Multisite Time-Resolved Near-Infrared Spectroscopy for Assessing Pulmonary and Cerebral Blood-Volume Distribution in Children with Ventricular Septal Defects

Pulmonary circulatory abnormalities are common in congenital heart disease and are central to perioperative management. We evaluated multisite time-resolved near-infrared spectroscopy (TR-NIRS) for simultaneous assessment of TR-NIRS-derived estimated regional pulmonary blood volume index (PBVi) and cerebral blood volume (CBV) in children undergoing ventricular septal defect surgery. This retrospective study included 87 surgical episodes in 72 children undergoing pulmonary artery banding (PAB, n = 28), primary intracardiac repair (ICR, n = 42), or second-stage ICR (n = 17). PBVi and CBV indices were measured before and after surgery. Perioperative changes were analyzed using mixed-effects models, and associations with conventional hemodynamic indices were assessed using Spearman correlation. Preoperative PBVi/CBV ratios were 1.91 in the PAB group, 1.19 in the primary ICR group, and 0.94 in the second-stage ICR group. PBVi/CBV ratio correlated with Qp/Qs (r = 0.41, p = 0.002), while PBVi correlated with pulmonary-artery index (r = 0.48, p = 0.001) and left ventricular end-diastolic volume index (r = 0.30, p = 0.029). Multisite TR-NIRS may provide complementary physiological information regarding regional pulmonary and cerebral blood-volume distribution in children with congenital heart disease, although further validation of thoracic TR-NIRS measurements is required.