Abstract:
:Twenty-nine patients were monitored overnight for breathing distress patterns during postoperative analgesia. Nasal flow apnoea monitoring and pulse oximetry data were recorded at 50 Hz. Respiratory inductive plethysmography (RIP) tracked tidal volume (TV) thoracoabdominal motion, and supplemented the flow monitoring by identifying detected apnoea type. TVs were computed from linear combinations of the RIP signals, but calibrations showed that multiple regression approaches with fitting errors <1% had highly variable coefficients and estimate precisions. Simple least squares theory showed that unstable parameter calculation and coefficient variation with signal conditions were inherent in RIP calibration models. Principal components (PC) methods were well suited to mitigating these problems because the RIP signals were highly correlated. The two PCs tracked the relative changes in TVs and indicated the degree of signal asynchrony, enabling improved uncalibrated monitoring. For accurately measuring RIP phase differences, the cross-correlation function was calculated. A simple version of PC analysis is developed, avoiding matrices, to help clarify how RIP calibration problems can be addressed. The methods are illustrated for calibration in normal breathing, and for postoperative monitoring during Cheyne-Stokes breathing. Sum and difference combinations of the RIP signals could discriminate central from obstructive apnoeas to help improve flow monitoring efficacy on-line.
journal_name
Physiol Measjournal_title
Physiological measurementauthors
Millard RKdoi
10.1088/0967-3334/20/2/307subject
Has Abstractpub_date
1999-05-01 00:00:00pages
175-86issue
2eissn
0967-3334issn
1361-6579journal_volume
20pub_type
杂志文章abstract::Non-contact vital sign monitoring enables the estimation of vital signs, such as heart rate, respiratory rate and oxygen saturation (SpO2), by measuring subtle color changes on the skin surface using a video camera. For patients in a hospital ward, the main challenges in the development of continuous and robust non-co...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/ab525c
更新日期:2019-12-02 00:00:00
abstract::An accurate reproducible measurement of left ventricular volume is important in the evaluation of cardiac disease. Four methods of left ventricular volume measurement by radionuclide ventriculography have been compared and their reproducibility assessed in a patient group. The methods studied were a geometric method, ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/14/1/004
更新日期:1993-02-01 00:00:00
abstract::This paper investigates the main characteristics of the magneto-hemodynamic (MHD) response for application as a biomarker of vascular blood flow. The induced surface potential changes of a volunteer exposed to a 3 T static B0 field of a magnetic resonance imaging (MRI) magnet were measured over time at multiple locati...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/33/2/117
更新日期:2012-02-01 00:00:00
abstract::Electrical impedance tomography (EIT) has shown significant promise for lung imaging. One key challenge for EIT in this application is the movement of electrodes during breathing, which introduces artefacts in reconstructed images. Various approaches have been proposed to compensate for electrode movement, but no comp...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/36/6/1119
更新日期:2015-06-01 00:00:00
abstract::Although people spend a third of their day engaged in sedentary activities, research on heart activity during sitting is almost nonexistent because of the discomfort experienced when electrocardiogram (ECG) measurement electrodes are attached to the body. Accordingly, in this study, a system was developed to monitor h...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/36/3/N61
更新日期:2015-03-01 00:00:00
abstract::In magnetic resonance electrical impedance tomography (MREIT) we inject currents through electrodes placed on the surface of a subject and try to reconstruct cross-sectional resistivity (or conductivity) images using internal magnetic flux density as well as boundary voltage measurements. In this paper we present a st...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/24/2/367
更新日期:2003-05-01 00:00:00
abstract:OBJECTIVE:Observational studies suggest that obesity might have a Mendelian origin, but it is not clear if gene expression patterns observed in obese subjects are secondary to genetic traits or not. APPROACH:Here we test a transcriptomic signature of obesity previously identified by our group on a large cohort of twin...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aab85a
更新日期:2018-04-26 00:00:00
abstract::The assessment and diagnosis of lower limb peripheral arterial occlusive disease (PAOD) is important since it can lead progressively to disabling claudication, ischaemic rest pain and gangrene. Historically, the first assessment has been palpation of the peripheral pulse since it can become damped, delayed and diminis...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/26/5/018
更新日期:2005-10-01 00:00:00
abstract:OBJECTIVE:The aim of the study was to explore the feasibility of titrating tidal volume (V T) and positive end-expiratory pressure (PEEP) during one-lung ventilation (OLV) based on ventilation distribution and oxygenation. APPROACH:Twenty-four consecutive patients requiring intubation with a double-lumen tube and subs...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aaaeb2
更新日期:2018-03-29 00:00:00
abstract::We present the results of using electrical impedance tomographic spectroscopy (EITS) to follow the changes in lung water induced by oleic acid. Measurements were made on three goats before and after the injection of oleic acid. In addition to the EITs measurements, lung water was also measured using a double-indicator...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/17/4a/016
更新日期:1996-11-01 00:00:00
abstract::Remote sensing of the reflectance photoplethysmogram using a video camera typically positioned 1 m away from the patient's face is a promising method for monitoring the vital signs of patients without attaching any electrodes or sensors to them. Most of the papers in the literature on non-contact vital sign monitoring...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/35/5/807
更新日期:2014-05-01 00:00:00
abstract::The purpose of this study was to determine the validity and reliability of a timed 5 km cycle ergometer ride to predict maximum oxygen uptake (VO2max). Fifty-two healthy volunteers had their VO2max determined during a maximal treadmill run. They also performed a timed 5 km cycle ergometer ride. The resistance setting ...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1088/0967-3334/17/4/009
更新日期:1996-11-01 00:00:00
abstract::This paper describes a method of reducing the influence of the data error caused by non-ideal boundary shape and electrode placement on reconstructed images. A data calibration and a modified Newton-Raphson reconstruction are combined in the method to ensure rapid convergence and small reconstruction error. The method...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/15/2a/022
更新日期:1994-05-01 00:00:00
abstract::This study was done to introduce new parameters derived by time frequency analysis of heart rate variability data. Four simulation experiments were carried out to compare the short-time Fourier transform (STFT) analysis method to the traditional overall spectral analysis method. Sinusoidal signals were generated with ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/21/2/303
更新日期:2000-05-01 00:00:00
abstract::There are currently no objective means of quantifying chest wall vibrations during manual physiotherapy. The aims of the study were to (i) develop a method to quantify physiotherapy-applied forces and simultaneous changes in respiratory flow and pressure, (ii) assess the feasibility of using this method in ventilated ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/28/9/004
更新日期:2007-09-01 00:00:00
abstract::False intensive care unit (ICU) alarms induce stress in both patients and clinical staff and decrease the quality of care, thus significantly increasing both the hospital recovery time and rehospitalization rates. In the PhysioNet/CinC Challenge 2015 for reducing false arrhythmia alarms in ICU bedside monitor data, th...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/37/8/1273
更新日期:2016-08-01 00:00:00
abstract::In this work, we describe a beat-by-beat method for assessing the clinical utility of pulsatile waveforms, primarily recorded from cardiovascular blood volume or pressure changes, concentrating on the photoplethysmogram (PPG). Physiological blood flow is nonstationary, with pulses changing in height, width and morphol...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/33/9/1491
更新日期:2012-09-01 00:00:00
abstract::Gastro-oesophageal pH measurements are routinely carried out to quantify and determine if levels of acid reflux are responsible for symptoms. Although considered the 'gold standard', evidence suggests that pH measurements do not correlate well with the degree of oesophagitis seen during endoscopy. In this study the cu...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/24/4/006
更新日期:2003-11-01 00:00:00
abstract:OBJECTIVE:Plots of blood volume measurements over time (profiles) may identify euvolemia during fluid removal for acute heart failure. We assessed agreement between two noninvasive measurements of blood volume profiles during mechanical fluid removal, which exemplifies the interstitial fluid shifts that occur during di...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/ab21af
更新日期:2019-07-01 00:00:00
abstract::The holy grail of neuroimaging would be to have an imaging system, which could image neuronal electrical activity over milliseconds. One way to do this would be by imaging the impedance changes associated with ion channels opening in neuronal membranes in the brain during activity. In principle, we could measure this ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/25/1/040
更新日期:2004-02-01 00:00:00
abstract::Sedentary behaviour (SB) is associated with a number of adverse health outcomes. Studies that have used ActiGraph monitors to define sedentary time tend to use a threshold of <100 counts per minute (cpm) for classifying SB; however, this cut-point was not empirically derived for adults. It is not known whether ActiGr...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/37/10/1669
更新日期:2016-10-01 00:00:00
abstract::We used finite element analysis to study the relationship between the intraventricular blood conductance and the right ventricular volume. Previous studies reported a quasi-linear dependence between these two quantities. We quantified the effects of the resistivities of the surrounding tissues (e.g. heart wall, lungs)...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/15/1/004
更新日期:1994-02-01 00:00:00
abstract::Electrical impedance tomography (EIT) is expected to become a valuable tool for monitoring mechanically ventilated patients due to its ability to continuously assess regional lung ventilation and aeration. Several sources of interference with EIT examinations exist in intensive care units (ICU). Our objectives are to ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/12/F01
更新日期:2011-12-01 00:00:00
abstract::In nine healthy subjects, magnetic resonance imaging was used to measure blood flow waveforms in the common (CCA), internal (ICA) and external (ECA) carotid arteries. Useful data were acquired from 14 carotid arteries in total. Flow rates were determined from regions of interest placed over the arteries in CINE-phase ...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/25/3/009
更新日期:2004-06-01 00:00:00
abstract::Non-contact heart and lung activity monitoring would be a desirable supplement to conventional monitoring techniques. Based on the potential of non-contact magnetic induction measurements, requirements for an adequate monitoring system were estimated. This formed the basis for the development of the presented extendab...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/29/6/S25
更新日期:2008-06-01 00:00:00
abstract::EPR oximetry is a promising, relatively non-invasive method for monitoring the partial pressure of oxygen in tissue (PtO2) that has proved useful in following changes under various physiologic and pathophysiologic conditions. Optimal utilization of the method will be facilitated by systematic comparisons with other av...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/25/6/007
更新日期:2004-12-01 00:00:00
abstract::Nasal obstruction is common and may disturb well-being during daytime and sleep. Its objective assessment by standard methods requires patient cooperation and inconvenient instrumentation. Therefore, the purpose of this study was to develop a novel, unobtrusive technique for continuous monitoring of changes in nasal c...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/25/2/014
更新日期:2004-04-01 00:00:00
abstract::A method was developed for simultaneously measuring plasma resistance, cell interior resistance and cell membrane capacitance of blood. A three-element circuit model for simulating the impedance of blood was evaluated by comparing measured and calculated impedance frequency curves and was found feasible. The values of...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/14/2/006
更新日期:1993-05-01 00:00:00
abstract::Cerebral autoregulation has been studied by linear filter systems, with arterial blood pressure (ABP) as the input and cerebral blood flow velocity (CBFV-from transcranial Doppler Ultrasound) as the output. The current work extends this by using adaptive filters to investigate the dynamics of time-varying cerebral aut...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/31/10/001
更新日期:2010-10-01 00:00:00
abstract::A magnetic pulse generator has been set up in order to study gastric activity. Two coils 1.05 m in diameter, arranged in a Helmholtz configuration, were used. The system generated magnetic field pulses higher than 15 mT, of duration 17.3+/-1.2 ms. Measurements were performed in 11 male volunteers, with average age 29....
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/25/5/015
更新日期:2004-10-01 00:00:00