Transient systolic hypotension. A serious problem in the management of head injury.

OBJECTIVE: To determine the frequency and clinical impact of transient systolic hypotension (systolic blood pressure < 100 mm Hg) in patients with severe anatomic head injury.
DESIGN: Retrospective case-control study.
SETTING: Urban level 1 trauma center. PATIENTS: Consecutive trauma patients admitted to the intensive care unit (ICU) with severe anatomic head injury, defined as Head and Neck Abbreviated Injury Scale Score of 4 or higher. One thousand thirteen trauma patients were admitted to the ICU during the study period, 157 of whom met inclusion criteria. MAIN OUTCOME MEASURES: Acute mortality, defined as death during initial ICU admission, and functional status of ICU survivors, assessed as level of function sufficient for discharge to home.
RESULTS: One hundred fifty-seven patients with severe head injury had a total of 831 episodes of systolic hypotension. Fifty-five percent of the patients suffered at least one event. Patients were grouped by total number of low systolic blood pressure events and by average number of events per ICU day. The total number of hypotensive events was associated with increased mortality rates and decreased rate of discharge to home. Average daily frequency of events was associated with increased mortality rates. After stratification by admission Glasgow Coma Scale score, the effects were most dramatic in patients with an initial Glasgow Coma Scale score higher than 8.
CONCLUSIONS: Transient hypotension is common in the ICU and is associated with increased acute mortality and decreased functional status in patients with head injury. The impact of this secondary insult is greatest in patients with less severe primary injury. Strict avoidance of hypotension through enhanced monitoring and active treatment appears to be important, especially in patients with higher presenting Glasgow Coma Scale scores.