To validate Clinical Risk Index for Babies (CRIB) and CRIB II mortality prediction scores in a UK population of infants born at <=32 weeks’ gestation, and investigate CRIB II calculated without admission temperature.
Infants born at 22–32 weeks’ gestation to mothers resident in a UK region in 2005–2006 admitted for neonatal care were identified. Predictive probabilities for mortality were calculated using CRIB, CRIB II and CRIB II without admission temperature (CRIB II(-T)) using published algorithms and after recalibration.
Predictive performance was investigated overall and for groups defined by gestation and admission temperature and summarised by area under receiver-operating curve, Cox’s regression, Brier scores and Spiegelhalter’s z-scores.
3268 infants were included: 317 (9.7%) died before discharge. Using published algorithms each score showed excellent discrimination (area under the curve = 0.92). The total number of deaths was predicted well for CRIB (324.4) but for both versions of CRIB II the number of deaths was underpredicted (255.2 and 216.6). All scores performed poorly for subgroups.
After recalibration CRIB II displayed excellent predictive characteristics overall (Spiegelhalter’s z-score p = 0.52) and in the gestation groups (p = 0.44 and 0.57) but not for the temperature groups (p = 0.026 and 0.97). CRIB II(-T) displayed excellent predictive characteristics for all groups: overall p = 0.53; gestation groups p = 0.64 and 0.42; temperature groups p = 0.42 and 0.66.
The published algorithm for CRIB II was poorly calibrated but simple linear recalibration provided good results. The CRIB II score without admission temperature showed good predictive characteristics once recalibrated and this version of the score should be used when benchmarking mortality in neonatal intensive care units.
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.
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.
Survival to term, predicted from information available at birth, and at the onset of labour or delivery.
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.
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.
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.
To compare the perinatal characteristics, neonatal morbidity and mortality of preterm singletons, twins and triplets born at 22–31 weeks’ gestation and admitted to neonatal intensive care units (NICU) in New South Wales and Australian Capital Territory between 1994 and 2005.
Perinatal characteristics and neonatal outcome data were obtained from the regional NICUS data collection to test for a priori hypothesis. The 10 068 very premature infants studied included 7304 (72.5%) singletons, 2444 (24.2%) twins and 320 (3.2%) triplets.
Assisted conception was associated with a higher maternal age and increased twins and triplets admissions into NICU than spontaneous conceptions (twins OR 6.9, 95% CI 6.1 to 8.0; and triplets OR 35.6, 95% CI 27.6 to 45.8). Major neonatal morbidities were similar between the three groups of singletons, twins or triplets. While twins of 22–27 weeks’ gestation (adjusted OR 1.39, 95% CI 1.12to 1.72) had higher mortality compared with singletons, mortality only diverged below 24 weeks’ gestation. Mortality was predicted by decreasing gestational age, male gender and lack of antenatal steroids, whereas assisted conception was protective against mortality (adjusted OR 0.69, 95% CI 0.57 to 0.86).
Assisted conception contributed to higher very premature NICU admissions of twins and triplets. Preterm twins at the very extreme of viability had higher mortality compared with singletons. The protective effect of assisted conception against mortality requires further research.
The effect of delayed analysis on cerebrospinal fluid (CSF) white blood cell (WBC) count and glucose has never been studied in neonates.
Prospective cohort study.
Level III newborn unit.
Neonates undergoing lumbar puncture were enrolled after consent. CSF was analysed at baseline (30 minutes) for protein, WBC and glucose; and from the same sample for WBC and glucose after a lag of 2 h and 4 h after lumbar puncture. Those with traumatic/inadequate CSF were excluded. Subjects were classified in three groups (n = 20 each) based on baseline WBC count: no WBC, 1–30 WBC and >30 WBC/µl. Analysis was by repeated-measures ANOVA.
There was a significant decline in mean (SD) CSF glucose from baseline to 2 h and 4 h (41.0 (19) to 38.3 (19) and 36.2 (20) mg/dl, respectively) and WBC count (36 (45) to 28.6 (38) and 23.8 (34) cells/µl, respectively; both p<0.001). CSF glucose and WBC declined in all three groups (p<0.001). High baseline CSF WBC (p<0.001) and protein (p<0.001) was associated with a more rapid decline in the levels of CSF WBC, but not glucose. True CSF parameters could be predicted from 4-h parameters: "baseline glucose 5.4 + 0.98 (4-h glucose)" (adjusted R2 97.2%, p<0.001) and "baseline WBC 1.3 (4-h WBC) +0.05 (protein)" (adjusted R2 98.8%, p<0.001). In group 3, a diagnosis of meningitis (based on pleocytosis) would be missed in 52.6% and 78.9% subjects at 2 h and 4 h, respectively.
CSF WBC count and glucose decrease significantly with time. Reliance on WBC counts of delayed samples can result in underdiagnosis.
Benchmarking is that process through which best practice is identified and continuous quality improvement pursued through comparison and sharing. The Vermont Oxford Neonatal Network (VON) is the largest international external reference centre for very low birth weight (VLBW) infants. This report from 2004–7 compares survival and morbidity throughout Ireland and benchmarks these results against VON.
A standardised VON database for VLBW infants was created in 14 participating centres across Ireland and Northern Ireland.
Data on 716 babies were submitted in 2004, increasing to 796 babies in 2007, with centres caring for from 10 to 120 VLBW infants per year. In 2007, mortality rates in VLBW infants varied from 4% to 19%. Standardised mortality ratios indicate that the number of deaths observed was not significantly different from the number expected, based on the characteristics of infants treated. There was no difference in the incidence of severe intraventricular haemorrhage between all-Ireland and VON groups (5% vs 6%, respectively). All-Ireland rates for chronic lung disease (CLD; 15–21%) remained lower than rates seen in the VON group (24–28%). The rates of late onset nosocomial infection in the all-Ireland group (25–26%) remained double those in the VON group (12–13%).
This is the first all-Ireland international benchmarking report in any medical specialty. Survival, severe intraventricular haemorrhage and CLD compare favourably with international standards, but rates of nosocomial infection in neonatal units are concerning. Benchmarking clinical outcomes is critical for quality improvement and informing decisions concerning neonatal intensive care service provision.
To determine the short-term outcomes of newborn infants and mothers exposed to antenatal amphetamines in the state of New South Wales and the Australian Capital Territory during 2004.
Amphetamine exposure was determined retrospectively using ICD-10 AM morbidity code searches of hospital medical records and from records of local drug and alcohol services. Records were reviewed on site. All public hospitals (n = 101) with obstetric services were included.
Amphetamines were used by 200 (22.9%) of the 871 identified drug-using mothers. Most women (182, 91%) injected amphetamines intravenously. Compared with the other 669 drug users, amphetamine-using mothers were significantly more likely to use multiple classes of drugs (45.0% vs 7.8%), be subject to domestic violence (32.1% vs 17.5%), be homeless (14.8% vs 4.9%) and be involved with correctional services (19.8% vs 9.7%). The incidence of comorbid psychiatric illnesses were significantly higher (57.4% vs 41.7%) and their infants were more likely to be preterm (29.5% vs 20.4%), notified as children at risk (67.0% vs 32.8%), fostered before hospital discharge (14.5% vs 5.5%) and less likely to be breastfed (27.0% vs 41.6%).
Amphetamine-exposed mothers and infants in public hospitals of NSW and the ACT are at significantly higher risk of adverse social and perinatal outcomes even when compared with mothers and infants exposed to other drugs of dependency. Increased vigilance for amphetamine exposure is recommended due to a high prevalence of use, especially in Australia, as a recreational drug.
To assess for lenticulostriate vasculopathy (LSV) on cranial ultrasound (cUS) scans of very preterm infants: incidence and aetiology, evolution during neonatal period, association with clinical parameters, and MRI equivalent.
Prospective study.
Tertiary neonatal referral centre.
Very preterm infants (<32 weeks) underwent sequential cUS throughout the neonatal period and MRI around term age. cUS were evaluated for LSV and other changes, and MRI for changes in signal and myelination in deep grey matter. LSV was divided into early-onset (<=7 postnatal days) and late-onset (>7 postnatal days). Perinatal clinical parameters were collected for all infants and compared between groups.
In 22/111 (20%) infants LSV was detected: early-onset in 5 and late-onset in 17. LSV mostly presented some weeks after birth and persisted for several months. There were no associations between LSV and other changes on cUS or deep grey matter changes on MRI. Infants with late-onset LSV were younger and smaller at birth than infants with early-onset LSV. Postmenstrual age at first detection was comparable for both LSV groups. There were no associations between LSV and perinatal clinical parameters, but infants with LSV had less episodes of hypotension than infants without LSV.
LSV is a frequent finding on cUS in very preterm infants, but does not show on MRI. The postmenstrual age, rather than gestational and postnatal age, seems important in LSV development. LSV is not associated with clinical parameters. When encountered in otherwise healthy preterm infants, LSV is probably a benign temporary phenomenon.
Right to left shunt and regional hypoventilation (reduced ventilation/perfusion ratio (VA/Q)) have different effects on the curve relating inspired oxygen (PIO2) to oxygen saturation measured by pulse oximetry (SpO2) and can be derived non-invasively from measurements of SpO2 and inspired oxygen pressure (PIO2) using complex models of gas exchange. We developed a simpler computerised "slide-rule" method of making these derivations.
To describe the slide-rule method and determine agreement between measurements derived with this and a more complex algorithm.
Series of PIO2 versus SpO2 data points obtained during 43 studies in 16 preterm infants with bronchopulmonary dysplasia were analysed. Percentage shunt and the degree of right shift (kPa) of the PIO2 versus SpO2 curve compared with the oxyhaemoglobin dissociation curve (a measure of VA/Q) were determined for each dataset with both methods, and the results were compared using the method of Bland and Altman.
The computer slide-rule method produced results for all 43 datasets. The more complex model could derive results for 40/43 datasets. The mean differences (95% limits of agreement) between the two methods for measurements of shunt were –1.7% (–6.5 to +3.5%) and for measurements of right shift were 0.3 kPa (–2.9 to +3.6 kPa).
The slide-rule method was reliable for deriving shunt and right shift (reduced VA/Q) of the PIO2 versus SpO2 curve when compared with the more complex algorithm. The new method should enable wider clinical application of these measurements of oxygen exchange.
In preterm infants with respiratory distress syndrome (RDS) nasal continuous positive airway pressure (nCPAP) with the "InSurE" procedure (intubation, surfactant, extubation) is increasingly used. However, its effect on cerebral oxygenation and brain function is not known.
To evaluate the effects of the "InSurE" procedure in infants with RDS on regional cerebral oxygen saturation (rScO2) and relative cerebral fractional tissue oxygen extraction (cFTOE) using near infrared spectroscopy and on electrical brain activity using amplitude-integrated electroencephalography (aEEG).
Sixteen infants with RDS, treated with the "InSurE" procedure, and 16 matched controls with nCPAP, were monitored for mean arterial blood pressure (MABP), arterial oxygen saturation (SaO2), rScO2, cFTOE and aEEG. Ten-minute periods were selected and averaged at 120 and 20 minutes before, during the procedure and at 30 minutes, 1, 2, 6, 12 and 24 h after the start of the "InSurE" procedure. aEEG was analysed by quantitative and qualitative (Burdjalov score) methods.
MABP was not different between groups on all time points. rScO2 and cFTOE were comparable between groups, but there was a trend towards lower rScO2 and higher cFTOE 30 minutes after opioid administration in the "InSurE" infants compared with controls (62% (SD 11) vs 68% (SD 10) and 0.30 (SD 0.10 ) vs 0.28 (SD 0.11), respectively). aEEG amplitudes and Burdjalov scores were significantly lower in "InSurE" infants from 30 minutes after opioid administration up to 24 h after the start of the procedure (p<0.05).
In the present study, the "InSurE" procedure did not induce perturbation of cerebral oxygen delivery and extraction, whereas electrical brain activity decreased for a prolonged period of time.
Most infants born through meconium-stained amniotic fluid (MSAF) are observed clinically for 24 h postnatally. Only 5% of infants born through MSAF develop the meconium aspiration syndrome (MAS), a serious condition requiring medical intervention.
To evaluate the value of 24-h postnatal observation of infants born through MSAF.
A cohort of 394 term neonates born through MSAF was studied. Data were collected on Apgar scores, the development of MAS and other perinatal factors.
Nineteen of the 394 (4.8%) infants born through MSAF developed MAS. 298 (76%) infants had a 5-minute Apgar score (5'AS) of >=9. In this group the number of infants developing MAS (1; 0.3%) was significantly lower compared with the 5'AS <=8 group (18; 19%).
MAS develops rarely in infants born through MSAF with 5'AS above 8. These infants can be safely discharged from the hospital shortly after birth.
Group B streptococcus (GBS) is the most common cause of early onset (EO) neonatal infection in the UK. National guidelines for its prevention were introduced in 2003. We assessed the opportunities for prevention amongst cases of EO GBS using the electronic Neonatal Infection Surveillance Network (NeonIN).
Culture proven EO GBS cases occurring between 2004 and 2007 were identified prospectively in eight neonatal units participating in NeonIN. Data concerning risk factors, intrapartum antibiotic (IAP) use and infant outcome were collected retrospectively.
There were 48 cases of GBS over the 4 years (0.52/1000 live-births); 22 male, median gestation 38 weeks. The most common clinical presentation was sepsis and the GBS-attributable mortality was 6%. Risk factors were present in 67% (32) and adequate IAP was given to six of these mothers (19%). If all women with risk factors received prophylaxis, 23 cases (48%) may have been prevented.
Better GBS prevention strategies are required in the UK.