The goal of this study is to determine whether omitting tracheal suctioning immediately prior to extubation is non-inferior to routine tracheal suctioning with respect to early postoperative oxygenation among adult surgical patients (aged 18-90 years, American Society of Anesthesiologists [ASA] physical status I-III) undergoing elective surgery under general anesthesia with endotracheal intubation.

The study addresses the following questions:

• Primary outcome (non-inferiority):
• Is the risk of postoperative desaturation (oxygen saturation [SpO₂] <92% within 60 minutes after extubation) in the no-suction group not worse than in the routine-suction group by more than 10 percentage points?
• Secondary outcomes (superiority):
• Does omitting tracheal suctioning reduce postoperative cough severity and sore throat?
• Does omitting tracheal suctioning avoid increasing extubation-related adverse events?

Participants will be randomly assigned (1:1) to one of two groups:

• Routine suctioning (SUC): Endotracheal suctioning plus oropharyngeal suctioning immediately before extubation
• No suctioning (NON-SUC): Oropharyngeal suctioning only, without endotracheal suctioning

All participants will receive standard anesthetic care and postoperative monitoring in the post-anesthesia care unit (PACU) for 60 minutes. Follow-up for airway symptoms and patient satisfaction will be conducted at 24 hours after surgery.

Inclusion Criteria:

• Adults aged 18-90 years with American Society of Anesthesiologists (ASA) physical status I-III.
• Scheduled for elective surgery under general anesthesia requiring endotracheal intubation.
• Planned tracheal extubation in the operating room at the end of surgery.

Exclusion Criteria:

• Inability to provide informed consent or the presence of a significant language barrier that prevents effective communication with the clinical team.
• Known diagnosis of obstructive sleep apnea (OSA), active pneumonia, or chronic pulmonary disease (e.g., chronic obstructive pulmonary disease, restrictive lung disease).
• Body mass index (BMI) >35 kg/m².
• Pregnancy or increased aspiration risk (e.g., full stomach).
• Scheduled for maxillofacial, head and neck, or airway surgery.
• Anticipated surgical duration >3.5 hours.
• Anticipated difficult airway, defined as the presence of ≥2 predictors of difficult mask ventilation (DMV) based on Langeron et al., or a documented history of difficult intubation.

Individual participant data will not be shared because the ethics committee approval and institutional data governance policies do not allow external sharing of identifiable or de-identified participant-level data. Access to study data is restricted to the research team to protect participant confidentiality and comply with local regulatory requirements.

The anesthesiologist performing the intervention, the participants, and the investigators involved in intraoperative care and data collection were not masked because the suctioning procedures could not be concealed. The outcomes assessor, responsible for recording postoperative oxygen saturation, airway symptoms, and patient-reported outcomes, was blinded to the group assignment.