Avoiding secondary brain injury after severe head trauma: monitoring and management.

Research has demonstrated that much of the mortality and morbidity in severely head-injured patients is due to secondary injury. The development of techniques to monitor cerebral blood flow, arteriovenous difference of oxygen or saturation of jugular venous blood flow with oxygen, and cerebral metabolic rate of oxygen has led to recognition, treatment, and prevention of secondary insults. This article examines the theoretical basis for the utilization of these techniques to guide the treatment of severely injured patients. Special emphasis is given to the factors governing both cerebral blood flow and cerebral blood volume, and how these factors can be monitored and manipulated to strike an optimal balance between the two. This information can aid in determining when it is safe to operate on patients with non-life-threatening conditions.