Arterio-jugular difference of oxygen content and outcome after head injury

This study investigated AJDo₂ (arterio-jugular difference of oxygen content) in a large sample of severely head-injured patients to identify its pattern during the first days after injury and to describe the relationship of AJDo₂ with acute neurological severity and with outcome 6 mo after trauma. In 229 comatose head-injured patients, we monitored intracranial pressure, cerebral perfusion pressure, and AJDo₂. Outcome was defined 6 mo after injury. Jugular hemoglobin oxygen saturation (Sjo₂) averaged 68%. The mean AJDo₂ was 4.24 vol% (SD, 1.3 vol%). There were 80 measurements (4.6%) with Sjo₂ 75%. AJDo₂ was higher than 8.7 vol% in 8 measurements (0.4%) and was lower than 3.9 vol% in 718 (42%) measurements. AJDo₂ was higher during the first tests and decreased steadily over the next few days. Cases with a favorable outcome had a higher mean AJDo₂ (4.3 vol%; SD, 0.3 vol%) than patients with severe disability or vegetative status (3.8 vol%; SD, 1.3 vol%) and patients who died (3.6 vol%; SD, 1 vol%). This difference was significant (P <0.001). We conclude that low levels of AJDo₂ are correlated with a poor prognosis, whereas normal or high levels of AJDo₂ are predictive of better results.