Exposure to repeat doses of antenatal glucocorticoids is associated with altered cardiovascular status after birth

OBJECTIVE

To determine if exposure to more than one course of antenatal glucocorticoids is associated with changes in infant blood pressure and myocardial wall thickness in the first month after birth.

DESIGN

Prospective cohort study.

SETTING

Tertiary neonatal intensive care unit.

PARTICIPANTS

Mothers who were eligible for but declined to enter a randomised trial of repeated doses of antenatal glucocorticoids (ACTORDS)-that is, who had a singleton, twin, or triplet pregnancy at <32 weeks gestation, had received an initial course of glucocorticoids seven or more days previously, and were considered to be at continued risk of preterm birth.

MAIN OUTCOME MEASURES

Blood pressure daily for the first week then weekly until 4 weeks of age. End diastolic interventricular septal and left ventricular posterior wall (EDIVS and EDLVPW) thickness at 48-72 hours after birth.

RESULTS

Thirty seven women were enrolled and delivered 50 infants. Thirty mothers (39 infants) were exposed to one course of glucocorticoids, and seven mothers (11 infants) to more than one course. Blood pressures were higher in the first week after birth in infants exposed to multiple courses of glucocorticoids, and in infants with a latency between last exposure and delivery of less than seven days. Systolic blood pressure on day 1 was >2SD above published normal ranges in 67% of babies exposed to multiple courses and 24% of babies exposed to a single course of glucocorticoids (p = 0.04). There was no difference between groups in thickness of the EDIVS or EDLVPW. However, 44/50 (88%) babies had EDIVS and 49/50 (98%) babies had EDLVPW thickness >2 SD above the expected mean for birth weight and gestation. EDIVS but not EDLVPW thickness increased with increasing latency (mean 0.02 mm/day, p = 0.03).

CONCLUSION

Future randomised trials should assess the long term effects of exposure to antenatal glucocorticoids, particularly multiple courses, on the cardiovascular status of the infant.

Variation in identifying neonatal percutaneous central venous line position

OBJECTIVE

The study objective was to obtain data on interpretation, including intra and interobserver variation and action taken for a given line tip location, for a series of radiographs demonstrating neonatal long lines.

METHODS

Nineteen radiographs taken to identify line tip position were digitized and published on an internet site. One film was included twice in order to assess intraobserver variation giving a total of 20 images. Fourteen used radio-opaque contrast and five no contrast. Australian and New Zealand Neonatal Network members and National Women's Hospital NICU staff were invited to participate in the study. For each radiograph, participants were asked to identify if long line tip could be identified, the likely anatomical position and desired action. Interobserver agreement was assessed by the maximum proportion of agreement per radiograph and by the number of different options selected. Intraobserver agreement was assessed by comparing the two reports from the duplicate radiograph.

RESULTS

Twenty-seven responses were received. Overall, 50% of the reports stated that the long line tips could be identified. The most commonly reported position was in the right atrium (31%) and most commonly reported action was to pull the line back (53%). The median agreement of whether the line was seen was 68%, agreement on position 62% and agreement on action 86%. On analysis of intraobserver variability, from the identical radiographs, 27% of respondents differed on whether the line tip could be visualized.

CONCLUSION

Interobserver and intraobserver reliability was poor when using radiographs to assess long line tips. The major determinant of line repositioning was the perceived location.

Does radio-opaque contrast improve radiographic localisation of percutaneous central venous lines?

BACKGROUND

Percutaneous central venous lines (long lines) are commonly used in neonatal practice. The position of these lines is important, because incorrect placement may be associated with complications.

AIMS

To determine whether the addition of radio-opaque contrast material improves the localisation of long line tips over plain radiography.

METHODS

Radiographs taken to identify long line position were identified in two periods; 106 radiographs without contrast taken between October 1999 and August 2000, and 96 radiographs with contrast between September 2001 and July 2002. Two observers independently reviewed each radiograph to identify the position of the line tip. The formal radiology report was recorded as a third observer.

RESULTS

The use of contrast increased the proportion of radiographs in which all observers reported they could see the long line tip (53 (55%) v 41 (39%)). It also increased the proportion where they agreed on anatomical position (57 (59%) v 39 (37%)) and there was a higher kappa coefficient for agreement (0.56 v 0.33).

CONCLUSIONS

The use of contrast while taking radiographs for the localisation of long line position improves the likelihood that an observer can see a long line tip and reduces inter-observer variability. Even using contrast, precise localisation of a long line tip can be difficult.

Primary pulmonary hypoplasia: a case report and review of the literature

A case of primary pulmonary hypoplasia in a term female neonate presenting with severe respiratory distress at birth is reported. Respiratory failure persisted and she died at 12 days of age. Primary pulmonary hypoplasia is a rare condition not associated with other maternal or fetal disorders.

Staphylococcus aureus endocarditis in preterm neonates

This article describes three extremely low birth weight infants with Staphylococcus aureus septicemia associated with insertion of a percutaneous central venous catheter who later developed endocarditis. Echocardiography demonstrated large vegetations although only one infant had a murmur. Following a 6-week course of intravenous flucloxacillin and netilmicin, the endocarditis completely resolved and further intervention was unnecessary, although one baby died later as a result of volvulus and chronic lung disease. Echocardiography should be performed to exclude invasive infection in infants with S. aureus septicemia even when there is no murmur or other evidence of endocarditis. If endocarditis is identified, a good outcome is possible with appropriate aggressive antibiotic therapy.

Chest physiotherapy and porencephalic brain lesions in very preterm infants

OBJECTIVE

National Women's Hospital is one of two hospitals to report a destructive brain lesion, namely encephaloclastic porencephaly (ECPE), in extremely preterm infants. It has been associated with non-cephalic presentation, early hypotension and the number of chest physiotherapy treatments in the first month. The aim of the present study was to determine the temporal relationship between ECPE and chest physiotherapy use in very low-birth weight (VLBW) infants in our unit.

METHODOLOGY

Cerebral ultrasound scan reports, post-mortem reports, clinical and physiotherapy records and, if indicated, original ultrasound films were reviewed for all VLBW babies admitted between 1985 and 1998.

RESULTS

Over the 14 year period in question, 2219 babies with a birth weight < or = 1500 g were admitted. Encephaloclastic porencephaly was found in only the 13 previously reported babies born between 1992 and 1994. Encephaloclastic porencephaly was excluded in 1564 (70%) babies. In 621 (28%) babies who did not have late ultrasound scans, ECPE was thought to be unlikely either because the babies never had any chest physiotherapy (n=479) or because they had chest physiotherapy but were known to be neurodevelopmentally normal on follow up (n=142). Data were incomplete for 21 babies (0.9%). The number of chest physiotherapy treatments per baby decreased from a median of 95 prior to 1989 to 38 and the age of starting treatment increased from 5 to 8 days after 1990. The use of chest physiotherapy ceased in 1995.

CONCLUSIONS

Encephaloclastic porencephaly emerged as a problem at a time when the use of chest physiotherapy had decreased. The cluster of cases seen between 1992 and 1994, although associated with the number of chest physiotherapy treatments given, began to appear because of some other factor.

Pervasive seizures caused by hypoxic-ischemic encephalopathy: treatment with intravenous paraldehyde

Seizures are commonly associated with hypoxic-ischemic encephalopathy. Although the majority of cases are controlled with first- or second-line therapy, others develop pervasive seizures, requiring multiple anticonvulsants. To provide data on the incidence of seizures and response to anticonvulsant therapies, a cohort of 90 term infants with hypoxic-ischemic encephalopathy treated at our institution between January 1, 1995, and July 1, 1999, was reviewed. Of the 60 infants who developed seizures, 59 received phenobarbital initially; in 29 cases, the seizures resolved. The remaining 30 infants received phenytoin as a second-line anticonvulsant, and seizures stopped in 10 cases. The 20 infants with ongoing pervasive seizures were treated with intravenous paraldehyde.

Neurodevelopmental outcome of infants treated with head cooling and mild hypothermia after perinatal asphyxia

OBJECTIVES

To determine the neurodevelopmental outcome of infants treated with head cooling with systemic hypothermia after hypoxic-ischemic encephalopathy.

STUDY DESIGN

Infants >/=37 weeks' gestation, who had an umbilical artery pH </=7.09 or Apgar score </=6 at 5 minutes, plus clinical encephalopathy. Infants with major congenital abnormalities were excluded.

TRIAL DESIGN

Infants were allocated to either no cooling (rectal temperature = 37.0 +/- 0.2 degrees C, n = 15), or, sequentially, to head cooling accompanied by different levels of systemic hypothermia, including minimal cooling, rectal temperature 36.5 degrees C to 36 degrees C (n = 6), and mild cooling, to either 35.9 degrees C to 35.5 degrees C (n = 6), 35 +/- 0.5 degrees C (n = 6) or 34.5 +/- 0.5 degrees C (n = 7). Head cooling was accomplished by circulating cooled water through a coil of tubing wrapped around the head for up to 72 hours. Survivors were followed up with regular neurologic examination by a neonatologist until 18 months of age, then with blinded developmental testing using the revised Bayley Scales.

RESULTS

A total of 40 term infants were enrolled from 2 to 5 hours after birth. The control and the cooled groups were not significantly different for gestation, birth weight, Apgar score, and initial pH. There were 6 early neonatal deaths (3 normothermic and 3 cooled), and 1 death in infancy associated with severe spastic cerebral palsy in a normothermic infant. Six normothermic, 1 minimally cooled, and 4 mildly cooled infants had early stage 1 encephalopathy; all but 1 had a good outcome. Among infants with early stage 2 or 3 encephalopathy, an adverse outcome was found in 4 of 9 normothermic infants (44%) and 4 of 5 minimally cooled infants (80%), whereas in the combined mildly cooled groups, an adverse outcome was found in 4 of 15 infants (26%, odds ratio 0.46 [0.08, 2.56] vs normothermia).

CONCLUSIONS

The present study supports the safety of hypothermia, with no evidence of late adverse effects in any infant. Among infants with moderate to severe encephalopathy at enrollment, there was a tendency toward better outcome. These results emphasize the relatively wide range of outcomes using purely clinical criteria for enrollment. Therapeutic hypothermia should not be used outside of stringent, multicenter trials.

Magnetic resonance imaging of the brain in very preterm infants: visualization of the germinal matrix, early myelination, and cortical folding

OBJECTIVE

To investigate preterm infants, we have installed in our neonatal intensive care unit a dedicated magnetic resonance (MR) imaging system which was specifically designed for neonatal use. The aim of this study was to describe the MR appearances of the brain in preterm infants who were first scanned between 25 and 32 weeks gestational age (GA) and to outline changes to the brains of these infants between their first scan and term.

METHODS

Preterm infants of 25 to 32 weeks GA were imaged using the 1T neonatal MR system (Oxford Magnet Technology, Eyensham, Oxfordshire, England/Picker International, Cleveland, OH). The scanning protocol included T1-weighted conventional spin echo (repetition time [TR], 600; echo time, 20 ms), inversion recovery fast spin echo (TR, 3530; effective echo time, 30; inversion time, 950 ms), and T2-weighted fast spin echo (TR, 3500; effective echo time, 208 ms) sequences.

RESULTS

Seventeen infants of median 28 weeks GA (range, 24 to 31 weeks) at birth were imaged a total of 53 times between birth and term. The median number of images per infant was two (range, 1 to 9). In infants of < 30 weeks GA, the germinal matrix was visualized at the margins of the lateral ventricles. It had a short T1 and short T2 and the bulk of it involuted at between 30 and 32 weeks GA. The white matter had a relatively homogeneous low signal except for bands of altered signal (probably originating from regions containing radial glia and migrating cells) which were most apparent anterolateral and posterolateral to the lateral ventricles. Myelination was seen in the posterior brainstem, cerebellum, and region of the ventrolateral nuclei of the thalamus. Infants had very little cortical folding at 25 weeks GA but this developed later in an orderly fashion.

CONCLUSION

The neonatal MR system allowed extremely preterm infants to be studied safely with MR imaging. The images acquired demonstrated the germinal matrix, early myelination, and early cortical folding. Evolution of these features was demonstrated with serial studies.

Neonatal cranial ultrasonographic findings in preterm twins complicated by severe fetofetal transfusion syndrome

OBJECTIVE

To investigate cranial ultrasonographic findings in survivors of monochorionic pregnancies complicated by fetofetal transfusion syndrome.

STUDY DESIGN

Case details of all monochorionic twin pregnancies complicated by fetofetal transfusion syndrome were obtained from the Centre for Fetal Care database for a 3-year period. Fetofetal transfusion syndrome was diagnosed according to ultrasonographic criteria. Eligible for entry were twin pregnancies resulting in live-born preterm infants and complicated by fetofetal transfusion syndrome severe enough to require amnioreduction. Cranial ultrasonographic scans performed within 48 hours of birth were reviewed for evidence of abnormality.

RESULTS

Seventeen pregnancies were eligible for inclusion in the study. Median gestational age was 25 weeks (between 17 and 29 weeks) at diagnosis and 30 weeks (between 25 and 35 weeks) at delivery. Three infants died before ultrasonography could be performed. The remaining 31 twin infants received an early cranial ultrasonographic scan. One of the 31 had a major cerebral infarct; 10 others had evidence of other, more minor, antenatally acquired lesions.

CONCLUSIONS

Both donor and recipient survivors from pregnancies complicated by fetofetal transfusion syndrome are at significant risk for antenatally acquired cerebral lesions. Long-term neurologic follow-up studies are indicated to determine the clinical significance of these lesions.