A 20-year-old man comes to a general practitioner office complaining of dry, irritating cough, shortness of breath, dyspnoea and increased limitation of physical activity over the past seven days. He has no other comorbid diseases. During examination, the patient is alert, fully orientated but obviously dyspnoic (unable to complete a sentence). On auscultation breathing is diminished in lower lung fields on both sides, tachypnoea. Cardiac rythm is regular, sounds without murmur, tachycardia. Oxygen saturation of the patient's blood is 88 %. What are you going to do next as a general practitioner?