Non Invasive Measurement With Trans Cranial Doppler Versus Invasive Measurement in Pediatric Age

An iIncrease in intracranial pressure (ICP) is an important cause of secondary brain damage. The cerebral perfusion pressure (CPP), defined as the mean arterial pressure value (MAP) minus the ICP value (CPP = MAP-ICP), represents the pressure gradient that is responsible for cerebral flow. The gold standard for measuring ICP is represented by invasive methods that are intra-parenchymal or intra-ventricular catheters positions by neurosurgeons. The placement of these catheters can cause complications, mainly bleeding and infections.

The most used non-invasive (nICP) methods are obtained through a medical device such as bed-side ultrasound, routinely used in the management of children in Pediatric Intensive Care: arterial Trancranial Doppler (TCD) and ultrasound measurement of the diameter of the optic nerve sheath (ONSD ).

Arterial TCD is one of the most studied methods in adults for the non-invasive estimation of ICP. Formulas derived from the measurement of cerebral flow velocities (VF) such as the Pulsatility Index (PI) and the formula based on the Diastolic Flow Rate (FVdICP) have been shown to have a correlation with the iICP. According to the literature, a PI> 1 is associated with an ICP value> 20 mmHg. Schmitd, Czosnyka et al. subsequently proposed a new formula for the non-invasive measurement of CPP and therefore of ICP (FVdICP), demonstrating the accuracy of CPP measured with the invasive technique The ONSD is a rapid and repeatable method for making a rapid diagnosis of increased ICP not only in adults but also in children, considering the diameter of the optic nerve sheath equal to 4.5 mm in children as the upper limit of the norm. 1 year of age and 4 mm in children under 1 year.

In this study it is proposed to compare the measurement of nICP obtained with the TCD and with the ONSD versus the measurement obtained by the invasive monitoring (iICP) already present.