RT Journal Article SR Electronic T1 Reduction in cardiorespiratory fitness after lung resection is not related to the number of lung segments removed JF BMJ Open Sport & Exercise Medicine JO BMJ OPEN SP EX MED FD BMJ Publishing Group Ltd SP e000032 DO 10.1136/bmjsem-2015-000032 VO 1 IS 1 A1 Elisabeth Edvardsen A1 Sigmund A Anderssen A1 Fredrik Borchsenius A1 Ole Henning Skjønsberg YR 2015 UL http://bmjopensem.bmj.com/content/1/1/e000032.abstract AB Aim To evaluate the effect of lung cancer surgery on cardiorespiratory fitness (CRF), and to assess the agreement between the predicted postoperative (ppo) V̇O2peak and actually measured postoperative peak oxygen uptake (V̇O2peak).Methods Before and 4–6 weeks after lung cancer surgery, 70 patients (35 women) underwent measurements of pulmonary function and CRF via a cardiopulmonary exercise test. In addition, the 23 non-exercising patients underwent measurements after 6 months. The ppo V̇O2peak calculated from the number of functional segments removed was compared with the actually measured postoperative values of V̇O2peak for accuracy and precision.Results After surgery, the V̇O2peak decreased from 23.9±5.8 to 19.2±5.5 mL/kg/min (−19.6±15.7%) (p<0.001). The breathing reserve increased by 5% (p=0.001); the oxygen saturation remained unchanged (p=0.30); the oxygen pulse decreased by −1.9 mL/beat (p<0.001); the haemoglobin concentration decreased by 0.7 g/dL (p=0.001). The oxygen pulse was the strongest predictor for change in V̇O2peak; adjusted linear squared: r2=0.77. Six months after surgery, the V̇O2peak remained unchanged (−3±15%, p=0.27). The ppo V̇O2peak (mL/kg/min) was 18.6±5.4, and the actually measured V̇O2peak was 19.2±5.5 (p=0.24). However, the limits of agreement were large (CI −7.4 to 8.2). The segment method miscalculated the ppo V̇O2peak by more than ±10 and ±20% in 54% and 25% of the patients, respectively.Conclusions The reduction in V̇O2peak and lack of improvement 6 months after lung cancer surgery cannot be explained by the loss of functional lung tissue. Predicting postoperative V̇O2peak based on the amount of lung tissue removed is not recommendable due to poor precision.Trial registration number NCT01748981.