Investigações
Primeiras investigações a serem solicitadas
oxygen saturation on pulse oximetry
Exame
Recommended to be performed for all patients with a possible acute exacerbation of COPD, when available. It should be performed when vital signs are obtained. During an episode, oxygen saturation is frequently depressed below the patient's baseline level, arterial blood gas testing should be considered if the level is <92%.[1]
Resultado
depressed below the patient's baseline level
chest x-ray
Exame
Rarely diagnostic; principal purpose is to exclude alternate diagnoses and identify significant respiratory, cardiac or musculoskeletal comorbidities. A chest x-ray should be performed in people with moderate to severe disease and where pneumonia or other potential diagnoses (e.g., pneumothorax, congestive heart failure, pleural effusion, pulmonary thromboembolism) are being considered.[113]
Resultado
hyperinflation, hyperlucency of the lungs, rapid tapering of vascular markings, flattened diaphragms, increased retrosternal airspace, bullae, and a small, vertical heart
ECG
Exame
Cardiovascular disease is common in people with COPD.[127] Additionally, the possibility of a myocardial infarction, pneumothorax, or pulmonary embolus should be considered if chest tightness or other chest discomfort is present. Patients with COPD are at higher risk to develop cardiac ischemia and/or arrhythmias that can also lead to dyspnea.
How to record an ECG. Demonstrates placement of chest and limb electrodes.
Risk of cardiovascular events (acute coronary syndrome, arrhythmia, heart failure, and pulmonary hypertension) is elevated during an acute exacerbation of COPD.[1][128]
Resultado
may be right heart enlargement or right ventricular strain, arrhythmia, ischemia
ABG
Exame
ABG testing should be performed for people with a moderate to severe acute exacerbation of COPD, to detect chronic hypercarbia and assess for acute respiratory acidosis. Comparison of results to prior baseline ABG is crucial (when available). Acute respiratory acidosis may be a sign of impending respiratory failure.
PaO2 <60 mmHg indicates potential respiratory failure. PaO2 <50 mmHg, PaCO2 ≥45 mmHg, or pH <7.35 indicate a potentially life-threatening illness that requires consideration for intensive care and initiation of assisted ventilation.[129]
Resultado
respiratory acidosis and compensatory metabolic alkalosis
CBC with differential
Exame
Should be considered for patients with moderate to severe exacerbations to screen for abnormalities that may suggest additional medical disorders such as infection or anemia.
Resultado
may show elevated hematocrit, elevated WBC count or anemia
eosinophil count
Exame
The eosinophil count may also be a useful indicator of likelihood of benefit from inhaled corticosteroids.[1] Evidence suggests that on average blood eosinophil counts are higher in COPD patients. In patients with frequent exacerbations and elevated blood eosinophil levels, addition of inhaled corticosteroids to the double bronchodilator regimen should be considered.[1]
Resultado
corticosteroids may be less effective in treating exacerbations in patients with lower levels of blood eosinophils
CRP
Exame
CRP is also a potential biomarker to guide the use of antibiotics during exacerbations of COPD. A decision to withhold antibiotics, based on low CRP levels at the point of care, has been associated with reduced antibiotic prescriptions without worse clinical outcomes.[1][114][115][116]
Resultado
may be elevated in bacterial infections
basic metabolic panel for electrolytes, BUN, + creatinine
Exame
Should be considered for patients with moderate to severe exacerbations. An abnormal result may suggest additional medical disorders. Patients with COPD exacerbations may have decreased oral intake and may become volume depleted. Patients with renal insufficiency may have metabolic acidosis that can increase ventilatory demand.
Resultado
usually normal
Investigações a serem consideradas
sputum culture + Gram stain
Exame
In severe disease, and if the patient's sputum is purulent and hospitalization is being considered, a sputum Gram stain and culture should be obtained to assess for potential bacterial pathogens that may have triggered the episode.
Resultado
may suggest bacterial infection
respiratory virus diagnostics
Exame
In severe disease and, if hospitalization is being considered, testing for respiratory virus pathogens (where feasible) should be considered both to identify any treatable agent (e.g., influenza, SARS-CoV2), and to identify the need for use of expanded infection control precautions.[1]
Resultado
may confirm viral infection, rhinovirus, influenza, parainfluenza, and metapneumovirus are mostly commonly isolated
cardiac troponin
Exame
Elevations in cardiac troponin can occur due to unrecognized myocardial injury resulting from COPD exacerbation. Elevations in troponin may be associated with increased mortality.[130]
Risk of myocardial infarction is elevated during an acute exacerbation of COPD.[1][128]
Resultado
normal if no myocardial injury
B-type natriuretic peptide (BNP)
Exame
Exacerbations of congestive heart failure (systolic or diastolic) commonly mimic acute COPD exacerbation.
Elevations in serum BNP levels can help determine if an exacerbation of congestive heart failure is present.
Risk of heart failure elevates during an acute exacerbation of COPD.[1][128]
Resultado
normal if no congestive heart failure
CT scan of chest
Exame
Consider in patients with persistent or refractory exacerbations, symptoms disproportionate to lung function parameters, FEV₁ <45% with significant hyperinflation and gas trapping, or who qualify for lung cancer screening.[1]
May be useful to exclude alternate diagnoses, including tracheobronchomalacia and especially pulmonary embolus, if the diagnosis and basis of respiratory decompensation remains uncertain after routine chest x-ray.
Can identify bronchiectasis which is associated with increased frequency of exacerbations, and increased mortality.[1]
Resultado
normal if no pneumonia, pleural effusion, malignancy, pulmonary embolus, or tracheobronchomalacia present
Novos exames
procalcitonin
Exame
Emerged as a biomarker for the diagnosis of bacterial infections as it tends to be higher in severe bacterial infections and low in viral infections. The Food and Drug Administration has approved procalcitonin as a test for guiding antibiotic therapy in patients with acute respiratory tract infections. However, evidence for the efficacy of procalcitonin-guided protocols is conflicting and further research is required to establish its use in clinical practice.[1][117][118][119][Evidência B] The Global Initiative for Chronic Obstructive Lung Disease does not currently recommend the use of procalcitonin-based protocols for management of patients with COPD exacerbations.[1] The US Choosing Wisely initiative advises not to perform procalcitonin testing without an established, evidence-based protocol.[120]
It should not be used to guide antibiotic use in patients with severe COPD exacerbations requiring intensive care.[118]
Resultado
may be elevated in severe bacterial infections and low in viral infections
vitamin D
Exame
Assessment of vitamin D levels should be considered in patients with a history of COPD exacerbations.
Low vitamin D levels are associated with an increased risk of COPD exacerbation.[131] See Secondary prevention.
Resultado
may be low in patients with history of COPD exacerbations
immunoglobulins
Exame
Assessment of immunoglobulins levels should be considered in patients with a history of COPD exacerbations.
Hypogammaglobulinaemia is associated with increased risk of COPD exacerbation.[121][122][123] Low immunoglobulin levels are also associated with increased 1-year mortality.[132] See Secondary prevention.
Result
may be low in patients with history of COPD exacerbations
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