VBG/ABG
Perform if SpO2 <90% or concerned about symptomatic hypercapnia, however its routine use is not recommended
Monitoring the patient's clinical status and pulse oximetry is often sufficient
The decision to start noninvasive ventilation or to intubate should be guided to by the clinical state of the patient, presence of fatigue and response to therapy
For every increase in PaC02 of 10 mmHg, the pH should change by 0.08
Peak flow
<100 L/min indicates severe exacerbation
CXR
Consider if concerned for alternative/additional diagnoses (e.g. pneumonia, CHF, pneumothorax, effusions)
Sputum culture
Usually not indicated except for patient with recent antibiotic failure
ECG
The most common dysrhythmias are atrial fibrillation and multifocal atrial tachycardia
Blood tests add little to the treatment of a<unk> 
Perform if SpO2 <90% or concerned about symptomatic hypercapnia, however its routine use is not recommended
Monitoring the patient's clinical status and pulse oximetry is often sufficient
The decision to start noninvasive ventilation or to intubate should be guided to by the clinical state of the patient, presence of fatigue and response to therapy
For every increase in PaC02 of 10 mmHg, the pH should change by 0.08
<100 L/min indicates severe exacerbation
Consider if concerned for alternative/additional diagnoses (e.g. pneumonia, CHF, pneumothorax, effusions)
Usually not indicated except for patient with recent antibiotic failure
The most common dysrhythmias are atrial fibrillation and multifocal atrial tachycardia
GOLD Grading (based on post-bronchodilator FEV1/FVC less than 70%):
I (mild<unk>  -> FEV1 ≥ 80% of predicted
II (moderate<unk>  -> 50% ≤ FEV1 < 80% predicted
III (severe<unk>  -> 30% ≤ FEV1 < 50% predicted
IV (very severe<unk>  -> FEV1 < 30% of predicted
I (mild<unk>  -> FEV1 ≥ 80% of predicted
II (moderate<unk>  -> 50% ≤ FEV1 < 80% predicted
III (severe<unk>  -> 30% ≤ FEV1 < 50% predicted
IV (very severe<unk>  -> FEV1 < 30% of predicted
COPD exacerbation
Pulmonary
Acute asthma exacerbation
Airway obstruction
Acute asthma exacerbation 
Anaphylaxis
Aspiration pneumonia and pneumonitis
Angioedema