What is a critical indicator of tissue oxygen supply during shock?

C. ScvO2, or central venous oxygen saturation, is a critical indicator of tissue oxygen supply during shock. It reflects the balance between the amount of oxygen consumed by the tissues and the amount of oxygen delivered via the circulation. In states of shock, when there is inadequate perfusion or oxygen delivery to tissues, ScvO2 may decrease, indicating that tissues are extracting more oxygen than what is available.

Monitoring ScvO2 is particularly valuable because it provides insights into the overall oxygenation status of the entire body, not just the systemic blood pressure or individual organ perfusion. A lower than normal ScvO2 suggests that the body is in a state of increased oxygen demand or is unable to adequately supply oxygen to the tissues, which is a hallmark of shock. In critically ill patients, it allows healthcare providers to assess the effectiveness of resuscitation efforts and manage fluid therapy and vasopressors more effectively.

Other parameters like blood pressure, heart rate, and respiratory rate can provide some information about a patient’s condition in shock, but they do not directly measure the adequacy of oxygen supply at the tissue level as ScvO2 does.