Comparison of Acute Airway/Respiratory Complications and Intervention Requirements in Extubations Performed During On-Hours Versus Off-Hours: A Prospective Observational Cohort Study

Perioperative airway and respiratory complications remain a leading cause of significant morbidity and mortality in anaesthetic practice, as rigorously highlighted by the Royal College of Anaesthetists and Difficult Airway Society's 4th National Audit Project (NAP4), which comprehensively mapped the epidemiology of major airway events across anaesthesia, intensive care, and emergency departments, while particularly emphasising the disproportionately severe outcomes in emergency surgeries and non-theatre settings, as well as the pivotal role of system-level and team-related factors in shaping these adverse events. Building upon this foundation, the recently published analyses from the 7th National Audit Project (NAP7) have further substantiated that airway and respiratory complications-most notably laryngospasm, failed airway management, and pulmonary aspiration-account for a considerable proportion of perioperative cardiac arrests, reaffirming the persistent vulnerability of the airway across the entire perioperative continuum. Nevertheless, despite the invaluable contributions of NAP4 and NAP7, these landmark audits are fundamentally designed as national surveillance programmes focused on catastrophic endpoints such as major airway incidents and cardiac arrest; consequently, they have not provided prospective, standardised, and granular data on the much more frequently encountered acute airway and respiratory events that occur specifically during the extubation phase-including desaturation, laryngospasm, upper airway obstruction, bronchospasm, and regurgitation/aspiration-nor on the corresponding requirement for active clinical interventions in real-time practice, which remains a conspicuous and clinically relevant knowledge gap. This gap is further compounded by the observation that even the limited number of prospective studies concentrating on the adult extubation period have reported widely variable complication spectra and employed inconsistent definitions across different institutions, underscoring the pressing need for standardised, multicentre or single-centre prospective data that can inform robust quality benchmarks and facilitate meaningful comparisons across settings. Concurrently, a growing body of literature has raised legitimate concerns regarding the heightened perioperative risk associated with off-hours and on-call working conditions, wherein the convergence of increased workload due to concurrent emergency cases, diminished availability of senior supervisory staff, and the progressive accumulation of clinician fatigue and sleep deprivation may collectively predispose to suboptimal clinical performance and adverse patient outcomes; indeed, while off-hours surgery has been associated with higher mortality relative to daytime procedures, the existing evidence remains of low certainty, and patient-specific as well as surgical characteristics do not fully account for this observed association, thereby necessitating further investigations that specifically target human and organisational factors as explanatory variables. Within this context, the objective and validated assessment of clinician fatigue becomes particularly pertinent, and the Karolinska Sleepiness Scale (KSS), which has been widely employed in anaesthesia research, verified against electroencephalographic (EEG) measurements, and previously utilised to evaluate sleepiness levels under on-call conditions, offers a practical and psychometrically sound tool to objectively quantify the impact of fatigue on airway management performance during extubation. Motivated by these converging imperatives, this prospective observational cohort study at Kocaeli City Hospital is designed to compare the incidence of acute airway and respiratory complications, along with the associated intervention requirements, at the moment of extubation and during the immediate 30-minute post-extubation period, between extubations performed during on-hours (08:00-16:00) and those conducted during off-hours (after 16:00, as well as weekends and public holidays), with the overarching aims of strengthening institutional patient safety practices, driving evidence-based process improvements, and ultimately contributing to the broader discourse on perioperative airway safety. Notably, this investigation carries a distinctive scientific value, as it will be the first prospective observational study specifically designed to test NAP7's off-hours risk hypothesis at the extubation stage, thereby directly addressing a critical evidence gap in the current anaesthesia literature and offering actionable insights that may inform future guidelines and organisational policies regarding safe extubation practices across different times of the day.

Inclusion criteria

• Age ≥ 18 years

Undergoing elective or emergency surgery under general anaesthesia with endotracheal intubation

Planned tracheal extubation in the operating theatre or post-anaesthesia care unit (PACU)

Provision of written informed consent (or deferred consent for emergency cases, in accordance with national regulations)

Exclusion criteria

• Patients undergoing surgery under regional anaesthesia or sedation without endotracheal intubation

Patients with a tracheostomy in situ

Patients who remain intubated and are transferred to the intensive care unit (ICU) postoperatively

Patients undergoing cardiothoracic surgery involving cardiopulmonary bypass

Emergency airway management performed outside the operating theatre (e.g., ICU, emergency department)

Patients with known or suspected difficult airway requiring awake fibreoptic intubation

Patients who refuse to provide informed consent or withdraw consent during the study

Pregnant patients