Biomedical subjects

Hans Ulrich Bucher

Publications and source records attributed to Hans Ulrich Bucher.

3 recordsLinked to original sources

PubMed2003

Slow blood sampling from an umbilical artery catheter prevents a decrease in cerebral oxygenation in the preterm newborn.

OBJECTIVE: Blood sampling from an umbilical artery catheter (UAC) placed in a high position (thoracal 6-9) has the potential to produce clinically significant changes in cerebral blood flow and, thereby, in cerebral oxygenation. This may contribute to cerebral impairment in preterm newborn infants. Therefore, we set up a study to determine the effects of different sampling speeds through a UAC on cerebral oxygenation in preterm infants. METHODS: Thirty pairs of measurements were conducted on 20 preterm infants (median gestational age: 30.14 weeks; median birth weight: 1170 g). For each infant, 2 blood samplings (both 2.3 mL, including flush volume) through the UAC in high position were taken at 2 different speeds (20 and 40 seconds) in alternating sequence. Cerebral oxygenation was measured noninvasively by near-infrared spectroscopy. Concentration changes in cerebral oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb), along with the tissue oxygenation index (TOI; O2Hb/[O2Hb + HHb] x 100), were recorded while blood was withdrawn and subsequently reinfused. RESULTS: A significant decrease in O2Hb and TOI occurred during blood sampling within 20 seconds (median DeltaO2Hb: -1.5 micromol/L; range: -4.1-2.3; median DeltaTOI: -0.6%; range: -6.3-2.3), whereas HHb increased (median DeltaHHb: 0.4 micromol/L, range: -1.1-3.9). No significant change was found in O2Hb, HHb, and TOI when sampling time was extended to 40 seconds. CONCLUSION: Our results show that blood withdrawal over 20 seconds from a UAC in high position significantly decreases cerebral O2Hb and TOI in preterm infants. Prolonging sampling time to 40 seconds can prevent this phenomenon.

Blood Specimen Collection↗

PubMed2002

Liver tissue oxygenation as measured by near-infrared spectroscopy in the critically ill child in correlation with central venous oxygen saturation.

OBJECTIVE: To evaluate the clinical usefulness of near-infrared spatially resolved spectroscopic quantitative assessment of liver tissue oxygenation for simple, non-invasive estimation of global tissue oxygenation in critically ill neonates and children. DESIGN: Prospective observational clinical study. SETTING: A tertiary multidisciplinary neonatal and paediatric intensive care unit (23 beds). PATIENTS: One hundred neonates and children consecutively admitted to the paediatric intensive care unit. MEASUREMENTS AND RESULTS: Near-infrared spectroscopic single-point assessment of liver tissue oxygenation index (TOI(Liver)) was compared with global tissue oxygenation as measured by central venous oxygen saturation (SvO(2)) and derived haemodynamic parameters. Data were compared using linear and multiple regression analysis. Overall correlation between TOI(Liver)and SvO(2) was good ( r=0.72, p<0.0001). Multivariable regression revealed that SvO(2) alone explained 51% of the observed variance of TOI(Liver). However, our data demonstrated large inter-individual differences between SvO(2) and TOI(Liver) values. CONCLUSION: Near-infrared spatially resolved spectroscopic quantitative measurement of liver tissue oxygenation correlates well with SvO(2) in critically ill neonates and children. Large inter-individual SvO(2) to TOI(Liver) differences may prevent its use for non-invasive single-point estimation of global tissue oxygenation. Further clinical studies are required to validate the method with other regional and global haemodynamic parameters and to evaluate its clinical use for continuous non-invasive haemodynamic monitoring.

Catheterization, Central Venous↗

PubMed2002

Growth, developmental milestones and health problems in the first 2 years in very preterm infants compared with term infants: a population based study.

UNLABELLED: The outcome of very preterm infants varies widely from centre to centre and from country to country. The aim of this study was to evaluate growth, developmental milestones and post-discharge morbidity of infants born before 32 weeks of gestation in Switzerland. A questionnaire was sent to the parents of 456 survivors born in 1996. A total of 309 (68%) parents responded and their infants were matched with 309 control infants born at term. At the corrected age of 24 months, the very preterm infants had significantly lower weight (-1.0 z-scores), lower length (-1.23 z-scores), and lower head circumference (-.64 z-scores). Very preterm infants were reported to eat with a spoon later than those born at term (50% at 7.5 months corrected for prematurity versus 10 months. P<0.001), to drink later out of a cup (50% at 16.5 months versus 13.5 months, P=0.03) and to walk later independently (50% at 14.5 months versus 13.5 months, P=0.04), whereas timing of sitting unsupported was no different (50% at 7.4 months versus 7.2 months, P=0.9). Of very preterm infants, 16% were not able to walk at least three steps unsupported at 18 months after term which puts them at an increased risk for cerebral palsy. Some 35% of very preterm infants had to be readmitted to hospital during the first 24 months compared with 20% of control infants born at term (P<0.05). There was no difference between very preterm and term infants in respect to episodes of fever > 38.5 degrees C, episodes of coughing > 3 days and treatment with antibiotics. CONCLUSION: these data based on a national survey allow to quantify growth retardation, developmental delay and post-discharge health problems within the first 2 years in preterm infants born before 32(0)/7 weeks.

Child Development↗