Cranial ultrasound screening of preterm and term neonates

Abstract A cranial ultrasound examination was performed between 48 and 96 h of age on 580 neonates of 25–42 weeks gestation. The incidence of cerebroventricular haemorrhage (CVH) in infants less than 32 weeks gestation was 37%, compared with an incidence of 2.7% in infants of 32 weeks or more. The incidence of CVH in unselected healthy term infants (between 37 and 42 weeks) was only 1.1%.
Of the 13 infants of 32 weeks or more who were found to have a haemorrhage, nine had a small (Grade I) haemorrhage (69%) and none of these infants had abnormal neurological signs in the neonatal period. The remaining four infants with Grade II, III or IV haemorrhage developed either seizures or episodes of apnoea. Two of the 13 infants of 32 weeks or more with a haemorrhage died, one during the newborn period and the other at 5.5 months of age.
CVH in asymptomatic infants of 32 weeks or more gestation is uncommon and does not justify routine cranial ultrasound scanning.     

Quantitative ultrasound assessment of bone in preterm and term neonates

There is a need to explore novel methods of assessing bone health in sick preterm infants. This study of the speed of sound in the long bones of newborn term and preterm infants shows that, in this population, this technique is not site specific and has a high degree of interobserver and intraobserver precision. The speed of sound in newborn infants is primarily dependent on gestation rather than birth weight.     

Cranial ultrasound in preterm infants: long term follow up.

One hundred and twenty nine high risk preterm infants (gestational ages 26-36 weeks, mean 31.2 weeks; birth weights 800-3880 g, mean 1490 g) were studied by cranial ultrasound during the neonatal period, over a period of one week to three months, and at the age of 1 year. Neonatal ultrasound scanning was performed with an ATL Mk III real time echoscope, and follow up ultrasound scans at the age of 1 were performed with an Octoson static compound scanner. The neonatal scans of 66 infants were abnormal. Cerebroventricular haemorrhages were detected in 53 infants and other lesions in 19, six of whom also had haemorrhages. Posthaemorrhagic changes developed in 30 infants. The follow up scans at 1 year were abnormal in 27 children. One large parenchymal cyst was detected. All 27 scans showed ventricular dilatations; 19 were asymmetrical. About 95% of the children with normal neonatal scans and 60% with abnormal neonatal scans had normal scans at 1 year. The size and shape of the ventricular system had changed in 20% of all infants. As no major changes were seen in the ultrasound images of those studied beyond the age of 2 months cranial ultrasound follow up in high risk preterm infants should therefore be continued until the age of 2-3 months; follow up beyond that age would only rarely be necessary.     

Cranial ultrasound and clinical studies in preterm infants

Serial ultrasound imaging of the brain was used to determine the ventricular index (VI), and the ratio (VR) of the VI to the cranial hemidiameter during the nursery course and first year post-term in preterm infants of less than 33 weeks gestation. Twenty-nine of the infant survivors with no intracranial hemorrhage or major medical complication during their nursery course composed group 1. Twenty-two survivors with intracranial hemorrhage unassociated with early ventricular dilation composed group 2. Group 3 was comprised of 10 other survivors who had neonatal intraventricular hemorrhage with early ventriculomegaly; all 10 infants had at least one major medical complication during their neonatal course. In groups 1 and 2 the VR decreased and the VI increased significantly with age post-conception. Infants in group 3, compared with those in groups 1 or 2, had decreased occipitofrontal growth during the early postnatal period and increased VR and VI during the neonatal period and first year post-term. These results suggest that the ventriculomegaly associated with neonatal intracranial hemorrhage cannot be explained by posthemorrhagic hydrocephalus alone and may also be related to cerebral atrophy or decreased brain growth or both. Neurodevelopmental assessments at 20 to 30 months of age disclosed significantly lower Bayley Motor Development scores in group 3 compared with groups 1 or 2. Four infants in group 3, but none in groups 1 or 2, had cerebral palsy. The neurodevelopmental deficits in group 3 infants may reflect the complex pathogenesis of the ventriculomegaly as well as the effects of the intraventricular hemorrhage and posthemorrhagic hydrocephalus.     

Temperature measurement in term and preterm neonates

Body temperatures of 99 term and 44 preterm infants were measured at four sites: core (5 cm beyond the anus, with an electronic telethermometer), rectum (2 cm, with a mercury-in-glass thermometer), axilla, and between the skin and mattress. Temperatures measured at the four sites agreed closely in this group of largely normothermic infants. However, five of seven term infants with abnormal core temperature (greater than 1.5 SD below or above the mean) would have been judged to be normothermic by each of the three other measurements. The temperatures in preterm infants were lower and varied less with the site of measurement, indicating a smaller core-surface temperature gradient because of their relative lack of thermal insulation by body fat. Axillary temperature was as reliable as rectal temperature measured in the usual way with a mercury-in-glass thermometer. Measurement of the temperature between the skin and mattress was nearly as accurate as the other more frequently used methods. Ninety percent of temperatures were within 0.1 degree C of their final stabilization readings by 5 minutes for each type of thermometer and measurement site.     

Tympanic membrane temperature of term and preterm neonates

Deep body temperatures of 70 term and 24 preterm newborn infants were measured at two sites: deep rectum (5 cm beyond the anus) and tympanic membrane. A significant correlation was found between deep rectal and tympanic membrane temperatures in both term and preterm infants. Mean deep rectal and tympanic membrane temperatures in term infants were 37.01°C and 36.83°C, respectively. Mean deep rectal and tympanic membrane temperatures in preterm infants were both 36.69°C.     

Echocardiographic measurements in normal preterm and term neonates

To the purpose of better defining normative data on intracardiac dimensions and systolic time intervals in very low birth weight infants, we collected M-mode echocardiograms from 210 healthy preterm and term neonates with birth weights between 780 and 5,350 g and gestational ages ranging from 26 to 43 weeks. Fifty-nine neonates were less than 24 h, 62 were 25-48 h, and 89 were 48-144 h of age. Diastolic and systolic left ventricular dimensions increased gradually with advancing birth weight (r = +0.84 and 0.78). Left atrial and aortic root dimensions tended to show a parabolic relationship with birth weight, increments were reduced at higher birth weights (r = +0.92 and 0.85). The shortening fraction of the left ventricle (mean +/- SD 33.8 +/- 4.9%) and the left atrial/aortic ratio (1.16 +/- 0.10) were constant throughout all weight subgroups. Pre-ejection periods and ejection times of both ventricles were reduced in preterm infants due to their higher heart rates, but left and right ventricular PEP/ET ratios in preterm and term infants were comparable. Septal thickness in diastole and in systole tended to increase slowly with advancing birth weight, but correlation coefficients were low. This information is currently used as data base for a computer program to interpret M-mode echocardiograms performed in our nursery.     

Urinary N-acetyl-beta-D-glucosaminidase excretion in term and preterm neonates

Urinary N-acetyl-beta-D-glucosaminidase (NAG) excretion was measured in term and preterm neonates on days 1, 4, 7, 14 and 28 of life. Urinary NAG showed a peak level on day 4 or 7 in these infants. In addition, it tended to be higher with the degree of prematurity. In sick preterms who were depressed at birth and had respiratory failure, the NAG activity was further elevated during the first 2 weeks, suggesting the presence of renal tubular injury in this period. These observations thus suggest that urinary NAG may be a sensitive measure of renal maturation or damage in neonates.     

Thyroid hormone levels in term and preterm neonates

Screening for thyroid hormone levels in the first week of life is extremely important to identify infants with CH. Worldwide neonatal screening programs have been successful in decreasing childhood mental retardation related to CH by early detection and treatment. To successfully screen for CH, nurses must understand how to draw blood that will yield valid results on the metabolic screening filter paper. It is also important for the nurse to understand that thyroid levels are normally decreased in preterm infants and that regular follow-up of those low thyroid levels is crucial because levels may return to normal and eventual treatment is necessary. Early follow-up testing and treatment are essential. A thyroid scan or ultrasonography is optional and decided on by evaluating the risk-benefit ratio.     

Pulmonary artery pressure in term and preterm neonates

Systolic pulmonary artery pressure (PAP) during the first 4 days after birth was determined in 41 healthy term and 46 preterm infants by measuring ductal Doppler flow velocity and systemic arterial pressure (SAP). Among preterm infants, 21 had respiratory distress syndrome (RDS) and 25 did not. Sequential indices within 96 h of age were presented respectively. At the ages of 2 and 12 h the ratio between pulmonary and systemic arterial pressure was significantly higher in term than in preterm infants without RDS ( p < 0.05). At the age of 24 h, PAP to SAP ratio was similar in all study groups. Between 48 and 72 h, PAP to SAP ratio was significantly higher in preterm infants with RDS than in infants without RDS ( p < 0.05). Our findings indicated that: (1) in healthy fullterm infants pulmonary artery pressure fell to subsystemic level during the first 12 h. indicating the critical time in circulatory transition; (2) prematurity did not affect ductal closure times significantly; and (3) RDS was associated with prolonged ductal patency and delayed postnatal circulatory adaptation characterized by pulmonary hypertension.     

Gentamicin dosage in preterm and term neonates.

Pre-dose and peak serum levels of gentamicin were measured in 82 neonates (25-42 weeks'' gestational age), and for comparison in 10 infants and 9 children. Dosage was 2-2.5 mg/kg twice daily for the neonates, and three times daily for infants and children. Neonates were subdivided according to gestational age and weight. Serum levels of gentamicin were very variable in all groups. Preterm neonates of low gestational age (25-30 weeks) showed a 66% incidence of pre-dose levels exceeding 1 microgram/ml, indicating possible accumulation. In the less premature neonates this incidence was still 20-29%. The level of 4 microgram/ml, the minimum concentration required to inhibit most of the bacteria sensitive to gentamicin, was reached in increasing numbers of neonates as their gestational age rose (from 30% in the 31- to 35-week gestational age group, to 60% at term); those small-for-gestational age had consistently lower levels. It is concluded that term neonates require dosage to be individualized and serum levels of the drug to be monitored.     

Reticulated platelet percentages in term and preterm neonates

OBJECTIVES: The authors aimed to determine whether their reticulated platelet percentage (RP%) analysis technique was suitable for use in term and preterm neonates and to characterize RP% values among nonthrombocytopenic neonates. METHODS: The authors modified a whole blood method that uses dual-color CD41 staining for platelet gating and thiazole orange for RNA content, combined with RNase treatment of half the sample to subtract non-RNA fluorescence. The RP% was measured in samples from 10 healthy adults and then a longitudinal study was performed in 15 nonthrombocytopenic preterm neonates on days of life 0 to 1, 2 to 5, 6 to 10, and then weekly until day 28. The authors also performed a cross-sectional study of RP% in 22 nonthrombocytopenic neonates of different gestational age (GA) and postconceptional age (PCA). RESULTS: Overall, neonates had a higher RP% (2.7 +/- 1.6%) than adults (1.1 +/- 0.5%; P < 0.01). In preterm neonates, an increase in the RP% occurred between days 0 and 1 (3.3 +/- 1.3%) and days 2 and 5 (5.1 +/- 1.8%; P = 0.003). By days 6 to 10, the RP% decreased to 3.2 +/- 1.1% and remained unchanged throughout the rest of the study period. In neonates less than 7 days old, an inverse relationship was observed between RP% and GA (n = 20, r = -0.70; P = 0.0005). A correlation between RP% and PCA was not seen in neonates 7 days of age or older. CONCLUSIONS: This method for determining RP% is suitable for use in term and preterm neonates. In preterm infants, the RP% significantly increases over the first 2 to 5 days of life and then decreases to a stable level over the first 28 days. RP% is generally higher in neonates than in adults. Among preterm infants in the first week of life, the RP% is inversely related to GA.     

Granulocyte-macrophage progenitor cells in term and preterm neonates

In groups of adults, and term and preterm neonates, we determined: the blood concentration, the proliferative rate, and the variety of progeny of committed granulocyte-macrophage progenitor cells (CFU-GM). In five of eight term neonates and in all premature infants, a potentially significant limitation of neutrophil production was detected. Unlike the slowly proliferating CFU-GM present in the blood of healthy adult subjects (7% thymidine suicide, range 0% to 32%), the circulating CFU-GM in the premature subjects were proliferating at a near maximal rate (55%, range 40% to 75%, P less than 0.001). Because CFU-GM proliferation is nearly maximal in the baseline, noninfected state, neonates may have restricted ability to increase neutrophil production from CFU-GM during times of increased neutrophil need, such as during bacterial infection. Such inability may predispose neonates to exhaustion of the neutrophil supply during bacterial infection.     

Level of conus medullaris in term and preterm neonates

AIMS—To compare the levels of conus medullaris in preterm and term neonates; to show the time of ascent to normal; and to evaluate the babies with low conus medullaris levels for tethered cord syndrome.METHODS—Levels were assessed using ultrasonography in 41 preterm and 64 term neonates.RESULTS—In the preterm group the conus medullaris level in one infant (2.4%) was below L4. In three infants (7.2%) it was between L2 and L3 and in 37 infants (90.4%) it was above L2. In the term group it was below L4 in one baby (1.6%), between L2 and L3 in four (6.3%), and above L2 in 57 babies (92.1%). The difference in the conus medullaris levels between term and preterm neonates and genders was not significant. Two patients, one with a conus medullaris level at L4-L5, and the other at L2-L3, had Down''s syndrome.CONCLUSION—The ascent of conus medullaris seems to occur early in life. It is important to follow up patients with conus medullaris levels at or below the 4th lumbar vertebra for the development of tethered cord syndrome.     

Fluid and electrolyte management in term and preterm neonates

Disorders of fluid and electrolyte are common in neonates and a proper understanding of the physiological changes in body water and solute after birth is essential to ensure a smooth transition from the aquatic in-utero environment. The newborn kidney has a limited capacity to excrete excess water and sodium and overload of fluid or sodium in the first week may result in morbidities like necrotizing enterocolitis, patent ductus arteriosus and chronic lung disease. Simple measures like use of transparent plastic barriers, coconut oil application, caps and socks are effective in reducing insensible water loss. Guidelines for the management of fluids according to birth weight, day of life and specific clinical conditions are provided in the protocol.     

Fluid and electrolyte management in term and preterm neonates

Disorders of fluid and electrolyte are common in neonates. Proper understanding of the physiological changes in body water and solute after birth is essential to ensure a smooth transition from the aquaticin utero environment. The newborn kidney has a limited capacity to excrete excess water and sodium and overload of fluid or sodium in the first week may result in conditions like necrotizing enterocolitis and patent ductus arteriosus. The beneficial effect of fluid restriction on the neonatal morbidity has been shown in multiple clinical trials. Simple measures like use of transparent plastic barriers, caps and socks are effective in reducing insensible water loss. Guidelines for the management of fluids according to birth weight, day of life and specific clinical conditions are provided in the protocols.     

Intraosseous lines in preterm and full term neonates.

AIM: To evaluate the use of intraosseous lines for rapid vascular access in primary resuscitation of preterm and full term neonates. METHODS: Thirty intraosseous lines were placed in 27 newborns, in whom conventional venous access had failed. RESULTS: All the neonates survived the resuscitation procedure, with no long term side effects. CONCLUSION: Intraosseous infusion is quick, safe, and effective in compromised neonates.