Correlation Between Invasive and Noninvasive Technique of Intracranial Pressure Measurement in Children With Traumatic Brain Injury: An Observational Study

Abstract

Background: Direct measurement of intracranial pressure (ICP) is an invasive technique with potential complications, which has prompted the development of alternative, noninvasive, methods of ICP assessment. The aim of this study was to determine the relationship between noninvasive ultrasound-based measurement of optic nerve sheath diameter (ONSD), transcranial Doppler-derived pulsatility index (PI), and invasive ICP measurements in children with traumatic brain injury (TBI). Methods: Children aged 1 to 18 years undergoing invasive ICP monitoring following TBI were included in the study. Noninvasive ONSD and PI measurements were compared with simultaneous invasive ICP. Results: In all, 406 measurements of ONSD and PI were obtained in 18 patients. ONSD and PI correlated with ICP (r=0.76 and 0.79, respectively), combining ONSD and PI resulted in an even stronger correlation with ICP (r=0.99). Formulas were derived from mixed-effect models that best fitted the data for noninvasive ICP estimation. A combination of ONSD and PI had the highest ability to detect ICP >20 mm Hg (area under the receiver operating characteristic curve=0.99, 95% confidence interval: 0.99-1.00). Optimal cutoff values for the prediction of intracranial hypertension were 5.95 mm for ONSD (sensitivity, 92%; specificity, 76%) and 1.065 for PI (sensitivity, 92%; specificity, 87%). Conclusions: In children with TBI, a combination of ONSD and PI strongly correlates with invasive ICP and has potential to screen for intracranial hypertension noninvasively. ONSD and PI may be useful tools for assessing ICP where invasive monitoring is unavailable or contraindicated.

Ultrasound Detection of Intracranial Hypertension in Brain Injuries

“…Good sensitivity and specificity in the detection of increased ICP was found, even if the cut-off values where very different among the papers. Most of the papers agreed in determining the cut-off for the presence of increased ICP when ONSD was more than 5.0 mm ( 46 – 49 ), whereas other suggested different values, such as 4.1 mm ( 50 ), 5.205 mm ( 51 ), 5.7 mm ( 52 ), 5.86 mm ( 53 ), 5.95 mm ( 54 ), 6.6 mm ( 55 ), and 7 mm ( 56 ).…”

An update on pediatric traumatic brain injury

“…Recent interest in non-invasive methods for measuring ICP and CPP has grown, especially for using them as screening or monitoring tools for patients in whom the indication for invasive monitoring is not met. Optic nerve sheath ultrasound in particular has seen a surge in interest, with varied degrees of correlation with measured ICP being reported [62][63][64][65]. There remain some concerns about interobserver agreement, measurement precision, and observer bias [66,67], but it is likely that interest will remain high and techniques will improve.…”

Non-Invasive Quantitative Approximation of Intracranial Pressure in Pediatric Idiopathic Intracranial Hypertension Based on Point-of-Care Ultrasound of the Optic Nerve Sheath Diameter

“…A number of studies have investigated the relationship between ONSD and ICP in both children and adults [16][17][18]. In studies of pediatric patients, there is some controversy regarding the correlation between ONSD and ICP, with some describing an intermediate to high correlation while others found a weak or no clear correlation [15,16,29,30]. In general, there is an age dependence in children, with a good correlation (with r around 0.63 [16] to 0.66 [15]) in children over 1 year of age and a poor correlation in very young children with patent fontanels [16,18].…”