Near-infrared spectroscopy to monitor cerebral and renal oxygen saturation during cardiopulmonary bypass surgery for paediatric congenital heart disease: study protocol for a prospective observational cohort trial.

BACKGROUND: Current indicators for monitoring intraoperative organ function remain predominantly indirect, delayed and non-specific, particularly in paediatric populations undergoing congenital heart surgery, where multifactorial influences further complicate functional assessments. Emerging evidence suggests that the use of near-infrared spectroscopy (NIRS) technology to continuously monitor the regional oxygen saturation (rSO₂) of intraoperative organs can predict the postoperative organ functional status. This study aims to investigate the associations between intraoperative cerebral/renal rSO₂ fluctuations monitored by NIRS and postoperative neurological injury or acute kidney injury (AKI) in paediatric congenital heart disease (CHD) surgery.

METHODS AND ANALYSIS: In this prospective observational cohort study, patients ≤18 years, scheduled for CHD surgery under cardiopulmonary bypass (CPB), will be enrolled after obtaining written informed consent. Exclusion criteria include pre-existing neuropsychiatric disorders, chronic kidney disease or other related disorders. Dual-channel NIRS probes will be applied to simultaneously monitor cerebral and renal rSO₂ from anaesthesia induction until the patient is transferred to the cardiac care unit. Serum S100 calcium-binding protein B (S100B) levels will be measured before CPB, at the end of the surgery and on postoperative day 1 to quantify cerebral injury. AKI will be diagnosed using the paediatric risk, injury, failure, loss, end-stage renal disease (pRIFLE) criteria based on dynamic creatinine changes. Health-related quality of life will be assessed through the paediatric quality of life (PedsQL) inventory at preoperative baseline and postoperative day 30.

ETHICS AND DISSEMINATION: This study has been approved by the Institutional Review Board of Beijing Children's Hospital (approval number: [2024]-Y-093-D). Prior to enrolment, written informed consent will be obtained from the parents or legal guardians of all participating minors. The findings of this research will be disseminated through peer-reviewed publications and presentations at relevant conferences and shared with participating communities via lay summaries and social media platforms.

TRIAL REGISTRATION NUMBER: The study was registered with the Chinese Clinical Trial Registry on 18 April 2024 (ChiCTR2400083225).