Correlation of Cardiac Index Measured by the PRAM Method With NIRS and Lactate Levels in Pediatric Aortic Coarctation Surgery

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

This prospective observational study aims to evaluate the correlation between cardiac index measured by the MostCare™ system (Pressure Recording Analytical Method, PRAM) and cerebral/renal regional oxygen saturation measured by near-infrared spectroscopy (NIRS) and arterial lactate levels in neonates and infants (body weight 2.5-3.5 kg, age 0-3 months) undergoing surgical repair of aortic coarctation. Measurements will be recorded at four intraoperative time points: after anesthesia induction, before aortic cross-clamp, 3 minutes after cross-clamp release, and at end of surgery. No additional intervention beyond standard anesthesia and surgical care will be applied.

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.

Inclusion Criteria:

• Neonates and infants planned for surgical repair of aortic coarctation
• Body weight between 2.5 and 3.5 kg
• Postnatal age between 0 and 3 months
• Considered hemodynamically stable for anesthesia and surgery
• Written informed consent obtained from legal guardians

Exclusion Criteria:

• Severe multiorgan dysfunction
• Additional major congenital heart defect (e.g., Tetralogy of Fallot, Transposition of Great Arteries, Hypoplastic Left Heart Syndrome)
• Surgery requiring cardiopulmonary bypass
• Preoperative metabolic acidosis or sepsis
• Inability to obtain informed consent from legal guardians