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Biomedical subjects

R W Cooke

Publications and source records attributed to R W Cooke.

At least 19 recordsLinked to original sources
PubMed1992

Annual audit of neonatal morbidity in preterm infants.

Annual odds ratios, standardised for known confounding variables, were used to examine trends in major neonatal morbidities among 3220 preterm infants of less than 35 weeks' gestation admitted to a regional referral centre between 1980 and 1991. Despite improved survival, the risk of major cerebral haemorrhage, ventriculoperitoneal shunt insertion, and necrotising enterocolitis was unchanged. A recent reduction in risk of pneumothorax and persistence of the arterial duct was noted. An increased risk for chronic lung disease over time could be accounted for by increased survival, although a similar increase in risk for infection remained unexplained.

Bacterial Infections↗
PubMed1992

Plasma hypoxanthine: a marker for hypoxic-ischaemic induced periventricular leucomalacia?

Cerebral ischaemia of the immature brain may result in cavitating periventricular leucomalacia (PVL), an important association of cerebral palsy. Hypoxanthine measured by high performance liquid chromatography was used as a marker of peripartum hypoxia and ischaemia in 116 infants at risk of PVL. PVL was detected by ultrasound. The 81 infants who were unaffected had median (range) gestation of 30 weeks (24-32), weight of 1336 g (724-3790), and a plasma hypoxanthine concentration of 7.8 mumol/l (2.4-48.9). The seven infants who had cavitating PVL had a median gestation of 28 weeks (26-30), weight of 1165 g (682-1860), and a hypoxanthine concentration of 31.9 mumol/l (7.1-149). Cavitating PVL was significantly dependent only on hypoxanthine when controlling for the effects of weight and gestation. This suggests that peripartum hypoxia-ischaemia may be one of the aetiological factors in cavitating PVL. Oxidation of hypoxanthine during reperfusion generates free radicals which may contribute to the tissue destruction of PVL. The association of hypoxia-ischaemia with PVL suggests that PVL may be modified by reducing free radical activity.

Biomarkers↗
PubMed1992

Receiver operating characteristic curves for comparison of serial neutrophil band forms and C reactive protein in neonates at risk of infection.

The performance of indirect indices of infection in the newborn vary because of differences in techniques, including diagnostic cut off levels. We have compared serial neutrophil band cell counts with C reactive protein measured by rate nephelometry. The 'gold standard' was a positive culture and the performance of the tests was compared by the technique of receiver operating characteristics (ROC) as well as sensitivity and specificity. A total of 172 septic screens were performed in 56 patients. The operational diagnostic cut off values were: C reactive protein greater than 8 mg/l, immature:total neutrophil ratio (I:T ratio) greater than 0.2, and band count greater than 5%. Compared with the sensitivity of C reactive protein (71%), I:T ratio (34%) was significantly different but band count (69%) was not. The specificity of C reactive protein (72%) was better than band count (39%) but no better than I:T ratio (73%). ROC curves were constructed for all possible diagnostic cut off values of the tests and superior performance was demonstrated for C reactive protein compared with band count and I:T ratio. We conclude that C reactive protein is a useful early indicator of infection in neonates and that ROC curves permit comprehensive and graphic comparison between tests and the calculation of optimal diagnostic cut off values.

Bacteria↗
PubMed1991

Predicting costs and outcomes of neonatal intensive care for very low birthweight infants.

A geographically determined cohort of all infants of less than 1,500 g born in 1980 and 1981 were clinically followed up to age four to determine their disabilities which were classified as mild, moderate or severe. A quality adjustment coefficient, determined by the severity of the disability, was used to calculate the number of quality adjusted lives produced. The total cost of care for these children was assessed as the sum of hospital costs to age four (which were specifically determined) and an estimate of the life-time costs of care of disabled children from information provided by the Education and Social Service departments. A very poor predictive power of birthweight with cost was obtained with the ungrouped birthweight data, whereas clinical factors explained up to 60% of the variance of the initial hospital costs for survivors and up to 30% of the variance of life-time costs and the cost of quality adjusted lives produced. Rules for the allocation of resources based on discrimination by birthweight are flawed but the application of clinical discretion is important.

Birth Weight↗
PubMed1991

Prolonged low dose indomethacin for persistent ductus arteriosus of prematurity.

A total of 121 infants who required indomethacin for persistent ductus arteriosus in Liverpool and Cambridge over a four year period were randomised to receive either 0.1 mg/kg daily for six days or 0.2 mg/kg every 12 hours for three doses. The groups were of similar birth weight and gestational and postnatal age, though those treated with a low dose were by chance receiving a higher percentage of oxygen at the start of treatment and there were more deaths from bronchopulmonary dysplasia in this group. Of 59 infants treated with the prolonged course 53 (90%) responded initially to indomethacin compared with 48 of 62 (77%) treated conventionally--a difference of 13% (95% confidence interval for the difference 0 to 26%). Of the 53 responders 11 (21%) relapsed after low dose indomethacin, whereas after the shorter course 19 of 48 (40%) relapsed. This difference was significant (95% confidence intervals 3 to 37%). Side effects, mainly gastrointestinal haemorrhage, were similar in both groups. Significantly fewer infants experienced a rise in serum creatinine or urea concentration after treatment with low dose indomethacin. A prolonged low dose course of indomethacin offers advantages over conventional treatment.

Ductus Arteriosus, Patent↗
PubMed1991

Trends in preterm survival and incidence of cerebral haemorrhage 1980-9.

The annual survival rates and incidence of cerebral haemorrhage in 2618 preterm infants of 34 weeks' gestation or less were examined in one referral centre over a 10 year period from January 1980 to December 1989. Survival was independently related to weight, gestation, sex, and inborn delivery. When these variables had been taken into account, survival was 56% greater at the end of the decade compared with 1980. The incidence of cerebral haemorrhage (diagnosed by cranial ultrasound scanning) was related to birth weight, gestation, sex, inborn delivery, and caesarean section, but there was no significant trend in the incidence with time. Rates of caesarean section in this group increased from 31% in 1980 to over 50% more recently. Haemorrhage affecting the brain parenchyma was related to gestation and inborn delivery, and showed a small but significant decline over time. The lack of association between changes in survival rates and rates of cerebral haemorrhage may indicate that factors associated with both neonatal mortality and the incidence of cerebral haemorrhage may not be causally related as previously assumed.

Analysis of Variance↗
PubMed1991

The incidence of renal calcification in preterm infants.

A total of 79 infants born at less than 32 weeks' gestation were studied with serial renal ultrasound scans to assess the incidence of nephrocalcinosis. Twenty one infants developed renal calcification giving an overall incidence of 26.6% in the study group. Affected infants were significantly smaller (mean (SD) birth weight 940 (323) g) and significantly less mature (mean (SD) gestation 26.9 (1.9) weeks). In 17 patients the calcification was represented by hyperechogenic renal pyramids alone, and in four patients renal calculi were demonstrated. Factors associated with renal calcification included hypophosphataemia, hypercalcaemia, hypercreatininaemia, and prolonged oxygen requirement during the first month of life. Multivariate analysis showed that the strongest clinical indicator of calcification was duration of oxygen treatment. Infants who still required oxygen treatment at 28 days had a 62% chance of developing renal calcification.

England↗
PubMed1991

Factors associated with chronic lung disease in preterm infants.

Among 659 infants of 30 weeks' gestation or less born in a regional perinatal centre between 1983 and 1989, 195 were ventilated for four days or more and survived to 28 days, and 87 of these developed chronic lung disease. There was a sevenfold increase in the annual incidence of chronic lung disease over time. During the same period there were significant increases in the number of infants who survived, the incidence of septicaemia, and the use of parenteral lipid emulsions. Chronic lung disease was significantly associated with low birth weight, shorter gestation, duration of ventilation, vaginal delivery, sepsis, and the use of lipid. Respiratory and physiological measurements at 96 hours were significantly worse in infants who subsequently developed chronic lung disease. Initial logistic regression showed that gestation, arterial carbon dioxide tension (PaCO2), and ventilation rate at 96 hours; and birth in 1988 or 1989, were independently associated with chronic lung disease, but when septicaemia and use of lipid during the first 21 days were included, only gestational age (odds ratio 0.64, 95% confidence interval (CI), 0.49 to 0.81 for each week) and use of lipid (odds ratio 8.1, 95% CI, 2.32 to 28.0) remained significantly associated with chronic lung disease. The observed increase in incidence of chronic lung disease in this population was associated with earlier use of parenteral lipids in infants of very low gestation rather than with changes in population, survival, or ventilator treatment of respiratory distress syndrome.

Birth Weight↗
PubMed1990

Cerebral palsy in very low birthweight infants.

Eighty one very low birthweight survivors with cerebral palsy were matched with controls by sex, gestational age, and place of birth. Using discriminant analysis, the perinatal profiles for infants with cerebral palsy and their controls were shown to differ significantly. When infants with various types of cerebral palsy were analysed with their controls the discriminating variables differed. Diplegic infants could be differentiated from controls on antenatal variables alone, but significant discrimination of hemiplegic and quadriplegic infants required the addition of postnatal variables. Cranial ultrasound appearances differed appreciably between types of cerebral palsy. Future studies should differentiate between types of cerebral palsy and include ultrasound data. Cerebral palsy in very low birthweight infants is unlikely to prove a useful outcome indicator for neonatal intensive care.

Brain↗
PubMed1990

Five year outcome of preterm sextuplets related to size at birth.

Preterm sextuplets were studied to examine whether growth retardation affects long term outcome. All were growing normally at 5 years. Intelligence quotients (IQ) ranged from 105-116 and motor impairment scores from 1.0-7.0. No neurological or behavioural abnormalities were found. The largest sextuplet has maintained her position for growth and IQ. No relation between test scores and birth weight or perinatal variables was found in the remaining siblings.

Birth Weight↗
PubMed1990

Birthweight specific trends in cerebral palsy.

A register of infants with cerebral palsy born to mothers resident in the Mersey region from 1967-84 has been maintained using various sources of information. A total of 1056 patients are registered of whom 331 (31%) have hemiplegia or mixed hemiplegia, 236 (22%) have diplegias or mixed diplegia, and 369 (35%) have quadriplegia or mixed quadriplegia. The remainder have dyskinetic or dystonic forms except for seven, who are unclassified. There has been no significant change in the prevalence of cerebral palsy among infants of normal birth weight (greater than 2500 g). Among low birthweight infants (less than or equal to 2500 g) there has been a significant increase in prevalence of all the main clinical types. This increase started later among the very low birthweight infants (less than or equal to 1500 g) than among those weighing 1501-2500 g. These changes in prevalence could be the result of either improved survival of prenatally impaired infants because of improvements in medical care, or a reflection of failure to maintain optimal conditions at or around the time of birth.

Birth Weight↗
PubMed1989

Blood pressure and cerebral haemorrhage and ischaemia in very low birthweight infants.

Hourly blood pressures were recorded directly in 131 very low birth weight infants in intensive care during the first 4 days of life. Cranial ultrasound evidence of intraventricular haemorrhage correlated well with periods of hypotension, but not of hypertension. Ischaemic lesions did not correlate with periods of hypotension, but were associated with previous haemorrhage. The findings suggest that hypotension predisposes to primary intraventricular haemorrhage and that later parenchymal ischaemic lesions relate to local factors rather than hypotension.

Brain Ischemia↗
PubMed1989

Maturation of the cortical evoked response to posterior-nerve stimulation in the preterm neonate.

Short-latency somatosensory evoked potentials elicited by stimulation of the posterior tibial nerve at the ankle were studied in 75 preterm infants. Normative data for the latency of the first cortical component (P1) were obtained for infants from 27 weeks gestation to term, and showed a linear decrease with increasing gestational age. As the pathway of this response traverses areas of the brain likely to be affected by ischaemic and haemorrhagic lesions, abnormalities in the response might indicate later motor disorder.

Afferent Pathways↗
PubMed1989

Laterality and prematurity.

Lateral preferences were determined by postal questionnaire for 240 children, without major neurological impairment, who were born at less than 31 weeks' gestation to examine the association between neonatal brain injuries and later lateral preference. Left hand preference was reported in 64 (26.7%) children at a median age of 52 months (range: 24-104 months). Left foot preference was shown by 70 (29.2%) and left eye preference by 86 (35.8%). Significantly more preterm children were left handed compared with parents or siblings in whom expected frequencies of left handedness were found. All index children had serial neonatal cerebral ultrasound examinations, of which 95 were abnormal. Left preference occurred at similar frequencies in those with normal neonatal scans (26.9%), bilateral lesions (28.3%), left sided lesions (23.8%), and right lesions (23.8%). Lateral preference appears to be unaffected by the side or extent of neonatal brain injury in children without major impairments.

Brain↗
PubMed1989

Cranial ultrasound assessment of gestational age in low birthweight infants.

The anatomical features of the cerebral hemispheres of 97 infants were studied by ultrasonography. A scoring system was devised based on anatomical and ultrasound appearances and compared with gestational age calculated from the date of the mother's last period. There was a significant positive correlation between gestational age and ultrasound score. Cranial ultrasonography is an accurate and reproducible method of assessing gestational age in low birthweight infants.

Brain↗
PubMed1989

Electrolytes and glucose in cerebrospinal fluid of premature infants with intraventricular haemorrhage: role of potassium in cerebral infarction.

Potassium, sodium, and glucose concentrations in cerebrospinal fluid and plasma were determined in 73 infants whose gestational ages ranged from 25 to 40 weeks. Six of 29 (21%) neonates with intraventricular haemorrhages had raised potassium concentrations in the cerebrospinal fluid (3.7-30 mmol/l); five developed cerebral infarctions. There was a significant correlation between sodium and glucose concentrations in plasma and cerebrospinal fluid with prolonged hypoglycorrhachia accompanying posthaemorrhagic hydrocephalus. Raised concentrations of potassium in cerebrospinal fluid occur with intraventricular haemorrhage and may contribute to the development of cerebral infarction.

Blood Glucose↗
PubMed1989

Motor skills in extremely low birthweight children at the age of 6 years.

Fifty three children aged 6 years old who had weighed less than 1251 g at birth without cerebral palsy and receiving mainstream education, were entered into a controlled study of motor skills. The index and control children were matched by age, sex, and school. The index group were considered by their teachers to have similar academic performances to their index group were considered by their teachers to have similar academic performances to their controls, although two index cases were receiving remedial teaching. On the test of motor impairment extremely low birthweight children had significantly more motor difficulties than controls. In addition, the index group had more minor neurological signs, lower intelligence quotients, and more adverse behavioural traits. The higher motor impairment scores among index children were independent of differences in intelligence quotient between the two groups. There was no association between impairment score and the presence or degree of periventricular haemorrhage or periventricular leucomalacia on neonatal cerebral ultrasound. Children with Apgar scores at five minutes of less than 7 had significantly higher impairment scores compared with those whose scores were 7 or more. Three perinatal factors (Apgar score at five minutes, neonatal septicaemia, and abnormal movements) explained 32% of the variance in impairment score at the age of 6 years. In children who do not have cerebral palsy perinatal factors may still be important in the development of motor skills. The presence of subtle neuromotor impairments at 6 years of age has implications for schooling that need further evaluation.

Child↗