Weight Gain after Lung Reduction Surgery Is Related to Improved Lung Function and Ventilatory Efficiency

Abstract

Rationale: Lung volume reduction surgery (LVRS) is associated with weight gain in some patients, but the group that gains weight after LVRS and the mechanisms underlying this phenomenon have not been well characterized. Objectives: To describe the weight change profiles of LVRS patients enrolled in the National Emphysema Treatment Trial (NETT) and to correlate alterations in lung physiological parameters with changes in weight. . We compared BMI groups and LVRS and medical groups within each BMI stratum with respect to baseline characteristics and percent change in BMI (%DBMI) from baseline. We examined patients with (DBMI > 5%) and without (DBMI , 5%) significant weight gain at 6 months and assessed changes in lung function and ventilatory efficiency (V E/V CO 2 ). Measurements and Main Results: The percent change in BMI was greater in the LVRS arm than in the medical arm in the underweight and normal weight groups at all follow-up time points, and at 12 and 24 months in the overweight group. In the LVRS group, patients with DBMI > 5% at 6 months had greater improvements in FEV 1 (11.53 6 9.31 vs. 6.58 6 8.68%; P , 0.0001), FVC (17.51 6 15.20 vs. 7.55 6 14.88%; P , 0.0001), residual volume (-66.20 6 40.26 vs. -47.06 6 39.87%; P , 0.0001), 6-minute walk distance (38.70 6 69.57 vs. 7.57 6 73.37 m; P , 0.0001), maximal expiratory pressures (12.73 6 49.08 vs. 3.54 6 32.22; P ¼ 0.0205), and V E/V CO 2 (-1.58 6 6.20 vs. 0.22 6 8.20; P ¼ 0.0306) at 6 months than patients with DBMI , 5% at 6 months. Conclusions: LVRS leads to weight gain in nonobese patients, which is associated with improvement in lung function, exercise capacity, respiratory muscle strength, and ventilatory efficiency. These physiological changes may be partially responsible for weight gain in patients who undergo LVRS.

Nutritional assessment and therapy in COPD: a European Respiratory Society statement

“…Furthermore, in addition to an increased cost of ventilation due to abnormal pulmonary mechanics, a higher ATP cost of muscular contraction [28] may contribute to decreased mechanical efficiency of lower limb exercise [29] and elevated daily energy requirements in some COPD patients [30]. In support of this, weight gain after lung volume reduction surgery was associated with improved lung function and reduced work of breathing [31]. Collectively, this indicates a hypermetabolic state that may contribute to weight loss if energy requirements are not fully met and provides a convincing rationale for caloric supplementation to maintain or increase fat mass.…”

Exercise ventilatory inefficiency in mild to end-stage COPD

“…The V′E-V′CO 2 relationship has been used to assess disease progression [9][10][11], identify the presence of comorbidities [12][13][14][15] and to evaluate the effect of therapeutic interventions [16][17][18][19] in such patients. This is physiologically justified by evidence of COPD progression being associated with increased ventilation-perfusion mismatch and lower exercise tolerance, leading to poorer ventilatory efficiency [20].…”

“…Secondly, we wished to examine associations between those measures with ventilatory capacity and patient centred outcomes (dyspnoea and exercise tolerance), across the continuum of COPD severity. We reasoned that these data would provide a more sound physiological background to clinically interpret the relationship in this patient population [9][10][11][12][13][14][15][16][17][18][19].…”

Evaluation of nutritional status and nutritional therapy in chronic obstructive pulmonary disease

“…Помимо увеличения энергети ческих затрат на вентиляцию, обусловленных нару Клинические рекомендации шением механики дыхания, мышечное сокращение тоже требует большего количества аденозинтрифос фата (АТФ) [28], за счет чего у некоторых больных ХОБЛ снижается энергетическая эффективность нагрузки на нижние конечности [29] и повышаются суточные энергетические потребности [30]. В под тверждение этого увеличение МТ после хирургичес кой редукции объема легких сопровождается улуч шением легочной функции и снижением работы дыхания [31]. В совокупности это означает гиперме таболическое состояние, которое может вносить дополнительный вклад в снижение МТ, если потреб ности в энергии не удовлетворяются полностью, и стать причиной усиленного восполнения калорий, направленного на сохранение или увеличение ЖМ.…”