Oxygen Saturation of Jugular Vein

Abstract

  In critically ill, brain-damaged patients, it is difficult to directly evaluate cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO₂) , because their circulatory instability sometimes Iimits radiological examinations, especially magnetic resonance spectroscopy. However, oxygen saturation of jugular vein (SjvO₂) is an index of the balance between CBF and CMRO₂. Because the fiberoptic jugular venous catheter makes continuous monitoring of SjvO₂ possible, this catheter is useful especially in exhibiting changes in cerebral oxygen demand/supply balance. Changes in fiberoptic SjvO₂ in response to therapeutic maneuvers provide valuable information about ongoing pathophysiology in the brain and the appropriateness of planned therapeutic goals. SjvO₂ is important from the standpoint of brain-oriented therapu but also from that of a systemic therapeutic approach, because SjvO₂ is affected by respiratory, circulatory and body fluid parameters: arterial carbon dioxide tension, arterial oxygen tension, mean arterial blood pressure, and hemoglobin concentration. Jugular venous blood is also a source of information on pH, carbon dioxide tention, blood lactate, blood glucose and temperature. Comparison of these parameters in jugular venous blood with those obtained from arterial blood gives further information concerning cerebral ischemia. SjvO₂, especially fiberoptic SjvO₂, along with the other parameters obtained by jugular venous sampling, is of value in critically ill brain-damaged patients, because signals from the brain are very limited in these patients.