Pulse transit time (PTT) is the time it takes for a pulse wave to travel through an artery. PTT has various applications, including as an indicator of arteriosclerosis, for sleep apnea, and for cuffless blood pressure measurement. Traditional methods for calculating PTT use both an electrocardiogram (ECG) and pulse wave, but there are alternative methods. For example, PTT can be measured using only fingertip pulse waves without relying on an ECG. This approach has the advantage of simplifying measurement devices and procedures compared to conventional methods. This study examined this approach in two aspects. The first examination proposes a formula to calculate PTT using only fingertip pulse waves measured at the distal phalanx of the left index finger with a photoplethysmograph (PPG) . The unknown variables of the proposed formula were determined using a least-squares method on a dataset publicly available on the web. Subsequently, the PTT calculated with the proposed formula using pulse waves generated in a simulation was compared with the PTT calculated using pulse waves generated with artifacts. This comparison confirmed the extent of the impact of artifacts on the proposed formula. The study demonstrated that the PTT formula determined from fingertip pulse waves was minimally affected by artifacts. The second examination compared the PTT obtained from the proposed formula with traditional PTT. This examination used fingertip pulse waves and ECG waveforms from the dataset. A Bland-Altman plot was used to compare the means and assess the difference between the PTT obtained from the proposed formula and the traditional PTT. The results showed that the PTT calculated from fingertip pulse waves and the PTT calculated from ECG and pulse waves agreed within a 68%confidence interval (-0.007±0.022s) for approximately 70%of the subjects (8 out of 11 subjects) .

As technology advances, a wide variety of biomaterials have been developed. Biomaterials are materials that are used to support body functions or to replace organs that are no longer functioning. Today, a wide variety of biomaterials are in use and their properties are being used to advantage. Research on these biomaterials will become even more important in the future of medicine. In this manuscript, the basics of biomaterials, their classification, and their applications are introduced.