Institutional review board-approved, prospective, observational cohort study.
SETTING: Level I or II trauma centers in New York State.
PATIENTS: We calculated the survival rates and relative risks of mortality for patients with severe
traumatic brain injury based on predefined age-specific cerebral perfusion pressure thresholds. A higher threshold and a lower threshold were defined for each age group: 60 and 50 mm Hg for 12 years old or older, 50 and 35 mm Hg for 6-11 years, and 40 and 30 mm Hg for 0-5 years. Patients were stratified into age groups of 0-11, 12-17, and 18 years old or older. Three exclusive groups of
CPP-L (events below low cerebral perfusion pressure threshold),
CPP-B (events between high and low cerebral perfusion pressure thresholds), and
CPP-H (events above high cerebral perfusion pressure threshold) were defined. As an internal control, we evaluated the associations between cerebral perfusion pressure events and events of
hypotension and
elevated intracranial pressure. Survival was significantly higher in 0-11 and 18 years old or older age groups for patients with
CPP-H events compared with those with
CPP-L events. There was a significant decrease in survival with prolonged exposure to
CPP-B events for the 0-11 and 18 years old and older age groups when compared with the patients with
CPP-H events (p = 0.0001 and p = 0.042, respectively). There was also a significant decrease in survival with prolonged exposure to
CPP-L events in all age groups compared with the patients with
CPP-H events (p< 0.0001 for 0- to 11-yr olds, p = 0.0240 for 12- to 17-yr olds, and p < 0.0001 for 18-yr old and older age groups). The 12- to 17-year olds had a significantly higher likelihood of survival compared with adults with prolonged exposure to
CPP-L events (< 50 mm Hg).
CPP-L events were significantly related to systemic
hypotension for the 12- to 17-year-old group (p = 0.004) and the 18-year-old and older group (p < 0.0001).
CPP-B events were significantly related to systemic
hypotension in the 0- to 11-year-old group (p = 0.014).
CPP-B and
CPP-L events were significantly related to
elevated intracranial pressure in all age groups.
CONCLUSIONS: Our data provide new evidence that cerebral perfusion pressure targets should be age specific. Furthermore, cerebral perfusion pressure goals above 50 or 60 mm Hg in adults, above 50 mm Hg in 6- to 17-year olds, and above 40 mm Hg in 0- to 5-year olds seem to be appropriate targets for treatment-based studies. Systemic
hypotension had an inconsistent relationship to events of low cerebral perfusion pressure, whereas
elevated intracranial pressure was significantly related to all low cerebral perfusion pressure events across all age groups. This may impart a clinically important difference in care, highlighting the necessity of controlling intracranial pressure at all times, while targeting systolic blood pressure in specific instances.