Abstract
Objectives Secondary insults due to high ICP, low CPP and impaired cerebral pressure reactivity (PRx) are presumed important after severe traumatic brain injury (TBI), however the incidence, co-occurrence, and relative prognostic importance is unclear.
Methods Severe TBI patients requiring computerized ICP monitoring were included. Secondary insults due to ICP, PRx, and CPP were defined as having at least 1 hour with a mean value above (or below for CPP) a respective threshold (ICP 20, CPP 60, and PRx 0.25). Percentage time with isolated or co-occurring insults was calculated (impaired ICP only, impaired CPP only, impaired PRx only, impaired ICP and PRx, impaired ICP and CPP, impaired CPP and PRx, impaired ICP CPP and PRx). Prognostic importance for mortality was assessed using a multivariable logistic regression model.
Results 822 patients were included of which 76% had elevated ICP, 92% had disturbed pressure reactivity and 55% had low CPP for at least an hour. Percentage of overall monitoring time spent with isolated insults were: 2.9% for CPP; 22% for ICP; and 23% for PRx. Percentage time of combined insults were: 5.8% PRx and ICP; 1.6% for CPP and ICP; 1.5% for CPP and PRx; and 1% for CPP ICP and PRx. Combined insults of CPP, ICP and PRx had the strongest relation with mortality on multivariable analysis (OR 1.18 95%CI1.11–1.28, p<0.001).
Conclusion ICP and autoregulation insults are common after TBI and often occur independently. Concurrent ICP, CPP and PRx insults portend worse prognosis than when a single variable is deranged.
