An acknowledged objective of critical-care medicine is a timely, accurate, readily deployable, cost-effective, and, importantly, safe means of assessing and/or monitoring critical aspects/parameters of patient condition such as intracranial pressure (ICP). However, ICP monitoring is complicated by a large set of variables related to the patients themselves — presented symptoms, circumstances, and related information indicating such measurement, and relevant accompanying issues. These conditions and the various combinations thereof present attending physicians with the choice of many alternatives regarding key parameters including, but not limited to urgency, availability, appropriability, and accuracy to a minimum standard. Cost, complexity, ease-of-use, and other issues are also meaningful factors, but the bottom line for any of the various technical approaches, whether invasive or noninvasive, is performance. Key to this technology is its capability to correlate closely with established tympanic membrane displacement (TMD) ICP monitoring technology.
This technology, and a product based on it, offers new analytical capabilities for assessment of intracranial dynamics. It offers the possibility for the monitoring of transcranial expansion and related physiological phenomena in humans resulting from variations in intracranial pressure (ICP) caused by injuries to the head and/or brain pathologies. The technology uses constant frequency pulse phase-locked loop (CFPPLL) technology to measure skull expansion caused by pressure and its variations in time. This approach yields a more accurate, more robust measurement capability with improved bandwidth that allows new analytical approaches for assessing the physiology of skull expansion under pulsatile cerebral blood flow. The dynamical quantities assessable with the CFPPLL include skull volume expansion and total fluid.
Such an instrument can serve to measure intracranial dynamics with equation-based algorithms, and offers a path to measure or determine quasistatic ICP, along with the pulsatile-related ICP increments. Supportive measurements, such as time-dependence of arterial pressure waveforms, together with time-dependent phase change of transcranial expansions, can serve as the basis of noninvasive techniques to measure ICP.