This study is a prospective randomised trial where a computer will randomly allocate

patients to one of two possible methods of delivering oxygen during the procedure of

bronchoscopy. This trial compares high flow nasal cannula (HFNC) with nasal prongs in

delivering oxygen to patients undergoing endo-bronchial ultrasound guided trans-

bronchial nodal aspiration (EBUS-TBNA) a specialised form of bronchoscopy procedure.

HFNC uses humidified higher gas flow rates than conventional low flow systems such as

nasal prongs which are limited by the respiratory rate and effort.

Inclusion Criteria:

• Subjects with a peripheral arterial pulse oximetry ≥ 90% breathing room air
• Age ≥ 18 years
• Able to breathe spontaneously throughout the procedure

Exclusion Criteria:

• Respiratory or cardiac failure
• Recent myocardial infarction < 6 weeks ago
• On long term oxygen therapy, those with tracheostomy and/ or non-invasive or invasive mechanical ventilation
• Nasal and/ or nasopharyngeal disease
• Inability to give informed consent
• Dementia
• Hepatic or end stage renal disease
• Pregnancy