Prevention of secondary ischemic insults after severe head injury

Objective: The purpose of this study was to compare the effects of two acut e-care management strategies on the frequency of jugular venous desaturatio n and refractory intracranial hypertension and on long-term neurologic outc ome in patients with severe head injury. Design: Randomized clinical trial. Setting: Level I trauma hospital. Patients: One hundred eighty-nine adults admitted in coma because of severe head injury. Interventions: Patients were assigned to either cerebral blood Row (CBF)-ta rgeted or intracranial pressure (ICP)-targeted management protocols during randomly assigned time blacks. In the CBF-targeted protocol, cerebral perfu sion pressure was kept at >70 mm Hg and PaCO2 was kept at approximately 35 torr (4.67 kPa). In the ICP-targeted protocol, cerebral perfusion pressure was kept at >50 mm Hg and hyperventilation to a PaCO2 of 25-30 torr (3.33-4 .00 kPa) was used to treat intracranial hypertension, Measurements and Main Results: The CBF-targeted protocol reduced the freque ncy of jugular desaturation from 50.6% to 30% (p = .006). Even when the fre quency of jugular desaturation was adjusted for all confounding factors tha t were significant, the risk of cerebral ischemia was 2.4-fold greater with the ICP-targeted protocol. Despite the reduction in secondary ischemic ins ults, there was no difference in neurologic outcome. Failure to alter long- term neurologic outcome was probably attributable to two major factors. A l aw jugular venous oxygen saturation was treated in both groups, minimizing the injury that occurred in the ICP-targeted group, The beneficial effects of the CBF-targeted protocol may have been offset by a five-fold increase i n the frequency of adult respiratory distress syndrome. Conclusions: Secondary ischemic insults caused by systemic factors after se vere head injury can be prevented with a targeted management protocol. Howe ver, potential adverse effects of this management strategy may offset these beneficial effects.