## 1 Introduction
These devices are costly, making them impractical for routine monitoring. Therefore, these types of implantable devices are only used in scenarios like surgery and emergency care and are not suitable for long-term health monitoring. In response to the above challenges, there is an urgent need to create a device capable of high accuracy in both dynamic and static pressure measurements and that is easy to use. Therefore, this paper proposes and develops a high-precision interventional pressure measurement catheter with a compact structure. This catheter uses the interventional in vivo pressure measurement method shown in Figure 1. The front end of the catheter body is placed at the in vivo pressure measurement point (such as blood vessels, urethra, etc. ), utilizing the saline inside the catheter to transmit pressure to the pressure sensor, ensuring the accuracy of static pressure measurements. The main body of the pressure measurement catheter uses a compact structure, the design philosophy of which is as follows: The internal part of the catheter body must conform to the size and puncturing method requirements of the human body's measurement site (such as blood vessels and the urethra), while the external part of the catheter body should adhere to the principles of reducing length and increasing diameter. This structure can reduce the dynamically varying pressure loss caused by the long size of existing invasive pressure measurement devices and, thus, meeting the accuracy requirements for dynamically varying pressure measurements needed to monitor constantly changing pressures within the human body. The prototype of the designed pressure measurement catheter has an external part that is only 30 mm long with an internal diameter of 3.4 mm, and it includes a wireless communication module, eliminating the cumbersome wiring of traditional invasive blood pressure monitors and making wearable measurements possible. To validate the dynamic and static pressure measurement precision of the high-precision interventional pressure measurement catheter with a compact structure, we first fabricated the pressure measurement catheter and set up a testing system for precision verification. The pressure measurement catheter with a compact structure was made from polydimethylsiloxane (PDMS), which contains a large number of methyl side chains in its molecules. Additionally, this material demonstrates significant stability within biological systems [26], and is widely used in the research of microfluidic chips, miniature implanted sensors, and medical devices [27; 28]. It is a type of silicone tubing material with excellent performance in the research phase. Additionally, to provide the sensor (BMP280; Bosch) with the ability to resist bodily fluid penetration, Parylene C was used for surface modification treatment. Subsequently, a high-precision static testing system was utilized to verify the static pressure precision indicators of the pressure measurement catheter (non-linearity, repeatability, hysteresis, etc.) [29]. Furthermore, a dynamic testing system established in this study explored the impact of different catheter sizes on dynamic measurement precision, thereby validating the effects of the compact structure on enhancing dynamically varying pressure measurement precision.