A 50-year-old man with motor neurone disease presents to hospital with respiratory distress following two (2) days of fever and malaise. He is alert and anxious, and an arterial blood gas performed on oxygen (8L/min semi-rigid mask) revealed PaO2 45 mmHg, PaCO2 65 mmHg, pH 7.36 and HCO3 36 mmol/L. He has used a motorised wheelchair for three (3) years but continues to work as an accountant. His attentive wife states that they have discussed mechanical ventilation and are keen for him to receive full Intensive Care support.
• On day 7 of his admission he become febrile, develops a leukocytosis and a chest x-ray shows a new infiltrate in his left lower lobe. Discuss the investigation and management of this problem.