The Effect of Umbilical Vein Catheterization on Splanchnic Oxygenation in Preterm Infants

Inclusion Criteria: * Parents agreed to participate in the study * Infants born in our hospital, who were followed up in the NICU, with a gestational age of \<34 weeks and a birth weight of 1000-2000 grams * Infants who indicated UVC placement, and for whom NIRS measurements were taken both before and after UVC placement were included in the UVC (+) Study Group * Infants who did not have a UVC but matched the Study Group regarding gestational age and birth weight constituted the UVC (-) Control Group Exclusion Criteria: * Infants who died during the first week of life * Transferred to another hospital * Chromosomal anomalies * Major congenital anomalies affecting splanchnic bed monitoring (such as congenital heart disease, abdominal wall defects, or congenital diaphragmatic hernia) * Inherited metabolic disorders * Hydrops fetalis * TORCH infections * Multiple organ failure * Spontaneous intestinal perforation * Lesions in the area where the NIRS sensor was placed * If UVC was removed for any reason before 24 hours * Severe anemia or polycythemia (Infants with a birth hemoglobin (Hb) level of 10 g/dl or below were considered severe anemic, and those with a Hb level of 22 g/dl or above were considered polycythemic)