Correlation between nucleated red blood cells and pulse oxygen saturation in neonatal asphyxia

Abstract

Background Neonatal asphyxia is the major cause of neonataldeath at a rate of approximately 23%. The incidence of asphyxiais higher in developing countries, due to limited availability ofperinatology facilities. Hypoxia due to asphyxia is characterizedby low pulse oxygen saturation (Sp02), which basic health carefacilities are unable to monitor. The number ofnucleated red bloodcells (nRBCs) in asphyxia increases in order to compensate forthe hypoxia. Few studies have reported on nRBCs as they relateto pulse oxygen saturation in neonatal asphyxia.Objective To assess for a correlation between nRBCs and pulseoxygen saturation in neonatal asphyxia.Methods In this cross-sectional study, asphyxia was assessed byway of Apgar scores; pulse oxygen saturation was monitored bypulse oximetry; and nRBCs were determined by blood smears.Statistical analysis used was Spearman's test.Results Subjects were 41 neonates with asphyxia, 15 of whomhad 5th minute Apgar scores S 6. Subjects with Apgar scores S 6had significantly higher umbilical venous nRBC counts [20.0 (SD13.09) /100 white blood cell] than subjects with Apgar score >6 [8.81 (SD 8.71) /100 white blood cell] ; (P = 0.004). Subjectswith Apgar S 6 had significantly lower 5th minute Sp02 values[76.46 (SD 6.17) %] than subjects with Apgar scores > 6 [87.03(SD 6.29)]; (P < 0.0001). Spearmans' test revealed a significantcorrelation between higher nRBC counts and lower pulse oxygensaturation (r = -0.804; P<0.0001) .Conclusion In asphyxia neonatorum there is a correlationbetween umbilical vein nRBC counts and the 5th minute Sp02.As such, we recommend using nRBC examinations to predictpulse oxygen saturation as a means to assess the severity ofhypoxia in peripheral areas where pulse oximetry machines maybe unavailable