1132 NONINVASIVE MEASUREMENT OF INTRACRANIAL PRESSURE: EVALUATION OF A TECHNIQUE

Abstract

In 1976 a new technique for measuring intracranial pressure transcutaneously across the anterior fontanel using an aplanation fiberoptic methodology was introduced. The present study attempted to duplicate the previous work. Materials and methods: 4 infants with open fontanels and suspected increased intracranial pressure were studied. The Ladd Intracranial Pressure Monitoring Device (model 1700, Roche Medical Electronics) was applied to the anterior fontanel as per the original authors. Continuous digital and graphic displays of measured pressures were obtained. Results: A pressure range of 10-26 cm H2O was obtained by altering tension applied to the straps which hold the transducer in place. Manipulation of the straps did not result in a reproduciple baseline. Pressures measured represented the sum of intracranial (transfontanel) pressure and externally applied pressure and interpretation of data became impossible. Conclusion: Previous results using this technique could not be duplicated. The application of an aplanation transducer to measure pressure across a deformable membrane necessitates establishment of co-planarity of transducer and membrane and the introduction of external pressure into the system. The technique under study does not quantify the amount of external pressure required to achieve co-planarity and thus cannot give meaningful data.