Biomedical subjects

Helmut Küster

Publications and source records attributed to Helmut Küster.

5 recordsLinked to original sources

PubMed2006

Bilirubin measurement for neonates: comparison of 9 frequently used methods.

OBJECTIVE: High blood concentrations of bilirubin are toxic to the brain and may cause kernicterus. Therefore, determination of bilirubin levels is performed for many newborns, and several different methods are available. We compared 9 frequently used methods for bilirubin determination among newborns under routine conditions, to define their sequence of use. METHODS: In a prospective study, bilirubin concentrations were determined with 9 different methods, ie, 3 skin test devices, 3 nonchemical photometric devices (including 2 blood gas analyzers), and 3 laboratory analyzers. RESULTS: A total of 124 samples were obtained. All 3 laboratory methods showed very strong correlations with each other, and their means were used as comparison values. To these comparison values, the skin test devices had correlation coefficients between 0.961 and 0.966, and the nonchemical photometric devices between 0.980 and 0.994. Bland-Altman plots demonstrated good agreement with the comparison values for all nonchemical photometric devices. All skin test devices and 1 nonchemical photometric device underestimated bilirubin levels, particularly at high concentrations. CONCLUSIONS: In the routine care of newborns, the first method for bilirubin testing should be a skin test. If the skin test result exceeds 200 micromol/L and other analytes are to be determined with a nonchemical photometric device, then bilirubin can be included in this analysis and the result trusted up to 250 micromol/L. If the skin test result exceeds 200 micromol/L and only bilirubin concentrations are needed, then a standard laboratory method is the first choice, to avoid repeated blood sampling. Bilirubin concentrations from nonchemical photometric devices that exceed 250 micromol/L should be confirmed with standard laboratory methods.

Bilirubin↗

PubMed2006

Genetic polymorphisms of hemostasis genes and primary outcome of very low birth weight infants.

BACKGROUND: Recent investigations have reported an influence of thrombophilic mutations and antithrombotic risk factors with development of intraventricular hemorrhage. It was our objective for this study to investigate the impact of genetic polymorphisms of hemostasis genes on the primary outcome measures of sepsis, bronchopulmonary dysplasia, intraventricular hemorrhage, and periventricular leukomalacia in a large cohort of very low birth weight infants. METHODS: There were 586 very low birth weight infants enrolled prospectively in a multicenter trial between September 2003 and July 2005, and an additional 595 very low birth weight infants, who had been recruited in a previous prospective trial, were studied. DNA samples were taken by buccal swab, and genotypes of factor V Leiden mutation, prothrombin G20210A mutation, the factor VII-323 del/ins polymorphism, and the factor XIII-Val34Leu polymorphisms were determined by polymerase chain reaction and restriction enzyme digestion. RESULTS: In contrast to data published previously, the frequency of intraventricular hemorrhage or periventricular leukomalacia was not significantly influenced by any of the genetic variants tested. Carriers of the factor XIII-Val34Leu polymorphism, however, had a higher sepsis rate and a longer period of hospital care compared with noncarriers. The factor VII-323 del/ins polymorphism was found to be a potential protective factor against bronchopulmonary dysplasia. CONCLUSIONS: We could not confirm previously reported associations of hemostasis gene variants and development of intraventricular hemorrhage in very low birth weight infants. To better understand gene-disease associations in very low birth weight infants, the prospective development of large-scale cohorts with well-defined phenotypes and corresponding DNA samples is essential.

3' Untranslated Regions↗

PubMed2006

The Apgar score.

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Apgar Score↗

PubMed2005

The Accutrend sensor glucose analyzer may not be adequate in bedside testing for neonatal hypoglycemia.

UNLABELLED: The aim of this prospective observational study was to compare a bedside test with the reference laboratory method in routine postnatal glucose monitoring. Term newborns with increased risk or clinical signs of hypoglycemia were screened with a bedside test. In case of a glucose value below 2.25 mmol/L, a second blood sample was taken and a duplicate glucose measurement done in the laboratory using a bedside test (Accutrend sensor) and the reference laboratory method (hexokinase method) at the same time and from the same sample. From 110 term newborns, 122 blood samples were obtained for duplicate measurements (median 1.69 mmol/L, SD 0.45 mmol/L). Of these 122, Accutrend correctly identified 97% as being <2.25 mmol/L by the laboratory method. A Bland-Altman plot revealed a mean underestimation of the Accutrend of only -0.09 mmol/L. However, due to high scattering, the maximal over- and underestimation was 0.89 and 1.39 mmol/L, respectively. Only 75% of the results from the Accutrend were within +/-20% of the result of the laboratory method. If the cut-off for low glucose concentrations was set 0.6 mmol/L higher for the bedside test as compared to the laboratory method, all patients except one would have been correctly identified as hypoglycemic. CONCLUSION: When using the Accutrend sensor, single infants with even marked hypoglycemia might be missed. Some delay in receiving accurate measurements might be more helpful for clinical decisions and long-term outcome than immediate but potentially misleading results.

Blood Glucose↗

PubMed2005

Evaluation of the Glucometer Elite XL device for screening for neonatal hypoglycaemia.

UNLABELLED: To prevent persistent neurodevelopment and physical growth deficits in neonatal care, it is mandatory to determine blood glucose levels as quickly and precisely as possible, preferably using micro-methods. However, most commercially available instruments have not been validated and approved for this purpose. The aim of this study was to validate the Glucometer Elite XL, a newly developed device for point-of-care testing (POCT). In samples from 869 newborn infants, glucose levels were simultaneously measured by the Glucometer Elite XL in whole blood and by an accepted clinical laboratory method in haemolysed blood using the ECA 2000 device. An acceptable method agreement was found between the POCT and the ECA 2000 method (mean difference 0.013 mmol/l, SD 0.69). As determined by regression analysis (Passing-Bablok), the slope was 1.086 with a y-intercept of -0.4 mmol/l ( r =0.959, P <0.05). The differences between measurement pairs of both assays versus the haematocrit were negligible. With a cut-off for hypoglycaemia at 2.6 mmol/l glucose in haemolysed blood, the sensitivity of the POCT device was 0.63 and specificity was 0.98. Raising the cut-off of the Glucometer Elite XL to 3.2 mmol/l, the sensitivity and specificity incremented to 1.0 and 0.89, respectively. CONCLUSION: The Glucometer Elite XL instrument can be recommended for point-of-care blood glucose measurement in newborn infants if its character as a screening method is taken into account. To compensate deviating results, we advise to shift its cut-off for hypoglycaemia recognition to a safe threshold of 3.2 mmol/l. However, hypoglycaemia has to be confirmed by a valid glucose measurement in the clinical laboratory.

Blood Chemical Analysis↗