BACKGROUND Evaluating the accurate responses of the cardiovascular system to external stimuli is important for a deeper understanding of cardiovascular homeostasis. However, the responses should be distorted by the conventional time domain analysis when a frequency of the effect of external stimuli matches that of intrinsic fluctuations. OBJECTIVES The purpose of this study is to propose a mi...

Obstruction of the large and small airways occurs in several diseases, including asthma, chronic obstructive pulmonary disease, cystic fibrosis, bronchiectasis, and bronchiolitis. This article discusses the role of ventilator waveforms in the context of factors that contribute to the development of respiratory failure and acute respiratory distress in patients with obstructive lung disease. Dis...

OBJECTIVES The goal of this study was to investigate the relation between serum cholesterol, arterial stiffness and central blood pressure. BACKGROUND Arterial stiffness and pulse pressure are important determinants of cardiovascular risk. However, the effect of hypercholesterolemia on arterial stiffness is controversial, and central pulse pressure has not been previously investigated. METH...

INTRODUCTION The aim of this study was to validate an automated, objective and standardized algorithm for quantifying and displaying patient-ventilator interaction. METHODS Using a new method to detect patient-ventilator synchrony, the present study re-analyzed previously acquired and published data from 24 mechanically ventilated adult patients (Colombo et al., Crit Care Med. 2011 Nov;39(11)...

Arterial pressure waves have been described in one dimension using several approaches, such as lumped (Windkessel) or distributed (using Navier-Stokes equations) models. An alternative approach consists of modeling blood pressure waves using a Korteweg-de Vries (KdV) equation and representing pressure waves as combinations of solitons. This model captures many key features of wave propagation i...

Aortic systolic and pulse pressure rise with age because of aortic stiffening. Two factors are responsible: a larger incident wave because of increased aortic characteristic impedance and premature return of wave reflection from peripheral sites. This study aimed to determine the relative contribution of each factor before and after age 60 years. Aortic pressure waveforms were generated for 368...

We investigated the system identification approach for potentially improved estimation of pulse transit time (PTT), a popular arterial stiffness marker. In this approach, proximal and distal arterial waveforms are measured and respectively regarded as the input and output of a system. Next, the system impulse response is identified from all samples of the measured input and output. Finally, the...

Central Pressure and Pulse Wave Amplification in the Upper Limb To the Editor: The important review of pulse pressure (PP) amplification1 was directed at better understanding of central (ascending aortic or carotid) pressure generated from upper limb measurements of cuff arterial pressure and pressure waveforms. One important issue, not addressed by the authors, is how 2 different noninvasive t...

Photoplethysmogram (PPG) signals collected using a pulse oximeter are increasingly being used for screening and diagnosis purposes. Because of the non-invasive, cost-effective, and easy-to-use nature of the pulse oximeter, clinicians and biomedical engineers are investigating how PPG signals can help in the management of many medical conditions, especially for global health application. The stu...

Assessment of the jugular venous pressure is often inadequately performed and undervalued. Here, we review the physiologic and anatomic basis for the jugular venous pressure, including the discrepancy between right atrial and central venous pressures. We also describe the correct method of evaluating this clinical finding and review the clinical relevance of the jugular venous pressure, especia...