Effect of Working Hours and Night Shifts on Airway Management in Surgical Patients: A Prospective Cohort Analysis of Tracheal Intubation Complications and Duration

Airway management is one of the most critical steps of anesthesia, and its complications can be life-threatening. Reduced staffing, differences in personnel experience, and physical and mental fatigue during off-hours (evenings, nights, weekends, and holidays) may affect the quality of care and patient safety - a phenomenon described in the literature as the "after-hours effect." While this effect has been studied for outcomes such as cardiac arrest and intensive care mortality, evidence specific to airway management safety remains limited. This prospective observational cohort study aims to evaluate the effect of shift timing on the safety and efficiency of tracheal intubation in adult surgical patients undergoing general anesthesia at a single center. Based on the actual start time of anesthesia, patients will be categorized into an in-hours group (08:00-16:00) or an off-hours group (16:01-07:59), without any investigator-assigned intervention. The frequency and type of intubation-related complications, intubation duration, and the pre-intubation sleepiness level of the performing anesthesiologist (assessed using the Karolinska Sleepiness Scale) will be compared between groups. The investigators hypothesize that intubations performed during off-hours are associated with a higher complication rate and longer intubation duration than those performed during in-hours. Approximately 1000 patients will be enrolled over a period of up to 2 years.