Measurement of Blood Pressure by Ultrasound—The Applicability of Devices, Algorithms and a View in Local Hemodynamics

Objective: Due to ongoing technical progress, the ultrasonic measurement of blood pressure (BP) as an alternative to oscillometric measurement (NIBP) or the continuous non-invasive arterial pressure method (CNAP) moves further into focus. The US method offers several advantages over NIBP and CNAP, such as deep tissue penetration and the utilization of different arterial locations. Approach: Ten healthy subjects (six female, aged 30.9 ± 4.6 years) volunteered in our investigation. In the ultrasonic BP measurement, we differentiated between the directly measured (pulsatile diastolic and systolic vessel diameter) and indirectly calculated variables at three different artery locations on both arms, with two different ultrasound devices in the transversal and longitudinal directions of the transducer. Simultaneously, NIBP monitoring served as reference BP, while CNAP monitored the steady state condition of the arm under investigation. The Moens–Korteweg algorithm (MKE) and the algorithm of the working group of San Diego (SanD) were selected for the indirectly calculated ultrasonic BP data. Main results: With US, we were able to measure the BP at each selected arterial position. Due to the investigation setup, we found small but significant interactions of the main effects. Bland and Altman analysis revealed that US-BP measurement was similar to NIBP, with superior accuracy when compared to the established CNAP method. In addition, US-BP measurement showed that the measurement accuracy of both arms can be regarded as identical. In a detailed comparison of the selected arterial vascular sections, systematic discrepancies between the right and left arm could be observed. Conclusion: In our pilot study, we measured BP effectively and accurately by US using two different devices. Our findings suggest that ultrasonic BP measurement is an adequate alternative for live and continuous hemodynamic monitoring.

From palpation of the pulse to cuff-free methods: evolution of arterial pressure measurement methods

The arterial pressure is an important physiological indicator. The review describes the different techniques of measurement of arterial pressure, their advantages and limitations. Moreover, it also represents a historical reference about the main stage of the development of clinical sphygmomanometrya that nowadays is a relevant method for measuring arterial pressure. The emergence and the development of devices for daily monitoring of arterial pressure and modern techniques for non-invasive arterial pressure measurement are described too.

Detection of hypotension during spinal anesthesia for caesarean section with continuous non-invasive arterial pressure monitoring and intermittent oscillometric blood pressure monitoring in patients treated with ephedrine or phenylephrine

Introduction/Objective. Despite frequent side effects such as hypotension, spinal anesthesia (SA) is still one of the best anesthetic methods for elective cesarean section (CS). Intermittent, oscillometric, non-invasive blood pressure monitoring (NIBP) frequently leads to the missed hypotensive episodes. Our goal was to compare continuous non-invasive arterial pressure (CNAP) monitoring with NIBP in the terms of efficiency to detect hypotension. Methods. In this study, we compared CNAP and NIBP monitoring for hypotension detection in 76 patients divided into two groups of 38 patients treated with ephedrine (E) or phenylephrine (P), during 3 min intervals, starting from SA, by the end of the surgery. Results. In group E, significantly lower mean systolic blood pressure (SBP) values with CNAP compared with NIBP (p = 0.008) was detected. CNAP detected 31 (81.6%) hypotensive patients in E group and significantly lower number 20 (52.6%) with NIBP (p = 0.001), while in P group CNAP detected 34 patients (89.5%) and NIBP, only 18 (47.3%), p = 0.001. CNAP detected significantly higher number of hypotensive intervals in E and P groups (p < 0.001). Umbilical vein pH was lower within hypotensive compared with normotensive patients in E and P groups, with CNAP and NIBP, respectively (p < 0.001, p = 0.027 in E, and p = 0.009, p < 0.001, in P group). Conclusion. CNAP is much more efficient in hypotension detection for CS during SA, which allows faster treatment of hypotension, thus improving fetal and maternal outcome.