Arterial Blood Pressure (ABP) is one of the most often measured vital parameters in daily clinical practice. State-of-the-art noninvasive ABP measurement technologies have noticeable limitations and are mainly based on uncomfortable techniques of complete or partial occlusion of arteries by cuffs. Additionally, most commonplace devices provide only intermittent measurements, and embodiments of continuous systems are bulky and difficult to apply correctly for nonprofessionals. Continuous cuffless ABP measurements are still an unmet clinical need and a topic of ongoing research with only very few commercially available devices.
This paper discusses surrogate-based noninvasive blood pressure measurement techniques (NIBP). It covers measurement methods of continuously and noninvasively inferring blood pressure from surrogate signals without applying external pressures, except for reference or initialization purposes. The blood pressure is then estimated by processing signal features, hereafter called surrogates, which are modulated by variations of this blood pressure. Discussed techniques include well-known approaches such as the popular pulse transit time (PTT) and pulse arrival time (PAT) techniques, pulse wave analysis (PWA) or combinations thereof. Despite a very long research history, these methods have not found widespread use in clinical and ambulatory practice, in part due to technical limitations and the lack of a standardized regulatory framework.
This work summarizes findings from an invited workshop of experts in the fields covering clinical expertise, engineering aspects, commercialization and standardization issues. It provides an outline of recommended research directions and includes a detailed overview of clinical use case scenarios for these technologies, opportunities and limitations.