ARE ADULT TRANSCRANIAL DOPPLER SYSTEMS SUITABLE FOR APPLICATION IN NEONATES

Transcranial Doppler systems have not been available for monitoring of cerebral blood flow velocities in neonates because of potential hazar dous effects of energy output from standard instruments developed for adult application. Aim of the study was to test commercially available transcranial Doppler instruments for their applicabiltiy in neonates and to develop guidelines for adaptation for safe neonatal use. Energy output of five commercially available transcranial Doppler instrument s was measured with a hydrophone system and a radiation force balance. At tile highest setting and at the nominal 10% attenuation level, fiv e out of five and two out Of five instruments, respectively, had an en ergy output above the recommended limits. Power reduction was not line ar in one instrument. Evaluation of safety devices (alarm, freeze mode , energy reduction facilities. display of energy values) showed that n one of the tested instruments had an optimal setting fur safe neonatal application. Conclusion Commercially avail able transcranial Doppler Instruments should be evaluated critically for their energy output pri or to their application in neonates, Special software for neonatal app lication of transcranial Doppler systems should be developed in order to provide extremly low energy output levels and devices indication of duration of Doppler insonation and energy output.