Category: Neurology
Keywords: stroke, positioning, LVO, thrombectomy (PubMed Search)
Posted: 8/12/2025 by Nicholas Contillo, MD
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The concept of positioning the head of bed flat in a patient with a neurologic catastrophe seems like a recipe for badness. For most neurologic emergencies, elevating the head of the bed (HOB) to 30° is standard to help control intracranial pressure and reduce aspiration risk. However, emerging evidence indicates that acute large vessel occlusion (LVO) stroke patients—particularly before thrombectomy—may be an important exception.
The ZODIAC trial, published in June of this year, was a prospective, randomized, multicenter study comparing 0° (flat) versus 30° HOB positioning in patients with confirmed LVO stroke awaiting endovascular thrombectomy. The rationale stems from physiologic studies, including transcranial Doppler ultrasonography, showing that flat positioning can improve cerebral perfusion to ischemic tissue.
The primary outcome was early neurologic deterioration (>2-point worsening in NIHSS prior to thrombectomy). Safety endpoints included hospital-acquired pneumonia and all-cause mortality at 3 months.
In the trial’s 92 enrolled patients, flat positioning markedly reduced early neurologic deterioration, which occurred in 2.2% in the 0° group versus 55.3% in the 30° group. There were no significant differences in pneumonia or 3-month all-cause mortality. The authors also found a statistically insignificant improvement in 90-day functional outcomes in the 0° group. Due to the magnitude of benefit, the study was stopped early at interim analysis.
This technique represents a simple, cost-free, and practical method of preventing neurologic decline ahead of definitive management for LVO. This may be especially beneficial for LVO patients who require interhospital transfer to a thrombectomy-capable center.
Bottom Line: For patients with LVO stroke awaiting thrombectomy, flat (0°) head positioning is safe and significantly reduces early neurologic decline by improving blood flow to ischemic brain tissue.
