Pulsatility Index Reflects Intracranial Pressure Better than Resistive Index in Patients with Clinical Features of Intracranial Hypertension

Abstract

Background The intracranial pressure (ICP) is measured through various noninvasive methods to overcome complications of invasive ICP monitoring. In this study, transcranial Doppler was used to measure pulsatility index (PI) and resistive index (RI) that were correlated with opening intraventricular ICP. The opening intraventricular ICP was measured with the placement of intraventricular catheter in lateral ventricle without loss of cerebrospinal fluid. Methods The prospective, observational study was conducted on 40 patients with clinical and radiological features of raised ICP who underwent either endoscopic third ventriculostomy or ventriculoperitoneal shunt surgery. The PI and RI were measured simultaneously with opening ICP measurements under general anesthesia. Both PI and RI were correlated with ICP by using Pearson correlation coefficient. The receiver operating characteristic (ROC) curve was used to get the optimal values of PI ad RI for corresponding ICP values. Results The mean PI was 1.01 ± 0.41 and mean RI was 0.59 ± 0.32. The mean opening ICP value was 21.81 ± 8.68 mm Hg. The correlation between PI and RI with ICP was a statistically significant with correlation coefficient of 0.697 and 0.503, respectively. The ROC curve shown statistically significant association between PI and ICP from 15 to 40 mm Hg, whereas the association between RI and ICP was from 15 to 25 mm Hg, with various sensitivity and specificity. Conclusion The opening intraventricular ICP correlated better with PI than RI in patients with features of raised ICP.

A New Transcranial Doppler Parameter for Intracranial Hypertension Assessment in Patients with Traumatic Brain Injury

“…Previous studies correlating the PI with IH have shown diverse results 18,22,23 . Nevertheless, the use of TCD as a screening tool for high ICP when deciding on operating, placing an ICP catheter or shunting 18,23 seems to be more reliable than using TCD as a surrogate technique after these procedures 24,25 .…”

“…Previous studies correlating the PI with IH have shown diverse results 18,22,23 . Nevertheless, the use of TCD as a screening tool for high ICP when deciding on operating, placing an ICP catheter or shunting 18,23 seems to be more reliable than using TCD as a surrogate technique after these procedures 24,25 . Furthermore, when interpreting the PI in the setting of acute brain injuries one should take into account that other factors may increase the PI, as aging 26 , diabetes 27 , arterial hypertension 28 , sepsis 29 , dehydration and blood viscosity 30 , oxygenation 31 and sedatives as barbiturates 32 for example.…”

Lactate Predicts Neurological Outcomes after Perinatal Asphyxia in Post-Hypothermia Era: A Prospective Cohort Study

“…The reason for the PI better than RI in our study is not clear. The PI primarily depends on mean velocity, whereas the RI is mainly affected by systolic velocity [37]. It can be hypothesized that PI involves mean flow velocity that included both peak-systolic and end-diastolic flow velocity and could represent the cerebral vascular changes of the entire cardiac cycle better than systolic velocity only.…”

Noninvasive methods to monitor intracranial pressure

“…Several parameters of transcranial Doppler (TCD) ultrasound, such as cerebral blood flow velocity (CBV), pulsatility index, and the ability to measure the diameter of the optic nerve sheath (discussed in a later section), have been studied as noninvasive biomarkers of ICP [84][85][86]. Although several early studies and a few recent studies have shown a strong correlation between TCD and ICP [87], a number of studies have shown varying correlations between TCD-determined ICP and invasively obtained ICP or have failed to show a correlation [84,[88][89][90][91].…”