Cerebral perfusion pressure between 50 and 60 mm Hg may be beneficial in head-injured patients: a computerized secondary insult monitoring study

Abstract

Objective: To describe the occurrence of secondary insults using a computerized monitoring data collecting system and to investigate their relationship to outcome when the neurointensive care was dedicated to avoiding secondary insults.

Methods: Patients 16 to 79 years old admitted to the neurointensive care unit between August 1998 and December 2002 with traumatic brain injury and 54 hours or more of valid monitoring within the first 120 hours after trauma (one value/min) were included. Monitoring of intracranial pressure (ICP), cerebral perfusion pressure (CPP), systolic blood pressure (BPs), and mean blood pressure (BPm) was required, and insult levels were defined (ICP >25/>35, BPs <100/<90/>160/>180, BPm <80/<70/>110/>120, and CPP <60/<50/>70/>80 mm Hg). Insults were quantified as proportion of valid monitoring time at the insult level. Logistic regression analyses were performed with admission and secondary insult variables as explanatory variables and favorable outcome as dependent variable.

Results: Eighty-one patients, 63 men and 18 women, with a mean age of 43.0 years, fulfilled the inclusion criteria. Seventy-two patients (89%) had Glasgow Coma Scale scores of 8 or less. Thirty-one patients (38%) had diffuse injury, and 50 (62%) had mass lesions. Mean Injury Severity Score was 26.6. After 6 months, 54% of the patients had achieved a favorable outcome. Most patients spent 5% or less of the monitoring time at the insult level except for CPP greater than 70 mm Hg. Low age, high Glasgow Coma Scale motor score, low Injury Severity Score, and CPP less than 60 mm Hg insults were significant predictors of favorable outcome in the final multiple logistic regression model.

Conclusion: Overall, the secondary insults were rare, except for high CPP. The results suggest that patients with traumatic brain injury might benefit from a CPP slightly less than 60 mm Hg.