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The following is a summary of “Critical thresholds of long-pressure reactivity index and impact of intracranial pressure monitoring methods in traumatic brain injury,” published in the July 2024 issue of Critical Care by Hong et al.
Researchers conducted a retrospective study to establish critical thresholds of LPRx, comparing different time windows for calculating LPRx as well as evaluating LPRx determined through external ventricular drains (EVD) vs. intraparenchymal pressure device (IPD) intracranial pressure (ICP) monitoring.
They analyzed 435 patients with traumatic brain injury (TBI) and categorized them into alive vs. dead and favorable vs. unfavorable outcomes based on the 1-year Glasgow Outcome Scale (GOS). Pearson’s chi-square values were assessed to determine the effectiveness of different LPRx and ICP thresholds in predicting outcomes. The thresholds provided the highest chi-squared values, and the analysis also compared results based on monitoring methods (EVD vs. IPD) and the timing of data collected during the hospital stay.
The results showed that LPRx calculated within 10-120 minutes had similar chi-square values ranging from around 0.25 – 0.35 for both survival and favorable conditions. The first 4 days were observed, showing that LPRx thresholds were linked with patients’ outcomes. Minimal differences in LPRx values (around 0.3) between patients were monitored with EVD and IPD.
They concluded that factors causing impairment in cerebrovascular reactivity can be detected by lower-resolution PRx metrics, with LPRx effectively derived from just 10-minute intervals of MAP and ICP data. Additionally, LPRx obtained from EVD, despite intermittent cerebrospinal fluid draining, showed a prognostic value similar to that of LPRx from IPD.
Source: ccforum.biomedcentral.com/articles/10.1186/s13054-024-05042-7
