Endoscopic retrograde cholangiopancreatography (ERCP) is considered the gold standard in diagnosing and treating biliary and pancreatic diseases. Patients planned for ERCP often have additional comorbidities that make them high-risk candidates for general anesthesia so; the optimized choice of the anesthetic technique represents a real challenge. apparent aspiration is noticeable however microaspiration is hard to detect clinically. our study aims at determining whether general anesthesia with endotracheal intubation or deep sedation is safer in ERCP patients.

Endoscopic retrograde cholangiopancreatography (ERCP) is considered the gold standard in diagnosing and treating biliary and pancreatic diseases. In fact, with the wide use of ERCP, many critical patients in whom conventional surgery was a high-risk procedure could be managed by endoscopic treatment.

Compared to other endoscopic procedures, ERCP is considered a relatively longer and more complex one, with a substantially higher complication rate. Anesthetic techniques must facilitate the success of this procedure without adding to morbidity.

Patients planned for ERCP often have additional comorbidities that make them high-risk candidates for general anesthesia so; the optimized choice of the anesthetic technique represents a real challenge.

Many anesthetic techniques are used, ranging from conscious sedation to general anesthesia. The worldwide accepted method is deep sedation in the presence of an anesthetist without endotracheal intubation. Intubation is recommended in very exceptional cases, for example is morbidly obese patients.

According to some authors, general anesthesia is less used as an anesthetic technique in ERCP; drawbacks of GA include: the lengthier time required for induction of and recovery from anesthesia which affects patients' turnover, the risk of residual neuromuscular blockade, the higher cost as well as ERCP is usually a day case procedure favoring the sedation technique. On the other hand, monitored anesthesia care or deep sedation in remote locations can avoid these drawbacks.

For ERCP cases, which can be very challenging, few studies have addressed what is the best anesthetic choice, i.e. deep sedation or general anesthesia with intubation. Significant complications such as aspiration, hypoxemia, and hypotension are potential risks in patients undergoing ERCP procedures, and important factors that can modify these events' severity include patients' ASA status, patients' hydration and oxygenation status, and monitoring techniques used during the procedure.

Perioperative pulmonary aspiration (POPA) may lead to clinically significant morbidities and/or mortality. The risk factors for pulmonary aspiration are usually overlooked unless the patient has a history of gastrointestinal diseases (for example gastroesophageal reflux disease, upper gastrointestinal bleeding, or intestinal obstruction). However, aspiration pneumonia is seldom observed in healthy patients undergoing regular endoscopy. On the other hand, prolonged or difficult procedures may be associated with increased risks of regurgitation and aspiration.

Apparent aspiration is a notable adverse event during gastrointestinal endoscopy, on the other hand, microaspiration is an underreported complication, and data about it is scarce. Since hypoxemia is a common manifestation of pulmonary aspiration and pulse oximetry monitoring is a routine practice, therefore, postoperative hypoxemia (POH) can be used as a potential signal for POPA.

There is no conclusive data to support or refuse the need for endotracheal intubation to avoid microaspiration during ERCP; therefore, the participants in the study decided to prospectively compare both techniques as regards the risk of microaspiration.

Inclusion Criteria:

1. ASA 1-3.
2. Age above 18 years old.
3. Preoperative pulmonary stability criteria (defined as a respiratory rate 12-24 breaths per minute, SpO2 ≥ 94% on room air) -

Exclusion Criteria:

1. Age < 18 years.
2. Morbid obesity BMI ≥ 40 Kg/ m2.
3. Pregnancy.
4. Fasting ≤ 6 hours for solid food and ≤ 2 hours for clear liquids. 4
5. A pre-existing lung condition in patients requiring supplemental oxygen, inhalational bronchodilator, or systemic bronchodilator or steroid.
6. Patients in the intensive care unit and/or requiring mechanical ventilation prior to the procedure.
7. Previously intubated patients during the same hospitalization.
8. Tracheostomized patients.
9. Patients with swallowing disorders.
10. Bowel obstruction.
11. Anticipated difficult intubation.

the population of the study will be randomly selected from the daily scheduled cases undergoing ERCP in the Gastroenterology department of Theodor Bilhrarz research institute.