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

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.

• MostCare (PRAM) (Device), also known as Pressure Recording Analytical Method: Real-time, calibration-free cardiac index monitoring via arterial pressure waveform analysis using the MostCare™ system. Used as part of routine intraoperative hemodynamic monitoring.
• Near-Infrared Spectroscopy (NIRS) (Device), also known as INVOS Oximeter: Non-invasive monitoring of regional cerebral and renal oxygen saturation (rSO2) using the INVOS™ oximeter as part of standard intraoperative care.
• Arterial Blood Gas with Lactate (Procedure): Arterial blood gas sampling for lactate measurement at four intraoperative time points as part of routine clinical monitoring.

Primary outcomes

• Correlation between PRAM-derived Cardiac Index and Cerebral NIRS (rSO2c) [Intraoperative (at 4 time points: after anesthesia induction, before aortic cross-clamp, 3 minutes after cross-clamp release, and at end of surgery)]: Pearson or Spearman correlation coefficient between cardiac index (CI, L/min/m²) measured by MostCare™ (PRAM method) and cerebral regional oxygen saturation (rSO2c, %) measured by INVOS™ oximeter at four intraoperative time points.

Secondary outcomes

• Correlation between PRAM-derived Cardiac Index and Renal NIRS (rSO2r) [Intraoperative (at 4 time points: after anesthesia induction, before aortic cross-clamp, 3 minutes after cross-clamp release, and at end of surgery)]: Pearson or Spearman correlation coefficient between cardiac index (CI, L/min/m²) and renal regional oxygen saturation (rSO2r, %) at four intraoperative time points.
• Correlation between PRAM-derived Cardiac Index and Arterial Lactate Level [Intraoperative (at 4 time points: after anesthesia induction, before aortic cross-clamp, 3 minutes after cross-clamp release, and at end of surgery)]: Pearson or Spearman correlation coefficient between cardiac index (CI, L/min/m²) and arterial lactate level (mmol/L) at four intraoperative time points.

Sex: All, ages: any to 3 Months

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

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• Bedia Mine Hanedan, MD, Principal investigator, Konya City Hospital