Other physiological parameters

The physiological parameters BP and SpO₂ were measured using a vital functions monitor (Carescape Monitor V100, GE Healthcare). The measurements were acquired immediately after the ECG recording using an oscillometric method for BP and Masimo pulse oximetry method for SpO₂. Respiratory rate was measured visually using a stopwatch every 5 min during the ECG recording. Additionally, the status and clinical condition were evaluated based on the core body temperature measured using a standard neonatal thermometer, basic characteristic data (gestational age, birth weight, Apgar score), and selected laboratory parameters (acid-base parameters, glycaemia, serum bilirubin).