Patient-Specific Thresholds and Doses of Intracranial Hypertension in Severe Traumatic Brain Injury

Abstract

Based on continuous monitoring of the pressure reactivity index (PRx), we defined individualized intracranial pressure (ICP) thresholds by graphing the relationship between ICP and PRx. We hypothesized that an "ICP dose" based on individually assessed ICP thresholds might correlate more closely with 6-month outcome compared with ICP doses derived from the recommended universal thresholds of 20 and 25 mmHg. Data from 327 patients with severe traumatic brain injury (TBI) were analyzed. ICP doses were computed as the cumulative area under the curve above the defined thresholds in graphing ICP versus time. The term Dose 20 (D20) was used to refer to an ICP threshold of 20 mm Hg. The markers D25 and DPRx were calculated similarly. The discriminative ability of each dose with regard to mortality was assessed by receiver operating characteristics analysis using fivefold cross-validation (CV). DPRx was found to be the best discriminator of mortality, despite the fact that D20 was twice as large as DPRx. Individualized doses of intracranial hypertension were stronger predictors of mortality than doses derived from the universal thresholds of 20 and 25 mm Hg. The PRx could offer a method of individualizing the ICP threshold.

Patient-specific ICP Epidemiologic Thresholds in Adult Traumatic Brain Injury: A CENTER-TBI Validation Study

“…Previous publications employed manual direct observation of the relationship between PRx and ICP, via error bar plotting, to determine the individual ICP threshold. [4,5] It must be acknowledged that these individual thresholds for ICP do not represent therapeutic targets, but an individualized epidemiological thresholds, derived from the relationship between cerebrovascular reactivity values associated with global long-term outcome. Thus the derived individual thresholds quoted within the manuscript should not be considered as therapeutic in nature, and purely preliminary exploratory work into personalized ICP thresholds in TBI.…”

“…[1][2][3] Aside from individualized CPP targets, individualized epidemiologic intracranial pressure (ICP) thresholds have been suggested based on a single center retrospective study in adult TBI. [4][5][6] Using the relationship between continuously monitored cerebrovascular reactivity, using the pressure reactivity index (PRx), and ICP, one can find the ICP threshold where all subsequent higher ICP values yield PRx measures consistently above +0.20, [4] a threshold value for PRx known to be associated with impaired cerebrovascular reactivity and global outcome in adult TBI. [7][8][9][10] This has been termed the patientspecific or individualized ICP threshold, identifiable in approximately 68% of patients.…”

Severe Traumatic Brain Injury in French-Speaking Pediatric Intensive Care Units: Study of Practices

“…16 18 As we understand that ICP and CPP should be interpreted and tailored to patient's age, it is logical to assume that uptake of these techniques would optimize the individualization of TBI care. 27 28 Over the years, a dynamic protocol for monitoring CPP based on the autoregulatory capacity of the cerebral vascular system (pressure reactivity index [PRx]) has been proposed to determine optimal CPP (CPP opt ) for each patient. The PRx correlates well with Glasgow outcome scale 29 and is associated with improved survival.…”

Controlled Decompression Attenuates Brain Injury in a Novel Rabbit Model of Acute Intracranial Hypertension

“…The mortality rate rose from 0% to 13% when ICP was above 40 mmHg, which was consistent with our animal experiment results. Some studies [35,36] suggested that the mortality rate begins to rise when ICP reaches 20–25 mmHg. Therefore, the target ICP set at 38 mmHg would be appropriate in the model, which not only caused brain injury, but ensured a low mortality rate.…”