Correlation of Cardiac Index Measured by the Pressure Recording Analytical Method (PRAM) With Near-Infrared Spectroscopy (NIRS) and Arterial Lactate Levels in Neonates and Infants Undergoing Surgical Repair of Aortic Coarctation: A Prospective Observational Study

Low cardiac output syndrome (LCOS) is a major determinant of postoperative morbidity and mortality in neonatal cardiac surgery, particularly in lesions affecting systemic circulation such as aortic coarctation. Reliable intraoperative assessment of cardiac output is therefore critical in this patient population.

The MostCare™ system uses the Pressure Recording Analytical Method (PRAM) to provide real-time, calibration-free cardiac index (CI) measurement derived solely from the arterial pressure waveform. Previous studies in infants have demonstrated good correlation between PRAM and echocardiography; however, data in neonates weighing less than 3.5 kg remain very limited.

Near-infrared spectroscopy (NIRS) allows non-invasive monitoring of regional cerebral and renal oxygen saturation (rSO2), serving as an early indicator of tissue oxygenation. Arterial lactate is a biochemical marker of cellular hypoperfusion and is strongly associated with postoperative outcomes.

In this study, CI (MostCare™), cerebral and renal NIRS (INVOS™ oximeter), and arterial lactate will be simultaneously recorded at four intraoperative time points in neonates and infants undergoing aortic coarctation repair. The primary aim is to assess the correlation between PRAM-derived CI and cerebral NIRS. Secondary aims include the correlation between CI and renal NIRS, and between CI and arterial lactate levels.