Pediatric heart surgeries for congenital conditions pose significant risks of brain and kidney injury, primarily due to the complex interplay between immature physiology and cardiopulmonary bypass (CPB). Traditional monitoring indicators such as lactic acidosis and hypotension are often delayed or nonspecific. In response, a novel observational study published in BMJ Open proposes an advanced method using near-infrared spectroscopy (NIRS) to monitor real-time regional oxygen saturation (rSO₂) in both the brain and kidneys during pediatric cardiac surgery.
This single-center, prospective cohort trial is being conducted at Beijing Children’s Hospital and targets children aged 18 years or younger undergoing CHD (congenital heart disease) surgery involving CPB. The primary objective is to examine how intraoperative fluctuations in cerebral and renal oxygenation—captured via NIRS—correlate with postoperative brain and kidney injury. The broader aim is to establish whether rSO₂ data can predict and possibly prevent such complications.
Study Design and Methodology
Eligible participants must not have preexisting neuropsychiatric disorders, chronic kidney disease, or other serious health issues. NIRS probes will be attached to the forehead and right paravertebral kidney region to monitor oxygen levels from anesthesia induction until ICU transfer. Real-time rSO₂ data will be hidden from clinical staff to avoid intervention bias.
Cerebral injury will be quantified through serial measurements of the S100B protein, a biomarker linked to brain trauma, taken before CPB, immediately after surgery, and on postoperative day one. Kidney injury will be diagnosed via the pediatric RIFLE (pRIFLE) criteria based on dynamic changes in serum creatinine.
A follow-up on quality of life using the PedsQL questionnaire will be conducted on the day of surgery and 30 days postoperatively, capturing both physical and emotional impacts of surgery.
Oxygenation Monitoring and Data Analysis
Measurements are categorized into three operative phases—pre-CPB, during CPB, and post-CPB. Researchers will analyze average oxygen saturation, total desaturation/oversaturation time, and the area-under-the-curve (AUC) for deviations from baseline. The desaturation threshold is set at 10% below baseline, a conservative cutoff considering the vulnerability of the pediatric brain to hypoxia.
With a planned enrollment of at least 117 participants, the sample size calculation accommodates 10 key covariates including age, weight, cyanotic status, baseline hematocrit, and mean arterial pressure. These factors will be adjusted for using regression models to strengthen causal inference.
Secondary Goals and Broader Implications
Secondary objectives involve identifying perioperative variables linked to organ injuries—ranging from surgical type to anesthetic management—and evaluating how these injuries influence postoperative quality of life. Additionally, hospital stay length and healthcare costs will be tracked as economic indicators.
Importantly, the study includes a sensitivity analysis to test data robustness, accounting for potential loss to follow-up. A retrospective comparison between participants and non-participants will assess selection bias.
Potential Clinical Impact and Future Research
While past research has hinted at the prognostic value of cerebral and renal NIRS in adult and neonatal populations, findings have been mixed and occasionally contradictory. Some studies suggest that cerebral desaturation correlates with poor cognitive outcomes; others refute this. Likewise, renal oxygenation metrics have shown both protective and adverse associations with AKI.
This study’s strength lies in its detailed protocol, multi-phase analysis, and the integration of both biological markers and patient-reported outcomes. If successful, it may establish reliable NIRS thresholds that allow clinicians to intervene preemptively, thus enhancing intraoperative management and postoperative recovery.
The trial is registered with the Chinese Clinical Trial Registry (ChiCTR2400083225) and has passed ethical review by the Beijing Children’s Hospital Institutional Review Board. The final results, expected post-July 2025, will be shared through peer-reviewed publications and conferences, and disseminated to participating communities via lay summaries and social media.
By aiming to transform how pediatric surgical teams monitor organ function during complex cardiac procedures, this trial could set new benchmarks in surgical safety and child healthcare.
