Effects of CO2 on dynamic cerebral autoregulation measurement.


:Arterial pCO2 is known to influence cerebral autoregulation but its effect on the dynamic relationship between mean arterial blood pressure (ABP) and mean cerebral blood flow velocity (CBFV), obtained from spontaneous fluctuations in ABP, has not been established. In 16 normal subjects, ABP was measured non-invasively (Finapres), CBFV was estimated with Doppler ultrasound in the middle cerebral artery, and end-tidal CO2 (EtCO2) was measured with an infrared capnograph. Recordings were made before, during and after breathing a mixture of 5% CO2 in air. The coherence function, amplitude and phase frequency responses, and impulse and step responses for the effects of ABP on CBFV were calculated by spectral analysis of beat-to-beat changes in mean ABP and CBFV before (mean CO2 5.55 +/- 0.38 kPa), during (6.43 +/- 0.31 kPa) and after 5% CO2 (5.43 +/- 0.26 kPa). During 5% CO2, the coherence function and the amplitude frequency response were significantly increased for frequencies below 0.05 Hz and the phase was reduced for the frequency range 0.02-0.1 Hz. The impulse and step responses indicated that 5% CO2 reduces the efficiency of the autoregulatory mechanism. A 20.7% average increase in CBFV induced by a 14.4% increase in EtCO2 was found to be mediated by a 25.9% reduction in critical closing pressure, while the change in resistance area product was non-significant.


Physiol Meas


Panerai RB,Deverson ST,Mahony P,Hayes P,Evans DH




Has Abstract


1999-08-01 00:00:00












  • An abdominal wall simulator for testing suprapubic urinary catheters.

    abstract::Urinary catheters (drainage tubes) are in widespread use. The most common type of long-term catheter is the Foley, which is made from natural or synthetic rubber. Foley catheters are passed into the bladder via the urethra or the suprapubic puncture channel (through the abdominal wall). A simulator for the abdominal w...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Coveney VA,Gröver D

    更新日期:2001-08-01 00:00:00

  • A practical approach to storage and retrieval of high-frequency physiological signals.

    abstract:OBJECTIVE:Storage of physiological waveform data for retrospective analysis presents significant challenges. Resultant data can be very large, and therefore becomes expensive to store and complicated to manage. Traditional database approaches are not appropriate for large scale storage of physiological waveforms. Our g...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Goodwin AJ,Eytan D,Greer RW,Mazwi M,Thommandram A,Goodfellow SD,Assadi A,Jegatheeswaran A,Laussen PC

    更新日期:2020-04-20 00:00:00

  • Modelling the electrical properties of bladder tissue--quantifying impedance changes due to inflammation and oedema.

    abstract::Electrical impedance spectroscopy has been developed as a potential method for the diagnosis of carcinoma in epithelial tissues. An understanding of the influence of structural changes in the tissue on the properties measured using this technique is essential for interpreting measured data and optimization of probe de...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Walker DC,Smallwood RH,Keshtar A,Wilkinson BA,Hamdy FC,Lee JA

    更新日期:2005-06-01 00:00:00

  • Invasive and noninvasive means of measuring intracranial pressure: a review.

    abstract::Measurement of intracranial pressure (ICP) can be invaluable in the management of critically ill patients. Cerebrospinal fluid is produced by the choroid plexus in the brain ventricles (a set of communicating chambers), after which it circulates through the different ventricles and exits into the subarachnoid space ar...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Zhang X,Medow JE,Iskandar BJ,Wang F,Shokoueinejad M,Koueik J,Webster JG

    更新日期:2017-07-24 00:00:00

  • Improved ultrasound transducer positioning by fetal heart location estimation during Doppler based heart rate measurements.

    abstract:OBJECTIVE:Doppler ultrasound (US) is the most commonly applied method to measure the fetal heart rate (fHR). When the fetal heart is not properly located within the ultrasonic beam, fHR measurements often fail. As a consequence, clinical staff need to reposition the US transducer on the maternal abdomen, which can be a...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Hamelmann P,Vullings R,Schmitt L,Kolen AF,Mischi M,van Laar JOEH,Bergmans JWM

    更新日期:2017-09-21 00:00:00

  • Patient-specific simulations and measurements of the magneto-hemodynamic effect in human primary vessels.

    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


    authors: Kyriakou A,Neufeld E,Szczerba D,Kainz W,Luechinger R,Kozerke S,McGregor R,Kuster N

    更新日期:2012-02-01 00:00:00

  • Detection of animal tissue thickness using simple vertical electric sounding (VES).

    abstract::Tetrapolar linear arrays are commonly used in geophysics to explore the vertical distribution of resistivity values in a geological section of a specific point on the earth. This technique, known as vertical electric sounding (VES), uses different electrode configurations. For our experiments, we utilized its more pop...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Gonzalez CA,offniga O,Padilla LE

    更新日期:1997-02-01 00:00:00

  • A medical thermal imaging device for the prevention of diabetic foot ulceration.

    abstract::In this paper a description is given of the development, characterisation and first results of a thermal imaging device aimed at significantly reducing the incidence of diabetic foot ulceration (DFU). These devices will be used in three clinical centres and in two preliminary clinical trials. The first will be on heal...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Machin G,Whittam A,Ainarkar S,Allen J,Bevans J,Edmonds M,Kluwe B,Macdonald A,Petrova N,Plassmann P,Ring F,Rogers L,Simpson R

    更新日期:2017-03-01 00:00:00

  • Wavelet-based real-time calculation of multiple physiological parameters on an embedded platform.

    abstract:OBJECTIVE:This paper aims to present how physiological signals can be processed based on wavelet decomposition to calculate multiple physiological parameters in real-time on an embedded platform. APPROACH:An ECG and PPG are decomposed to the appropriate scale based on a quadratic spline wavelet base in order to obtain...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Tang M,Xia P,He Z,Zhao Z,Chen X,Yang T,Zhang Z,Zhan Q,Li X,Fang Z

    更新日期:2020-03-06 00:00:00

  • Physiological motion monitoring: a wearable device and adaptative algorithm for sit-to-stand timing detection.

    abstract::A simple wearable device for sit-to-stand timing detection was designed and constructed with rate gyroscopes and accelerometers and a dedicated adaptive algorithm. The method was validated by comparison with optoelectronic equipment. Results from the comparison showed a maximal error always lower than 2.5 x 10(-2) s f...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Giansanti D,Maccioni G

    更新日期:2006-08-01 00:00:00

  • A multifrequency multichannel electrical impedance data acquisition system for body fluid shift monitoring.

    abstract::This paper discusses some important issues for the design of electrical impedance measurement systems intended for body fluid shift monitoring, in particular during dialysis treatments. We have studied two common signal generation systems: digital synthesis and carrier recovery. We have found that in prolonged measure...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Lozano A,Rosell J,Pallás-Areny R

    更新日期:1995-11-01 00:00:00

  • Sleep stage classification with ECG and respiratory effort.

    abstract::Automatic sleep stage classification with cardiorespiratory signals has attracted increasing attention. In contrast to the traditional manual scoring based on polysomnography, these signals can be measured using advanced unobtrusive techniques that are currently available, promising the application for personal and co...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Fonseca P,Long X,Radha M,Haakma R,Aarts RM,Rolink J

    更新日期:2015-10-01 00:00:00

  • Cardiorespiratory coupling in young healthy subjects.

    abstract:OBJECTIVE:To quantify the presence of cardiorespiratory interaction in a group of 41 healthy subjects performing a subset of the Ewing test battery. APPROACH:We measure the empirical distribution of the cardiorespiratory coupling time (RI), defined as the time from inspiration onset to R peaks in the ECG. The study pr...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Sobiech T,Buchner T,Krzesiński P,Gielerak G

    更新日期:2017-11-30 00:00:00

  • Life-threatening false alarm rejection in ICU: using the rule-based and multi-channel information fusion method.

    abstract::False alarm (FA) rates as high as 86% have been reported in intensive care unit monitors. High FA rates decrease quality of care by slowing staff response times while increasing patient burdens and stresses. In this study, we proposed a rule-based and multi-channel information fusion method for accurately classifying ...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Liu C,Zhao L,Tang H,Li Q,Wei S,Li J

    更新日期:2016-08-01 00:00:00

  • Validation of a new dielectric device to assess changes of tissue water in skin and subcutaneous fat.

    abstract::Easily applicable and inexpensive water-specific techniques to evaluate local oedema, swollen tissue problems and fluid retention in humans are not available. In the present investigation a recently constructed non-invasive device for a local measurement of changes in tissue water in human skin and subcutaneous fat (S...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Nuutinen J,Ikäheimo R,Lahtinen T

    更新日期:2004-04-01 00:00:00

  • Circuit modeling of the electrical impedance: II. Normal subjects and system reproducibility.

    abstract::Part I of this series showed that the five-element circuit model accurately mimics impedances measured using multi-frequency electrical impedance myography (MFEIM), focusing on changes brought on by disease. This paper addresses two requirements which must be met if the method is to qualify for clinical use. First, th...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Shiffman CA,Rutkove SB

    更新日期:2013-02-01 00:00:00

  • Monitoring nasal conductance by bilateral nasal cannula pressure transducers.

    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


    authors: Thurnheer R,Bloch KE

    更新日期:2004-04-01 00:00:00

  • Repeatability of body sway measurements; day-to-day variation measured by sway magnetometry.

    abstract::The postural stability of 30 normal subjects in the age range 15 to 64 years was measured on five separate occasions, using the sway magnetometry technique, to determine the day-to-day repeatability of this measurement technique. On each occasion the pathlength and area enclosed by movement of the hips in a horizontal...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Elliott C,Murray A

    更新日期:1998-05-01 00:00:00

  • Gastrointestinal arrhythmias are associated with statistically significant fluctuations in systemic information dimension.

    abstract::Although cardiac arrhythmias have been studied extensively, little is known about arrhythmic phenomena in the gastrointestinal (GI) system. In this study, we demonstrate for the first time that the onset of GI arrhythmias is associated with statistically significant fluctuations in the information dimension of the ass...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Irimia A,Wikswo JP Jr

    更新日期:2008-05-01 00:00:00

  • Sensitivity matrix and reconstruction algorithm for EIT assuming axial uniformity.

    abstract::In electrical impedance tomography (EIT) two-dimensional models continue to be applied despite their known inability to provide correct reconstruction. In this paper, a reconstruction algorithm that assumes a translationally invariant conductivity distribution is described. A more precise forward solver is obtained by...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Jerbi K,Lionheart WR,Vauhkonen PJ,Vauhkonen M

    更新日期:2000-02-01 00:00:00

  • Neural network analysis of oxygenation signals in infants during sleep.

    abstract::The use of artificial neural networks (ANNs) to interpret sleep monitoring signals is described. Recordings from ten infants with apparent life threatening episodes were assigned into training feedforward R-PROP networks. In order to separate good signal from artefact, 60 second time frames of SaO2 and TcPO2 signals w...

    journal_title:Physiological measurement

    pub_type: 临床试验,杂志文章


    authors: Taktak AF,Simpson S,Patel S,Meyer G

    更新日期:2000-08-01 00:00:00

  • An analytic solution to the homogeneous EIT problem on the 2D disk and its application to estimation of electrode contact impedances.

    abstract::An analytic solution of the potential distribution on a 2D homogeneous disk for electrical impedance tomography under the complete electrode model is expressed via an infinite system of linear equations. For the shunt electrode model with two electrodes, our solution coincides with the previously derived solution expr...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Demidenko E

    更新日期:2011-09-01 00:00:00

  • Effects of muscle injury severity on localized bioimpedance measurements.

    abstract::Muscle injuries in the lower limb are common among professional football players. Classification is made according to severity and is diagnosed with radiological assessment as: grade I (minor strain or minor injury), grade II (partial rupture, moderate injury) and grade III (complete rupture, severe injury). Tetrapola...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Nescolarde L,Yanguas J,Lukaski H,Alomar X,Rosell-Ferrer J,Rodas G

    更新日期:2015-01-01 00:00:00

  • Energy scavenging sources for biomedical sensors.

    abstract::Energy scavenging has increasingly become an interesting option for powering electronic devices because of the almost infinite lifetime and the non-dependence on fuels for energy generation. Moreover, the rise of wireless technologies promises new applications in medical monitoring systems, but these still face limita...

    journal_title:Physiological measurement

    pub_type: 杂志文章,评审


    authors: Romero E,Warrington RO,Neuman MR

    更新日期:2009-09-01 00:00:00

  • Machine learning for nocturnal mass diagnosis of atrial fibrillation in a population at risk of sleep-disordered breathing.

    abstract:OBJECTIVE:In this research, we introduce a new methodology for atrial fibrillation (AF) diagnosis during sleep in a large population sample at risk of sleep-disordered breathing. APPROACH:The approach leverages digital biomarkers and recent advances in machine learning (ML) for mass AF diagnosis from overnight-hours o...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Chocron A,Efraim R,Mandel F,Rueschman M,Palmius N,Penzel T,Elbaz M,Behar JA

    更新日期:2020-11-06 00:00:00

  • Development of a noncontact heart rate monitoring system for sedentary behavior based on an accelerometer attached to a chair.

    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


    authors: Lim E,Lee HK,Myoung HS,Lee KJ

    更新日期:2015-03-01 00:00:00

  • The effect of ambient air temperature on whole-body bioelectrical impedance.

    abstract::It has previously been shown that extreme changes in ambient air temperature can affect whole-body bioelectrical impedance. The purpose of this study was to determine if more moderate changes in ambient air temperature, such as those experienced in most laboratory settings, would also affect bioelectric impedance anal...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Buono MJ,Burke S,Endemann S,Graham H,Gressard C,Griswold L,Michalewicz B

    更新日期:2004-02-01 00:00:00

  • Home monitoring of within-breath respiratory mechanics by a simple and automatic forced oscillation technique device.

    abstract::Spirometry is the gold standard to determine the presence of airflow obstruction, but it requires volitional participation and needs qualified supervision. The forced oscillation technique (FOT) measures respiratory input impedance (Zrs) during spontaneous breathing and it could be useful for unsupervised monitoring o...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Dellacà RL,Gobbi A,Pastena M,Pedotti A,Celli B

    更新日期:2010-04-01 00:00:00

  • Real-time chest-wall-motion tracking by a single optical fibre grating: a prospective method for ventilator triggering.

    abstract:OBJECTIVE:The ventilators involved in non-invasive mechanical ventilation commonly provide ventilator support via a facemask. The interface of the mask with a patient promotes air leaks that cause errors in the feedback information provided by a pneumatic sensor and hence patient-ventilator asynchrony with multiple neg...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: Ivanović MD,Petrovic J,Savić A,Gligorić G,Miletić M,Vukčević M,Bojović B,Hadžievski L,Allsop T,Webb DJ

    更新日期:2018-04-26 00:00:00

  • Dynamic profiles of volatile organic compounds in exhaled breath as determined by a coupled PTR-MS/GC-MS study.

    abstract::In this phenomenological study we focus on dynamic measurements of volatile organic compounds (VOCs) in exhaled breath under exercise conditions. An experimental setup efficiently combining breath-by-breath analyses using proton transfer reaction mass spectrometry (PTR-MS) with data reflecting the behaviour of major h...

    journal_title:Physiological measurement

    pub_type: 杂志文章


    authors: King J,Mochalski P,Kupferthaler A,Unterkofler K,Koc H,Filipiak W,Teschl S,Hinterhuber H,Amann A

    更新日期:2010-09-01 00:00:00