Chronic obstructive pulmonary disease (COPD) is a common preventable and treatable respiratory disease characterized by persistent and progressive airflow limitation accompanied by an increased chronic inflammatory response of the airways and lungs to harmful particles or gases. Acute exacerbations and their comorbidities can affect the overall severity of the patient’s disease. In recent years, acute exacerbations of COPD (AECOPD) have been included in the definition of COPD, which fully illustrates the clinical importance of AECOPD.
I. Definition Covering acute onset and exacerbation of symptoms
The 2011 revision of the COPD Global Strategy revised the definition of AECOPD as an acute onset process characterized by a deterioration of respiratory symptoms beyond the daily variability that requires a change in drug therapy. AECOPD can be caused by a variety of factors, the most common causes being viral upper respiratory tract infections and tracheal and bronchial infections. Acute exacerbations are of great importance to COPD patients, and their exacerbations are associated with many hazards, usually in the form of decreased quality of life and increased dyspnea, with significant deterioration of the patient’s condition. The problem of COPD treatment in China is that many patients do not pay enough attention to the stable phase, but come to the hospital in a hurry only after the onset of AECOPD. Patients in the acute stage seek medical attention because they feel that their shortness of breath is significantly worse than before, their cough is more intense, and their sputum volume increases. Patients are already having difficulty breathing, and they are forced to seek medical attention only when an acute exacerbation occurs and symptoms worsen significantly. At the same time, the patient also has symptoms of deteriorating lung function. However, when acute exacerbations occur in patients with chronic obstructive pulmonary disease, it is often difficult for patients to cooperate with pulmonary function tests due to their condition. In this case, blood gas analysis can be performed, which usually reveals a decrease in partial pressure of oxygen and an increase in partial pressure of carbon dioxide in the arterial blood. If the partial pressure of oxygen is less than 60 mmHg and/or the partial pressure of carbon dioxide is greater than 45 mmHg, the patient is in respiratory failure.
The risk of acute exacerbation is frequent, leading to worsening of the disease.
The diagnosis of AECOPD is based on the degree of deterioration of clinical symptoms beyond the normal variation of the patient, and once diagnosed, the condition requires a change in treatment. Nowadays, there are clinical and laboratory criteria for the diagnosis of many diseases, such as elevated transaminases in hepatitis, elevated blood pressure in hypertension, and increased fasting glucose in diabetes, but there are no easy-to-grasp clinical and laboratory indicators for AECOPD, and no relevant laboratory indicators, clinically meaningful biological markers, or recognized assessment questionnaires have been identified. The clinical diagnosis of AECOPD is still difficult. Of course, the existing laboratory diagnostic criteria for pulmonary function tests: after inhalation of bronchodilators, the first second exertional volume of breath (FEV1) is <70%. This criterion is applicable to the diagnosis of stable COPD.
The symptoms of AECOPD are mainly dyspnea, cough and sputum, and the diagnosis is made when these three symptoms are exacerbated beyond the daily variation, and a change in treatment is required. The most common nowadays is dyspnea, which is manifested by increased wheezing, followed by cough and sputum.
AECOPD has many serious consequences, not only increasing the financial burden, but also dramatically decreasing the patient’s lung function with each exacerbation. Acute exacerbations therefore accelerate the overall progression of COPD. With one AECOPD attack, the disease worsens, lung function decreases significantly, and FEV1 becomes lower and lower. Therefore, many patients with COPD die from respiratory failure, heart failure and other complications. Therefore, the COPD global strategy has paid great attention to acute exacerbations and paid clinical attention to these serious consequences.
Third, the causative factors Infection is the main cause
Currently, bacteria, viruses and pollution are considered the three main causes of AECOPD. Among them, viral upper respiratory tract infection is the most common triggering factor, and viral infection may be followed by bacterial infection.
In addition, there are several other factors that trigger AECOPD.
(1) Climate change: Patients are very sensitive to changes in temperature.
(2) Environmental factors: such as air pollution.
(3) Individual factors: Patients with concomitant disease exacerbations can also trigger acute exacerbations of COPD.
In essence, the most important thing is infection, including upper respiratory tract infection and viral infection.
The core of prevention and treatment is to relieve symptoms and reduce recurrence.
The goal of COPD treatment is twofold: first, to rapidly relieve the patient’s symptoms and reduce clinical manifestations; second, to reduce the risk of future health deterioration, such as recurrent AECOPD attacks. Therefore, clinicians should focus on both short- and long-term treatment effects for patients with COPD.
The current goals of COPD management are to reduce symptoms, improve exercise capacity, improve health status, prevent disease progression, prevent acute exacerbations, and reduce mortality.
The first step is to reduce the degree of acute exacerbation. The 2011 GOLD Global Strategy for COPD states that acute exacerbations should be treated to prevent reoccurrence of acute exacerbations while relieving the patient’s symptoms. However, many patients are not sufficiently aware of this, so physicians need to be reminded that it may be more important to prevent reoccurrence of AECOPD than to relieve symptoms.
Many patients are readmitted within a short period of time after discharge because they have not been treated appropriately for COPD stabilization. Therefore, doctors should explain clearly the medications used in the stabilization phase when the patient is discharged from the hospital and urge the patient to adhere to the medications in order to relieve the symptoms and prevent recurrence.
V. Drug regimen Combination of drugs is preferred
To prevent AECOPD relapse, we must pay attention to the treatment of the stable phase. There are many international studies on how to prevent recurrence of AECOPD in patients, and there is evidence in the literature that long-term oral antibiotic prophylaxis for AECOPD is not advisable because of antibiotic-related side effects and the tendency to induce antibiotic resistance, and the COPD Global Strategy specifically emphasizes that oral antibiotics are not recommended for AECOPD prophylaxis.
In particular, the use of some bronchodilators and inhaled glucocorticoids (ICS) during the stabilization period can prevent reoccurrence of acute exacerbations in patients. The COPD Global Strategy suggests that patients with chronic obstructive pulmonary disease must remain on treatment during the stable phase if AECOPD is to be prevented. One way is to use ICS combined with long-acting bronchodilators to relieve symptoms and prevent recurrence of AECOPD.
Conclusion
The treatment of COPD has only a starting point and no end. Once diagnosed, patients need lifelong treatment, which is exactly the same as the treatment concept of hypertension and diabetes. The concept of COPD treatment is exactly the same as that of hypertension and diabetes mellitus, and as long as there are no drug side effects and AECOPD has not occurred, the treatment should be basically stable at the same drug level. This should be taken seriously by COPD patients and actively guided by doctors.