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Biomedical subjects

B Friis-Hansen

Publications and source records attributed to B Friis-Hansen.

At least 19 recordsLinked to original sources
PubMed1992

[Treatment of severe respiratory distress syndrome with surfactant].

The first Danish experience of treatment of the respiratory distress syndrome (RDS) in preterm infants with exogenous surfactant is described. Fifteen infants with birthweights of 645-1,865 g and gestational ages of 25-32 weeks, all receiving artificial ventilation with at least 60% oxygen for severe RDS, were treated with purified porcine surfactant (Curosurf) within the first 28 hours of life. Pulmonary function improved immediately in all of the infants. Four infants (27%) died, four (27%) developed bronchopulmonary dysplasia (pulmonary fibrosis) and two (13%) had late neurological sequelae. These preliminary results are considered to be promising and they are in complete agreement with the results of randomised, controlled investigations from abroad. Systematic registration is, however, still necessary.

Biological Products↗
PubMed1991

The relation between perinatal conditions and developmental outcome in low birthweight infants. Comparison of two cohorts.

We have compared the relations between perinatal conditions and developmental outcomes at age four years for two cohorts of children with birthweights 2,300 g or less, who did not develop cerebral palsy--one from Southeastern Wisconsin (children born 1975-76) and the other from Copenhagen (children born 1980-82). We examined the general effects of parental education and socioeconomic status, the use of Cesarean section, the degree of prematurity and neonatal complications on outcome. The methods of latent path structural analysis were used to form two models among 15 latent variables: one for children from Copenhagen and a similar model for children from Wisconsin. The impact of parental education and socioeconomic status was somewhat greater in Wisconsin. Several neonatal complications were related to outcome in Wisconsin: the early condition of the infant, use of a respirator, pneumothorax, and anemia/apnea. The only neonatal complication with a significant relation to outcome in Copenhagen was pneumothorax and to a much lesser degree major germinal layer haemorrhage. The degree of prematurity per se had a greater impact in Copenhagen. The use of Cesarean section and mechanical ventilation in the smallest infants was much more frequent in Denmark, but no association could be shown between this increased use and improved developmental outcome.

Child Development↗
PubMed1990

[Near infrared spectrophotometry--a non-invasive, continuous method for monitoring of cerebral status in newborn infants].

Hypoxic-ischaemic injury to the brain is the commonest cause of permanent neurodevelopmental disability in the very preterm and other children who survive after neonatal intensive care. Non-invasive techniques are therefore needed to examine the mechanisms of damage to the brain. Near infrared spectroscopy provides continuous cot-side information about cerebral oxygenation and metabolism in sick preterm infants by measurements of oxyhaemoglobin, deoxyhaemoglobin and oxidized cytokrom aa3. The cytokrome aa3 signal may, however, be artifactual due to interference from oxyhaemoglobin. Future investigations may clarify this problem.

Brain Damage, Chronic↗
PubMed1990

Vasoparalysis associated with brain damage in asphyxiated term infants.

The relationship of cerebral blood flow to acute changes in arterial carbon dioxide and mean arterial blood pressure (MABP) was determined during the first day of life in 19 severely asphyxiated term infants supported by mechanical ventilation. For comparison, 12 infants without perinatal asphyxia were also investigated. Global cerebral blood flow (CBF infinity) was determined by xenon 133 clearance two or three times within approximately 2 hours. During the cerebral blood flow measurement, the amplitude-integrated electroencephalogram and visual-evoked potential were recorded. Changes in arterial carbon dioxide pressure followed adjustments of the ventilator settings, whereas MABP fluctuated spontaneously. Arterial oxygen pressure and blood glucose concentration were in the normal range. Five of the asphyxiated infants had isoelectric electroencephalograms and died subsequently with severe brain damage. They had a high CBF infinity (mean 30.6 ml/100 gm/min) and abolished carbon dioxide and MABP reactivity. Lower CBF infinity (mean 14.7 ml/100 gm/min) and abolished MABP reactivity were found in another five asphyxiated infants with burst-suppression electroencephalograms in whom computed tomographic or clinical signs of brain lesions developed. The carbon dioxide reactivity was preserved in these infants. In the remaining nine asphyxiated infants without signs of central nervous system abnormality, carbon dioxide and MABP reactivity were preserved, as was also the case in the control group. We conclude that abolished autoregulation is associated with cerebral damage in asphyxiated infants and that the combination of isoelectric electroencephalograms and cerebral hyperperfusion is an early indicator of very severe brain damage.

Asphyxia Neonatorum↗
PubMed1990

Cerebral blood flow reactivity in spontaneously breathing, preterm infants shortly after birth.

In 18 spontaneously breathing, preterm infants (mean gestational age 30.3 weeks) cerebral blood flow (CBF) was investigated twice, 2 and 3 hours after birth when spontaneous changes in arterial carbon dioxide tension (PaCO2) and mean arterial blood pressure (MABP) were expected. Transcutaneous oxygen tension (TcO2) was kept normal by adjusting the inspiratory oxygen fraction. In 12 infants, plasma adrenaline and noradrenaline were constant throughout the study. Changes in CBF infinity (CBF infinity) were significantly related to changes in PaCO2 (p = 0.0001) whereas neither changes in MABP nor TcO2 reached a significant association to changes in CBF infinity (p = 0.67 and p = 1.0, respectively). The calculated CBF infinity -CO2 reactivity of 28.9% per kPa PaCO2 (95% confidence interval 16.1-43.0) is comparable to findings in older newborns and healthy adults. Only one of 18 infants developed germinal layer haemorrhage (grade I) in spite of the hypercapnic state which was observed during the first hours of life. Periventricular leucomalacia was not detected. It is suggested that the cerebral blood flow is well regulated within physiological variations of PaCO2 and MABP in the healthy, preterm newborn even shortly after birth.

Blood Gas Monitoring, Transcutaneous↗
PubMed1990

Carbon dioxide-related changes in cerebral blood volume and cerebral blood flow in mechanically ventilated preterm neonates: comparison of near infrared spectrophotometry and 133Xenon clearance.

Carbon dioxide-induced changes in near infrared spectrophotometry recordings were compared with changes in cerebral blood flow estimated by 133Xenon clearance (global cerebral blood flow (infinity)) at serial measurements in 24 mechanically ventilated preterm infants (mean gestational age 30.2 wk). In all infants, three measurements were taken at different arterial carbon dioxide tension levels (mean 4.4 kPa, range 2.1-7.8) obtained by adjustment of the ventilator settings. Mean arterial blood pressure changed spontaneously, whereas arterial oxygen tension was kept within normal range. At all wavelengths (904, 845, 805, and 775 nm), the OD increased at higher arterial carbon dioxide tension levels, indicating cerebral vasodilation. This conclusion was supported by conversion of the data to changes in oxygenated and deoxygenated Hb concentration. A parallel increase in cerebral blood volume index and global cerebral blood flow (infinity) was found (p less than 0.0001). The oxygenation level of cytochrome aa3 increased with increases in oxygen delivery (p less than 0.0001). This observation, however, may have been artifactual due to cross-talk between the oxidized cytochrome aa3 and the oxygenated Hb signals, as these signals were closely interrelated in the present experimental design. We suggest that near infrared spectrophotometry may be used for estimation of the cerebral blood volume index/cerebral blood flow-CO2 reactivity within a wide range of arterial carbon dioxide tension. Knowledge of the light path length would put this estimation on a quantitative basis.

Birth Weight↗
PubMed1990

Status at four years of age in 280 children weighing 2,300 g or less at birth.

To assess the functional ability in low birth weight children at age 4-5, 114 survivors with very low birth weight (VLBW) less than or equal to 1,500 g, 166 survivors with birth weight 1,501-2,300g (LBW), and 115 comparison children with normal birth weight (NBW) were enrolled in a follow-up study. Twenty-four (21%) VLBW and 11 (6.6%) LBW-children had major clinical abnormalities compared to 1 (0.9%) of the NBW children. Twenty-two percent of the VLBW-children were below the 3rd-centile for height and weight. Fewer VLBW than LBW-children were neurologically and ophthalmologically normal. Even after exclusion of the handicapped children, the LBW as well as the VLBW children scored significantly lower than the NBW children in the McCarthy Scales of Children's Abilities, most markedly in the motor and perceptual performance scales. A simple test using grooved pegs clearly demonstrated the poor visual-motor integration in VLBW and LBW children. A marked difference between the NBW and the two LBW groups was seen in a qualitative evaluation of motor performance. Only 5% of VLBW children scored at or above the median for the NBW in all of three fields: general cognitive, motor performance, and pegboard, as opposed to 11% of LBW and 18% of NBW children. Neither sex, age corrected for prematurity, nor psycho-social background factors explained the differences between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗
PubMed1990

Increased cerebral blood flow and plasma epinephrine in hypoglycemic, preterm neonates.

Cerebral blood flow, plasma epinephrine, and plasma norepinephrine were measured in 25 spontaneously breathing, preterm neonates (mean gestational age 30.4 weeks) 2 hours after birth, during a routine screening for low blood glucose levels. Increased cerebral blood flow and plasma epinephrine values were observed when blood glucose levels were low, whereas plasma norepinephrine was constant throughout the blood glucose range. Hypoglycemia (defined as blood glucose concentration less than 30 mg/dL) was found in 13 neonates who were treated with intravenous glucose and milk enterally. Blood glucose levels were normal in the remaining 12 control neonates who received milk by a gastric line. Approximately 30 minutes after treatment with intravenous glucose and/or milk, cerebral blood flow had decreased by a mean of 11.3% in the 13 hypoglycemic neonates but was still 37.5% higher than cerebral blood flow in the control neonates despite normalization of plasma epinephrine concentration. Mean arterial blood pressure and blood gas values were identical between groups throughout the investigation. It is suggested that a normal coupling between cerebral metabolic demands and flow is present in very preterm neonates and that epinephrine may play a role in the cerebral hyperperfusion. Although none of the neonates had clinical signs of hypoglycemia, the data suggest that counterregulatory mechanisms are invoked when blood glucose values are less than 30 to 45 mg/dL.

Blood Glucose↗
PubMed1989

Heterogeneity of cerebral vasoreactivity in preterm infants supported by mechanical ventilation.

The reaction of cerebral blood flow to acute changes in arterial carbon dioxide pressure (PaCO2) and mean arterial blood pressure was determined in 57 preterm infants supported by mechanical ventilation (mean gestational age 30.1 weeks) during the first 48 hours of life. All infants had normal brain sonograms at the time of the investigation. In each infant, global cerebral blood flow was determined by xenon-133 clearance two to five times within a few hours at different levels of PaCO2. Changes in PaCO2 followed adjustments of the ventilator settings. Arterial oxygen pressure was intended to be kept constant, and mean arterial blood pressure fluctuated spontaneously between measurements. The data were analyzed by stepwise multiple regression, with changes in global cerebral blood flow, PaCO2, mean arterial blood pressure, and postnatal age or intracranial hemorrhage used as variables. In infants with persistently normal brain sonograms, the global cerebral blood flow-carbon dioxide reactivity was markedly lower during the first day of life (mean 11.2% to 11.8%/kPa PaCO2) compared with the second day of life (mean 32.6/kPa PaCO2), and pressure-flow autoregulation was preserved. Similarly, global cerebral blood flow-carbon dioxide reactivity and pressure-flow autoregulation were present in infants in whom mild intracranial hemorrhage developed after the study. In contrast, global cerebral blood flow reactivity to changes in PaCO2 and mean arterial blood pressure was absent in infants in whom ultrasonographic signs of severe intracranial hemorrhage subsequently developed. These infants also had about 20% lower global cerebral blood flow before hemorrhage, in comparison with infants whose sonograms were normal, a finding that suggests functional disturbances of cerebral blood flow regulation. Several perinatal factors were tested, but only birth after abruptio placentae was related to subsequent periventricular hemorrhage (p = 0.037).

Age Factors↗
PubMed1988

Compensatory increase of CBF in preterm infants during hypoglycaemia.

Cerebral blood flow (CBF00) was investigated in 24 preterm infants (mean 30.8 weeks of gestational age) by use of intravenous 133-Xe clearance technique while screening simultaneously for low blood glucose after birth (mean 3 hours). CBF was significantly increased in 10 infants with blood glucose lower than 1.7 mmol/l compared to normoglycaemic infants and tended to decrease rapidly after treatment. Nine of the 10 hypoglycaemic infants were monitored for cerebral function. Well defined visual evoked cortical potentials were elicitable in all and the aEEG was not less active during the hypoglycaemic episode. Therefore, it is suggested that compensatory increase of CBF may have supported the cerebral metabolism during uncomplicated hypoglycaemia.

Blood Gas Monitoring, Transcutaneous↗
PubMed1987

Pulse oximetry versus transcutaneous pO2 in sick newborn infants.

A pulse oximeter (Ohmeda Biox 3700) and two transcutaneous systems (Radiometer TCM3) were applied simultaneously to 18 newborn infants with respiratory insufficiency. All infants had either an umbilical catheter placed in the mid thoracic aorta or a radial artery catheter. The average monitoring time was 2 hours. Arterial blood pO2, pCO2 and pH (Radiometer ABL300), arterial sO2, HbCO and metHb (Radiometer OSM3), erythrocyte 2,3 DPG concentration, and fetal hemoglobin fraction (alkali denaturation kinetic method) were measured. Using arterial sO2 and pO2 as reference, the analytical bias of pulse oximetry (-0.5 +/- 1.0%, mean +/- 1 SD) corresponded in magnitude, when converted to pO2, to that of transcutaneous - pO2 (0.6 +/- 1.4 kPa for combined O2-CO2 electrode and -0.1 +/- 2.3 kPa for single O2 electrode). Transcutaneous pCO2 showed the smallest bias (0.3 +/- 0.3 kPa). Both pulse oximetry and transcutaneous pO2 electrodes were good as trend monitors detecting rapid changes in the infants' oxygenation status. The pulse oximeter offers certain advantages in not requiring calibration or heating. The variations in the levels of fetal hemoglobin fraction (44 to 97%), pH (7.27 to 7.49), pCO2 (3.3 to 6.8 kPa) and 2,3 diphosphoglycerate concentration (1.6 to 5.9 mmol/l) between the infants studied, resulted in a variable pO2-sO2 relation (p50 2.5 to 3.5 kPa). This presents difficulties in interpreting sO2 values in sick newborn infants, and we therefore recommend caution in using a pulse oximeter to apply strict limits for avoiding hypoxia and hyperoxia in this population.

Blood Gas Monitoring, Transcutaneous↗
PubMed1987

The measurement of TcPO2 and TcPCO2 in newborn infants at 44 degrees C, 42 degrees C and 37 degrees C after initial heating to 44 degrees C.

Prolonged measurement of the transcutaneous O2 and CO2 tension at an electrode temperature of 44 to 45 degrees C often causes a second degree burn of the underlying skin. To avoid this, we compared the readings at 44 degrees C, 42 degrees C and 37 degrees C, after 2 hours pre-heating of the skin by the electrodes at 44 degrees C. In order to eliminate the electrodes' own temperature coefficients, electrodes with a built-in temperature correction were used. The changes observed therefore represent changes in the O2 and CO2 tension in the skin. The obtained values were compared to repeated arterial samples. We found that the TcPO2 and TcPCO2 values obtained at 42 degrees C and 37 degrees C were lower than those obtained at 44 degrees C, but when corrected for the in vivo temperature coefficients previously found by us the TcPO2 values at 42 were quite similar to the 44 degrees C values, whereas the 37 degrees values remained lower. TcPCO2 values at 44, 42 and 37 degrees were all similar. The temperature coefficient of PO2 was calculated to be 0.044 +/- 0.008 and for TcPCO2 as 0.049 +/- 0.007.

Blood Gas Monitoring, Transcutaneous↗
PubMed1985

Blood pressure responses to care procedures in ventilated preterm infants.

Responses of mean aortic blood pressure to sequences of routine care procedures in 22 ventilated, preterm infants were studied daily for the first 3 days of life. In the first 11 infants standard care procedures were used, whereas the next 11 infants were preoxygenated by a preceding 10% increase in inspired oxygen concentration; in these infants, chest physiotherapy was entirely omitted while the frequency of endotracheal suctioning was reduced. A total of 259 blood pressure responses were recorded. In general, responses were biphasic, consisting of an initial blood pressure drop followed by a greater blood pressure rise of longer duration. Baseline blood pressure, as well as the minimum and maximum blood pressure during the care procedures, increased with gestational age and with postnatal age. The blood pressure drop was most pronounced in the infants requiring the most intensive ventilatory support and was reduced by modifying the care procedures. The blood pressure rise was the least in the infants receiving pancuronium and phenobarbitone. Eight infants, 4 in each group, had intraventricular haemorrhage; in these infants, the care procedures induced more pronounced blood pressure drops in the first day of life when compared to the infants without haemorrhage.

Blood Pressure↗
PubMed1985

Evaluation of a transcutaneous oxygen and carbon dioxide monitor in a neonatal intensive care department.

Transcutaneous-PO2 (tc-PO2 (tc-PCO2) at 44 degrees C and transcutaneous-PCO2) at 38, 42, 43 and 44 degrees C were measured with a currently available monitoring system (TCM222, Radiometer, Copenhagen) in 64 newborn infants with severe respiratory insufficiency during the first five days of life. Tc-PCO2 at all four temperatures correlated better with arterial blood-PCO2 (aB-PCO2), than tc-PO2 with aB-PO2. However, the sensitivity and specificity of tc-PO2 and tc-PCO2 were similar with regard to maintaining aB-PO2 and aB-PCO2 within specified limits. Tc-PCO2 increased relatively with increasing electrode temperature by a factor which was similar to the anaerobic temperature coefficient of PCO2 in blood. The coefficient of variation of duplicate measurements was 10% for tc-PO2 and 5% for tc-PCO2. Electrode drift after an average of 3 hours patient monitoring was 2% +/- 6% (1 SD) for tc-PO2 and -3% +/- 6% for tc-PCO2. We conclude that tc-PO2 and tc-PCO2 are a valuable supplement to arterial blood gas measurements, but the variable correlation with arterial blood gas values and the electrode drifts which may occur, mean that they cannot fully replace arterial sampling.

Blood Pressure↗
PubMed1984

Cerebral blood flow in the newborn infant: comparison of Doppler ultrasound and 133xenon clearance.

Two techniques of Doppler ultrasound examination, continuous-wave and range-gated, applied to the anterior cerebral artery and to the internal carotid artery, were compared with 133xenon clearance after intravenous injection. Thirty-two sets of measurements were obtained in 16 newborn infants. The pulsatility index, the mean flow velocity, and the end-diastolic flow velocity were read from the Doppler recordings. Mean cerebral blood flow was estimated from the 133Xe clearance curves. The correlation coefficients between the Doppler and the 133Xe measurements ranged from 0.41 to 0.82. In the subset of 16 first measurements in each infant, there were no statistically significant differences between the correlation coefficients of the various Doppler ultrasound variables, but the correlation coefficients were consistently lower for the pulsatility index than for mean flow velocity or end-diastolic flow velocity, and they were consistently higher for the range-gated than for the continuous-wave Doppler technique.

Blood Flow Velocity↗
PubMed1984

Hydrops foetalis in 3 infants of a mother with acquired chronic pure red cell aplasia: transitory red cell aplasia in 1 of the infants.

A young woman with acquired chronic pure red cell aplasia (PRCA) gave birth to 3 infants with foetal hydrops. The 1st infant died shortly after birth, while the 2nd was stillborn with severe anaemia. Both had signs of increased erythropoiesis at autopsy. The 3rd infant was saved by foetal intrauterine red cell transfusions into the hepatic part of the umbilical vein. This infant had red cell aplasia lasting for about 3 months after birth, but then recovered. We believe that antibodies to red cell progenitors in the bone marrow were transferred transplacentally from mother to foetus, giving rise to severe affection of these infants. To the best of our knowledge this has not been reported previously in PRCA.

Antibodies↗
PubMed1984

Analysis of cranial 133-Xenon clearance in the newborn infant by the two-compartment model.

Cranial and chest clearance curves after intravenous administration of 133-Xenon was obtained on 112 occasions in 62 newborn infants admitted to our neonatal intensive care unit. The mean postnatal age was 5.1 days. The cranial clearance curves were submitted to two-compartment analysis. The compartmental clearance rate constants were 1.49 +/- 0.61/min and 0.099 +/- 0.033/min respectively while the fractional flow to the fast compartment was 0.51 +/- 0.14. Possible artefacts, particularly relevant to newborns, were analysed by computer simulation. It is concluded that the cranial 133-Xenon clearance curves varied considerably within the group of ill newborns and that the mean two-compartment parameter values differed considerably from those of healthy premature infants or adults, with or without cerebral illness. But the computer simulations demonstrated that the two-compartment parameters had high coefficients of variation and were significantly biased by right-to-left shunting of blood through the foramen ovale, by heterogeneity of the flow to the fastest compartment and by contamination of the cranial clearance curves by 133-Xenon in the airways. The radiation dose was 1.3 mGy to the lungs and 0.2 mGy to other tissues.

Adult↗