The PREM score: a graphical tool for predicting survival in very preterm births.

OBJECTIVE: To develop a tool for predicting survival to term in babies born more than 8 weeks early using only information available at or before birth. DESIGN: 1456 non-malformed very preterm babies of 22-31 weeks' gestation born in 2000-3 in the north of England and 3382 births of 23-31 weeks born in 2000-4 in Trent. OUTCOME: Survival to term, predicted from information available at birth, and at the onset of labour or delivery. METHOD: Development of a logistic regression model (the prematurity risk evaluation measure or PREM score) based on gestation, birth weight for gestation and base deficit from umbilical cord blood. RESULTS: Gestation was by far the most powerful predictor of survival to term, and as few as 5 extra days can double the chance of survival. Weight for gestation also had a powerful but non-linear effect on survival, with weight between the median and 85th centile predicting the highest survival. Using this information survival can be predicted almost as accurately before birth as after, although base deficit further improves the prediction. A simple graph is described that shows how the two main variables gestation and weight for gestation interact to predict the chance of survival. CONCLUSION: The PREM score can be used to predict the chance of survival at or before birth almost as accurately as existing measures influenced by post-delivery condition, to balance risk at entry into a controlled trial and to adjust for differences in "case mix" when assessing the quality of perinatal care.

How effectively can clinical examination pick up congenital heart disease at birth?

AIMS: To assess what proportion of all cardiac abnormality can be suspected at birth when all clinical examination before discharge is undertaken by a small stable team of clinicians. METHODS: A prospective audit of all the 14 572 births in a maternity unit only staffed by nurse practitioners between 1996 and 2003. RESULTS: 1.2% of all babies born in the unit were found to have a structural defect (as confirmed by echocardiography) within a year of birth. The number not suspected before discharge declined over time, and only 6% were first suspected after discharge in the last four years of this eight year study. Four potentially life threatening conditions initially went unsuspected in 1996-8, but none after that. A policy of referring every term baby with a murmur at 1 day of age that was still present at 7-10 days resulted in 4.2% requiring cardiac referral; 54% of these babies still had a murmur when assessed one to two weeks later, and 33% had a structural defect. Parents said in independent, retrospectively conducted, interviews that they found it confidence building to have any possible heart defect identified early and the cause of any murmur clearly and authoritatively explained. CONCLUSIONS: Effective screening requires experience and a clear, structured, referral pathway, but can work much better than most previous reports suggest. Whether staff bring a medical or nursing background to the task may well be of less importance.

Can all neonatal resuscitation be managed by nurse practitioners?

AIM: To assess the ability of nurse practitioners to manage the care of all babies requiring resuscitation at birth in a unit without on site medical assistance. METHOD: A prospective review, and selective external audit, of the case records of all 14 572 babies born in a maternity unit in the north of England during the first eight years after nurse practitioners replaced resident paediatric staff in 1996. RESULTS: Every non-malformed baby with an audible heart beat at the start of delivery was successfully resuscitated. Twenty term babies and 41 preterm babies were intubated at birth. Eight term babies only responded after acidosis or hypovolaemia was corrected following umbilical vein catheterisation; in each case the catheter was in place within six minutes of birth. Early grade 2-3 neonatal encephalopathy occurred with much the same frequency (0.12%) as in other recent studies. Independent external cross validated review found no case of substandard care during the first hour of life. CONCLUSION: The practitioners successfully managed all the problems coming their way from the time of appointment. There was no evidence that their skill decreased over time even though, on average, they only found themselves undertaking laryngeal intubation once a year. It remains to be shown that this level of competence can be replicated in other settings.

Vitamin K--what, why, and when.

Policies for giving babies vitamin K prophylactically at birth have been dictated, over the last 60 years, more by what manufacturers decided on commercial grounds to put on the market, than by any informed understanding of what babies actually need, or how it can most easily be given. By a pure fluke a 1 mg IM dose, designed to prevent early vitamin deficiency bleeding ("haemorrhagic disease of the newborn") has been found to protect against late deficiency bleeding-a condition unrecognised at the time this policy took hold. Alternative strategies for oral prophylaxis are now opening up (see pp 109 and 113), but these are also, at the moment, dictated more by what the manufacturers choose to provide than by what would make for ease of delivery either in poor countries, or in the developed world.

Pulse oximetry, severe retinopathy, and outcome at one year in babies of less than 28 weeks gestation.

AIM: To determine whether differing policies with regard to the control of oxygen saturation have any impact on the number of babies who develop retinopathy of prematurity and the number surviving with or without signs of cerebral palsy at one year. METHODS: An examination of the case notes of all the 295 babies who survived infancy after delivery before 28 weeks gestation in the north of England in 1990-1994. RESULTS: Babies given enough supplemental oxygen to maintain an oxygen saturation of 88-98%, as measured by pulse oximetry, for at least the first 8 weeks of life developed retinopathy of prematurity severe enough to be treated with cryotherapy four times as often as babies only given enough oxygen to maintain an oxygen saturation of 70-90% (27.2% v 6.2%). Surviving babies were also ventilated longer (31.4 v 13.9 days), more likely to be in oxygen at a postmenstrual age of 36 weeks (46% v 18 %), and more likely to have a weight below the third centile at discharge (45% v 17%). There was no difference in the proportion who survived infancy (53% v 52%) or who later developed cerebral palsy (17% v 15%). The lowest incidence of retinopathy in the study was associated with a policy that made little use of arterial lines. CONCLUSIONS: Attempts to keep oxygen saturation at a normal "physiological" level may do more harm than good in babies of less than 28 weeks gestation.

Increasing rates of cerebral palsy across the severity spectrum in north-east England 1964-1993. The North of England Collaborative Cerebral Palsy Survey.

OBJECTIVES: To report epidemiological trends in cerebral palsy including analyses by severity. DESIGN: Descriptive longitudinal study in north-east England. Every child with suspected cerebral palsy was examined by a developmental paediatrician to confirm the diagnosis. Severity of impact of disability was derived from a parent completed questionnaire already developed and validated for this purpose. SUBJECTS: All children with cerebral palsy, not associated with any known postneonatal insult, born 1964-1993 to mothers resident at the time of birth in the study area. MAIN OUTCOME MEASURES: Cerebral palsy rates by year, birth weight, and severity. Severity of 30% and above defines the more reliably ascertained cases; children who died before assessment at around 6 years of age are included in the most severe group (70% and above). RESULTS: 584 cases of cerebral palsy were ascertained, yielding a rate that rose from 1.68 per 1000 neonatal survivors during 1964-1968 to 2.45 during 1989-1993 (rise = 0.77; 95% confidence interval 0.2-1.3). For the more reliably ascertained cases there was a twofold increase in rate from 0.98 to 1.96 (rise = 0.98; 95% confidence interval 0.5-1.4). By birth weight, increases in rates were from 29.8 to 74.2 per 1000 neonatal survivors < 1500 g and from 3.9 to 11.5 for those 1500-2499 g. Newborns < 2500 g now contribute one half of all cases of cerebral palsy and just over half of the most severe cases, whereas in the first decade of this study they contributed one third of all cases and only one sixth of the most severe (chi(2) and chi(2) for trend p < 0.001). CONCLUSIONS: The rate of cerebral palsy has risen in spite of falling perinatal and neonatal mortality rates, a rise that is even more pronounced when the mildest and least reliably ascertained are excluded. The effect of modern care seems to be that many babies < 2500 g who would have died in the perinatal period now survive with severe cerebral palsy. A global measure of severity should be included in registers of cerebral palsy to determine a minimum threshold for international comparisons of rates, and to monitor changes in the distribution of severity.

A cost analysis of neonatal care in the UK: results from a multicentre study. ECSURF Study Group.

BACKGROUND: A number of papers have recently been published examining the magnitude of scale economies in neonatal care and the level of activity at which these become attainable. Although these agree there is scope for economies in the production of neonatal care, they debate the extent to which such economies are attainable and how they might best be detected. A major multicentre study of neonatal units in the United Kingdom has produced costing and activity data allowing these issues to be explored afresh. METHODS: A postal questionnaire was used to determine neonatal cost and activity levels in 57 UK neonatal units. Costs for the financial year 1990-1991 related to clinical staffing, support (such as pathology) and overheads (such as heat, light, power and administrative overheads). Activity related to the total number of care days provided and the number of these that were intensive in nature. All data were scrutinized to ensure consistent definitions. A multivariate regression analysis was used to investigate the relationship between costs and activity. RESULTS: A double-log function relating variations in total costs to total days, case-mix and an interaction term provided the best fit to the data. The analysis suggests that significant economies of scale are possible within the observed range of provision of intensive care. CONCLUSIONS: Significant economies of scale may be attainable. Nevertheless, these results should be carefully interpreted. In particular, the costs of neonatal care should not be examined in isolation but in relation to outcomes. In certain instances, units of inefficient scale but acceptable outcome may be defensible on grounds of ease of access.

Six years' experience of prophylactic oral vitamin K.

AIMS: The ability of oral vitamin K to eliminate all risk of vitamin K deficiency bleeding during the first three months of life was studied. METHODS: Babies (n=182,000) in the north of England judged well enough to be offered milk within 12 hours of birth were given 1 mg of phytomenadione (vitamin K(1)) suspended in a medium chain triglyceride oil by mouth at delivery between 1993 and 1998. The parents of those who were breastfed were given a further three doses to give to the baby once every two weeks after discharge. RESULTS: Four breastfed babies developed late vitamin K deficiency bleeding. In two, staff failed to follow policy guidelines, and in two there was undiagnosed alpha(1) antitrypsin deficiency. Audit suggested that 93% of breastfed babies had all four doses, as advised. CONCLUSIONS: An oral product that parents can administer themselves would be popular if licensed, but the total dose offered may need to be more than in this study if babies with undiagnosed liver disease are to be protected.

Surfactant-deficient respiratory distress after elective delivery at 'term'.

Babies of 37-41 wk gestation are, by international convention, said to be born at 'term', but some still develop respiratory distress. It is not clear how mature a baby has to be to be free of risk of primary surfactant deficiency. An area-based retrospective study of all the 179,701 babies of 34 or more weeks' gestation born alive in a defined area of the north of England in 1988-92 identified 149 babies with features of respiratory distress typical of surfactant deficiency severe enough to be managed with ventilatory support and with no evidence of aspiration or intrapartum infection. Gestation was carefully cross-validated against antenatal information, including at least one ultrasound assessment in the first half of pregnancy. Thirty-six of these babies were born at or after 37 wk gestation. Only 4 of the 35 delivered at 37-38 wk went into spontaneous labour. Seven became ill enough to be candidates for ECMO and two died. A review of all neonatal deaths in the study area between 1981 and 1995 identified four similar deaths in 1981-87 and two in 1993-95. Babies who are not premature, using the internationally agreed definition, can show signs of potentially lethal pulmonary immaturity at birth, especially if subjected to pre-labour Caesarean delivery. Those born at 37-38 wk are 120 times more likely to receive ventilatory support for surfactant deficiency than those born at 39-41 wk. Elective delivery should only be undertaken before 39 wk gestation for good medical reasons.

Effect of maternal anticonvulsant treatment on neonatal blood coagulation.

AIMS: To investigate the impact of maternal anticonvulsant use on the ability of cord blood to coagulate. METHODS: Cord blood prothrombin times were measured, over 15 years in a consecutive series of 137 term babies born to women taking phenobarbitone, phenytoin, and/or carbamazepine while pregnant. The response to parenteral vitamin K was measured in 83 neonates. RESULTS: Only 14 of the 105 babies born to the mothers who had therapeutic anticonvulsant blood concentrations at birth had a prolonged prothrombin time (outside the 95% reference range). None had an overt bleeding tendency. The abnormality was corrected within 2 hours by 1 mg of parenteral vitamin K, but rapid intravenous prophylaxis produced complications in three infants. CONCLUSIONS: A policy of giving vitamin K throughout the last third of pregnancy to all women being treated with anticonvulsants, as recently recommended, is not justified by the available evidence. The belief that there is a distinct, early form of neonatal vitamin K deficiency that is different from, and more dangerous than, the classic form of the disease, is not supported by a review of the published evidence.

Renal processing of glucose in well and sick neonates.

AIMS: To determine the extent of renal processing of glucose in sick and well neonates. METHODS: Glomerular filtration rate (GFR) and the renal processing of glucose, sodium, and water were measured using prolonged inulin infusion in 47 infants of 26-40 weeks of gestation, aged 1-13 days. RESULTS: GFR rose by 15% after ventilatory support was withdrawn, and was unaffected by clinical instability. Fractional glucose excretion was low in the stable unventilated babies except at very high filtered loads, but rose in one unstable, unventilated baby. It was higher in ventilated babies, and remained high for at least six days after ventilation. For water and sodium, net differences between intake and urine excretion were not affected by ventilation, clinical stability, or glycosuria. CONCLUSIONS: A combination of a low GFR and a high fluid intake, urine flow, and urine concentrating capacity, makes neonates very unlikely to develop an osmotic diuresis due to glycosuria while they have a blood glucose below 12 mmol/l, despite assertions to the contrary.