Near-infrared Spectroscopy Monitoring Abdominal Oxygen Saturation Associated With Feeding Intolerance In Preterm Infants

Objective Near infrared spectroscopy（NIRS）was used to dynamically monitor the changes of blood oxygen saturation in the abdominal tissues（A-r SO₂）of preterm infants,and to explore its correlation with feeding intolerance（FI）.Methods Preterm infants who met the inclusion criteria and were admitted to the neonatal intensive care unit（NICU）of the hospital within 24h from June 2021 to December 2022 were selected.NIRS monitored A-r SO₂and brain tissue oxygen saturation（C-r SO₂）1 to 14 days after life,and the ratio of brain-visceral oxygenation ratio（CSOR）was calculated.The children with FI during the NIRS monitoring were set as the experimental group,that is,the FI group;the children with no FI during the NIRS monitoring were the control group,namely the feeding tolerance（FT）group.All the clinical basic data such as gestational age,birth weight,gender,production mode and feeding type were recorded,and the changes and differences of A-r SO₂and CSOR mean within 14days after birth between the two groups were compared.Results 1.General data:A total of 89children completed the 14-day monitoring content,including 47 patients in FT group and 42patients in FI group.The basic clinical data of the two groups were summarized,and there was no statistical difference between gender,production mode and feeding type（P>0.05）.There were statistical differences between gestational age and birth group（P<0.05）,while mean gestational age and birth weight were lower in the FI group.2.mean changes in A-r SO₂and CSOR within 14 days of birth in the two groups:no significant change in A-r SO₂and CSOR within 14 days in the FT group（P>0.05）.In the FI group,the mean values of A-r SO₂and CSOR were firstly decreased and then increased at 14 days after birth（P<0.001）.3.Comparison of A-r SO₂and CSOR between the two groups:the means of A-r SO₂and CSOR in the FI group were lower than the mean of A-r SO₂and CSOR in the FT group,with statistically significant differences（P<0.05）.4.The relationship between the mean changes of A-r SO₂and CSOR and FI symptoms in the FI group:A-r SO₂and CSOR in the FI group from3 days to the day of symptoms(P_trend<0.001).Conclusions 1.Small for gestational age and low birth weight children are more likely to develop FI.2.The mean values of A-r SO₂and CSOR in the FT group did not change significantly within the first 14 days of birth,but the mean levels of A-r SO₂and CSOR in the FI group decreased significantly during the period of FI symptoms.Therefore,the monitoring of A-r SO₂and CSOR by NIRS could well reflect intestinal ischemia and hypoxia.3.The mean values of A-r SO₂and CSOR in the FI group showed A downward trend from 3 days before the onset of symptoms to the day of symptoms,that is,they had started to change before the onset of symptoms of FI.The application of bedside NIRS monitoring A-r SO₂and CSOR could help realize early detection of FI in premature infants and make clinical intervention as soon as possible.It can further improve the prognosis of FI in premature infants.