Endoscopic retrograde cholangiopancreatography (ERCP) procedures are commonly performed under deep sedation and are associated with a risk of hypoxemia, particularly in prone or semi-prone positions. High-flow nasal cannula (HFNC) therapy may improve oxygenation by delivering heated and humidified oxygen at high flow rates, while the Microstream Advance nasal cannula provides simultaneous nasal oxygen delivery and oral oxygen insufflation.

This prospective randomized study aims to compare the effectiveness of HFNC and Microstream Advance nasal cannula in maintaining oxygenation during ERCP procedures. Patients undergoing ERCP will be randomized into two groups receiving either HFNC or Microstream Advance nasal cannula oxygen support during sedation.

The primary outcomes are the incidence of desaturation and oxygen reserve index (ORi) measurements during the procedure. Secondary outcomes include time to achieve target ORi levels, respiratory complications, and procedure-related adverse events.

Inclusion Criteria:

• Patients aged 18 to 84 years
• ASA physical status I-III
• Patients scheduled to undergo ERCP
• Patients who provide written informed consent

Exclusion Criteria:

• Recent history of upper respiratory tract infection
• History of lung cancer
• Chronic obstructive pulmonary disease
• Asthma
• Body mass index greater than 35 kg/m²
• Refusal to participate in the study

Due to the nature of the oxygen delivery devices, masking of participants and care providers was not feasible.