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O Siggaard-Andersen

Publications and source records attributed to O Siggaard-Andersen.

At least 91 records · Page 5Linked to original sources
PubMed1982

[Enzymatic lecithin determination in amniotic fluid for antepartal diagnosis of lung maturity - a multi-center study (author's transl)].

A new test-combination for the enzymatic determination of lecithin in amniotic fluid for the assessment of fetal lung maturity has been developed by Boehringer Mannheim. This test was evaluated by 12 hospitals and has been compared with the L/S ratio, the foam-test or the densitometric determination of lecithin. The assay is based on the hydrolysis of lecithin by phospholipase C which starts an enzymatic chain reaction in which NADH consumption if measured photometrically. The intra- and interassay precision were characterized by CV values below 10%. Average recoveries of lecithin were 95-102%. It is recommended to centrifuge the samples (10 min, 700 g) and to start the analysis as soon as possible after receipt of the specimen. The total amount of time required is 2 hours for a single determination. Batches of up to 10 samples require little extra time. An opened test-combination can be used for a maximum of 30 single determinations. Comparison of the quantitative enzymatic lecithin determination with other methods showed that the critical value for lecithin is 5.0 mg/100 ml. Above 5.1 mg/100 ml no case respiratory distress syndrome was observed. The good precision accuracy and the simple handling make the enzymatic lecithin determination suitable for routine use.

Amniotic Fluid↗
PubMed1981

Plasma ionized calcium in the critically ill on total parenteral nutrition.

Eight patients were monitored three times daily for 3 consecutive days. Plasma calcium fluctuated slightly, whereas phosphate varied more and in two patients fell below 0.08 mmol/I. Necessary calcium and phosphate supply for adults was estimated to be 0.15 and 0.25 mmol per kg body mass per day, respectively. Plasma ionized calcium could be estimated form total calcium, albumin and pH with a standard deviation of 0.05 mmol/l. This is 5 times higher than by direct measurement with a new combined pH-pCa electrode system.

Adult↗
PubMed1980

International Federation of Clinical Chemistry scientific committee expert panel on pH and blood gases (EPpH) and International Union of Pure and Applied Chemistry division of clinical chemistry commission on quantities and units in clinical chemistry (CQUCC). Document stage 2, draft 1 (1979-10-10) with a view to a recommendation. Physico-chemical quantities and units in clinical chemistry with special emphasis on activities and activity coefficients.

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Chemical Phenomena↗
PubMed1980

International Federation of Clinical Chemistry, Scientific Committee Expert Panel on pH and blood gases (EPpH) and International Union of Pure and Applied Chemistry Division of Clinical Chemistry Commission on Quantities and Units in Clinical Chemistry (CQUCC). IFCC Document stage 2, Draft 1; 1979-10-10 with a view to a Recommendation. Physico-chemical quantities and units in clinical chemistry with special emphasis on activities and activity coefficients.

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Blood Gas Analysis↗
PubMed1978

Measurement of free calcium ion in capillary blood and serum.

We describe a new calcium ion-selective electrode for measurement of the substance concentration of free calcium ion [Ca2+] in the plasma phase of whole blood and in serum at 37 degrees C. A sample volume of 50 microliter suffices to obtain simultaneous values of pH and [Ca2+]. We found the within-series analytical standard deviation for serum to be 0.013 mmol/litre (CV, 1.1%) and day-to-day precision to be 0.022 mmol/litre (CV, 1.7%). The reference interval for [Ca2+] (at pH 7.40) in serum was found to be 1.184 +/- 0.054 mmol/litre (2 SD) from measurements on sera from 121 healthy blood donors. Measurements on capillary blood from 29 healthy volunteers gave a mean (+/- 2 SD) value for [Ca2+] (at pH 7.40) of 1.22 +/- 0.072 mmol/litre.

Bicarbonates↗
PubMed1977

Stoichiometric concentration and chemical potential.

It has been recommended to use SI units in clinical chemistry. A consequence of this is that pH is reported as the excess chemical potential (or standard chemical potential) of hydrogen ions with the unit kJ/mol. On the basis of the excess chemical potential of H+ it is possible to calculate the hydrogen ion concentration in the system = the equilibrium concentration of H+ = the concentration of free H+. This quantity must be clearly distinguished from the stoichiometric concentration of H+ = the excess concentration of total H+, which indicates the amount of added or removed H+. The latter quantity with opposite sign has been called the excess concentration of base, but the designation "stoichiometric concentration of H+" seems to be more logical. The general principles for description of a component in a chemical system are based on (1) an extensive quantity (the stoichiometric amount of substance), and (2) an intensive quantity (the excess chemical potential); the product of these has the dimension of energy.

Acid-Base Equilibrium↗
PubMed1977

The van Slyke equation.

The Henderson-Hasselbalch equation has always occupied a central place in the description of the acid-base status of the blood. An equation of similar importance is the equation for the CO2 equilibration curve of blood in vitro. It is proposed to name this the Van Slyke equation: a - 24.4 = - (2.3 X b + 7.7) X (c - 7.40) + d/(1 - 0.023 X b), where a = bicarbonate concentration in plasma/(mmol/l), b = hemoglobin concentration in blood/(mmol/l), c = pH of plasma at 37 degrees C, d = base excess concentration in blood/(mmol/l). These two equations provide an arithmetic algorithm for calculation of the various acid-base variables of the blood after measuring the pH, the pCO2, and the hemoglobin concentration.

Acid-Base Equilibrium↗
PubMed1977

Experiences with a new direct-reading oxygen saturation photometer using ultrasound for hemolyzing the blood.

The new oxygen saturation meter (OSM2, Radiometer A/S, Copenhagen) is fully automatic and measures the oxygen saturation and the hemoglobin concentration of whole blood or packed red cells. Volume requirement 20 mul, time 40 s. The blood is hemolyzed directly in the capillary cuvette by means of ultrasound generated piezo-electrically. The instrument measures the absorbance at wave lengths of 505 nm and 600 nm. Absorbance range 0-3. The results are calculated electronically and appear in digital display. Other applications are (1) determination of the oxygen affinity of the hemoglobin (P50) after equilibrating the blood with a known pO2 or after measuring the pO2 in the blood sample, (2) determination of carboxyhemoglobin after complete reduction of the hemoglobin by means of dithionite, (3) determination of methemoglobin after complete oxygenation of the blood.

Autoanalysis↗