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Biomedical subjects

G Greisen

Publications and source records attributed to G Greisen.

At least 37 records · Page 2Linked to original sources
PubMed2000

The haemodynamic effects of dopamine and volume expansion in sick preterm infants.

AIM: To determine the haemodynamic effects of dopamine and volume expansion in preterm neonates. Effect parameters were mean arterial blood pressure (MABP), left ventricular output (LVO) and global cerebral blood flow (CBF). METHODS: In a randomised, clinical control trial 36 preterm neonates were randomised to receive either dopamine 5 microg/kg per min, volume expansion with albumin 20% 15 ml/kg or no treatment. Parameters were measured before and 2 h after initiation of treatment. RESULTS: Dopamine was effective in increasing MABP; both treatments increased LVO, whereas no significant difference between the treatment groups and the control group could be demonstrated with regard to CBF. CONCLUSION: No effect on global cerebral blood flow could be demonstrated in this study, despite significant effects on systemic circulatory parameters. However, the variance on the measurement of cerebral blood flow indicates that a small but clinically significant effect may have been overlooked.

Blood Pressure↗
PubMed2000

Serial measurements of serum human placental lactogen (hPL) and serial ultrasound examinations in the evaluation of fetal growth.

Serial serum hPL measurements and serial ultrasound fetometry were compared in the evaluation of fetal growth by relating these two parameters to size at birth and to clinical factors known to influence size at birth. The data were from a prospective study of 1000 consecutive pregnant women considered to be at risk for fetal growth retardation with retrospective analysis. Serum hPL was measured by radioimmunoassay and fetal weight estimated by ultrasound every 3 weeks during the last trimester. hPL values were expressed as multiples of the median (MoM) and linear regression analysis of the hPL MoM values was carried out for each pregnancy to find the slope of the line (hPL-slope); at least 3 serum hPL values were required. The estimated fetal weight and weight-for-age at birth was expressed in Z-scores. The individual intrauterine growth velocity was calculated by regression analysis and expressed as change in Z-score for 12 weeks. At least two ultrasound measurements over an interval of at least 42 days were used to estimate the fetal growth velocity. In 588 women the file was complete. The main outcome measures were the individual mean hPL, hPL-slope, fetal growth velocity, birth weight deviation, smoking in pregnancy and diagnosis of preeclampsia. A significant correlation was found between the hPL-slope and the intrauterine fetal growth velocity (r=0.34), and between hPL-slope and birth weight deviation (r=0.32). Mean hPL was correlated to birth weight deviation (r=0.27), but only very weakly to intrauterine growth velocity (r=0.08). hPL-slope and intrauterine growth velocity independently predicted birth weight deviation. Heavy smoking which was stopped before the third trimester was not associated with low intrauterine growth velocity, but with a low hPL-slope. Preeclampsia was associated with a trend towards low and decreasing hPL and with an increasing intrauterine growth velocity and birth weight deviation. In conclusion the rate of change of serial hPL measurements correlated well to intrauterine fetal growth velocity in the third trimester as estimated by ultrasound and to the deviation in birth weight, but hPL seems to have a separate physiological significance, since it did not pick up when smoking was stopped and growth velocity was normalised and it did not at all detect the increased growth associated with preeclampsia.

Birth Weight↗
PubMed2000

Does a discrepancy between gestational age determined by biparietal diameter and last menstrual period sometimes signify early intrauterine growth retardation?

OBJECTIVE: To assess the association between gestational age estimated from the last menstrual period (GA(LMP)) or from the biparietal diameter (GA(BPD)), and the subsequent birthweight for gestational age. DESIGN: Population-based follow up study. SETTING: Of 21,936 pregnancies contained in the ultrasound database, 16,387 singleton pregnancies with a reliable last menstrual period date and an ultrasound examination between 12 and 22 weeks of gestation were included. MAIN OUTCOME MEASURES: Correlation between: 1) birthweight deviation (birthweight-expected weight for gestation); 2) birthweight; and 3) pregnancy length and (GA(LMP)-GA(BPD)). Relative risk of birthweight < 2,500 g and low birthweight for gestation (> 22% below normal weight) related to five levels of discrepancy between (GA(LMP)-GA(BPD)). RESULTS: (GA(LMP)-GA(BPD)) was not associated with deviation of birthweight related to GA(BPD). However the risk of low birthweight (< 2,500 g) and low birthweight for gestational age was significantly increased when (GA(LMP)-GA(BPD)) was > 7 days. CONCLUSION: A biparietal diameter smaller than expected from the last menstrual period date is mainly a problem of an error related to estimated time of ovulation. At the same time the relative risk of a low birthweight infant is slightly increased.

Adolescent↗
PubMed1999

[Deaths at the neonatal department. Withholding or interruption of life-support treatment].

The circumstances of 88 deaths in the Neonatal Department, Rigshospitalet Copenhagen, were reviewed with special emphasis on the clinical background for, and parental attitude to withholding life-sustaining treatment. We recorded whether these considerations appeared in the patient's medical record, the type of treatment withheld and the use of opioids. No infant died under ongoing maximal treatment. Fourteen infants were judged to have died with "almost certainty" (gr A), 48 infants were judged to have died with great probability (gr B) and 26 infants were judged to have had a considerable chance of survival (gr C). Opioids were used more often in the terminal course of treatment in group C as opposed to group B. Parental attitudes and clinical background were not fully described in the medical record for many patients. The decision to withhold life sustaining treatment in the severely ill neonate was made to avoid prolonged futile suffering, or survival with very severe handicaps.

Adult↗
PubMed1999

[The first Danish experiences with neonatal extracorporeal membrane oxygenation].

In 1995, neonatal extra-corporeal membrane oxygenation (ECMO) was established at the Department of Neonatology, Rigshospitalet, Copenhagen. The indication for ECMO is circulatory or respiratory failure with arterial oxygen tension below 8 kPa despite maximal conventional treatment. During the first two and a half years 17 newborn infants and one child of 21 months have been treated with ECMO at the Rigshospital. Fifteen survived, of 12 followed at least nine months, 11 have normal development and one has cerebral palsy. There were problems including surgical placement of the cannula, technical difficulties or bleeding in 12 patients. During the same two years at least eight newborns in Denmark fulfilled the ECMO indication, but were not treated, half were not transferred to the Rigshospital. Seven of these eight infants died. The need for ECMO treatment in newborn infants is documented but small. We have succeeded in establishing this complicated treatment due to teamwork between different specialities with a good result.

Contraindications↗
PubMed1999

Measurement of cerebral oxyhaemoglobin saturation and jugular blood flow in term healthy newborn infants by near-infrared spectroscopy and jugular venous occlusion.

Data of cerebral haemodynamics and oxygenation are important for optimal treatment and prognosis in neonatal intensive care. Mostly premature and asphyxiated infants have been examined, but near-infrared spectroscopy (NIRS) allows estimations in healthy term newborns. In this study, cerebral venous saturation (CVsO2) and jugular blood flow (JBF) was estimated in 11 healthy term newborns. Mean CVsO2 was 64.12 +/- 4.6%, which conform with expectations. Mean JBF was only 6.1 ml/100 g/min, which is unacceptably low compared to earlier published data. We discuss physiological and methodological aspects and conclude that the combination of NIRS and venous occlusion appears to be a reliable method for estimation of CVsO2 in normally healthy newborns, whereas the reason for the failure of the method for estimation of JBF is unclear.

Blood Flow Velocity↗
PubMed1999

Nasal continuous positive airway pressure and early surfactant therapy for respiratory distress syndrome in newborns of less than 30 weeks' gestation.

OBJECTIVE: To determine whether early versus late treatment with porcine surfactant (Curosurf) reduces the requirement of mechanical ventilation in very preterm infants primarily supported by nasal continuous positive airway pressure (nasal CPAP). DESIGN: Multicenter randomized, controlled trial. PATIENTS: The study population comprised 60 infants <30 weeks' gestation with respiratory distress syndrome (RDS) who had an arterial to alveolar oxygen tension ratio (a/APO2) of 0.35 to 0.22. The cohort from which the study population was generated comprised 397 infants. RESULTS: The need for mechanical ventilation or death within 7 days of age was reduced from 63% in the late-treated infants to 21% in early-treated infants. Increasing numbers of antenatal steroid doses also improved the outcome, especially in the early-treated infants. Six hours after randomization mean a/APO2 rose to 0.48 in the early-treated infants compared with 0.36 in the late-treated. The need of mechanical ventilation before discharge was reduced from 68% in the late-treated to 25% in the early-treated infants. CONCLUSIONS: Nasal CPAP in combination with early treatment with Curosurf significantly improves oxygenation and reduces the subsequent need for mechanical ventilation in infants <30 weeks' gestational age with RDS.

Biological Products↗
PubMed1998

[Prognosis after perinatal asphyxia in full-term infants. A literature review].

Reviewing the literature published during the last 30 years we found comparable systematic studies of outcome for 1042 term infants born alive after likely intrapartum hypoxia-ischaemia. Fifty-two percent had no sequelae, 8% had developmental delay without associated handicaps, 4% had a single handicap, 11% were multihandicapped and 14% were dead as a consequence of the intrapartum hypoxia-ischaemia. The frequency of single handicaps exceeded the frequency found among the controls and in population studies. The frequency of children with developmental delay did not differ from that found among the controls. Outcome is closely related to the severity of hypoxic-ischaemic encephalopathy in the newborn.

Asphyxia Neonatorum↗
PubMed1998

Regional cerebral blood flow during seizures in neonates.

With the use of 99mTc-D, L,-hexamethylpropylenamine oxime and single photon emission computed tomography, regional cerebral blood flow was measured ictally in 12 mature infants with recurrent seizures and compared with a reference group of nine interictal studies. The study indicates that both clinical and electrical seizures in neonates are associated with a focal cerebral hyperperfusion of the same amount as seen in adults.

Brain↗
PubMed1998

Randomized controlled trial of discontinuation of nasal-CPAP in stable preterm infants breathing room air.

This trial assessed the consequences of discontinuation of nasal-CPAP in stable preterm infants breathing room air. Eighty-eight infants with a mean gestational age of 29 (24-33) weeks and a mean birthweight of 1264 (665-2060)g, randomized to either discontinuation of CPAP or its continuation, were clinically observed and monitored for 6 h by cardiorespiratory monitor, pulse oximeter and transcutaneous blood gas monitor. The abdominal circumference and gastric air and aspirate volumes were measured prior to meals at trial entry and after 6 h. Discontinuation of CPAP led to a small but significant decrease in oxygenation at 1 and 6 h. During the trial, five infants in the experimental group required supplemental oxygen and one infant was put back on CPAP owing to excessive apnoeas. Discontinuation of CPAP did not influence the TcPCO2 or the number of apnoeas and bradycardias during the trial, but led to significantly increased respiratory rate, retractions, and flaring at 6 h. It also led to a significant decrease in the abdominal circumference and gastric air volume. Thirty-nine percent of infants were put back on CPAP some time after the trial, mainly because of recurrent apnoeas and bradycardias. Taking the infant off CPAP during the trial reduced subsequent use of CPAP.

Female↗
PubMed1998

Early cerebral metabolic and electrophysiological recovery during controlled hypoxemic resuscitation in piglets.

We tested the hypothesis that controlled hypoxemic resuscitation improves early cerebral metabolic and electrophysiological recovery in hypoxic newborn piglets. Severely hypoxic anesthetized piglets were randomly divided into three resuscitation groups: hypoxemic, 21% O2, and 100% O2 groups (8 in each group). The hypoxemic group was mechanically ventilated with 12-18% O2 adjusted to achieve a cerebral venous O2 saturation of 17-23% (baseline; 45 +/- 1%). Base excess (BE) reached -22 +/- 1 mM at the end of hypoxia. During a 2-h resuscitation period, no significant differences in time to recovery of electroencephalography (EEG), quality of EEG at recovery, or extracellular hypoxanthine concentrations in the cerebral cortex and striatum were found among the groups. BE and plasma hypoxanthine, however, normalized significantly more slowly during controlled hypoxemic resuscitation than during resuscitation with 21 or 100% O2. We conclude that early brain recovery during controlled hypoxemic resuscitation was as efficient as, but not superior to, recovery during resuscitation with 21 or 100% O2. The systemic metabolic recovery from hypoxia, however, was delayed during controlled hypoxemic resuscitation.

Animals↗
PubMed1998

Blood flow distribution in the normal human preterm brain.

Disturbances in cerebral blood flow (CBF) are a major factor in the etiology and pathogenesis of cerebral damage in the neonate. As most animals are more mature at birth than man, extrapolation from animal studies to the human is questionable. Therefore, we have measured regional CBF (rCBF) in preterm infants. rCBF flow was measured in 12 normotensive and normoxic preterm infants [mean birth weight 915 g (range 550 to 2680 g), mean gestational age 27.7 wk (25 to 32 wk)]. All infants had a normal cerebral ultrasound examination. rCBF was measured using a mobile brain dedicated fast-rotating four-head multidetector system specially designed for neonatal studies. The tracer was 99mTc-labeled D,L-hexamethylpropylenamine oxime in a dose of 4 Mbq/kg. rCBF of the subcortical white matter was 0.53 (0.48-0.58) of the global CBF. After correction for scattered radiation, the estimate of rCBF to the white matter was reduced to 0.39 (0.36-0.42). The flow to the basal ganglia was 2.33 (2.08-2.59) times the global CBF. After correction for partial volume effect, the cortical flow was higher than the flow to the basal ganglia and highest in the frontotemporal cortex (motor cortex). The flow to the cerebellum was of the same magnitude as the flow to the basal ganglia, but with a significantly higher variation. rCBF in 12 preterm infants showed a flow distribution similar to flow in other newborn mammals. The gray-white matter contrast, however, was greater. This new information, combined with existing data showing low global CBF, suggests that blood flow to the white matter in the preterm human neonate is extremely low.

Brain↗
PubMed1997

[Quality of life of young adults whose birth weight was under 1.500 g].

Quality of Life (QoL) has been assessed in eighty-five young adults, born in 1971-1974 with birthweight < 1500 g (VLBW) and admitted to the neonatal intensive care unit of the State University Hospital in Copenhagen, Denmark. Their QoL has been compared to that of 85 subjects with birth weight > 2500 g (NBW) born in the same period at The State University Hospital. The subjects were interviewed by telephone on the basis of well defined theories on QoL by Anton Aggernaes. Quality of Life was assessed both in objective terms and as judged by the interviewed person. Subjects born with VLBW who were free of handicaps had QoL-scores (both objective and subjective) fully comparable to the NBW group. VLBW subjects reporting various physical and mental handicaps had subjective QoL-scores comparable to scores in the NBW group but the objective QoL-scores were significantly lower.

Adult↗
PubMed1997

Intrauterine growth correlation to postnatal growth--influence of risk factors and complications in pregnancy.

In a population of 616 pregnant women with increased risk of intrauterine growth retardation, we examined the relationship of third trimester fetal growth to maternal and pregnancy risk factors, the infants condition at birth, and postnatal growth. Intrauterine growth velocity was calculated from repeated estimations of fetal weight using ultrasound. Postnatal growth up to 3 months was measured in 313 of the infants. Intrauterine growth velocity was directly correlated to birth weight deviation (R = 0.35, P < 0.0001) and inversely correlated to postnatal growth (R = 0.21, P = 0.0001). Heavy smoking throughout pregnancy was the most pronounced factor associated with loss of fetal growth percentiles (P = 0.006), and it was also associated with postnatal catchup (P = 0.01). Infants who needed neonatal care had significantly lower intrauterine growth velocities compared to the rest of the study group; no correlation was found between intrauterine growth velocity and Apgar scores or umbilical pH. It is concluded that growth retardation in the third trimester can be identified by ultrasound fetometry, and is associated with maladaptation at birth and postnatal catchup. However, the correlations were weak suggesting that deviation at birth reflects, only to a limited degree, acceleration or deceleration of growth in the third trimester.

Apgar Score↗
PubMed1997

99mTc-HMPAO as a tracer of cerebral blood flow in newborn infants.

Studies on the kinetics of 99mTc-D,L-hexamethylpropylene amine oxime (99mTc-HMPAO) in adults have shown that it is not an ideal tracer of CBF because it underestimates high-flow areas. Knowledge of the kinetics of the tracer is important in evaluating the studies. The kinetics of 99mTc-HMPAO in infants may be different from that in adults, therefore, we examined the cerebral uptake and retention of 99mTc-HMPAO in neonates and estimated the degree of brain-to-blood back diffusion by comparing corresponding 133Xe flow images and 99mTc-HMPAO distribution images. In addition, we measured the urinary excretion of 99mTc-HMPAO. Regional CBF was measured using a mobile brain-dedicated, fast-rotating, four-head multidetector system specially designed for neonatal studies. Tracers were 99mTc-HMPAO (4 MBq/kg) and 133Xe (500 MBq/kg). Cerebral uptake and leak-out of 99mTc-HMPAO were measured by a single scintillation crystal placed over the frontoparietal part of the infant's head. The cerebral retention of 99mTc-HMPAO was analyzed in 50 infants. The mean gestational age and birth weight (95% confidence interval) were 34.4 weeks (32.2-35.7) and 2,326 g (1,954-2,995), respectively. The cerebral uptake of 99mTc-HMPAO was examined in 16 of the 50 infants, and activity during 24 h was monitored in five. In 11 infants, corresponding 133Xe studies were performed. Urinary excretion was studied in 12 infants. The maximal activity in the brain was reached 90s after i.v. injection and was 104% (98-111) of the stable level, which was reached approximately 3 min after the injection. The decay corrected leakout of the tracer during the following 24 h was 1.0% (0.4-1.5) per hour. The cerebral retention was calculated at 6.8% (6.1-7.6), highest in the group of ictal studies and lowest in premature infants with intracranial hemorrhage. The mean value of the fixation/clearance ratio alpha was estimated at 3.4 (2.8-4.4). The mean urinary excretion over 24 h was 19.5% (11.4-27.7) and was significantly related to renal function as indicated by serum urea (p = 0.02 r2 = 0.55). A four-compartment model describing the kinetics of 99mTc-HMPAO is shown to be valid in neonates. The cerebral retention of the tracer is higher in neonates because of higher extraction and lower initial back diffusion from brain to blood. In linearizing 99mTc-HMPAO distribution images, a smaller correction is necessary, and we propose a value of the correction factor of 3.4. In this way, 99mTc-HMPAO is a more reliable tracer of the distribution of CBF in neonates compared with adults. The urinary excretion is significantly reduced compared with adults, and the radiation dose to the bladder wall is reduced. The effective dose is 0.3 mSv/MBq/kg.

Brain↗
PubMed1997

Near-infrared monitoring of cerebral tissue oxygen saturation and blood volume in newborn piglets.

Near-infrared spectrophotometry (NIRS) potentially provides a tool for noninvasive tissue oxygenation and blood volume monitoring. Cerebral monitoring could be useful in the prevention of hypoxic ischemic brain injury in newborns. This study sought to validate such NIRS measurements in normoventilated, hypocapnic, and hypoxemic states in the brain of newborn piglets vs. arterial (SaO2) and sagittal sinus blood hemoglobin saturation (SssO2) and blood volume measurements with 99mTc-labeled erythrocytes. NIRS measurements of cerebral blood volume (CBV) were performed with both oxyhemoglobin and indocyanine green as tracers, and changes in CBV were monitored by following the change in the concentration of total hemoglobin (i.e., oxyhemoglobin + deoxyhemoglobin). NIRS CBV measurements did not correlate well with the radioactive measurements. NIRS measurements of oxygenation, however, correlated well with a weighted mean value of SaO2 and SssO2 (r = 0.90; P < 0.0001). Multiple linear regression of the oxygenation index (i.e., oxyhemoglobin - deoxyhemoglobin) on SaO2 and SssO2 suggested that NIRS sees hemoglobin in tissue in a venous-to-arterial ratio of 2:1. Therefore, in this study, NIRS reliably monitored changes in cerebral tissue oxygenation but not in CBV.

Animals↗