Elevated jugular venous oxygen saturation after severe head injury

Object. The aim of this study was to investigate the incidence of elevated (≥ 75%) jugular venous oxygen saturation (SjvO₂) and its relationship to cerebral hemodynamic and metabolic parameters and to outcome after sever% head injury. Methods. Data from 450 severely head injured patients admitted to the Neurosurgical Intensive Care Unit of Ben Taub General Hospital were analyzed retrospectively. The SjvO₂ was measured in blood obtained from indwelling jugular bulb catheters. Patients were classified into the following categories: high (Group I), normal (Group II), or low SjvO₂ (Group III) if their mean SjvO₂ over the duration of monitoring was 75% or higher, 74 to 56%, or 55% or lower, respectively. A high SjvO₂ occurred in 19.1% of patients. There was no consistent relationship between SjvO₂ and simultaneous cerebral blood flow (CBF) or cerebral perfusion pressure measurements. Compared with Groups II and III, the patients in Group I had a significantly higher CBF and lower cerebral metabolic rate of oxygen (CMRO₂). In Group I, the outcomes were death or persistent vegetative state in 48.8% of patients and severe disability in 25.6%. These outcomes were significantly worse than for patients in Group II. Within Group I, the patients with a poor neurological outcome were older and more likely to have suffered a focal head injury; they demonstrated a lower CMRO₂ and a greater rate of cerebral lactate production than the patients who attained a favorable outcome. Conclusions. Posttraumatic elevation of SjvO₂ is common but cannot be automatically equated with hyperemia. Instead, elevated SjvO₂ is a heterogeneous condition that is associated with poor outcome after head injury and may carry important implications for the management of comatose patients.