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Biomedical subjects

A M Weindling

Publications and source records attributed to A M Weindling.

At least 55 records · Page 3Linked to original sources

Echocardiographic assessment of cardiac function in shocked very low birthweight infants.

The contribution of abnormal cardiac function to hypotension and metabolic acidosis, which affect approximately 40% of ventilated very low birthweight infants in the first 24 hours after birth was assessed using M mode, two dimensional, and Doppler echocardiography in 75 very low birthweight infants during the first few hours after birth. Thirty four infants whose blood pressure was less than the 10th centile or who had a metabolic acidosis in the first 24 hours were compared with 41 who showed neither feature. The median shortening fraction was significantly lower in the hypotensive/acidotic (shocked) group than in the controls. In 16 of 34 (47%) shocked infants left ventricular contractility and output were significantly worse than in the control subjects. One and five minute Apgar scores were also significantly lower in the shock group when compared with controls. Cardiac dysfunction was an important feature in the shocked very low birthweight infants. It is speculated that volume expansion may not always be the most appropriate first line treatment for such infants.

Acidosis↗

Pulmonary artery pressure changes in the very low birthweight infant developing chronic lung disease.

Pulmonary artery pressure may be estimated non-invasively in the premature newborn infant because of its negative correlation with the time to peak velocity:right ventricular ejection time (TPV:RVET) ratio calculated from the pulmonary artery Doppler waveform. We studied 54 very low birthweight infants on days 1, 2, 3, 7, 14, 21, and 28 after birth. Thirty four infants developed chronic lung disease (CLD). Twenty did not and acted as controls. After correcting the TPV:RVET ratio for heart rate (TPV:RVET(c)), during the first 14 days the TPV:RVET(c) ratio rose progressively in both groups suggesting a fall in pulmonary artery pressure. This occurred at a significantly slower rate in the CLD group. From days 14 to 28 there was a significant fall in the ratio in the CLD group only, suggesting an increase in pulmonary artery pressure. Using CLD as the end point, a TPV:RVET(c) ratio < 0.54 on day 7 had a predictive value of 78% (sensitivity 73%, specificity 65%). This rose to a predictive value of 97% (sensitivity 88%, specificity 95%) on day 28. The non-invasive assessment of pulmonary artery pressure may be useful in the early clinical management of the very low birthweight infant at risk of developing CLD.

Blood Flow Velocity↗

Nursing staff requirements for neonatal intensive care.

A study to estimate the number of nursing staff required for neonatal nursing was undertaken. Certain nursing tasks, such as transporting any infant, caring for the dying infant, and looking after the very unstable infant required continuous attention by one nurse (5.5 whole time equivalent (wte) nurses for each cot). The stable ventilated infant required 10.5 nursing hours each day-that is, 2.4 wte/cot. Infants with intravenous infusions, but not ventilated, required only slightly less nursing time: 9.25 nursing hours each day or 2.12 wte/cot. Each special care patient needed 6.50 nursing hours each day, or 1.49 wte/cot. It is emphasised that each neonatal unit will have to take its own practices into account when calculating neonatal nursing requirements.

England↗

Randomised controlled trial of plasma protein fraction versus dopamine in hypotensive very low birthweight infants.

Around 20% of very low birthweight infants admitted to a neonatal intensive care unit become hypotensive within 24 hours of their admission. Standard treatment is either expansion of the circulating volume by the infusion of plasma protein fraction or by using dopamine to improve cardiac function. The purpose of this study was to investigate by a randomised controlled trial which was the most appropriate treatment. Thirty nine infants were randomised to receive either plasma protein fraction or dopamine as first line treatment if they became hypotensive within 24 hours of admission to the neonatal intensive care unit. Seventeen of 19 (89%) infants responded to dopamine, whereas only 9/20 (45%) responded to plasma protein fraction. The median dose of dopamine needed to increase the blood pressure to at least the 10th centile was 7.5 micrograms/kg/min and was infused for a median duration of 18 hours. These observations suggest that dopamine should be used earlier in the treatment of these infants than has previously been recommended.

Blood Proteins↗

Neonatal meningococcal conjunctivitis associated with meningococcal meningitis.

Two infants are described in whom identical strains of meningococcus were isolated from both the eyes and the cerebrospinal fluid. This suggests that the eye may be a portal of entry in at least some cases of perinatally acquired neonatal meningococcal disease and has important implications for the management of purulent conjunctivitis in the newborn.

Conjunctivitis, Bacterial↗

Fast-scan magnetic resonance imaging in fetal visualization.

Magnetic resonance imaging has potential as an imaging technique in obstetrics. Its application has been limited by the amount of image degradation that occurs as a result of fetal movement during the long imaging times. By use of a fast-scan imaging technique good images are obtained of fetal anatomy in 3 to 14 seconds per image, depending on the setting used. Different organs could be visualized by varying the setting. Magnetic resonance imaging complements the role of ultrasonography in fetal visualization. It also allows clear fetal imaging in such high-risk situations as maternal obesity and oligohydramnios, where it may be difficult to produce clear images by ultrasonography. This technique will allow wider application of magnetic resonance imaging in obstetrics and give additional information about the developing fetus.

Female↗

Fast-scan magnetic resonance imaging of fetal anomalies.

OBJECTIVE: To identify those congenital fetal anomalies, previously identified by ultrasound scanning, in which fast-scan magnetic resonance imaging (F-SMRI) would give additional information for the perinatal management of the infants. DESIGN: Observational clinical study. SETTING: Hospital Department of Obstetrics and Gynaecology/Resonance Research Centre. SUBJECTS: Seven women carrying eight fetuses in whom congenital abnormalities had been identified using ultrasound scans. The duration of the pregnancies was 28 to 39 weeks gestation. INTERVENTIONS: Fast-scan magnetic resonance imaging at between 28 and 39 weeks gestation. MAIN OUTCOME MEASURES: Identification of fetal abnormalities. RESULTS AND CONCLUSIONS: F-SMRI was of limited value in the diagnosis of further assessment of fetuses with abnormalities of accumulation of tissue fluid. Renal anomalies were poorly identified unless associated with cystic formation of the kidney. Further study is required in the imaging of fetal central nervous system anomalies. Until echoplanar imaging is more widely available, MRI does not contribute to the diagnosis of cardiac anomalies. F-SMRI appears to be most useful in the diagnosis and management of soft tissue gastro intestinal abnormalities.

Abdominal Muscles↗

Phosphorus metabolites in the human placenta estimated in vivo by magnetic resonance spectroscopy.

Normal human placental metabolism has been studied in vivo by image localised 31P magnetic resonance spectroscopy in 13 women with anterior placentas; five, however, were too fat for useful spectral signals to be obtained. Magnetic resonance spectra of good quality which were considered to have arisen from the placenta were obtained from seven women with uncomplicated pregnancies (median gestational age 35 weeks, range 28-39). One other woman had a twin pregnancy in which one fetus had died a few days before. The phosphodiester signal from the placenta of the dead fetus was outside the 95% confidence intervals for normal placentas, suggesting that this technique may potentially be useful in the assessment of placental function.

Female↗

Assessment of fetal well-being with magnetic resonance.

The application of magnetic resonance techniques in the assessment of fetal growth, fetal growth patterns and fetal health was assessed. Eighty-four sets of fetal images were obtained using a fast-scan magnetic resonance imaging technique. Measurements were made of fetal subcutaneous fat thickness, uterine cavity length and width, fetal and uterine cross-sectional areas and fetal volume. Fetal area and fetal volume measurements were found to correlate well with birth weight. Measurement of subcutaneous fat thickness may prove to be a means of differentiating between those fetuses who are constitutionally as opposed to pathologically large or small. Thirteen women had additional spectroscopic studies carried out. Twelve of the women had normal pregnancies. One woman had a twin pregnancy in which one twin died. 31P phosphorus spectra were obtained from seven of the normal pregnancies. In the remainder, the depth of the abdominal wall prevented spectra being obtained from the placenta. Differences in phosphorus metabolites were obtained from the placenta of the dead twin compared to those from the healthy pregnancies.

Adipose Tissue↗

Maternal smoking, urinary cotinine levels and birth-weight.

The smoking habits of 300 consecutive pregnant women and of other members of their household were obtained by interview at 16 and 32 weeks' gestation and after delivery. Urine samples for estimation of cotinine were collected at the same times during pregnancy and on admission in labour. Both self-reports of active maternal smoking and urinary cotinine levels were significantly associated with lighter babies but urinary cotinine correlated the better. Active maternal smoking was associated with a decrease in birth-weight of 12 g for every cigarette smoked in a day while there was a decrease of 25 g in birth-weight for every microgram of cotinine/mg of urinary creatinine. Passive maternal smoking was associated with a decrease of 66 g in mean birth-weight but this decrease was not statistically significant. Self-reports of active and passive smoking accounted for 43% of the variation in urinary cotinine levels suggesting that urinary cotinine assays can be used to assess and monitor exposure to tobacco smoke in pregnancy.

Birth Weight↗

Alfentanil pharmacokinetics in preterm infants.

The pharmacokinetics of alfentanil were studied during the first four days after birth in 22 ventilated preterm infants who were all receiving muscle relaxants. Five minutes after a single dose of 20 micrograms/kg alfentanil median serum concentration was 66 ng/ml (range: 20-606). The median clearance was 0.87 ml/kg/min (range: 0.4-9.62) and median elimination half life 321 mins (64-1251). There were wide differences in the manner in which individual infants handled the drug and transient depression of blood pressure and heart rate was observed. These data were used to calculate an infusion dosage. In four infants 20 micrograms/kg alfentanil given by infusion over 30 minutes followed by 5 micrograms/kg/hour produced steady state median alfentanil concentrations of 54.5 ng/ml (range: 7-73 ng/ml) with no evidence of drug accumulation.

Alfentanil↗

Ciprofloxacin in neonatal Enterobacter cloacae septicaemia.

Multiresistant Enterobacter cloacae infection in six premature infants was eradicated with intravenous ciprofloxacin (10 mg/kg/day). Bacterial resistance did not develop. Adequate plasma ciprofloxacin concentrations were achieved in all treated patients. No clinical evidence of side effects was observed.

Ciprofloxacin↗