Search results for "Pressure"
showing 10 items of 4493 documents
Evaluation of the pulse wave arrival time as a marker for blood pressure changes in critically ill infants and children
1995
Objective. Pulse arrival time (PAT), which is the interval between the R wave of the electrocardiogram (ECG) and the arrival of the pulse wave peripherally, has been reported to be suitable for use as an indirect measure of blood pressure change. The purpose of this study was to evaluate, in critically ill infants and children, the degree to which 1/PAT covaries with systolic, diastolic, and mean blood pressure, as well as heart rate.Methods. A laboratory device was used to calculate PAT in real time from the ECG and the plethysmographic curve of pulse oximetry used for routine monitoring. Calculated PAT and corresponding blood pressures and heart rate were stored on hard disk. A total of 1…
Application of jäntti's method to volumetric adsorption measurements
2004
Jantti introduced a method to calculate the adsorption equilibrium by measuring the actual adsorbed amount three times after a change to the gas pressure. By this method the experimental time for adsorption measurement can be considerably shortened. The procedure was developed for use in adsorption measurements where the adsorbed masses are directly measured with a balance. In the present paper we will demonstrate that the method is particularly useful in volumetric (manometric) measurements.
The Use of 15N NMR for the Understanding of Nitrogen Physisorption.
1994
Abstract Nitrogen adsorption at liquid nitrogen temperature, 77K, is universally employed to determine pore dimensions. The nature of nitrogen physisorbed within the micropores of ZSM-5 zeolite was studied by in situ15N NMR as it depends on the partial pressure of the nitrogen and the temperature above and below 77K. An increase in the volume of adsorption of nitrogen at 77K occurs at a relative pressure of ~0.18 for this zeolite. The nature of the nitrogen was studied below and above this increase in nitrogen adsorption. We find that two states (phases) of nitrogen are evident. We conclude that two phases can be present but that a solid phase of nitrogen is not evident even as the temperat…
May Measurement Month 2018: an analysis of blood pressure screening results from Spain.
2020
Este artículo se encuentra disponible en la siguiente URL: https://academic.oup.com/eurheartjsupp/article/22/Supplement_H/H119/5898732 En este artículo también participan: Fernando Martínez, Blanca Carreras, Bettina de Berardinis, Thomas Beaney, Anca Chis Ster, Neil R. Poulter, Xin Xia y Luis M. Ruilope. Elevated blood pressure (BP) is the single most important contributing risk factor to the global disease burden, leading to over 10 million deaths each year. In Spain, hypertension (HTN) affects around 20% of the adult population and remains the greatest attributable cause of cardiovascular mortality. May Measurement Month (MMM) is a worldwide initiative aimed at increasing awareness of HTN…
Brain tissue pO2 related to SjvO2, ICP, and CPP in severe brain injury
2000
The aim of this report is to present first experience in comparing the course of brain tissue oxygen pressure values (PtiO2) to changes in jugular vein oxygen saturation (SjvO2), intracranial pressure (ICP), and cerebral perfusion pressure (CPP) after severe brain injury. PtiO2 monitoring was done using a polarographic Clark type microcatheter (LICOX pO2 probe) (GMS, Kiel, Germany) with a diameter of 0.5 mm and a sensitive area 7.9 mm long inserted in a right frontal position. The microcatheter was connected to a LICOX pO2 device. A fiber-optic catheter was used to measure SjvO2 and placed into the right internal jugular vein. The ICP monitoring was performed with a fiber-optic intraparench…
Entropy of balance--some recent results.
2010
Abstract Background Entropy when applied to biological signals is expected to reflect the state of the biological system. However the physiological interpretation of the entropy is not always straightforward. When should high entropy be interpreted as a healthy sign, and when as marker of deteriorating health? We address this question for the particular case of human standing balance and the Center of Pressure data. Methods We have measured and analyzed balance data of 136 participants (young, n = 45; elderly, n = 91) comprising in all 1085 trials, and calculated the Sample Entropy (SampEn) for medio-lateral (M/L) and anterior-posterior (A/P) Center of Pressure (COP) together with the Hurst…
Epinephrine and Norepinephrine Pattern in Elderly Patients with Borderline and Established Hypertension
1989
To evaluate the activity of sympathetic system and of plasm renin in elderly patients with borderline (BH) and established essential hypertension (EH), 31 BH mean age 38 years and 30 EH, mean age 39 years; 15 BH, mean age 66 years, and 15 EH, mean age 68 years, were studied at rest and after dynamic exercise. At the same time blood pressure and heart rate were automatically recorded, while blood samples were collected for PRA and plasma epinephrine (E) and norepinephrine (NE) assays. Plasma E levels showed no significant differences between the groups examined at rest. Nevertheless, young BH had higher plasma E levels than young EH after stress and elderly BH showed plasma E levels higher t…
Determination of four parabens and bisphenols A, F and S in human breast milk using QuEChERS and liquid chromatography coupled to mass spectrometry
2018
Abstract For the first time, a multiresidue, sensitive and high throughput method for determination of bisphenol A, F and S and 4 parabens (methyl paraben, ethyl paraben, propyl paraben and butyl paraben) in human breast milk was developed. The proposed method includes an extraction and clean-up procedure based on QuEChERS methodology followed by liquid chromatography coupled to triple quadrupole mass spectrometry determination. Negative atmospheric pressure chemical ionization in the selected reaction monitoring mode was used for mass detection. During the method validation the recoveries varied between 83 and 115% with a precision lower than 20% for all analytes using spiked levels from 0…
Goldmann Tonometry After Hyperopic Laser In Situ Keratomileusis
2004
PURPOSE To identify differences in applanation tonometry between retreated and nonretreated eyes (primary LASIK eyes) 6 months after hyperopic laser in situ keratomileusis. METHODS In a prospective study 100 eyes (100 patients) underwent conventional hyperopic laser in situ keratomileusis under a 160-microm flap. Central Goldmann applanation tonometry was determined before and 6 months after surgery in 78 (78%) primary LASIK eyes and before surgery and 6 months after the retreatment date in 22 (22%) retreated eyes. RESULTS Preoperative mean tonometry was 14.96 +/- 1.96 mm Hg and 15.30 +/- 1.95 mm Hg in primary LASIK and retreated eyes, respectively. Six months after surgery it was 12.99 +/-…
Changes in body composition, physical performance and cardiovascular risk factors after a 3-week integrated body weight reduction program and after 1…
2005
To investigate the short- and medium-term (ie, at 1-y follow-up) effects of a hospital-based body weight reduction (BWR) program lasting 3 weeks in severely obese individuals.Longitudinal, clinical intervention study entailing energy-restricted diet, tailored aerobic-strength exercise, psychological counselling and nutritional education during a 3-week period followed by 49 weeks of indirect supervision at home.In all, 45 women and 19 men aged 30.2 +/- 7.2 y (mean +/- s.d.) with severe obesity (BMI: 41.3 +/- 4.3 kg/m(2)), classified as weight losers (finalinitial weight) and regainers (finalor =initial weight).Body composition, physical performance and cardiovascular risk factors before and…