Improved Transcranial Doppler Waveform Analysis for Intracranial Hypertension Assessment in Patients with Traumatic...

Area of Science:

• Neurocritical Care
• Cerebrovascular Physiology
• Medical Diagnostics

Background:

• Transcranial Doppler (TCD) is a noninvasive tool for assessing cerebral hemodynamics, calculating the pulsatility index (PI) correlated with intracranial pressure (ICP).
• Traditional PI has limitations in predicting raised ICP due to confounding factors.
• The pulsatile apparent resistance (PaR) index was developed to correct PI for arterial blood pressure, aiming to reduce confounding influences.

Purpose of the Study:

• To compare the predictive value of the PaR index versus the PI for detecting intracranial hypertension (IH) in patients with traumatic brain injury (TBI).
• To evaluate the diagnostic performance of PaR and PI in identifying IH (ICP > 20 mm Hg).

Main Methods:

• Prospective study including TBI patients requiring invasive ICP monitoring in a neurocritical care unit.
• TCD measurements of middle cerebral arteries were performed to calculate PI and PaR.
• Area under the receiver operator characteristics curve (AUC) was used to assess discriminative power for IH (ICP ≥ 20 mm Hg).

Main Results:

• PaR demonstrated a higher discriminative power (AUC 0.77) for IH compared to PI (AUC 0.63) in 93 TBI patients.
• PaR showed a significant difference between patients with and without IH (median 0.169 vs. -0.052, p=0.001).
• Excluding patients who underwent neurosurgery further improved PaR's discriminative power (AUC 0.89), with a cutoff of -0.023 yielding 100% sensitivity.

Conclusions:

• The PaR index is a superior noninvasive parameter for discriminating intracranial hypertension in TBI patients compared to PI.
• PaR shows promise as a reliable noninvasive tool for IH detection.
• Further research is needed to establish clinical applications for PaR in neurosurgical decision-making and patient management.