Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 94 (1987), S. 0 
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary. In a serial study the changes in whole blood viscosity at different shear rates and its major determinants were determined in 24 healthy women with normal pregnancies. Whole blood viscosity and plasma viscosity were measured with a rotational viscometer. Red cell aggregation was measured by syllectometry. During normal pregnancy we found a decrease in whole blood viscosity at all shear rates until 29 weeks gestation, followed by a smaller increase between 30 and 37 weeks, which was most pronounced at higher shear rates, especially in nulliparae. The changes in whole blood viscosity were to a great extent determined by the changes in haematocrit and plasma viscosity. Haematocrit was more important for whole blood viscosity at lower shear rates, while plasma viscosity had more influence on high shear blood viscosity. The continuous increase in red cell aggregation had no demonstrable influence on low shear blood viscosity as measured in vitro in a rotational viscometer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Continuous intrapartum PO2 recordings were made in 25 fetuses, using a needle electrode that measures PO2 in the subcutaneous (sc) tissue of the scalp or the breech. This small electrode is combined with a spiral ECG electrode and can be easily applied in early labour. One hour after application of the electrode in the early first stage, a mean fetal scPO2 of 29.4±7.5 mm Hg was found. In the course of labour, scPO2 gradually fell to a mean value of 22.2±5.6 mm Hg, recorded just before the onset of bearing down contractions, and stabilised in the second stage of labour. ScPO2 values of less than 10 mm Hg were not recorded for a longer period except in one case of severe fetal distress. The relation between scPO2 just before delivery and cord arterial PO2 revealed a coefficient of correlation of 0.85. In general, scPO2 appeared higher than tcPO2 as described in the literature. This is ascribed to the different technique of measurement: the needle electrode measures in the deeper layers of the scalp, whereas the tc electrode is supplied with oxygen from the more superficial capillaries, where blood flow is more liable to be affected by mechanical factors.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 104 (1997), S. 0 
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objective The influence of the location of the sensor on reflectance pulse oximetry during fetal monitoring in labour was investigated using the newborn infant as a model.Methods Seven healthy infants were studied between 19 and 48 hours after term delivery. Recordings of reflectance pulse oximetry were obtained from eight different sites on the infant's head. The relative changes in red to infrared light (R/IR) were determined. In pulse oximetry R/IR values are converted to arterial oxygen values by means of an empirically derived calibration curve.Results Significantly lower R/IR values were found at the forehead compared with the fontanelle, the parietal and occipital position, and the temporal area. Conversion to oxygen saturation values revealed a difference of up to 13.4% in oxygen saturation between the forehead and the occipital area.Conclusion Assuming that the arterial blood oxygen saturation did not change substantially, our findings indicate that in reflectance pulse oximetry there is no unique relation between R/IR and arterial oxygen saturation. The differences in reflectance pulse oximetry at the various sites are explained by differences in optical properties (scattering and absorption) of the tissue underneath the sensor. These will affect the red and infrared light reaching the detectors in a different way, and consequently R/IR changes. Because during intrapartum monitoring exact positioning of the sensor on the fetal head is usually impossible, the accuracy of fetal reflectance pulse oximetry is impaired.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 184 (1959), S. 991-992 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We used thermistor catheters of the Delaunois type for recording velocity patterns rather than for measuring flow rates in the heart and large vessels. The dynamic response characteristics of the thermistor catheter had to be considerably improved in order to make it suitable for recording the ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 237 (1972), S. 149-150 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] An experimental technique for in vivo measurements of O2 dissociation curves is described. This allows rapid determination of Po2 and ...
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 35 (1957), S. 356-358 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Die spektrophotometrische Methämoglobinbestimmung (Messung bei 540 und 525 mµ) wird, durch Gebrauch von 0,1%igem NH3 für die 200fache Verdünnung der Blutproben, bei hohen Methämoglobinkonzentrationen gestört von der Bildung geringer Mengen alkalischen Hämatins. Die Störung läßt sich durch Einführung einer schwächeren NH3-Lösung (0,9 m.aeq/l) beheben. Eine Methämoglobinbestimmung (Messung bei 558 und 523 mµ) mit sehr kleiner Schichtdicke (d=0,013 cm) wurde entwickelt und mit der ersten Methode verglichen.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Es werden einige spektrophotometrische Methoden angegeben für die Bestimmung der wichtigsten Hämoglobinderivate im menschlichen Blute. Beschrieben werden Verfahren für die Bestimmung: 1. der Hämoglobintotalkonzentration, 2. der Sauerstoffsättigung des Hämoglobins, 3. der partiellen Kohlenoxydhämoglobinkonzentration, 4. der partiellen Methämoglobinkonzentration. Die Verfahren sind einfach und zuverlässig.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1432-2013
    Keywords: Gas exchange in the lung ; Arterial pH ; Disequilibrium pH ; Carbonic anhydrase inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract As a contribution to solving the problem of pH disequilibrium in arterial blood, the results of two modes of gas exchange in the lung have been calculated using an equilibrium state model of the blood. In both cases the HCO3 −/Cl− exchange was assumed to occur after the gas exchange in the pulmonary capillaries. When the gas exchange was assumed to be dependent on intra-erythrocytic carbonic anhydrase. the plasma pH in the arterial blood increased. Whe plasma and erythrocytes were assumed to equilibrate separately with the alveolar gas due to presence of extra-erythrocytic carbonic anhydrase, plasma pH in the arterial blood decreased. In each case there was a slight increase inpCO2 after the blood had left the pulmonary capillaries.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1432-2013
    Keywords: Cardiac output ; In-vivo CO2 bufferline ; CO2 equilibration ; Metabolic acidosis ; Respiratory acidosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract While maintaining the arterial CO2 tension constant near the normal level of the dog (4.3 kPa), we studied the influence of decreasing cardiac output on both the arterial and mixed-venous blood acid-base status in anaesthetized, artificially ventilated dogs. Cardiac output was manipulated by applying positive end-expiratory pressure (PEEP), and by β-adrenergic blockade to suppress a compensatory heart rate response. The systemic vascular response was attenuated by α-adrenergic blockade. Metabolic rate remained virtually unchanged when cardiac output decreased. Under these conditions a fall in cardiac output led to a shift of the arterial acid-base status in the direction of a metabolic acidosis. The changes occurring in the mixed-venous blood resembled those of an in-vivo CO2 bufferline, with the shift being such as if a respiratory acidosis was developing.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1432-2013
    Keywords: impedance cardiography ; electrical conductivity of blood ; stroma-free haemoglobin solution ; thoracic electrical impedance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In an anaesthetized dog an exchange transfusion was carried out with stroma-free haemoglobin solution. The total circulating blood volume was kept constant. The heart-synchronous changes in the thoracic electrical impedance (Z o ) were measured before and after the exchange transfusion.Z o consists of a parallel connection of a tissue impedance (Z t ) and a blood impedance (Z b ). With the aid of this model forZ o the relative variations inZ b (ΔZ b /Z b ) were calculated from the relative variations inZ o (ΔZ o /Z o ). The marked decrease of ΔZ b /Z b during the experiment can only be explained by the fact that apart from the heart-synchronous changes in vascular volume the impedance changes are also caused by flow-dependent changes in the electrical conductivity of blood caused by variations in orientation of the erythrocytes.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...