Relationship between the fall in blood pressure in the standing position and diaphragmatic muscle thickness: proof of concept study Background The diaphragm is an important muscle of respiration, and regulates the intrathoracic pressure. Blood pressure is regulated by the baroreceptor reflex system, and is also affected by intrathoracic pressure. We examined the relationship between the diaphragmatic muscle thickness and the degree of drop in blood pressure in the standing position. Methods We prospectively studied 15 healthy subjects. The diaphragmatic muscle thickness was measured using a B-mode ultrasonic imaging device. The blood pressure before and after standing was measured by a head-up tilt test. Results The diastolic blood pressure difference during expiration and inspiration showed a significant correlation with the diaphragmatic muscle thickness (r = 0.578, P = 0.024 and r = 0.518, P = 0.048, respectively). Conclusion The diaphragmatic muscle thickness was related to the fall in diastolic blood pressure in the standing position. This indicates that adequate diaphragmatic muscle thickness helps to maintain intrathoracic pressure and prevents excessive drop in blood pressure in the standing position. Received 11 January 2019 Accepted 5 August 2019 Correspondence to Atsushi Ichikawa, PhD, Department of Cardiovascular Control, Kochi Medical School, Oko-cho, Nankoku, 783–8505, Japan, Tel: +81 88 880 2587; fax: +81 88 880 2310; e-mail: ichik@kochi-u.ac.jp Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Simulator-based assessment of ankle arterial systolic blood pressure measurement skills Objective Learning basic vascular examination is a complex process. Very few studies have focused on the ability to measure the arterial systolic blood pressure at the ankle (ASBPa). The aim of this study was to objectively assess the effects of a 1-h practical educational intervention on the ability to measure ASBPa among medical students. Methods A total of 27 medical students were prospectively recruited. Two evaluation sessions of ASBPa measurement skills were conducted, before (T1) and after a 1-h practical lesson (T2). To assess the learning effect associated to the simulator-based evaluation, a control group composed by nonmedical students, not involved in the practical lesson, was also tested. Objective assessments of ASBPa measurements were performed by an instrumented leg prototype. Results There was a nonsignificant decreasing trend measurement time after practical lesson. The average pressure determination error (ΔP) was significantly reduced: ΔPT1: 10.5 ± 13.8 mmHg vs. ΔPT2: 5.7 ± 6.0 mmHg (P = 0.002). The mean deflation rate (DR) of the cuff was significantly decreased: DRT1: 12.9 ± 9.2 mmHg/s vs. DRT2: 8.7 ± 4.6 mmHg/s (P = 0.001). The control group did not show significant changes. Conclusion A 1-h practical learning could improve some parameters of the ASBPa measurement among medical students, but was not sufficient to allow the measured technical factors to reach established guidelines. Received 6 September 2018 Accepted 18 July 2019 Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website, www.bpmonitoring.com. Correspondence to Florian Congnard, IFEPSA, 49 rue des Perrins, 49130 Les Ponts-de-Cé, France, Tel: +33 (0)2 41 45 26 40; fax: +33 (0)2 41 45 26 44; E-mail: fcongna2@uco.fr Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

Evaluating the performance of automated sphygmomanometers using a patient simulator Background and objective: Automated sphygmomanometers use the oscillometric method to measure blood pressure, which is based on an algorithm that relates the amplitude of the oscillometric waveform pulses and the pressure inside the cuff. Validation uses empirical information from clinical trials conducted by each manufacturer. Consequently, measurement algorithms are not harmonized, being based on distinct arterial waveforms, according to each group of volunteers of the clinical test. In the present study, a patient simulator was used to generate standardized, consistent oscillometric waveform pulses to test the algorithms used in six sphygmomanometers. Materials and methods: Six different upper arm and wrist-based automated sphygmomanometers were tested using a patient simulator comprising four different blood pressure levels, Psys/dia (mmHg): 80/50; 120/80; 150/100; 200/150. The devices were also submitted to conformity assessment. The variance of repeatable measurements was also analyzed. Results: All tested automated sphygmomanometers complied with metrological requirements, presenting results within the range of ±2 mmHg for static calibration. Systematic discrepancies, greater than 20 mmHg, were observed between sphygmomanometers’ results from upper arm and wrist-based models. Differences reaching 12.8 mmHg in diastolic pressure results were observed among upper arm devices. Conclusion: These results may have a clinical impact and indicate the need for a standardized algorithm, with a harmonized approach for validation. Moreover, the algorithm of the wrist-based devices is being affected by the use of the brachial artery waveform as reference for its validation, which also reveals that the current approach needs standardization, especially regarding the use of patient simulators. Received 2 April 2019 Accepted 27 June 2019 Correspondence to Bruno Amado Rodrigues Filho, PhD, National Institute of Metrology, Quality and Technology–Inmetro, São Paulo Office, 1922 Santa Cruz St., São Paulo, SP 04122-002, Brazil, Tel: +551135812460; e-mail: bafilho@inmetro.gov.br Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.