Influence of spinal deformity on pulmonary function, arterial blood gas values, and exercise capacity in thoracic kyphoscoliosis

Objective: To evaluate the influence of thoracic spine curvatureon lung parameters in kyphoscoliosis.Methods: Twenty-one patients with kyphoscoliosis wereevaluated at the Vallabhbhai Patel Chest Institute, Delhi, Indiafrom January to June 2006 using spirometry, arterial blood gas(ABG), and 6-minute walk test. The degree of spinal deformitywas measured by Cobb’s method for angle of scoliosis and angleof kyphosis.Results: There were 13 males and 8 females (mean age47.38±20.10 years). Decreased lung volumes, hypoxemia,arterial oxygen desaturation, and decreased exercise capacity wasobserved in patients with kyphoscoliosis. The angle of scoliosisranged from 60-126° (78.1±18.3) and angle of kyphosis rangedfrom 5-48° (18.05±10.5). The forced vital capacity (FVC) was1.92±0.8 L (0.66-3.44), and the forced expiratory volume inone second (FEV1) was 1.51±0.5 L (0.6-2.6). The FEV1/FVCwas 60.9±12.9 (42-86%). The partial arterial oxygen tension was51.7±6.9 Hg. The partial pressure of carbon dioxide in arterialblood was 49.85±7.9 mm Hg. The functional oxygen saturationwas 84±3.7%. No correlation was found between pulmonaryfunction test (PFT) or ABG values with the degree of spinaldeformity. Mean oxygen desaturation (87.48-84.43%) and risein systolic blood pressure (118.48-126.67 mm Hg) during walktest correlated well with degree of spinal deformity.Conclusions: The severity of pulmonary impairment could notbe inferred from the angle of scoliosis alone. The 6-minute walktest gives an early indication of limitations and correlates wellwith structural deformity. The PFT and ABG parameters do notcorrelate well with the severity of deformity. Thus, the 6-minutewalk test must be included in the thorough evaluation of allpatients with kyphoscoliosis.