The relationship between umbilical artery blood gas analysis and Apgar scores in neonates

In the first minutes of life it’s important to assess newborn condition very fast but effective and decide about medical intervention as needed. Umbilical artery blood gas analysis and Apgar scoring are the most common assessment systems which studies are trying to more sensitive and accurate way.in this study we compare Apgar scoring system and umbilical blood gas analysis correlation with delivery prognosis. In the study of LU et al., Ph, pco2 and base excess indices decreased with decreasing Apgar score. Also, in infants with arterial acidity below 7.2, the Apgar score was 100%. Also, arterial acidity below 7.2 has reached 77.7% in Apgar scores 4-7 and 59.31% for 8-10 scores. (8) In the study of Yeh et al, The mean pH of the umbilical cord was 7.22. The risk of adverse neurological outcomes ranged from 0.16% to 0.36% and for people with a pH less than 7, this increased risk was about 2.95%. However, more than 75% of children with neurological disorders had an arterial pH of less than 7.10. (9)The study by Ahmadpour et al. Showed that a decrease in the pH of the umbilical artery was associated with increased frequency of resuscitation, increased need for NICU, longer hospital stay, greater delay in oral feeding, and increased prevalence of seizures and ischemic hypoxic encephalopathy. (10)In the Collaborative study, the pH of the umbilical artery had a positive relationship with the amount of base excess and both indices had a significant relationship with the neonatal Apgar score. Also, the pH of umbilical arterial blood gas had a significant correlation with organic lesions. (11)

This cohort study was conducted among Shahid Akbar Abadi maternity hospital in Tehran in 1396 . Sampling was convinced nonrandomized and based on sample size calculated with epidemiologist. All cases that lead to mismatch of the babychr('39')s Apgar score with arterial blood gases, such as: umbilical vein sampling instead of umbilical artery, umbilical cord prolapse, acute fetal bleeding, severe fetal heart failure, congenital neuromuscular diseases of the baby, severe prematurity (gestational age below 30 weeks) was excluded from the study and the initial evaluated indicators included PH, HCO3, PCO2, PO2, Base excess as well as demographic indicators, maternal age, gestational age, type of delivery, Apgar score, weight and sex of the infant by reviewing their file . Other data was calculated during admission. In this study, 116 newborns participated, and Apgar scores were calculated at 1 and 5 minutes after birth. At birth, the umbilical cord arterial blood sample is extracted by experienced personnel and analyzed by the hospital reference laboratory.The Apgar score was determined by a neonatologist or senior shift resident who had taken the course.  Data were analyzed by SPSS software and leve of significance was considered below 0.05. Ethical principles were considered in this study and the patientchr('39')s name and issues related to the patientchr('39')s file were not mentioned anywhere.

  One hundred and sixteen newborns participated in this study, of which 46% were girls and 54% were boys. 53 deliveries with a frequency of 45.6% were performed by natural childbirth and 63 deliveries (54.4%) were performed by cesarean section. 19 deliveries were performed 30-35 weeks with a frequency of 16.3% and 97 deliveries with a frequency of 83.4% were performed over 35 weeks. The mean neonatal weight was 2961.840 7 710 g. The mean age of newborns was 49.10 4. 4.1 cm, the mean head circumference was 34.1 8 2.8 cm, the mean fetal age was 37.63 3.5 3.5 weeks and the mean age of mothers was 28.97 6. 6.9 years. In this study, 6 infants with a frequency of 5.1% underwent positive pressure ventilation, 17 infants with a frequency of 14.65% underwent PPV and intubation, 6 infants with a frequency of 5.1% underwent intubation and cardiac massage and PPV. One infant also needed adrenaline injections after intubation and cardiac massage and PPV. The average Apgar score of the first minute is 6.23 1. 1.9 and the average score of the 5 minute Apgar score is 2.20 ± 6.73. The mean bicarbonate of umbilical cord samples was 16.05 6. 6.1, the mean base excess was 8.8 9. 9.8 - the mean pco2 was 24.23 ± 5.824 and the mean pH was 7.14. 0.14. The results of analytical analysis show that there is a correlation between the first minute Apgar score with pH r = 0.45) p = 0.007) but there is a relationship between the first minute Apgar score and base excess (p = 0.07) and bicarbonate (p = 0.16) There is no meaning. There was also a correlation between 5 minute Apgar and arterial pH (p = 0.009 and r = 0.44) and also between 5 minute Apgar and base excess r = 0.50) and p = 0.0025). But there was no relationship between Apgar score of 5 minutes and bicarbonate (p = 0.11) Also, there was a significant relationship between the need for resuscitation with Apgar, pH and base excess at 1 and 5 minutes (p = 0.004) and between birth weight and 5 minute Apgar and base excess (p <0.001). But there was no significant relationship between maternal age, type of delivery and sex of the baby with Apgar score, pH and base excess at 1 and 5 minutes. The limitations of the study included cases in which the pediatrician was called for resuscitation after the first minute and the Apgar score of the first minute was not determined by the pediatric team, which was excluded from the study to address these limitations.

 This study was performed to clarify the importance of the analyzed components of umbilical artery blood gases in predicting fetal asphyxia. Finally, our study showed that there is a significant relationship between Apgar score of 5 minutes and pH and basal excess of umbilical artery blood, which, like other studies mentioned, can predict the next condition of the baby and the risk of asphyxia. Contribute to hospitalization and the need to follow up on the possible consequences of asphyxia.