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Biomedical subjects

W Mindt

Publications and source records attributed to W Mindt.

5 recordsLinked to original sources
PubMed1979

An electrochemical sensor for continuous intravascular oxygen monitoring.

The intravascular PO2 sensor described in this paper essentialal routine use. The small dimensions of the sensor permit its introduction into the vessel through a conventional guiding catheter size 4 F or larger. With 5 F catheters, simultaneous blood sampling and/or blood pressure measurement is possible. The accuracy and stability of the sensor permit continuous PO2 measurement to be performed over several days.

Animals↗
PubMed1978

Principle and characteristics of the ROCHE tissue pH electrode.

A miniaturized probe for continuous measurement of tissue (interstitial fluid) pH is described. The electrode design follows closely the concept described by Stamm and co-workers. The pH sensitive tip has a length of 1 mm and is made of a Li-Ba-Si glass of low electrical resistivity. The reference electrode with a capillary type liquid junction is an integrated part of the electrode assembly. This paper summarizes the important design features of the electrode and describes its in vitro characteristics.

Electrodes↗
PubMed1978

Reliability of cutaneous oxygen measurement by skin sensors with large-size cathodes.

The oxygen partial pressure may be measured cutaneously by directly heated PO2 sensors attached to the surface of the skin. The use of a large-size cathods (diameter 4 mm) allows one to obtain an average PO2 value over a sufficiently large skin area. The permeability of the membrane for oxygen has to be kept low to prevent a disturbance of the oxygen profile in the cutaneous tissue as a result of the oxygen consumption of the sensor. When using of 6 micrometer Mylar membrane, the current can be limited by the diffusion of oxygen through the membrane and is a measure of the arterialized cutaneous PO2. One effect of using membrane of low permeability is that the response time of the sensor is long (tau 90% = ca 45 sec). The reliability of correctly reproducing cPO2 variations by sensors having different response times may be evaluated by determining the transfer function of the membrane which allows the calculation of the frequency characteristics for various membranes. The cutaneous tissue layer also acts as a filter for rapid PO2 fluctuations. The characteristic of this filter is essentially similar to that of a "slow" membrane such as Myler 6 micrometer. The information gained by using a "rapid" membrane such as Telfon 13 micrometer is negligible. In 490 comparative measurements in newborns performed with sensors heated to 44 degree C, the correlation between arterial PO2 and cutaneously measured PO2 is significant (correlation coefficient = 0.934) and the regression line does not deviate significantly from the identity line.

Blood Gas Analysis↗
PubMed1977

Skin sensors for continuous oxygen monitoring of newborns.

Since the introduction of the technique of cutaneous1 pO2 measurement by directly heated oxygen sensors in 1972, the clinical applications and limitations of this new method have been extensively investigated. The method has proven to be of particular value in monitoring of high risk newborns as it affords the possibility of continuously monitoring clinically significant changes in the oxygenation state of the newborn. In this paper, methodological criteria for the assessment of the reliability of cutaneous pO2 monitoring are discussed. Particular consideration is given to the oxygen and temperature profiles in the vicinity of the skin sensor and to the response time of the sensor. In view of the fact that the cutaneous pO2 reflects the oxygen partial pressure at the level of arterialized cutaneous tissue, the method has limitations if it is used as an indirect determinant of arterial pO2.

Blood Gas Analysis↗