Value of transcranial Doppler indices in predicting raised ICP in infantile hydrocephalus

Abstract

Cerebral hemodynamic changes in infants with progressive hydrocephalus have been studied with the transcranial Doppler (TCD) technique. Several authors have referred to the correlation between the hemodynamic changes and increased intracranial pressure (ICP). Despite conflicting conclusions on the value of pulsatility index (PI) and resistance index (RI) measurements for monitoring infantile hydrocephalus, these pulsatility indices are the most commonly used for this purpose. Although clinical signs of raised ICP are highly variable and unreliable in infants, assumptions have been made in most of the studies about the presence of elevated ICP on the basis of the patient's clinical state. Few studies have reported on actual ICP values, however, and a direct relationship between ICP and TCD changes has never been adequately demonstrated. In the present study, this relationship was investigated in long-term simultaneous TCD/ICP measurements, in an attempt to develop a noninvasive method of monitoring the effect of ICP on intracranial hemodynamics. Two groups of data sets were established. Group I consisted of pre- and postoperative (shunt implantation) TCD/ICP measurements. Group II were long-term simultaneous TCD/ICP recordings showing significant ICP variations. In most of the postoperative measurements there was a decrease in the average PI and RI values. The correlation between PI or RI and ICP in the long-term simultaneous recordings, however, was generally poor. The risk of obtaining false positive or false negative PI or RI values in short-term measurements was also demonstrated. It can be concluded from our results, besides the wide range of reference values for the Doppler indices and extracranial influences upon them, that the present Doppler indices are inadequate for monitoring the complex intracranial dynamic responses in patients with raised ICP.

Intracranial pressure and cerebral blood flow velocity in preterm infants with posthaemorrhagic ventricular dilatation

“…[15][16][17] It is doubtful whether the RI can be used as an indicator for the timing of intervention, because it can vary widely between individual preterm infants. Hanlo et al 18 found that cerebral blood flow variables do not correlate well with concomitantly measured values for ICP. Our study confirmed that flow velocities varied considerably between individual infants, and no correlation was found between the ICP and absolute flow velocities.…”

Measurement of intracranial pressure in children: a critical review of current methods

“…7,8 However, when the skull is fused, this means of examination is lost and the only definite feature on examination which allows a clinician to say that raised ICP is likely is by seeing papilloedema on fundoscopy. 9 Even this method is not entirely reliable as ICP may be raised without there being papilloedema, especially in the presence of optic atrophy.…”

“…During Doppler examination through the anterior fontanelle, the haemodynamic response to fontanelle compression can be used as a non-invasive predictor of progressive or persistently-elevated ICP in neonates with hydrocephalus. 7,8 OPTIC NERVE SHEATH DIAMETER The optic nerve is a part of the central nervous system. A rise in ICP directly affects the perioptic nerve space, which leads to an increase in optic nerve diameter.…”

The value of transcranial Doppler imaging in children with tuberculous meningitis

“…However, controversy exists whether TCDI-derived pulsatility index (PI) is a reliable marker of raised ICP. Some studies report a linear relationship between the PI and measured ICP in hydrocephalic children, whilst others have failed to find such correlation [2][3][4][5][6].…”