Table 1_Association between perioperative optic nerve sheath diameter and postoperative delirium after Bentall surgery: a prospective observational study.docx

Average perioperative ONSD was 0.250 mm higher with delirium (95% confidence interval 0.031–0.470; p = 0.025). Across outcome assignments, the difference ranged from 0.237 to 0.248 mm (p-values ≤ 0.029), whereas the time-by-group interaction was sensitive to assignment (p-values ranged from <0.001 to 0.094). No point-specific comparison survived Holm correction (smallest adjusted p = 0.078), and the post-closure T6 minus preoperative baseline showed no clear group difference (p = 0.147).

In an exploratory Firth analysis not adjusted for time-point selection, the odds ratio per 1-mm higher T6 ONSD was 3.75 (95% confidence interval 1.44–12.32; p = 0.005). Areas under the receiver operating characteristic curves were 0.654 for Preop, 0.689 for T0, 0.728 for T6, and 0.626 for change, without evidence of superior T6 discrimination. The five-variable model had an apparent area under the curve of 0.839 and a conditional optimism-corrected value of 0.778; predictor and time-point selection were not repeated during validation.

The internally selected 4.90-mm operating point was not an intracranial-hypertension threshold.</p>Conclusions<p>Higher perioperative ONSD was associated with documented delirium, but the temporal interaction was sensitive to unobserved outcomes, and the data did not establish a superior time point or a causal intraoperative change. These findings require external validation.</p>Trial registration<p>ClinicalTrials.gov NCT07452367; retrospectively registered 5 March 2026.</p>