Objective: To use a range of techniques to explore diffusion limitation as a mechanism of
cellular hypoxia in the setting of head injury. Design: A prospective interventional study.
Setting: A specialist neurocritical care unit. Patients: Thirteen patients within 7 days of closed
head injury underwent imaging studies. Tissue for ultrastructural studies was obtained from
a cohort of seven patients who required surgery. Interventions: Cerebral tissue PO 2 (PtO 2)
was obtained using a multiple-variable sensor, and images of oxygen extraction fraction …