Elevated jugular venous oxygen saturation after severe head injury

Abstract

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 severe 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.