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Biomedical subjects

P L Hope

Publications and source records attributed to P L Hope.

At least 19 recordsLinked to original sources

Outcome at school age following antenatal detection of absent or reversed end diastolic flow velocity in the umbilical artery.

AIM: To determine whether fetal compromise, manifested by abnormalities of Doppler recordings of umbilical artery velocity waveforms in utero, is associated with neurodevelopmental or educational abnormalities at school age. METHODS: A cohort of neonates born following high risk pregnancies had been previously identified for a study of the perinatal sequelae of absent (AEDFV) and reversed (REDFV) end diastolic flow velocities. Seventy six children were assessed at 5-12 years of age by a developmental paediatrician who was blinded to perinatal course and Doppler assessments. Forty children born following pregnancies with forward end diastolic flow velocities (FEDFV), were compared with 27 with AEDFV and nine with REDFV. Tests of cognitive, neurological, and sensory function were performed, and reports of behavioural and educational progress were obtained from parents and teachers. RESULTS: There were no significant differences between FEDFV and AEDFV groups, but on tests of mental ability and neuromotor function the REDFV group had worse scores than either FEDFV or AEDFV. Comparing REDFV and FEDFV groups, the British Ability Scales general conceptual ability mean scores were 87.7 versus 101, and the Quick Neurological Screening Test mean scores were 32.8 versus 21.5. CONCLUSIONS: Absence of EDFV is well recognised as a marker of fetal compromise which is associated with acute perinatal sequelae. This study suggests it is not associated with adverse neurodevelopmental outcome. However, we found reversal of EDFV on antenatal assessment to be associated with a wide range of problems at school age, suggesting that REDFV represents intrauterine decompensation which may have adverse effects on the developing brain.

Blood Flow Velocity↗

Educational and behavioural problems in babies of 32-35 weeks gestation.

AIM: To identify incidence of school and behaviour problems at age 7 years in children born between 32 and 35 weeks gestation, and investigate perinatal risk factors. METHOD: The study population consisted of all children born at 32-35 weeks gestation to mothers resident in Oxfordshire in 1990. General practitioners, parents, and teachers were asked about health, behaviour, and education by postal questionnaire. Teachers rated children on level of function in six areas using a five point scale. They also completed the Strengths and Difficulties behaviour questionnaire. Perinatal risk factors were identified for children with poor school performance using a univariate and multivariate analysis. RESULTS: Teacher responses were obtained for 117 (66%) of the 176 children in the cohort. Twenty nine (25%) required support from a non-teaching assistant, five (4%) had required a statement of special educational needs, and three (3%) were at special school. Poor outcome was reported for 32% in writing, 31% in fine motor skills, 29% in mathematics, 19% in speaking, 21% in reading, and 12% in physical education. On the behaviour questionnaire, 19% of the cohort achieved an abnormal hyperactivity score (population norm 10%). Multivariate analysis showed perinatal variables that remained significant, independent of other variables; they were discharge from the special care baby unit > 36 weeks postconceptional age (odds ratio 4.15; 95% confidence interval 1.43 to 12.05) and male sex (odds ratio 3.88; 95% confidence interval 1.42 to 10.6). CONCLUSION: Up to a third of children born between 32 and 35 weeks gestation may have school problems. As there are larger numbers in this gestational category compared with smaller babies, this finding has implications for educational services.

Adult↗

The role of micturating cystourethrography in antenatally detected mild hydronephrosis.

BACKGROUND: The postnatal imaging of infants with antenatally detected mild hydronephrosis remains controversial. OBJECTIVE: Our aim was to establish the role and timing of micturating cystourethrography (MCUG) in mild hydronephrosis. MATERIALS AND METHODS: We performed a retrospective study of 61 infants (122 kidneys) referred with an antenatal diagnosis of hydronephrosis who showed persistent postnatal dilatation. All had follow-up postnatal ultrasound (US) and MCUG performed. The degree of dilatation at each follow-up scan was recorded. RESULTS: Of the 122 kidneys, 65 showed mild hydronephrosis. A substantial proportion of these (21.5%) demonstrated reflux. Serial US of these infants showed that the 6-week scan was the most informative and that any changes that warranted further investigation had occurred by this time. CONCLUSION: We recommend that all infants with mild hydronephrosis should undergo MCUG. MCUG need not be delayed until 3 months but could be performed following a 6-week US scan.

Female↗

Neonatal risk factors for cerebral palsy in very preterm babies: case-control study.

OBJECTIVE: To identify neonatal risk factors for cerebral palsy among very preterm babies and in particular the associations independent of the coexistence of antenatal and intrapartum factors. DESIGN: Case-control study. SETTING: Oxford health region. SUBJECTS: Singleton babies born between 1984 and 1990 at less than 32 weeks' gestation who survived to discharge from hospital: 59 with cerebral palsy and 234 randomly selected controls without cerebral palsy. MAIN OUTCOME MEASURES: Adverse neonatal factors expressed as odds ratios and 95% confidence intervals. RESULTS: Factors associated with an increased risk of cerebral palsy after adjustment for gestational age and the presence of previously identified antenatal and intrapartum risk factors were patent ductus arteriosus (odds ratio 2.3; 95% confidence interval 1.2 to 4.5), hypotension (2.3; 1.3 to 4.7), blood transfusion (4.8; 2.5 to 9.3), prolonged ventilation (4.8; 2.5 to 9.0), pneumothorax (3.5; 1.6 to 7.6), sepsis (3.6; 1.8 to 7.4), hyponatraemia (7.9; 2.1 to 29.6) and total parenteral nutrition (5.5; 2.8 to 10.5). Seizures were associated with an increased risk of cerebral palsy (10.0; 4.1 to 24.7), as were parenchymal damage (32; 12.4 to 84.4) and appreciable ventricular dilatation (5.4; 3.0 to 9.8) detected by cerebral ultrasound. CONCLUSION: A reduction in the rate of cerebral palsy in very preterm babies requires an integrated approach to management throughout the antenatal, intrapartum, and neonatal periods.

Blood Transfusion↗

Apoptosis in the brains of infants suffering intrauterine cerebral injury.

This study addressed the hypothesis that in human infants severe in utero insults induce a significant proportion of brain cells to undergo apoptosis. Morphologic criteria were used to quantify apoptosis and necrosis in the cingulate gyrus of two groups of infants: six infants who died after severe birth asphyxia with hypoxic-ischemic encephalopathy, and six others who suffered unexpected and apparently sudden intrauterine death at or close to term. The fraction of apoptotic cells was much higher than basal levels determined in animal experiments, and within both groups increased in proportion to the severity of injury as determined by total cell death (p < 0.05). The mean fraction of apoptotic cells was similar in asphyxiated infants, 8.3% (95% confidence interval for the population, 3.7-12%), and in stillbirths, 6.7% (0.2-13.6%). In the asphyxiated group, 20.8% (11-30.6%) of cells were necrotic, but significantly less necrosis, 3% (0.4-5.6%), was seen in stillborn infants (p < 0.05). Cell death was apoptotic after birth asphyxia in 26% (1-51%) and 78% (41-100%) in stillborn infants. In situ end labeling studies confirmed the presence of DNA fragmentation in apoptotic cells. These results demonstrate that infants who die after intrauterine insults, both those with evidence of delayed cerebral injury after hypoxia-ischemia and those without, have a significant number of cells in the brain with the morphologic characteristics of apoptosis. They confirm that apoptosis contributes significantly to cerebral damage in the perinatal period.

Apoptosis↗

Ultrasound findings and clinical antecedents of cerebral palsy in very preterm infants.

OBJECTIVE: To investigate the incidence and timing of neonatal ultrasound lesions, and clinical details about pregnancy and the perinatal period, in a total population of extremely premature children with cerebral palsy, born to mothers who were resident in Oxfordshire. METHODS: Eighteen children born at less than 32 completed weeks of gestation were identified from a regional cerebral palsy register. Eighteen controls were matched for gestation, time, and place of birth. Perinatal records and ultrasound reports were systematically reviewed. Sequential neonatal ultrasound images stored on videotape were reanalysed, blind to the outcome of the infants. RESULTS: Sixteen (89%) of the cerebral palsy cases and one (6%) control had parenchymal cysts on neonatal brain scans. Of the cerebral palsy cases, none had cysts detectable on the first day. Six developed cysts within the first 10 days of life, and two of these had periventricular echodensities when first scanned postnatally. Antenatal complications were recorded in 16 cases and nine controls. The early postnatal appearance of cysts in a few babies with a history of severe antenatal complications suggested that antenatal factors may have contributed to the cerebral pathology. CONCLUSIONS: Intrauterine factors may have contributed to adverse neurological outcome, but 16/18 of the preterm cerebral palsy cases had an associated cerebral lesion which developed in the perinatal period.

Brain Diseases↗

Clinical associations and time of onset of cerebral white matter damage in very preterm babies.

Neuropathological examinations were carried out at necropsy on 83 very pre-term babies who died during their first hospital admission. Forty seven (57%) babies had evidence of cerebral damage-39 with ischaemic white matter damage. The time of onset of ischaemic lesions was thought to be prenatal in 12 cases (31%) and postnatal in a further 12 (31%). The exact timing of damage could not be determined in 15 (38%) cases. Maternal and neonatal case notes were reviewed to ascertain clinical associations of ischaemic white matter damage. There were no clear associations between adverse clinical factors and prenatal ischaemic white matter damage. In contrast, pre-eclampsia, intrauterine growth retardation, and delivery without labour were associated with postnatal damage as were neonatal sepsis, necrotising enterocolitis, and seizures. The absence of a clear association between the timing of adverse clinical factors and the timing of ischaemic cerebral damage suggests that cerebral damage in very preterm babies may result from a sequence of events rather than one specific insult.

Brain↗

Neonatal outcome after pregnancy complicated by abnormal velocity waveforms in the umbilical artery.

The neonatal outcome of 61 infants born after pregnancies complicated by absent or reversed end diastolic flow velocities (AREDFV) in the fetal umbilical artery was compared with that of 61 controls matched for gestational age born after high risk pregnancies with documented forward end diastolic flow velocities (EDFV). The AREDFV group was significantly more growth retarded, had lower platelet counts at birth, and were more likely to become significantly thrombocytopenic in the first week after birth. Owing to concerns about the possible increased risk of necrotising enterocolitis in newborn infants after AREDFV, this group was started on enteral feeds later and was more likely to receive parenteral nutrition than the EDFV group. Seven infants with AREDFV and one control infant developed necrotising enterocolitis.

Adolescent↗

Reduced use of surface cultures for suspected neonatal sepsis and surveillance.

Data on infection in a neonatal unit were collected prospectively for seven years. After the first four years, the number of surface cultures obtained from neonates with suspected sepsis and for surveillance was reduced. Rates of systemic infection (sepsis and meningitis) were not significantly different in the four years before and the three years after this change. Reduction in surface culture information made no observable difference to detection of colonisation in neonates with early onset sepsis (within first 48 hours of life) nor to antibiotic choice in late onset sepsis. Decisions concerning the length of antibiotic course in suspected infection were not adversely affected. Reduction in the number of surface cultures led to considerable saving of time, effort, and cost while appearing safe in terms of clinical practice and outcome.

Anti-Bacterial Agents↗

Intravenous aminophylline and cerebral blood flow in preterm infants.

The effect of aminophylline on cerebral blood flow (CBF) was studied in 10 preterm infants who were receiving 6.2 mg/kg intravenously over 20 minutes followed by a maintenance infusion. CBF was measured intermittently using near infrared spectroscopy. Heart rate, blood pressure, oxygen saturation, and transcutaneously measured carbon dioxide tension (TcPCO2) were recorded continuously. Aminophylline administration was associated with a fall in CBF from a median of 15.9 ml/100 g/min to 11.2 ml/100 g/min. Median fall in CBF was 4.1 ml/100 g/min (95% confidence interval 1.7 to 6.5). Heart rate rose and TcPCO2 fell in all infants, median fall being 0.66 kPa. The reduction in CBF was greater than would be expected on the basis of the modest fall in TcPCO2.

Aminophylline↗

Global and depth resolved phosphorus magnetic resonance spectroscopy to predict outcome after birth asphyxia.

Twelve normal and 32 asphyxiated neonates were studied using global and depth resolved phosphorus magnetic resonance spectroscopy (31PMRS). Eight of the asphyxiated group died or survived with major neurodevelopmental abnormalities. A global phosphocreatinine/inorganic phosphate (PCr/Pi) ratio below the range of values from normal infants predicted adverse outcome after asphyxia with a positive predictive value of 64%, sensitivity 88%, and specificity 83%. Corresponding values for global inorganic orthophosphate/adenosine triphosphate (Pi/ATP) ratios were positive predictive value 88%, sensitivity 96%, and specificity 88%. Spatially localised MRS data, obtained using phase modulated rotating frame imaging, showed cerebral energy metabolism to be more abnormal in deep than superficial regions after birth asphyxia. However, in this population of full term infants none of the regional metabolite concentrations were superior to global data for prediction of outcome.

Adenosine Triphosphate↗

Magnetic resonance spectroscopy.

MRS is a noninvasive technique that does not use ionizing radiation and can be used to measure relative metabolite concentrations in human tissues and organs in vivo. Phosphorus MRS can be used to study energy metabolites and intracellular pH. The first neonatal applications were described in 1983 in a study of cerebral metabolism. Since then, the value of cerebral MRS as research tool and an investigative technique has been confirmed, and its prognostic power in asphyxiated infants has been established. Techniques of spatial localization and quantitation have been developed, but studies of other organs and the use of other nuclei remain at a very preliminary stage. Considering the huge potential of MRS and the proliferation of high field magnets primarily designed for imaging, there has been a disappointing lack of progress in the development of clinical and research applications of spectroscopy. The logistic differences of studying sick infants in strong magnetic fields make MRS a time-consuming and labor-intensive investigation, which will inevitably limit its widespread routine use. Research studies are hampered by the diversity of spectroscopic and signal processing techniques, which make comparisons of data from different groups impossible. Some techniques for the assessment of cerebral hemodynamics such as doppler ultrasound and near infrared spectroscopy have the advantage of being available at the cotside, but MRS is unique in providing quantitative information about a wide range of intracellular metabolites. The altricial development of MRS as a clinical investigative tool in neonatology can be ascribed partly to practical difficulties, but these should not detract from the exciting possibilities opened up by a technique that gives a noninvasive insight into intracellular chemistry. The metabolic information from MRS is an invaluable addition to the information provided by other techniques and will certainly play an important role in unraveling the sequence of events between an hypoxic-ischemic insult and cell death. A better understanding of these mechanisms is a prerequisite to the development of rational therapeutic maneuvers following asphyxial insults.

Brain↗

Spatially localized magnetic resonance spectroscopy of the brains of normal and asphyxiated newborns.

Phase-modulated rotating frame imaging is a modification of magnetic resonance spectroscopy, which uses a linear radiofrequency field gradient to obtain spatially localized biochemical information. Phase-modulated rotating frame imaging was used to study regional cerebral energy metabolism in the brains of 9 normal newborns and 25 newborns after birth asphyxia. Relative concentrations of phosphorus-containing metabolites and intracellular pH were determined for brain tissue at three specified depths below the brain surface for all neonates. Wide variations in metabolite ratios were seen among normal neonates, and considerable metabolic heterogeneity was demonstrated in individual neonates by depth-resolved spectroscopy. Asphyxiated neonates with severe hypoxic-ischemic encephalopathy and a poor neurodevelopmental outcome showed the expected rise in inorganic orthophosphate and fall in phosphocreatine concentrations in both global and spatially localized spectra. Phase-modulated rotating frame imaging showed that metabolic derangement was less in superficial than in deeper brain tissue. The inorganic orthophosphate-adenosine triphosphate ratio from 1 to 2 cm below the brain surface was more accurate than any global metabolite ratio for the identification of neonates with a poor short-term outcome. These data are consistent with the known vulnerability of subcortical brain tissue to hypoxic-ischemic injury in the full-term neonate.

Adenosine Triphosphate↗

Neocerebellar hypoplasia in a neonate following intra-uterine exposure to anticonvulsants.

An infant with dysmorphic features was born to an epileptic mother who had taken phenytoin and sodium valproate throughout pregnancy. The infant began to have intractable seizures 10 minutes after delivery, and retrospective reports from the mother suggested they may have occurred in utero. Ultrasound examination of the brain showed a very wide subarachnoid space and CT confirmed cerebral and cerebellar underdevelopment. The infant died at three days of age and autopsy revealed a small brain with neocerebellar hypoplasia. This case might represent an extreme example of anticonvulsant teratogenicity.

Abnormalities, Drug-Induced↗

Neonatal pneumonia.

All babies admitted to the neonatal unit during a period of 41 months were prospectively studied to find out the incidence, aetiology, and outcome of neonatal pneumonia, and the value of routine cultures of endotracheal tubes. Pneumonia of early onset (before age 48 hours) occurred in 35 babies (incidence 1.79/1000 live births). In 20 (57%) it was caused by group B streptococci. Blood cultures showed the presence of organisms in 16 of the 35 (46%). There were 41 episodes of pneumonia of late onset in 39 babies. Thirty six of the 39 were preterm, and 34 were artificially ventilated (10% of all ventilated babies). Endotracheal tube colonisation had occurred in 94% of these, most commonly by Gram negative organisms and Staphylococcus epidermidis. In only one of seven cases with simultaneous bacteraemia was the same organism grown from cultures of the blood. After controlling for gestational age and duration of artificial ventilation there was no difference in the incidence or timing of endotracheal tube colonisation between babies who did and did not have pneumonia of late onset. Ten babies with pneumonia of early onset (29%) died; all were preterm infants. Only one death (2%) was associated with an episode of pneumonia of late onset. Routine surveillance cultures were not helpful in predicting and managing pneumonia of late onset.

Anti-Bacterial Agents↗

Reproducibility of cerebral artery Doppler measurements.

Intraobserver and interobserver variability were calculated for the measurement of cerebral artery pulsatility indices by five observers who made two recordings on each of 12 stable preterm infants. Variations in pulsatility indices of up to 0.21 were found; no measurement was below 0.55.

Cerebral Arteries↗

Conservative management of an echovirus 11 outbreak in a neonatal unit.

Two babies in a neonatal unit presented on the same day with meningitis due to echovirus 11, which was thought to have been introduced by staff. At this time echovirus 11 was also isolated from the stools of eight other babies; five of them did not have signs of infection. No intervention was made except to emphasise the importance of handwashing. There was evidence of secondary spread to two babies who were both clinically well. The attack rate was twelve (29%) of forty-one babies exposed. Seven of the twelve infected babies were born before 30 weeks' gestation and would have had little or no maternal antibody, yet only two of the seven babies had signs of infection. Despite lack of special measures, all babies recovered. Most cases of horizontally acquired neonatal echovirus infection are mild: extreme measures in the management of outbreaks are unnecessary.

Anti-Bacterial Agents↗