Predictive Value of Optic Nerve Sheath Diameter for Diagnosis of Intracranial Hypertension in Children With Severe Brain Injury

Abstract

Background and aims: Intracranial Hypertension (ICH) is a life-threatening complication of brain injury. The invasive measurement of intracranial pressure (ICP) remains the gold standard to diagnose ICH. Measurement of Optic Nerve Sheath Diameter (ONSD) using ultrasonography is a non-invasive method for detecting ICH. However, data on paediatric brain injury are scarce. The aim of the study was to determine the performance of the initial ONSD measurement to predict ICH occurring in children with severe brain injury and to describe the ONSD values in a control group.

Methods: In this cross-sectional study, ONSD was measured in children aged 2 months-17 years old with invasive ICP monitoring: before placement of ICP probe and within the 60 min after, and then daily during 3 days. ONSD was also measured in a control group.

Results: Ninety-nine patients were included, of whom 97 were analysed, with a median (IQR) age of 8.7 [2.3-13.6] years. The median (IQR) PIM 2 score was 6.6 [4.4-9.7] and the median (IQR) PELOD score was 21 [12-22]. Aetiologies of brain injury were trauma (n = 72), infection (n = 17) and stroke (n = 8). ICH occurred in 65 children. The median (IQR) ONSD was 5.58 mm [5.05-5.85]. ONSD performed poorly when it came to predicting ICH occurrence within the first 24 h (area under the curve, 0.58). There was no significant difference between the ONSD of children who presented with ICH within the first 24 h and the other children, with a median (IQR) of 5.6 mm [5.1-5.9] and 5.4 mm [4.9-5.8], respectively. Infants aged less than 2 years had a median (IQR) ONSD of 4.9 mm [4.5-5.2], significantly different from children aged more than 2 years, whose median ONSD was 5.6 mm [5.2-5.9]. Age, aetiology or ICP levels did not change the results. Thirty-one controls were included, with a median age of 3.7 (1.2-8.8) years. The median (IQR) of their ONSD measurement was 4.5 mm [4.1-4.8], significantly lower than the patient group.

Conclusion: In a paediatric severe brain injury population, ONSD measurement could not predict the 24 h occurrence of ICH. Severity of patients, timing and conditions of measurements may possibly explain these results.

Keywords: brain injury; children; intracranial hypertension; optic nerve; ultrasonography.

FIGURE 1

Patients’ flow diagram. ONSD, Optic Nerve Sheath Diameter; ICP, intracranial pressure.

FIGURE 2

Empirical ROC curve of Optic Nerve Sheath Diameter (ONSD) used to diagnose an intracranial hypertension occurring within the first 24 h following the measurement of ONSD in a paediatric brain injury population. AUC, area under the curve.

FIGURE 3

Initial Optic Nerve Sheath Diameter (ONSD) in a paediatric brain injury population according to the age. Box and whisker plots represent interquartile range and 95% CI, respectively, and the horizontal bar indicates the median, p < 0.001.

FIGURE 4

Initial Optic Nerve Sheath Diameter (ONSD) in a paediatric brain injury population according to the aetiology. CNS, central nervous system. Box and whisker plots represent interquartile range and 95% CI, respectively, and the horizontal bar indicates the median.

FIGURE 5

Time course of Optic Nerve Sheath Diameter (ONSD) in a paediatric brain injury population. Box and whisker plots represent interquartile range and 95% CI, respectively, and the horizontal bar indicates the median. ICP, intracranial pressure.

FIGURE 6

Initial Optic Nerve Sheath Diameter (ONSD) in a paediatric brain injury population. Comparison between patients with or without Intracranial Hypertension (ICH) and the control group. Box and whisker plots represent interquartile range and 95% CI, respectively, and the horizontal bar indicates the median.