included in COPD are simply and effectively summed up in Rosen's Emergency Medicine:

     Asthma = reactive airways

     Emphysema = airway collapse

     Chronic bronchitis = airway inflammation and secretions.

     Asthma is often excluded from the list of chronic obstructive pulmonary diseases because of its many dissimilarities, most notably the typical age of onset and episodic presentation. Yet, by the truest definition, asthma is a chronic obstructive pulmonary disease because it does reoccur and causes airway obstruction through airway reactivity and, in prolonged cases, plugging of airways by mucus secretions.

     This article will concentrate on chronic bronchitis and emphysema because of the similarities in age of occurrence and chronic presentation.

Pathophysiology
     Understanding the pathophysiology behind diseases makes assessment and treatment more intuitive.

     Alveoli have traditionally been described as grape-like clusters. This formation allows a maximum amount of alveolar surface area for gas exchange at the capillary level in the lungs. Capillaries weave around the alveoli so the entire surface of the "grapes" (as opposed to just the bottom surface) may exchange gases.

     Emphysema is a disease process characterized by gradual destruction of the walls between the alveoli, which eliminates much of the area where gas exchange takes place and results in significant air trapping. Severe emphysema may also cause damage to capillary beds and lung parenchyma (tissue). When this occurs, bullae (pockets of air within lung tissue) may form. In severe cases, rupture of a bullae may result in pneumothorax.

     The emphysemic patient is sometimes referred to as a "pink puffer." The patient with emphysema may have higher PO₂s than a patient with chronic bronchitis and exhibit shallow, puffing, tachypneic respirations through pursed lips. Patients with emphysema often appear very thin due to their increased metabolic rate, decreased calorie consumption and decreased desire to eat. The amount of work required to interrupt breathing in order to eat is often not worth the effort, and, as a result, the patient chooses to breathe rather than eat.

     It is common for patients with emphysema to have some level of chronic bronchitis. Chronic bronchitis is a condition where the bronchi are swollen, edematous and covered with mucus secretions. Damage to the bronchiolar lining reduces the ability of cilia to clear the airway. The chronic bronchitis patient has a chronic cough, which results from attempts to clear excess secretions in the airway. In early stages, the patient coughs mostly in the morning. As the disease progresses, the cough becomes more frequent and is often accompanied by purulent sputum production. The patient may frequently be treated for respiratory infection.

     The patient with chronic bronchitis is often called a "blue bloater," due to hypoxemia and edema. This person often experiences cor pulmonale (a reduction in right heart function caused by a respiratory condition), resulting in edema.

Patient History
     While many patients can tell you that they are experiencing a COPD exacerbation, there are still a significant number of conditions that appear similar to or coexist with emphysema or chronic bronchitis.

     While it isn't within our realm to diagnose new cases of COPD in the field, there are certain items in the history that help point to COPD. The most significant is a 20 or more pack/year history of smoking, defined as smoking one pack per day for a year. This method allows the EMS provider to get a relatively accurate assessment of potential harm to the lungs. To obtain a pack/year history, multiply the number of packs smoked per day by the number of years the patient has smoked. A patient who smoked two packs/day for 10 years would have the same potential for pulmonary damage as the patient who smoked one pack/day for 20 years. Both would be reported as 20 pack/year smokers.

     COPD exacerbations are frequently caused by respiratory infection. Exacerbations are the significant and relatively sudden worsening of the patient's condition. COPD usually worsens slowly and progressively over a period of years. This is different from an exacerbation, which occurs over a day or days. A recent history of respiratory infection, including increased cough and mucus production, fever and malaise, may be present.

     Note the color of any respiratory secretions. Patients with a long history of COPD will watch for a change in color of sputum or mucus and will be happy to show you the results of a productive cough in the multitude of tissues near their chair or bed.

     As with all patients suspected of having cardiac and respiratory conditions, it is important to determine the progression of symptoms and the relation of signs and symptoms to exertion and rest. All patients with respiratory complaints should be asked about chest pain, chest discomfort, fatigue and other signs and symptoms of cardiac conditions.

     Depending on the course and severity of the patient's COPD, a variety of medications ranging from bronchodilators and steroids to home oxygen may be in use. It is important to note all of the patient's medications as part of your history, but perhaps even more important to note which medications have been taken in response to this acute condition and how the patient responded to them.

Physical Exam Findings
     The patient with a history of COPD and potential exacerbation will exhibit some of the classic signs of respiratory distress, including shortness of breath and wheezing--especially on expiration--in conjunction with prolonged expiratory times, which are necessary to help the patient exhale gases trapped in the lower airways.

     The patient may also experience increased coughing, with or without producing mucus. The tripod position is common. You may also see other signs and symptoms including:

• JVD. This may be present because of increased pressure as a result of right heart failure. Kussmaul's sign (increasing JVD with inspiration) may occur in severe cases.
• Increased A-P chest diameter (barrel chest) as a result of increased pulmonary hyperinflation.
• Clubbing, a condition where chronic hypoxia has caused vasodilation and enlargement of the distal portion of the fingers. The clubbed appearance is defined by a greater than 165-degree angle between the proximal nail and the cuticle (it becomes more convex), resulting from a general thickening of the distal finger.
• Pursed-lip breathing. Patients exhale against partially closed (pursed) lips to help reduce lung hyperinflation by providing a back-pressure similar to PEEP (positive end-expiratory pressure).
• Mucus color. Changes in mucus color, especially to yellows, greens and brown/rust colors, may indicate infection.

     The pulse oximetry reading of a COPD patient may be routinely low. COPD patients on home oxygen have experienced 88% (PaO₂ of 55 mmHg or less, or 55–59 mmHg in the presence of right heart failure) or less to qualify for that oxygen, so assume that the room air pulse ox reading will be fairly low. However, in an early stage of the disease, it is possible to get a 100% pulse ox reading on a patient with supplemental O₂ because of oxygen retention.

Differential Diagnosis
     While it is important to use a differential diagnostic approach to all patients, in the COPD patient, the differentials frequently overlap (e.g., emphysema with chronic bronchitis or chronic bronchitis with right heart failure). Additionally, a respiratory infection that exacerbates a patient with COPD is treated by treating the signs and symptoms of COPD.

     The most significant differential in assessing the COPD patient is congestive heart failure. Complicating matters is the fact that it is common to have COPD and congestive heart failure concomitantly. In this case, treatment will differ between congestive heart failure and COPD, depending on which is believed to be the primary cause of the patient's respiratory distress.

     While it might appear easy to determine the difference between the two, many signs and symptoms overlap, including lung sounds, shortness of breath and JVD.

     The patient with congestive heart failure may differ from the COPD patient in that:

• The CHF patient often presents with bibasilar rales.
• The CHF patient may experience more pronounced orthopnea and paroxysmal nocturnal dyspnea.
• The CHF patient may experience acute weight gain with edema and ascites on a more acute basis.
• The COPD patient may present with a productive cough with purulent sputum.

     Pneumonia is another potential differential diagnosis for COPD, as the patient may have a productive cough and purulent sputum. The pneumonia patient may also exhibit fever, chills, night sweats and other signs of acute infection. It should be noted that patients who are in a weakened condition and who have pneumonia are also at risk for developing sepsis. Pneumonia typically involves a single lobe or congruent lobe and therefore presents with unilateral (or lobar) rales on auscultation.

     Pulmonary embolus (PE) is an elusive diagnosis for many reasons. Most notable is its rapid onset and high rate of death. A large percentage of pulmonary emboli are actually diagnosed at autopsy. The symptoms most common in pulmonary embolus (hemoptysis, dyspnea and chest pain) are actually found together in a small percentage of patients presenting with pulmonary embolus. Signs and symptoms that may resemble COPD include tachypnea, rales, wheezing, shortness of breath and tachycardia. In roughly 20% of all patients diagnosed with a PE, the ECG demonstrates the S₁, Q₃, T₃ pattern as explained below:

     S₁: Prominent S wave in Lead I

     Q₃: Q wave in Lead III

     T₃: Inverted T wave in Lead III

     Notable differences between pulmonary embolus and COPD include rapid onset of symptoms, which may include pleuritic chest pain, chest pain, pain in the back or shoulders and occasionally abdominal pain. Although not necessarily causes of pulmonary embolus, a history of birth control use (not including condoms), prior embolus, deep vein thrombosis, recent surgery and immobility (which may be common in patients with severe COPD) are significant.

     A patient with emphysema or chronic bronchitis may also have a history of reactive airway disease or asthma. It is difficult to differentiate between the conditions; however, they are treated identically. When asthma is the cause of respiratory distress, there may be a quicker response to beta agonists when compared with treatment of emphysema or chronic bronchitis.

     There are certain realities and limitations when making a field diagnosis. Due to the similarity of many conditions, treatment choices are made based on field assessment findings. Definitive diagnosis depends on several factors, including pulmonary function studies and radiographic images.

Treatment Decisions
     After a careful work-up, the patient experiencing a COPD exacerbation will require interventions to improve oxygenation and relieve shortness of breath. In severe cases, ventilatory support with a BVM will be required to assure adequate ventilation.

     All patients experiencing shortness of breath will receive oxygen. Much has been said over the years--and much misinformation exists--in reference to hypoxic drive in COPD patients. The axiom "All patients who need oxygen should receive it in the field" remains both accurate and a standard of care.

     Twenty years ago, ambulances carried three types of oxygen delivery devices: cannulas, masks and Venturi masks. Venturi masks went by the wayside, and cannulas became a distant second choice to the non-rebreather mask, which delivered high concentrations of oxygen to almost all patients.

     A middle ground has developed where patients with minor respiratory distress receive oxygen via cannula. The non-rebreather mask is still available to deliver high concentrations of oxygen to patients in moderate to severe distress.

     The choice of delivery device is somewhat subjective and should never be made based solely on pulse oximetry readings. The patient's perception of breathing difficulty and outward signs of distress are vital considerations in oxygenation decisions.

     A patient who calls to note sputum changes and possible infection with mimimal respiratory distress could likely be placed on a nasal cannula or continued on a cannula at home. Patients with more severe distress would benefit from the non-rebreather mask.

Medications
     Medications for COPD patients can be grouped into two broad categories: acute and long-term. Acute medications treat bronchospasm, while long-term medications help reduce inflammation and mucus secretion. Medications to reduce secretions can be used acutely in exacerbation.

     Beta agonists are the treatment of choice for acute COPD exacerbation. This can be done with a metered dose inhaler (assisted at the BLS level) or by nebulization, which is widely available to ALS providers and to a growing number of BLS providers. Albuterol is the most common medication used in this regard. Services may also use Xopenex (levalbuterol). Treatment with beta agonists is frequently beneficial with limited side effects.

     Steroids and anticholinergics are used to reduce inflammation and mucus production. Many patients have inhalers containing these medications for home use. Atrovent (ipratropium) is an example of an anticholinergic medication used to reduce secretions.

     Corticosteroids are used to reduce airway inflammation and secretions. Flovent (fluticasone) and Pulmicort Turbuhaler (budesonide) are commonly prescribed inhaled corticosteroids. The Advair Diskus (fluticasone propionate and salmeterol) combines the steroid with a longer-acting beta agonist.

     Prednisone and other oral steroids may be used to manage severe COPD and acute exacerbations, but, in addition to their increased effectiveness, they are likely to produce more significant side effects than the inhaled corticosteroids when used for a prolonged period of time at high doses. Doses over 10 mg are considered high, because they exceed the intrinsic glucocorticoid production rate of 10 mg per day.

     It is important to note that anticholinergics and inhaled steroids (including the Advair Diskus) should not be confused with beta agonist medications designed to provide immediate bronchodilation for acute COPD exacerbation.

     The use of metered-dose inhalers versus nebulizers for medication delivery also warrants discussion in this article. The metered-dose inhaler, when used properly, provides a very effective means of delivering medication to the tracheobronchial tree. Because the medication in the MDI is a fine powder, proper use of the device is critical to ensure the medication is actually distributed throughout the airway and not simply deposited on the tongue and oral mucosa, where it will have no effect. Spacer devices used in combination with the MDI help patients deliver medication to the airway efficiently.

     The nebulizer is helpful in providing a continuous flow of medication into the patient's airway and also when patients have difficulty following instructions or timing breaths when using an MDI. It can only be used in patients who are able to breathe adequately. Nebulized medications may be administered through a BVM when tubing is used to allow air flow through the nebulizer. The tubing and connection can be created or bought specifically for this purpose.

     Chronic obstructive pulmonary diseases are common and potentially serious calls. Your knowledge of pathophysiology, assessment and treatment of emphysema and chronic bronchitis are vital to your function as an EMS provider at any level.

Daniel D. Limmer, AS, EMT-P, is a paramedic with Kennebunk Fire-Rescue in Kennebunk, ME, and EMS Program Coordinator at York County Community College in Wells, ME. He is the author of several EMS textbooks and a nationally recognized lecturer.

Joseph J. Mistovich, MEd, NREMT-P, is a professor and chair of the Department of Health Professions at Youngstown (OH) State University, author of several EMS textbooks and a nationally recognized lecturer.

William S. Krost, BSAS, NREMT-P, is an operations manager and flight paramedic with the St. Vincent/Medical University of Ohio/St. Rita's Critical Care Transport Network (Life Flight) in Toledo, OH, and a nationally recognized lecturer.