It is known that perioperative respiratory complications occur more often in obstructive sleep apnea syndrome (OSAS) patients during general anesthesia. Although there are prospective RCTs in this area, the need for further and larger studies remains due to the heterogenity of the results. Moreover, the incidence of postoperative pulmonary complications in OSAS patients undergoing surgery in Turkey and the predictive factors affecting the respiratory adverse events are uncertain. Therefore, in this prospective observational cohort study, it was aimed to determine the incidence of postoperative pulmonary complications and the predictor factors associated with patient, anesthesia and surgery in surgical patients with a confirmed or highly suspected OSAS diagnosis undergoing general anesthesia.

Inclusion Criteria:

1. Age: 18-65 years
2. ASA physical status I-III
3. Preoperative OSAS diagnosis (with polysomnography or STOP-BANG questionnaire score)
4. Surgeries performed under general anesthesia
5. Endotracheal intubation facilitated by neuromuscular blockers

Exclusion Criteria:

1. ASA physical status IV or V
2. Planned admission to the ICU after surgery
3. Cardiac Surgery
4. Non-operating room anesthesia
5. Neuromuscular disease
6. Emergency or re-operational procedure
7. Laryngectomy
8. Pneumonectomy
9. Invasive airway access
10. Pregnancy
11. Outpatient surgery

ASA status I-III adult patients age between 18-65 years undergoing elective surgery with general anesthesia and diagnosis of OSAS will be recruited in this study.

All data will be anonymized by the local researcher. Therefore, data collection will be pseudonymous and the patient's name will not appear on any case report form or other study document. All collected data will be kept confidential. This study will be conducted in accordance with the revision of the Declaration of Helsinki (2008). ICH-GCP will be strictly adhered to.