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Biomedical subjects

P Tuchschmid

Publications and source records attributed to P Tuchschmid.

7 recordsLinked to original sources
PubMed1989

Oxygen affinity of haemoglobin modulates cerebral blood flow in premature infants. A study with the non-invasive xenon-133 method.

Low cerebral blood flow (CBF) is thought to cause ischaemic brain lesions in premature infants, but a normal outcome has also been observed. Low oxygen affinity of haemoglobin and high arterial oxygen content, independently, reduce CBF under normal, physiological conditions. Transfusions lower the amount of fetal haemoglobin [HbF] and therefore the oxygen affinity of premature babies. In 47 premature babies (range of gestational age 25-34 weeks, birthweight 740-1370 g), CBF was measured with the i.v. Xenon 133 method on days 1, 3 and 7. The relative amount of fetal haemoglobin [HbF] was used as a marker of oxygen affinity of haemoglobin and the haematocrit as representing the arterial oxygen content. A significant influence of [HbF] on CBF was found on days 1, 3 and 7 in ultrasonographically normal babies (n = 13). In babies with subependymal and/or intraventricular haemorrhage (n = 15), this correlation was significant only on day 3 and in those with abnormal intraparenchymal echodensities (n = 19) only on day 7. The correlation between haemoglobin concentration and CBF was not significant. Multiple regression analysis showed a significant influence of [HbF] on CBF independent of haematocrit, pCO2 and blood pressure. It appears that, after blood transfusion, normal babies, and to a lesser extent those with haemorrhages are able to lower their CBF according to the actual oxygen affinity of blood. However, low CBF (less than 10 ml/100 g/min) in non-transfused babies was often associated with later development of cystic periventricular leukomalacia.)

Blood Gas Analysis↗
PubMed1987

A simple method for HbF analysis.

Spectrophotometric methods with CO-oxymeters for measurements of carboxyhemoglobin and/or oxygen saturation in human blood include a systematic error depending on the percentage of fetal hemoglobin. It is of clinical importance to estimate the fetal hemoglobin to correct HbCO and SO2 values respectively. The described method is simple and less time consuming than conventional methods like HPLC or electrophoresis. The two measurements of oxy- and carboxyhemoglobin in the same blood sample with different oxygen saturation are needed for the estimation of the HbF and can be performed, including the deoxygenation procedure, in about 40 minutes.

Adult↗
PubMed1987

Effect of vitamin E substitution in very low birth weight infants. Active and inactive forms of vitamin E in plasma and red cells after moderate intramuscular supplementation.

Vitamin E supplementation was investigated in 38 very low birth weight infants after intramuscular substitution with two doses of 25 mg given on the 1st and 3rd day of life. Plasma and red cell concentrations of the biologically inactive tocopherol acetate and the active tocopherol were followed during the first month of life. Plasma levels of this substitution regime were compared with recent clinical studies. Although the applied dose was low in comparison to other studies, the levels obtained exceed the critical concentration of 12 microM which was reported to prevent retinopathy. Concentrations associated with side effects (84 microM) were found in nearly 50% of the babies but only for short duration (24 h). In more than 80% of the infants, biologically inactive tocopherol acetate was detected in plasma up to 1 day after substitution but not in red cells.

Erythrocyte Membrane↗