Effects of head direction during prone position on postoperative delirium in elderly patients undergoing thoracolumbar spine surgery: a study protocol for a randomised controlled trial
Bibliographic record
Abstract
Introduction Prone positioning with head rotation can influence cerebral haemodynamics, potentially affecting cerebral perfusion and oxygenation. Elderly patients with impaired brain perfusion and oxygenation are at an increased risk of developing postoperative delirium (POD). Despite this, few studies have explored whether head orientation during prone positioning contributes to POD in older adults, an aspect often overlooked by clinicians. This study aimed to evaluate the impact of head orientation during prone positioning on the incidence of POD in elderly patients undergoing thoracolumbar spine surgery. Methods and analysis This study is a single-centre, randomised, single-blind trial, with the assessors blinded to the intraoperative head position. Eligible participants are patients aged ≥65 years undergoing elective thoracolumbar spine surgery. A total of 500 patients will be randomly assigned to either the prone position with the head centred, or the prone position with the head deviated. The primary outcome is the incidence of POD, measured using the 3 min Diagnostic Interview for Confusion Assessment Method (3D-CAM) until postoperative day 5. Secondary outcomes include the severity of POD assessed by the Memorial Delirium Assessment Scale (MDAS), postoperative cognitive impairment evaluated using the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA), intraoperative regional cerebral oxygen saturation (rSO2), changes in vertebrobasilar artery and middle cerebral artery haemodynamics, and plasma levels of calcium channel-binding protein S100 subunit beta (S100B) and neuron-specific enolase (NSE). Ethics and dissemination Ethical approval was obtained from Yancheng No. 1 People’s Hospital Ethics Examination Committee (2023-K-120–01). The findings will be disseminated through presentations at annual conferences and publications in scientific journals. Trial registration number ChiCTR2300078839.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.031 | 0.035 |
| Meta-epidemiology (narrow) | 0.006 | 0.003 |
| Meta-epidemiology (broad) | 0.015 | 0.007 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.003 | 0.004 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.009 | 0.006 |
| Insufficient payload (model declined to judge) | 0.041 | 0.008 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".