Ultrasound non-invasive intracranial pressure assessment in paediatric neurocritical care: a pilot study

Background: The assessment of intracranial pressure (ICP) is essential in the management of neurocritical care paediatric patients. The gold standard for invasive ICP is an intraventricular catheter or intraparenchymal microsensor but is invasive and carries some risks. Therefore, a non-invasive method for measuring ICP (nICP) would be desirable especially in the paediatric population. The aim of this study is to assess the relationship between ICP and different ultrasound-based methods in neurocritical care paediatric patients.

Methods: Children aged < 16 years with indication for invasive ICP monitoring were prospectively enrolled. The following non-invasive methods were compared with the invasive gold standard: optic nerve sheath diameter ultrasound (ONSD)-derived nICP (nICP_ONSD); arterial TCD-derived pulsatility index (PIa) and a method based on the diastolic component of the TCD cerebral blood flow velocity and mean arterial blood pressure (nICP_FVd).

Results: We analysed 107 measurements from 10 paediatric patients. Results from linear regression demonstrated that, among the nICP methods, ONSD has the best correlation with ICP (r = 0.852 (p < 0.0001)). Results from receiving operator curve analysis demonstrated that using a threshold of 15 mmHg, ONSD has and area under the curve (AUC) of 0.94 (95% CI = 0.892-0.989), with best threshold at 3.85 mm (sensitivity = 0.811; specificity = 0.939).

Conclusions: Our preliminary results suggested that ONSD ultrasonography presents the best accuracy to assess ICP among the methods studied. Given its non-invasiveness, repeatability and safety, this technique has the potential of representing a valid option as non-invasive tool to assess the risk of intracranial hypertension in the paediatric population.