Two approaches in therapy of arterial hypotonia in premature newborns
AbstractArterial hypotension is a common problem in NICU. The incidence of arterial hypotension is 16-52%. Reduced perfusion of organs such as the brain, kidneys, heart, and gastrointestinal tract may lead to acute dysfunction and be associated with permanent injury. Various therapeutic strategies are used for cardiovascular support, including volume expansion, inotropes, corticosteroids. But the initiating therapy has traditionally been volume expansion. As we know, AH is poorly correlated to blood volume in preterm infants and hypovolemia is a rare reason of AH, especially in extremely preterm newborns. Also the excess volume expansion in condition of PDA can lead to deterioration of respiratory problems. The aim of our study was: to compare two ways of therapy of AН - Dopamine and volume expansion in ELBW.
Material and methods. Criteria of inclusion were: ELBW + Arterial Hypotension (Mean BP<GA in weeks). Criteria of exclusion were: congenital anomalies, obvious signs of a hypovolemia and shock. Randomization: odd-numbered infants received Dopamin and even-numbered - Normal saline. Intervention: Dopamine starting from 2 pg/kg/min with dose increase until BP became normal (BP>GA), NS - 10 ml/kg in 30 min. Sometimes one, sometimes two boluses were used, but never more, than two. If NS was inefficient, Dopamine was prescribed. We checked efficiency of therapy (BP normalization (mBP>GA)) after one hour, Diuresis (before/after intervention, within a day), effective dose of Dopamine (if needed), total dose of Dopamine within a week, total duration of inotrope support. Also we evaluated the heart hemodynamics (CO, EF, SF) and regional hemodynamics in АСА, AMS (Ri, Tamx, Pi, MD), blood sample (pH, lactate, BE, HCO3) and outcomes (PDA, MV duration, BPD, NEC, PVL, mortality before discharge, stay in NICU) 41 newborns were accepted according to the criteria of inclusion, 2 was excluded due to congenital heart diseases. 2 groups were founded (18 in NS group, 21 - Dopamine group).
Results. After one hour the mean BP was higher than GA in all newborns from Dopamine group (100%) and 38.8% in NS group exhibited the need for Dopamine for BP normalization. There were increasing of the diuresis and ejection fraction in both groups after infusion. The cerebral, renal and mesenterial blood flow were normalized. We found out that in the Dopamine group the cardiac output (CO) didn't increase, but in NS group the CO increased more, than 1, times. At the same time the efficiency of Dopamine in normalising the BP was 100%, and efficiency of the isolated volume loading - 61.2%. The effective daily dose of Dopamine (if needed), pg/kg/min was significantly higher in those, who had previously received NS (3.6±0.63 vs 1.85+0.64, p<0.0001) Duration of mechanical ventilation and observing in NICU was more in NS groupe, than in Domamine group (p=0.02 and p=0.03). Children from NS group had the bigger diameter of PDA also (1.6±1.44 vs 2.6 +1.47, p=0.04).
Conclusions. Dopamine was more effective in BP normalization than isolated NS for ELBW. If Dopamine was required, the dose sufficient for pressure normalization was higher for newborns who had previously received NS. Dopamine increases EF more effectively, but NS increases CO more effectively. Dopamine and NS are equally effective in blood flow normalization in ACA, AR, AMS. The incidence of sPDA and severe BPD were higher in newborns who received NS for AH treatment. The duration of MV and stay in NICU were longer for newborns who received NS for AH treatment.
Keywords:treatment, arterial hypotension, preterm infants, ELBW, dopamine