Correlations Between Regional Ventilation, Perfusion, and Lung Volumes in Children with Congenital and Infantile Kyphoscoliosis

Summary: 15 children undergoing VEPTR had CT assessment of lung volumes and V/Q scans before treatment. Reductions in regional ventilation and perfusion correlate closely with one another, suggesting normal ventilation-perfusion matching despite asymmetry of lung function between the right and left lungs. Regional loss of lung volume as a proportion of total lung volume correlates well with regional reduction in both ventilation and lung perfusion pre-operatively in children with kyphoscoliosis.

Introduction: Children with congenital and infantile scoliosis have asymmetric loss of lung volume as the spinal deformity progresses. It is unclear how regional loss of lung volume relates to regional ventilation or lung perfusion and what the impact of spinal defomrity is on ventilation/perfusion (V/Q) matching. We aimed to correlate; differences in regional (right and left) lung volumes with their respective regional lung ventilation and perfusion and the regional distribution of ventilation and lung perfusion for children with kyphoscoliosis.

Methods: Fifteen children with congenital and infantile scoliosis were evaluated for VEPTR and underwent thoracic CT scans at total lung capacity and V/Q scans at functional residual capacity. V/Q lung scans were reported as percentage of total counts to the right and left lungs respectively. Right and left lung volumes were assessed using a 3-dimensional reconstruction program (Vitrea 2) for thoracic CT scans. Correlations were made between proportions of total (right plus left) lung volume residing in the right lung and proportion of total lung perfusion to the right lung; between proportion of total lung ventilation and perfusion to the right lung.

Results Median age of the children was 3 years (1.5-13 yrs.) with average Cobb angle of 80 degree (45-99). A high correlation was observed between right lung ventilation and right lung perfusion (R2=0.92 p<0 .001); between right lung ventilation and CT volume (R2="0.75" p<0.001); perfusion p<0.001).

Summary: Reductions in regional ventilation and perfusion correlate closely with one another, suggesting normal ventilation-perfusion matching despite asymmetry of lung function between the right and left lungs. Regional loss of lung volume as a proportion of total lung volume correlates well with regional reduction in both ventilation and lung perfusion pre-operatively in children with kyphoscoliosis.