A computer-based method for continuous single pulse analysis of intracranial pressure waves

Introduction: The single pulse analysis of intracranial pressure waves prov ides valuable information about the autoregulative processes after head inj ury. This method has not been used for routine clinical assessment as yet. Current methods for evaluation of intracranial pressure waves are based on spectral analysis or related techniques. This imposes restrictions on the w ave sequences available for the investigation of ICP attributes. Therefore, we have developed a computer-based method, which enables continuous analys is of each pulse of the ICP wave, in any clinical setting. Method: Firstly, the raw data of the ICP wave is continuously recorded by the Multifunction al Anaesthetic Record System (MARS, Hewlett Packard). The recorded data is then subjected to single pulse wave analysis by our software. Each single p ulse is identified by the algorithm. The maximum, minimum and mean value, a s well as amplitude and gradient are calculated in each pulse pressure. All conceivable correlations of the listed parameters can be examined. Results : We applied our software in 9 cases with head injury and evaluated the mea surements over 59 days (1400 h). More than 7 million single pulse pressures have been analyzed off-line. The software proved to be accurate and easy t o apply. It was possible to calculate correlations between the different wa ve attributes on a broad basis of data. Parameters of special clinical inte rest were the amplitude of the single pulse pressure and the gradient. Conc lusion: This method is an improvement on ICP single pulse pressure analysis and facilitates its clinical application. It creates the possibility for c ontinuous long-term analysis of the ICP wave attributes under any clinical condition without loss of data. There are indications that the amplitude an d the gradient of the ICP pulse pressure could provide valuable additional information for clinical assessment. However, further evaluation is require d. (C) 1999 Elsevier Science B.V. All rights reserved.