Jugular venous oxygen saturation thresholds in trauma patients may not extrapolate to ischemic stroke patients: lessons from a preliminary study

The authors' first examinations of 10 patients with severe hemispheric stroke indicate that bedside monitoring of cerebral blood flow (CBF) is of clinical value as a prognostic tool for outcome and as therapy of elevated intracranial pressure (ICP). Jugular venous oximetry, which is easier to handle and provides on-line data, may also be of prognostic value in patients with ischemic stroke. No clinical studies are available on patients with hemispheric infarctions. Therefore, in a second data analysis from the same patient population, the authors' objective was to estimate the clinical value of monitoring cerebral hemodynamics and metabolism with jugular bulb catheters in treatment of severe postischemic brain edema. In 10 patients with severe hemispheric infarctions, ICP, jugular venous oxygen saturation (SjvO2), CBF, and cerebral metabolic rate of oxygen (CMRO2) were measured prospectively. A total of 101 ICP, SjvO2, and 92 CBF measurements were obtained. Only two SjvO2 values were below the critical thresholds to detect secondary ischemic events defined in trauma patients (SjvO2 < 50%). Intracranial pressure elevations more than 20 mm Hg and pupillary disturbances were treated with osmotherapy (mannitol or hypertonic NaCl hydroxyethyl starch solution) or mild hyperventilation in combination with tromethamine-buffer. In 8 of 17 pairs of measurements with treated elevated ICP, CMRO2 varied and changes of SjvO2 did not reflect changes in CBF. Jugular bulb oximetry should interpreted with caution in patients with severe hemispheric infarction. Critical thresholds defined in trauma patients may not be extrapolated to ischemic stroke.