$BACKGROUND$: Transcranial Doppler (TCD) has been used to estimate ICP noninvasively (nICP); however, its accuracy varies depending on different types of intracranial hypertension. Given the high specificity of TCD to detect cerebrovascular events, this study aimed to compare four TCD-based nICP methods during plateau waves of ICP.

$METHODS$: A total of 36 plateau waves were identified in 27 patients (traumatic brain injury) with TCD, ICP, and ABP simultaneous recordings. The nICP methods were based on: (1) interaction between flow velocity (FV) and ABP using a "black-box" mathematical model ($\backslash textit\{nICP\_BB\}$); (2) diastolic FV ($\backslash textit\{nICP\_FV\}$); (3) critical closing pressure ($\backslash textit\{nICP\_CrCP\}$), and (4) pulsatility index ($\backslash textit\{nICP\_PI\}$). Analyses focused on relative changes in time domain between ICP and noninvasive estimators during plateau waves and the magnitude of changes ($∆$ between baseline and plateau) in real ICP and its estimators. A ROC analysis for an ICP threshold of 35 mmHg was performed.

$RESULTS$: In time domain, $\backslash textit\{nICP\_PI,\; nICP\_BB,\}$ and $\backslash textit\{nICP\_CrCP\}$ presented similar correlations: 0.80 ± 0.24, 0.78 ± 0.15, and 0.78 ± 0.30, respectively. $\backslash textit\{nICP\_FV\}$ presented a weaker correlation (R = 0.62 ± 0.46). Correlations between ∆ICP and ∆nICP were better represented by $\backslash textit\{nICP\_CrCP\}$ and BB, R = 0.48, 0.44 (p < 0.05), respectively. $\backslash textit\{nICP\_FV\}$ and $PI$ presented nonsignificant $∆$ correlations. ROC analysis showed moderate to good areas under the curve for all methods: $\backslash textit\{nICP\_BB\}$, 0.82; $\backslash textit\{nICP\_FV\}$, 0.77; $\backslash textit\{nICP\_CrCP\}$, 0.79; and $\backslash textit\{nICP\_PI\}$, 0.81.

$CONCLUSIONS$: Changes of ICP in time domain during plateau waves were replicated by nICP methods with strong correlations. In addition, the methods presented high performance for detection of intracranial hypertension. However, absolute accuracy for noninvasive ICP assessment using TCD is still low and requires further improvement.