MRCP2-3729

A 75-year-old woman presents with dyspnea. She was diagnosed with malignant mesothelioma eight months ago and was referred to palliative care services as no treatment was suitable. Her functional status has declined significantly in the last fortnight, requiring substantial assistance at home and limiting her walking to a few yards. She has recently experienced increased breathlessness, particularly when lying flat, and has noticed facial swelling and flushing. Her oxygen saturation is 97% on room air. What is the most appropriate initial management for this patient?