Effects of Lung Volume Reduction Surgery on Gas Exchange and Breathing Pattern During Maximum Exercise

Criner, Gerard J.; Belt, Patricia; Sternberg, Alice L.; Mosenifar, Zab; Make, Barry J.; Utz, James P.; Sciurba, Frank C.

doi:10.1378/chest.08-1625

Cited by 42 publications

(37 citation statements)

References 35 publications

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“…The observed reductions of V E/ V CO 2 after LVRS may be due to decreases in VD/VT, alterations in breathing pattern, and a fall in resting Pa CO 2 (32). These improvements in ventilatory efficiency may explain the decreases in REE, thereby leading to a gain in weight for a given caloric input.…”

Section: Discussionmentioning

confidence: 95%

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

Kim

Kretschman

Sternberg

et al. 2012

Am J Respir Crit Care Med

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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.

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Section: Discussionmentioning

confidence: 95%

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

Kim

Kretschman

Sternberg

et al. 2012

Am J Respir Crit Care Med

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“…This is most likely because they found the partial pressure of arterial carbon dioxide to be lower at the isowatt level after surgery due to the increased alveolar ventilation. 27 Another study by Criner et al 26 showed that there was a decrease in ventilatory dead space during unloaded cycling and at maximum exercise after LVRS. With the increase in peak V E , the reduced dead space also suggested improvements in alveolar ventilation throughout exercise that resulted in improved carbon dioxide elimination.…”

Section: Discussionmentioning

confidence: 97%

“…23 After LVRS, the elastic recoil increases, 28,40 thereby decreasing TLC and RV and decreasing hyperinflation, which could explain the increase in peak V E seen in our subjects. Criner et al 26 found in their NETT exercise substudy that the improvements in exercise capacity following LVRS were due to less rapid and shallow breathing, reductions in ventilatory dead space, and enhanced carbon dioxide elimination. Our results support these findings, as those who improved their exercise capacity also significantly increased their peak V E and V CO 2 .…”

Section: Discussionmentioning

confidence: 99%

“…In COPD, abnormal lung mechanics often limit the capacity for V E . Because it is known that LVRS improves the clearance of CO 2 26-28 and V E in patients with COPD, 26,27 we hypothesized that there would be an improvement in ventilatory efficiency after LVRS. A previous study has assessed the impact of ventilatory efficiency's association with weight gain 29 and showed that weight gain after LVRS was related to improved lung function and ventilatory efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…Exercise capacity and gas exchange (not including V E /V CO 2 ) after LVRS have been studied. 13,26,27,30 Additionally, NETT trial papers have only reported arterial levels of CO 2 instead of V CO 2 , 26 so ventilatory efficiency could not be assessed directly. Because of this lack of thorough investigation regarding the change in ventilatory efficiency before and after LVRS in COPD, we sought to assess V E /V CO 2 in our LVRS subjects.…”

Section: Introductionmentioning

confidence: 99%

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Ventilatory Efficiency Before and After Lung Volume Reduction Surgery

et al. 2014

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BACKGROUND: Lung volume reduction surgery (LVRS) has been shown to improve the clearance of carbon dioxide and minute ventilation (V E ) in select patients with COPD. One variable often assessed in COPD is ventilatory efficiency (V E /V CO 2 ). METHODS: We compared 55 LVRS subjects with 25 controls from the National Emphysema Treatment Trial. V E /V CO 2 was calculated from cardiopulmonary exercise testing at baseline and 6-months. We sought to assess V E /V CO 2 changes with LVRS compared with controls who only received standard medical care. RESULTS: At 6 months, the LVRS group significantly increased peak V O 2 , work load, V E , V CO 2 , and tidal volume while lowering peak and lowest V E /V CO 2 (improved ventilatory efficiency) and end-tidal carbon dioxide pressure. The control group did not display these changes. The changes were greatest in the LVRS subjects who improved their exercise capacity after surgery (> 10 W). CONCLUSIONS: The changes were greatest in the LVRS subjects who showed the most functional improvement, indicating an association of improved ventilation with improved functional outcome.

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