Does variation in interpretation of ultrasonograms account for the variation in incidence of germinal matrix/intraventricular haemorrhage between newborn intensive care units in New Zealand?

The Frequency of Intraventricular Hemorrhage and its Risk Factors

BACKGROUND

Intraventricular hemorrhage (IVH) (is the most prevalent type of cerebrovascular accident in premature infants, which can result in lasting neurological complications. The aim of this study was to ascertain the frequency of IVH and its associated risk factors within our particular context.

MATERIALS AND METHODS

This cross-sectional study was carried out in a tertiary neonatal intensive care unit of a maternal and neonatal hospital from September 2018 to August 2019. Premature infants under 34 weeks of age and with birth weight < 1500 grams who did not have significant congenital anomalies participated in the study. A brain ultrasound was performed by a sonologist during the first week. The infants were subsequently categorized into two groups: those with and without IVH. A comparative analysis was conducted using the chi-square test and logistic regression. A significance level of p<0.05 was considered statistically significant.

RESULTS

Of the 205 premature infants who completed the study, IVH was reported in 107 cases (52.1%), of which 97.3% of ventricular hemorrhages were grade I and II and 2.7% accounted for severe bleeding (grade III and IV). Gestational age less than 28 weeks, weight less than 1000 g, vaginal delivery, asphyxia and resuscitation, history of intubation and mechanical ventilation, cord blood acidity, dopamine infusion, and history of fever and chorioamnionitis in the mother have been found to be significantly associated with increased risk of IVH (p<0.001). Antenatal corticosteroids decreased the risk (OR=10.63).

CONCLUSION

In this study, IVH has been found to be common in infants under 1500 g of weight, but the severe form was low in frequency and was observed significantly in high-risk pregnancies.

Risk factors and short-term complications of high-grade intraventricular hemorrhages in preterm neonates in training hospitals of Alborz

Objectives

The aim of this study is to determine risk factors and short-term complications of high-grade intraventricular hemorrhages (IVHs) in preterm neonates. Other topics of investigation include the increase in complications of IVH with its severity and the effect of IVH risk factors on the severity of IVH.

Materials & Methods

We conducted a retrospective case-control study of 436 consecutive preterm neonates with high-grade (3, 4) IVHs admitted in training hospitals of Alborz University in Karaj, Iran, from 2012 to 2017. The risk factors and short-term complications were assessed and analyzed in the subjects by SPSS 19.

Results

Out of 10 000 eligible neonates, we identified 1203 premature infants with IVH. A total of 436 infants with IVH grades 3 and 4 were allocated to the case group. The control group consisted of 767 infants with IVH grades 1 and 2. This study revealed that the most common risk factors of IVH include lack of corticosteroid use in 67.2%, low Apgar score in 10%, and surfactant use in 5.7% of the patients. Ten percent (31 cases) had short-term complications (18 hydrocephalus and 13 death cases). Male gender (P = .006) and lower gestational age (P = .0001) contributed to higher grades of IVH.

Conclusion

According to the results obtained in this study, it may be concluded that the lack of corticosteroid use is the most common risk factor for IVH, and short-term complications may be seen in one-tenth of the cases.

Cerebral palsy after very preterm birth - an imaging perspective

Neonatal brain imaging undoubtedly can provide the most accurate information from which to determine whether cerebral palsy is likely to affect an individual infant born preterm. The sensitivity and specificity of that information is different between cranial ultrasound and MRI, depending on what approaches and sequences are used and the timing of the examinations. In this chapter we highlight the changing incidence of different patterns of brain injury in the preterm newborn and present a comparison of cranial ultrasound and MRI for predicting cerebral palsy in preterm infants affected by the commoner intracranial pathologies.

Improving incidence trends of severe intraventricular haemorrhages in preterm infants <32 weeks gestation: a cohort study

OBJECTIVE

To describe the trend and risk factors for severe intraventricular haemorrhage (IVH) among infants <32 weeks gestation.

DESIGN

Population-based cohort study.

SETTING

Australia and New Zealand.

PATIENTS

All preterm infants <32 weeks gestation in the Australian and New Zealand Neonatal Network (ANZNN) from 1995 to 2012.

INTERVENTIONS

Comparison of IVH incidence between 6-year epochs.

MAIN OUTCOME MEASURES

Overall IVH and severe IVH incidence.

RESULTS

A total of 60 068 infants were included, and overall survival to discharge increased from 89% to 93% over the three epochs. As the percentage of infants with IVH decreased from 23.6% to 21.3% and 21.4% (p<0.001) from epoch 1 to 3, respectively, fewer survivors had severe IVH (4.0%, 3.3% and 2.8%, respectively, p<0.001). Over time, there were fewer antenatal complications, higher antenatal steroid usage and more caesarean-section births. Fewer infants were intubated at birth, had low 5 min Apgar score, had sepsis or pneumothorax needing drainage. Adjusted for perinatal confounders, there was significant reduction in odds of severe IVH from epoch 1 to 3 (adjusted OR (AOR) 0.8, 95% CI 0.7 to 0.9). Factors associated with development of severe IVH include no antenatal steroids (AOR 1.7, 95% CI 1.5 to 1.9), male (AOR 1.3, 95% CI 1.2 to 1.4), 5 min Apgar score <7 (AOR 2.0, 95% CI 1.9 to 2.2), intubated at birth (AOR 2.0, 95% CI 1.8 to 2.2), extremely low gestational age (AOR 4.0, 95% CI 3.7 to 4.4), outborn (AOR 1.6, 95% CI 1.5 to 1.8) and vaginal delivery (AOR 1.4, 95% CI 1.3 to 1.6).

CONCLUSIONS

Along with increased survival among infants born <32 weeks gestation, the incidence of severe IVH has decreased over the 18 years, especially in the most recent period. This coincided with reduction in rates of risk factors for severe IVH development.

Retinopathy of prematurity, visual and neurodevelopmental outcome, and imaging of the central nervous system

Recent findings indicate that retinopathy of prematurity (ROP), presently classified by clinical examinations of retinal vascular tissue, is associated with structural alterations of the central nervous system. Such alterations may be the correlate of the association between ROP and impaired long-term neurocognitive and visual development. The advent of imaging techniques such as structural and diffusion tensor magnetic resonance imaging of the brain, and optical coherence tomography of the retina, will allow the complete visual system to be characterized in greater detail. It has been suggested that ROP may be not only a vascular, but a neurovascular disease, being part of a spectrum that includes pathological development in both the retinal and cerebral neurovascular interphase. We review the present knowledge in the field and point to future directions for research to tackle these questions.

Intraventricular hemorrhage and neurodevelopmental outcomes in extreme preterm infants

OBJECTIVE

Not many large studies have reported the true impact of lower-grade intraventricular hemorrhages in preterm infants. We studied the neurodevelopmental outcomes of extremely preterm infants in relation to the severity of intraventricular hemorrhage.

METHODS

A regional cohort study of infants born at 23 to 28 weeks' gestation and admitted to a NICU between 1998 and 2004. Primary outcome measure was moderate to severe neurosensory impairment at 2 to 3 years' corrected age defined as developmental delay (developmental quotient >2 SD below the mean), cerebral palsy, bilateral deafness, or bilateral blindness.

RESULTS

Of the 1472 survivors assessed, infants with grade III-IV intraventricular hemorrhage (IVH; n = 93) had higher rates of developmental delay (17.5%), cerebral palsy (30%), deafness (8.6%), and blindness (2.2%). Grade I-II IVH infants (n = 336) also had increased rates of neurosensory impairment (22% vs 12.1%), developmental delay (7.8% vs 3.4%), cerebral palsy (10.4% vs 6.5%), and deafness (6.0% vs 2.3%) compared with the no IVH group (n = 1043). After exclusion of 40 infants with late ultrasound findings (periventricular leukomalacia, porencephaly, ventricular enlargement), isolated grade I-II IVH (n = 296) had increased rates of moderate-severe neurosensory impairment (18.6% vs 12.1%). Isolated grade I-II IVH was also independently associated with a higher risk of neurosensory impairment (adjusted odds ratio 1.73, 95% confidence interval 1.22-2.46).

CONCLUSIONS

Grade I-II IVH, even with no documented white matter injury or other late ultrasound abnormalities, is associated with adverse neurodevelopmental outcomes in extremely preterm infants.

Fish-oil fat emulsion supplementation reduces the risk of retinopathy in very low birth weight infants: a prospective, randomized study

BACKGROUND

Preliminary studies suggest that fish-oil lipid emulsion given parenterally to very preterm infants reduces the severity of retinopathy (ROP) and cholestasis.

METHODS

Infants weighing <1250 g at birth were randomly allocated to 2 groups: an experimental group of 60 infants that received an intravenous (IV) soybean, olive oil, and fish oil emulsion, and a control group of 70 infants that was given a parenteral soybean and olive oil emulsion. Plasma and erythrocyte concentrations of docosahexaenoic acid (DHA) were determined using a high-performance liquid chromatography-mass spectrometry analysis.

RESULTS

Nine infants in the fish oil group required laser therapy for ROP compared with 22 infants in the standard intralipid group (risk ratio [RR], 0.48; 95% confidence interval [CI], 0.24-0.96). Three infants in the fish oil group developed cholestasis compared with 20 infants in the standard intralipid group (RR, 0.18; 95% CI, 0.055-0.56). The mean plasma DHA concentrations in treated infants were 2.9-fold higher in the fish oil group than in control infants on the 7th and 14th days of life. The mean DHA content in erythrocytes of treated infants was 4.5-fold and 2.7-fold higher compared with controls at 7 and 14 days of age.

CONCLUSIONS

Premature infants receiving an IV fat emulsion containing fish oil had less ROP requiring laser treatment and less cholestasis than those receiving a standard lipid emulsion. These infants also had higher plasma and erythrocyte DHA levels at 7 and 14 days, suggesting potential long-term neurodevelopmental benefits.

Reader variability in the use of diagnostic terms to describe white matter lesions seen on cranial scans of severely premature infants: the ELGAN study

PURPOSE

To evaluate reader variability of white matter lesions seen on cranial sonographic scans of extreme low gestational age neonates (ELGANs).

METHODS

In 1,452 ELGANs, cranial sonographic scans were obtained in the first and second postnatal weeks, and between the third postnatal week and term. All sets of scans were read independently by two sonologists. We reviewed the use of four diagnostic labels: early periventricular leucomalacia, cystic periventricular leucomalacia, periventricular hemorrhagic infarction (PVHI), and other white matter diagnosis, by 16 sonologists at 14 institutions. We evaluated the association of these labels with location and laterality of hyperechoic and hypoechoic lesions, location of intraventricular hemorrhage, and characteristics of ventricular enlargement.

RESULTS

Experienced sonologists differed substantially in their application of the diagnostic labels. Three readers applied early periventricular leucomalacia to more than one fourth of all the scans they read, whereas eight applied this label to ≤5% of scans. Five applied PVHI to ≥10% of scans, while three applied this label to ≤5% of scans. More than one third of scans labeled cystic periventricular leucomalacia had unilateral hypoechoic lesions. White matter abnormalities in PVHI were more extensive than in periventricular leucomalacia and were more anteriorly located. Hypoechoic lesions on late scans tended to be in the same locations, regardless of the diagnostic label applied.

CONCLUSIONS

Experienced sonologists differ considerably in their tendency to apply diagnostic labels for white matter lesions. This is due to lack of universally agreed-upon definitions. We recommend reducing this variability to improve the validity of large multicenter studies.

The establishment of the Australian and New Zealand Neonatal Network

The Australian and New Zealand Neonatal Network was established in 1994 to monitor high-risk newborns admitted for care. Uniquely, all units in both countries have participated since inception, making it integral to the care of babies. The network's objectives include auditing care, publishing aggregated results annually, providing feedback to units, monitoring technologies and developing clinical indicators. Networking provides a forum for clinicians and a consortium of knowledge and advice. It facilitates collaborative research and clinical groups, producing projects from observational studies to randomised controlled trials. Members take a major role in reviewing the evidence for care and ensuring its effective use in clinical practice.

Does observer bias contribute to variations in the rate of retinopathy of prematurity between centres?

PURPOSE

We aimed to indirectly assess the contribution from observer bias to between centre variability in the incidence of acute retinopathy of prematurity (ROP).

METHODS

The Australian and New Zealand Neonatal Network (ANZNN) collected data on the highest stage of acute ROP in either eye in 2286 infants born at less than 29 weeks in 1998-1999 and cared for in one of 25 neonatal intensive care units (NICUs). Chi-squared analysis was used to detect differences in the proportion of stages of ROP for each neonatal intensive care unit. These proportions were compared with those reported in two large studies of treatment for ROP.

RESULTS

The incidence of acute ROP in the ANZNN cohort was 42% and the ratio of stage 1:2:3 ROP was 1.5:1.9:1. There was considerable variation in both the incidence of acute ROP and the proportions with stage 1:2:3 ROP between centres. A chi-squared test determined that the assignment of stages 1, 2 and 3/4 ROP was not independent of centre (chi(2)(48) = 165.2; P < 0.0001). Treatment of stage 3 ROP varied between 15% and 120%, indicating some eyes were treated at less than stage 3.

CONCLUSION

The data are highly suggestive of observer bias contributing to the observed between centre variation in the incidence of acute ROP. In neonatal intervention studies where acute ROP is an outcome it would seem important to have an accreditation process for examining ophthalmologists, and there are similar arguments for neonatal networks which collect these data.

Observer variability assessing US scans of the preterm brain: the ELGAN study

BACKGROUND

Neurosonography can assist clinicians and can provide researchers with documentation of brain lesions. Unfortunately, we know little about the reliability of sonographically derived diagnoses.

OBJECTIVE

We sought to evaluate observer variability among experienced neurosonologists.

MATERIALS AND METHODS

We collected all protocol US scans of 1,450 infants born before the 28th postmenstrual week. Each set of scans was read by two independent sonologists for the presence of intraventricular hemorrhage (IVH) and moderate/severe ventriculomegaly, as well as hyperechoic and hypoechoic lesions in the cerebral white matter. Scans read discordantly for any of these four characteristics were sent to a tie-breaking third sonologist.

RESULTS

Ventriculomegaly, hypoechoic lesions and IVH had similar rates of positive agreement (68-76%), negative agreement (92-97%), and kappa values (0.62 to 0.68). Hyperechoic lesions, however, had considerably lower values of positive agreement (48%), negative agreement (84%), and kappa (0.32). No sonologist identified all abnormalities more or less often than his/her peers. Approximately 40% of the time, the tie-breaking reader agreed with the reader who identified IVH, ventriculomegaly, or a hypoechoic lesion in the white matter. Only about 25% of the time did the third party agree with the reader who reported a white matter hyperechoic lesion.

CONCLUSION

Obtaining concordance seems to be an acceptable way to assure reasonably high-quality of images needed for clinical research.

Variable interpretation of ultrasonograms may contribute to variation in the reported incidence of white matter damage between newborn intensive care units in New Zealand

BACKGROUND

The incidence of cerebral white matter damage reported to the Australian and New Zealand Neonatal Network (ANZNN) varies between neonatal intensive care units (NICUs).

HYPOTHESIS

Differences in the capture, storage, and interpretation of the cerebral ultrasound scans could account for some of this variation.

METHODS

A total of 255 infants of birth weight <1500 g and gestation <32 weeks born between 1997 and 2002 and drawn equally from each of the six NICUs in New Zealand were randomly selected from the ANZNN database. Half had early cerebral ultrasound scans previously reported to ANZNN as normal, and half had scans reported as abnormal. The original scans were copied, anonymised, and independently read by a panel of three experts using a standardised method of reviewing and reporting.

RESULTS

There was considerable variation between NICUs in methods of image capture, quality, and completeness of the scans. There was only moderate agreement between the reviewers' reports and the original reports to the ANZNN (kappa 0.45-0.51) and between the reviewers (kappa 0.54-0.64). The reviewers reported three to six times more white matter damage than had been reported to the ANZNN.

CONCLUSION

Some of the reported variation in white matter damage between NICUs may be due to differences in capture and interpretation of cerebral ultrasound scans.