Correlation Between Cerebral Near-Infrared Spectroscopy and Hoffman Index With Central Venous Saturation in Children who Underwent Surgery for Congenital Heart Disease

Abstract

Background: After surgical repair of congenital heart disease with cardiopulmonary bypass, it is common for patients to present with a decrease in cardiac output with hemodynamic instability. Treatment goals should focus on achieving a balance between tissue oxygen availability and consumption. Central venous saturation (SvO2) provides valuable information about hemodynamics and global perfusion; however, it is not continuous and it is invasive. Near-infrared spectroscopy (NIRS) is a noninvasive technology that allows immediate and continuous monitoring of regional oxygen extraction and consumption in different organs. With multisite NIRS values (brain and kidney), global perfusion can be estimated through the Hoffman index. In this study we sought to determine the relationship between SvO2, Hoffman index, and cerebral NIRS (NIRSc) values in pediatric patients undergoing cardiovascular surgery with cardiopulmonary bypass. Methods: Prospective study in patients undergoing cardiovascular surgery with cardiopulmonary bypass who were admitted to the cardiovascular intensive care unit (CICU) at the Instituto Nacional de Pediatría, in Mexico City, from March 2021 to February 2022. Central venous oxygen saturation, cerebral, and renal NIRS values were recorded upon admission to the CICU, at 6 and 12 h. Results: A total of 41 patients were included with a median age of 19 months, 25/41 (61%) of the patients were male. The correlation between cerebral NIRS (NIRSc) and SvO2 was higher at 12 h (r = 0.55, P < .001), while a greater correlation was observed between Hoffman index and SvO2 at admission (r = 0.64, P < .001). When considering the 123 measurements, a better correlation was observed between Hoffman index and SvO2 (r = 0.72, P < .001), including patients with biventricular repair (r = 0.64, P < .001), univentricular physiology (r = 0.83, P < .001), and neonatal patients (r = 0.79, P < .001). Conclusion: The Hoffman index has a stronger correlation with SvO2 compared with NIRSc; both can be used as tools for hemodynamic monitoring of patients who underwent surgery for congenital heart disease.