Presented at the Neonatal Society 2001 Summer Meeting.
Kissack CM, Garr R, Wardle SP, Weindling AM
Department of Child Health, University of Liverpool
Background: A good coherence between systemic mean arterial blood pressure and cerebral oxygenation (expressed as HbD, the difference between HbO and Hb as measured by near infrared spectroscopy) has been shown to have an association with increased incidence of severe cerebral injury, when considering grade 3 or 4 intraventricular haemorrhage (IVH) and periventricular leucomalacia (PVL) as a single entity (1). Other work has not demonstrated any difference in the incidence of cerebral injury, again considering haemorrhagic parenchymal infarction (HPI), IVH, and PVL together, when comparing hypotensive with normotensive infants (2).
Aim: We aimed to study the changes in cerebral fractional oxygen extraction (CFOE) over the first three days after delivery, and to separately compare the findings in those with HPI and PVL with those who had no cranial ultrasound abnormality.
Methods: CFOE was calculated from the cerebral venous saturation, measured using near infrared spectroscopy (Hammamatsu 500, Hammmatsu UK Ltd) with the partial jugular venous occlusion technique (3). MABP was measured invasively via indwelling umbilical arterial catheter. LVO was measured using 2D and Doppler echocardiography. Cranial ultrasounds were performed as part of the routine care of the infants.
Results: 36 conventionally ventilated preterm infants were recruited, with median (range) gestation 26 weeks (23-30) and birthweight 929g (452-1378). Two infants had HPI and four had PVL on cranial ultrasound. These six infants did not differ in gestation or birthweight from the 30 with normal cranial ultrasound. The changes in CFOE over the three days are illustrated in figure 1.
Figure 1: CFOE for the first three days after birth for two infants who developed HPI (dotted line), four infants who developed PVL (thin solid line) and mean values for 30 infants with no cranial ultrasound abnormality (thick solid line).
Conclusions: The infants who went on to develop HPI had several measurements of CFOE higher than the 95th centile for those infants with no cerebral injury. Infants who developed PVL had CFOE values comparable to those infants with no severe cerebral injury. LVO and MABP tended to be low or normal in those with HPI (not illustrated) and normal or high in those with PVL (not illustrated).
References
1. Tsuji M, Saul JP, du Plessis A, et al. Pediatr 2000;106 :625-632.
2. Tyszczuk L, Meek J, Elwell C, Wyatt JS. Pediatr 1998;102:337-341.
3. Yoxall CW, Weindling AM, Dawani NH, Peart I. Ped Res 1995;38:319-323.