Does Time Under Anaesthesia Matter? Operative Duration As An Independent Predictor Of Airway Morbidity, Postoperative Discomfort And Patient Satisfaction When Endotracheal Tube Securement Is Standardised: A Prospective Observational Study

Abstract

Background: Peri-oral and airway injury arising from the endotracheal tube (ETT) is usually explained in terms of how the tube was fixed, how large it was and how tightly the cuff was inflated. How long the apparatus remains pressed against peri-oral and periocular tissue has attracted far less scrutiny in elective theatre practice, largely because heterogeneous fixation methods within a cohort make the effect of time difficult to isolate.

Objective: To establish whether the length of an operation independently predicts intraoperative airway and peri-oral morbidity, postoperative discomfort and patient satisfaction in a cohort where every tube was secured by one and the same device.

Methods: Sixty consecutive adults aged 18–60 years of ASA physical status I or II, scheduled for elective surgery under general anaesthesia with orotracheal intubation, were studied prospectively at a tertiary teaching hospital in South India between December 2024 and December 2025. A single integrated stabilisation device was used in every case, so that securement technique could not vary between participants. Actual operative time in minutes served as the exposure. Endpoints comprised tube migration exceeding 1 cm, peri-oral soft-tissue injury, bite-related occlusion of the tube, ocular complication, a composite of these four, postoperative discomfort graded on a visual analogue scale as mild or moderate, and reported satisfaction. Analysis used the Mann–Whitney U test, the Cochran–Armitage trend test, receiver-operating-characteristic (ROC) analysis and logistic regression adjusted for age, sex and ASA status.

Results: Operations lasted a median of 95 min (IQR 68–140). At least one composite event occurred in 28.3% of patients (95% CI 17.5–41.4). Affected patients had spent longer in theatre than unaffected patients (118.8 ± 42.3 versus 94.7 ± 41.2 min; p = 0.041), and the event rate climbed steadily across duration bands (6.7%, 29.6% and 44.4% for ≤60, 61–120 and >120 min; trend p = 0.017). Not one tube displacement or ocular event arose in an operation shorter than 120 min. After adjustment, operative time alone predicted moderate discomfort (OR 2.77 for every additional 30 min, 95% CI 1.41–5.44; p = 0.003) and was inversely related to the highest satisfaction rating (OR 0.49 per 30 min, 95% CI 0.26–0.91; p = 0.024). Discrimination for moderate discomfort was good (AUC 0.824, 95% CI 0.712–0.935), and a cut-point of 80 min yielded 96.2% sensitivity with 58.8% specificity.

Conclusion: Once the manner of tube securement is fixed across a whole cohort, elapsed operating time stands out as the leading, dose-related driver of airway and peri-oral morbidity and of how uncomfortable patients feel afterwards. Time in theatre deserves to be handled as an actionable risk exposure that should prompt deliberate airway reassessment somewhere beyond the 80- to 120-minute mark, instead of being logged passively at the end of the case.