Near-infrared spectroscopy in neonatal intensive care unit: do we make our life more difficult?

Abstract

The question has been the following: can the regional oxygenation monitoring change our clinical practices in neonatal intensive care?

Fifty newborns of gestational age ≤ 32 weeks were recruited for regional oxygenation continuous monitoring immediately after their admission. Of these newborns 44 showed a patent ductus arteriosus (PDA) with a left to right shunt. In these subjects, a progressive decrease of the renal oxygenation (rSO₂) up to values of 59.6 ± 3.6% and an increase of the renal oxygen extraction fraction (rFTOE) to 50.9 ± 3 were observed during the first hours of monitoring. The cerebral oxygenation (cSO₂) instead, remained relatively constant at 64.5(± 4.2%)-69.7(± 5.6%) with a cerebral oxygen extraction fraction (cFTOE) between 28.6 ± 4.7 and 24.6 ± 6.5.

Renal oxygenation improved in almost all the subjects, except that in three, up to values of rSO₂ of 75(± 1.0%)-82.2(± 4.9) with a rFTOE of 20.1(± 14.8)-13.4(± 3.5) after a three-six hours treatment with dopamine at 5-7.5 μg/kg/min.

These data, together with echodoppler findings, have allowed us to modify our approach to the newborn with PDA and the left-right shunt. It now consists in using dopamine as soon as ductal shunt has been left to right and waiting until the hemodynamic stability persists or until the end of the first week of life prior to consider the closure of the duct by cyclooxygenase inhibitors.

Besides, 42 newborns with a post-natal age ≥ 2 weeks were selected and submitted to a regional oxygenation monitoring once hematocrit had been less than 30%. Sixteen out of 42 newborns showed a decline of rSO₂ to 50 ± 5% and a rFTOE of 45 ± 3, with a cSO₂ of 69 ± 3% and a cFTOE of 23 ± 4. Of the 26 newborns with normal values of regional saturation, 10 showed a decrease of rSO₂ to 50 ± 3 with a rFTOE of 45 ± 3 when the hematocrit fell to 20-22%.

After a packed red cell transfusion, a progressive rise of the rSO₂ to 83.8 ± 9.4 and a decline of the rFTOE to 8.1 ± 3.4 were observed. These changes started at the end of the transfusion and became stable in the following 12-24 hours.

An increase of the cSO₂ to 82.2 ± 2.9 and a decrease of the cFTOE to 12.2 ± 2.90 were observed after the transfusion and after the progressive normalization of the renal oxygenation as well.

On the basis of these results, in our Unit only the newborns with a hematocrit ≤ 30 and clear sinking renal saturation values are transfused.

In the light of the reported observations, we recognize to the regional oxygenation monitoring a precise role in the process of personalization of the newborn cares in intensive contexts.

Despite the requirement for wider observations, the information drawn by the variations of the regional oxygenation in different pathophysiologic processes can substantially help in the prevention of the organ damage, particularly the brain, that upsets still today the results of the neonatal intensive cares.

Proceedings of the 9^th International Workshop on Neonatology · Cagliari (Italy) · October 23^rd-26^th, 2013 · Learned lessons, changing practice and cutting-edge research