Presented at the Neonatal Society 2012 Autumn Meeting.
Shim R, Gnanasekaran R, Boyle M1, Tarrant A, Ryan S, McCallion N
Neonatal Department, The Rotunda Hospital, Parnell Square, Dublin 1, Ireland
Background: Intraventricular haemorrhage (IVH) and Post Haemorrhagic Ventricular Dilation (PVHD) are serious complications in premature infants and are associated with a high risk of disability. These conditions are monitored by measuring the ventricular size (Levene Index) and by calculating the Ventricular Index (VI) or the ratio of the distance between the lateral sides of the ventricles and the biparietal diameter. Treatment decisions are made based on these measurements, which originate from data obtained 30 years ago (1). These centile charts do not include the extremes of gestations that are treated commonly today nor taken in to account the advances in perinatal and neonatal care over the intervening period. The aim of this study was to assess the relationship between Levene Index and grouped gestational ages in preterm infants, including the gestations less than 27 weeks and to establish normal ranges and median values for VI based on a more current cohort.
Methods: This was a retrospective study where serial cranial ultrasounds were reviewed of all preterm infants with gestation under 32 weeks admitted to Rotunda Hospital from January 2009 to December 2011. The data collected was grouped according to gestational age at the time of scan from 23 weeks to 45 weeks. Ventricular sizes from cranial ultrasounds were assessed using VI. An abnormal ultrasound was defined as one with evidence of IVH grade III or IV, PHVD and was excluded from the study
Results: From 253 infants, 816 cranial ultrasounds were reviewed. For Levene Index, the median values show a general trend of increase as gestation increases (Fig. 1). The normal ranges for left VI were 0.11 – 0.69 and right VI were 0.23 – 0.88. The median value for both left and right VI was 0.31.
Conclusion: This study shows that there is a slight increase in Levene Index as gestation at the time of scan increases and that the median values for VI did not significantly change with gestational age at scan. These results provide the basis for updated centile charts for current practice.
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1. Levene MI. Measurement of the growth of the lateral ventricles in preterm infants with realtime ultrasound. Arch Dis Child. 1981;56:900–904.