If hospital treatment is indicated then:
- investigations include: 
- chest X-ray
 - arterial blood gases (record inspired oxygen concentration)
 - ECG
 - blood tests 
- Full blood count and urea and electrolytes
 - Theophylline level on admission if patient is on theophylline therapy
 - Sputum microscopy and culture if purulent
 
 
 - further management 
- give oxygen to keep SaO2 above 90%
 - assess need for non-invasive ventilation:
- consider respiratory stimulant non-invasive ventilation not available
 - assess need for intubation
 
 - if poor response to nebulised bronchodilators then consider intravenous theophyllines
 
 
Once stable then consider for hospital-at-home or assisted-discharge scheme.
Before the patient is discharged then establish on optimal therapy and, if necessary, arrange multidisciplinary assessment.
Reference:
- National Institute for Health and Care Excellence. Chronic obstructive pulmonary disease in over 16s: diagnosis and management. Jul 2019 [internet publication].
 - Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: 2025 report. 2025 [internet publication].