Optimal Head-of-Bed Positioning Before Thrombectomy in Large Vessel Occlusion Stroke
Bibliographic record
Abstract
Importance: Small studies show that 0° head positioning of patients with large vessel occlusion (LVO) stroke improves penumbral blood flow and clinical stability. Understanding whether 0° head position maintains clinical stability would allow for optimal patient positioning before thrombectomy. Objective: To determine superiority of 0° over 30° head positioning at maintaining clinical stability in patients with LVO before thrombectomy. Design, Setting, and Participants: This was a prospective randomized clinical trial with blinding to study enrollment/end points conducted from May 2018 to November 2023. There were 3 planned interim analyses, and the study was conducted at certified thrombectomy hospitals in the US. Included in this analysis were consecutive consenting individuals with computed tomography (CT) angiography-positive anterior or posterior LVO who were candidates for thrombectomy (baseline mRS 0-1) and had viable penumbra (CT perfusion or Alberta Stroke Program Early Computed Tomography Score ≥6) within 24 hours of stroke onset. Enrollment of systemic thrombolysis more than 15 minutes from consent was discouraged to prevent confounding of head position effects; in addition, patients with disabilities who lacked a legal representative could not participate due to lack of consent. Interventions: Randomization to 0° or 30° head positioning with monitoring every 10 minutes using the National Institutes of Health Stroke Scale (NIHSS) until movement to a catheterization table. Main Outcome and Measures: The primary outcome was worsening of 2 or more NIHSS points before thrombectomy. Safety outcomes included severe neurologic deterioration (worsening ≥4 NIHSS points) before thrombectomy, hospital-acquired pneumonia (HAP) during hospitalization, and all-cause death within 3 months. Results: Planned enrollment included 182 patients. Before data and safety monitoring board study closure, a total of 92 patients (mean [SD] age, 66.6 [14.4] years; 48 male [52.2%]) were randomized: 45 patients to the group with 0° head positioning and 47 patients to the group with 30° head positioning. Patient characteristics were similar between groups; however, patients with head position at 30° experienced worsening on the NIHSS of 2 points or more, whereas patients with head position at 0° showed score stability (hazard ratio [HR], 34.40; 95% CI, 4.65-254.37; P < .001). One patient with 0° head positioning and 20 patients with 30° head positioning experienced worsening on the NIHSS of 4 points or more during positioning (HR, 23.57; 95% CI, 3.16-175.99; P = .002). No patients developed HAP; all-cause death occurred in 2 patients (4.4%) in the 0° group, compared with 10 patients (21.7%; P = .03) in the 30° group. Conclusions and Relevance: Results suggest that 0° head positioning for patients with acute LVO was a protective maneuver to maintain clinical stability in the prethrombectomy phase while awaiting definitive treatment. Trial Registration: ClinicalTrials.gov Identifier: NCT03728738.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 teacher head, 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".