Effect of hemoglobin content on cerebral oxygen saturation during surgery for scoliosis in pediatric patients

BACKGROUND: Although regional cerebral oxygen saturation (rScO(2)) monitoring has been widely used in clinical practice, the relationship between hemoglobin (dHB) content and rScO(2) is incompletely understood. The aim of this study was to analyze the effect of hemoglobin content on rScO(2) in pediatric patients undergoing general anesthesia for correction of scoliosis. METHODS: Ninety-two pediatric patients aged 3 to 14 years undergoing scoliosis correction surgery were enrolled. Continuous monitoring of bilateral regional cerebral oxygen saturation by near-infrared spectroscopy (NIRS, CASMED, USA) was performed after entering the operation room. rScO(2) was recorded when the patients entered the operating room (T(0), baseline), after anesthesia induced intubation (T(1)), and after radial artery puncture (T(2)). The lowest value of rScO(2) during surgery was also recorded. The arterial blood pressure (ABP), heart rate (HR), pulse oxygen saturation (SpO(2)), end tidal carbon dioxide partial pressure (PetCO(2)) were continuously recorded. Patients were classified as low rScO(2) or high rScO(2) group according to whether the lowest intraoperative rScO(2) was 15% lower than the baseline value. An analysis and comparison of differences in hemoglobin content in these two groups was carried out. RESULTS: The preoperative hemoglobin-postoperative hemoglobin of patients in the high rScO(2) group was significantly lower than that in the low rScO(2) group (t = − 7.86, p < 0.01), the amount of bleeding during the operation was also less than that in the low rScO(2) group (t = − 6.05, p < 0.01), and the systolic pressure of patients was higher than that in the low rScO(2) group (t = 4.27, p < 0.01). CONCLUSIONS: The decrease in hemoglobin level which occurs during surgery leads to a decrease in cerebral oxygen saturation. In order to ensure patient safety during surgery, it is necessary to carry out volume management and appropriate transfusion and fluid replacement in a timely manner. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1800016359. Registered 28 May 2018.