Changes in Near-Infrared Spectroscopy After Congenital Cyanotic Heart Surgery

Since oxygen saturation from pulse oximetry (SpO₂) and partial pressure of arterial oxygen (PaO₂) are observed to improve immediately after surgical correction of cyanotic congenital heart disease (CHD), we postulate that cerebral (CrO₂) and somatic (SrO₂) oximetry also improves immediately post-correction. We aim to prospectively examine CrO₂ and SrO₂, before, during, and after surgical correction as well as on hospital discharge in children with cyanotic CHD to determine if and when these variables increase.

This is a prospective observational trial. Eligibility criteria included children below 18 years of age with cyanotic CHD who required any cardiac surgical procedure. CrO₂ and SrO₂ measurements were summarized at six time-points for comparison: (1) pre-cardiopulmonary bypass (CPB); (2) during CPB; (3) post-CPB; (4) Day 1 in the pediatric intensive care unit (PICU); (5) Day 2 PICU; and (6) discharge. Categorical and continuous variables are presented as counts (percentages) and median (interquartile range), respectively.

Twenty-one patients were analyzed. 15 (71.4%) and 6 (28.6%) patients underwent corrective and palliative surgeries, respectively. In the corrective surgery group, SpO₂ increased immediately post-CPB compared to pre-CPB [99 (98, 100) vs. 86% (79, 90); p < 0.001] and remained in the normal range through to hospital discharge. Post-CPB CrO₂ did not change from pre-CPB [72.8 (58.8, 79.0) vs. 72.1% (63.0, 78.3); p = 0.761] and even decreased on hospital discharge [60.5 (53.6, 62.9) vs. 72.1% (63.0, 78.3); p = 0.005]. Post-CPB SrO₂ increased compared to pre-CPB [87.3 (77.2, 89.5) vs. 72.7% (65.6, 77.3); p = 0.001] but progressively decreased during PICU stay to a value lower than baseline at hospital discharge [66.9 (57.3, 76.9) vs. 72.7% (65.6, 77.3); p = 0.048].

CrO₂ and SrO₂ did not increase after corrective surgery of cyanotic CHD even up to hospital discharge. Future larger studies are required to validate these findings. (This study is registered with ClinicalTrials.gov ID: NCT02417259.).