Distal airway dysfunction in obese subjects corrects after bariatric surgery

Oppenheimer, Beno W.; Macht, Ryan; Goldring, Roberta M.; Stabile, Alexandra; Berger, Kenneth I.; Parikh, Manish

doi:10.1016/j.soard.2011.08.004

Cited by 28 publications

(39 citation statements)

References 56 publications

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“…These symptoms are unresponsive to bronchodilators, but improvements have been widely reported with weight loss (33,35). Surprisingly, spirometry often shows little or no change in lung function with weight loss (1,31,33,47), which makes it challenging to explore the mechanisms that link obesity and weight loss to changes in lung function and associated pathologies. Furthermore, lung function is typically assessed in the upright position, but the respiratory symptoms of obesity worsen in the supine position (10) and are thought to contribute to sleep disturbances (42).…”

Section: Introductionmentioning

confidence: 99%

“…These changes can be assessed by using oscillometry to calculate respiratory system resistance (Rrs) and reactance (Xrs). Indeed, several studies have used oscillometry to report significant improvements in lung mechanics at 12-24 mo after weight loss surgery (1,31,47); however, it is not clear whether these changes are either directly related to the mechanical effects of weight loss or to other factors such as metabolic effects that are associated with weight loss but with a different temporal course (34). By investigating the changes in lung mechanics early after weight loss surgery, the mechanisms linking obesity and weight loss to changes in lung function may be better assessed.…”

Section: Introductionmentioning

confidence: 99%

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Improvement in upright and supine lung mechanics with bariatric surgery affects bronchodilator responsiveness and sleep quality

Peters

Dechman

Hernández

et al. 2018

Journal of Applied Physiology

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Obesity and weight-loss have complex effects on respiratory physiology, but these have been insufficiently studied, particularly at early time points following weight-loss surgery and in the supine position. We evaluated 15 severely obese female participants before, and 5 weeks and 6 months after bariatric surgery using the Pittsburgh Sleep Quality Index (PSQI), spirometry, plethysmography, and oscillometry to measure respiratory system mechanics. Oscillometry and spirometry were conducted in the upright and supine position, and pre- and post-bronchodilation with 200µg of salbutamol. At 5 weeks post-surgery, weight-loss was 11.9±2.7kg with no effect on spirometric outcomes and a slight effect on oscillometric outcomes. However, at 6 months, weight-loss was 21.4±7.1kg with a 14.1±6.1% and 17.8±5.4% reduction in upright and supine Rrs,6, respectively. Ers also decreased by 25.7±9.4% and 20.2±7.2% in the upright and supine positions. No changes were observed in spirometry, but sleep quality improved from PSQI of 8.4±3.5 to 4.1±2.9. Bronchodilator responsiveness was low at baseline but increased significantly post-surgery, and this response was comparable to the improvement in Rrs produced by weight-loss. Modeling the impedance spectra with a two-compartment model demonstrated that improvements in lung mechanics with weight-loss begin in the upper or central compartment of the lungs and progress to include the peripheral compartment. Respiratory mechanics are impaired in the severely obese and is associated with poor sleep quality, but these improved substantially with weight-loss. Our data provide new evidence that severely obese individuals may have poor sleep quality due to abnormal respiratory mechanics that weight-loss improves.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improvement in upright and supine lung mechanics with bariatric surgery affects bronchodilator responsiveness and sleep quality

Peters

Dechman

Hernández

et al. 2018

Journal of Applied Physiology

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“…Previous studies from this laboratory have demonstrated reversal of oscillometric abnormalities following weight loss but could not attribute it to relief of mass loading alone since obesity associated airway inflammation and vascular congestion could also have improved. [20] Therefore, the present study evaluates lung function prior to weight loss, before and during a voluntary inflation maneuver targeted to acutely relieve airway compression by restoring end-expiratory volume (EELV) to predicted FRC. This maneuver should reverse the effect of mass loading on the lung allowing detection of functional abnormalities unrelated to mass loading per se.…”

Section: Introductionmentioning

confidence: 99%

Airway Dysfunction in Obesity: Response to Voluntary Restoration of End Expiratory Lung Volume

et al. 2014

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IntroductionAbnormality in distal lung function may occur in obesity due to reduction in resting lung volume; however, airway inflammation, vascular congestion and/or concomitant intrinsic airway disease may also be present. The goal of this study is to 1) describe the phenotype of lung function in obese subjects utilizing spirometry, plethysmography and oscillometry; and 2) evaluate residual abnormality when the effect of mass loading is removed by voluntary elevation of end expiratory lung volume (EELV) to predicted FRC.Methods100 non-smoking obese subjects without cardio-pulmonary disease and with normal airflow on spirometry underwent impulse oscillometry (IOS) at baseline and at the elevated EELV.ResultsFRC and ERV were reduced (44±22, 62±14% predicted) with normal RV/TLC (29±9%). IOS demonstrated elevated resistance at 20 Hz (R20, 4.65±1.07 cmH2O/L/s); however, specific conductance was normal (0.14±0.04). Resistance at 5–20 Hz (R5−20, 1.86±1.11 cmH2O/L/s) and reactance at 5 Hz (X5, −2.70±1.44 cmH2O/L/s) were abnormal. During elevation of EELV, IOS abnormalities reversed to or towards normal. Residual abnormality in R5−20 was observed in some subjects despite elevation of EELV (1.16±0.8 cmH2O/L/s). R5−20 responded to bronchodilator at baseline but not during elevation of EELV.ConclusionsThis study describes the phenotype of lung dysfunction in obesity as reduction in FRC with airway narrowing, distal respiratory dysfunction and bronchodilator responsiveness. When R5−20 normalized during voluntary inflation, mass loading was considered the predominant mechanism. In contrast, when residual abnormality in R5−20 was demonstrable despite return of EELV to predicted FRC, mechanisms for airway dysfunction in addition to mass loading could be invoked.

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“…However, the same study also showed that exercise induces dynamic increases in FRC which attenuates progressive expiratory flow limitation in obese subject. Impulse oscillometry (IOS) studies in obese subjects elucidate that obesity enhances frequency dependence in the airway resistance and increases lung reactance, suggesting that obesity states primarily affects the small airways and impart elastic load on lung mechanics [101, 102]. Oppenheimer et al [102] showed that excess body weight resulted in enhanced resistance and reactance in the distal airways which reversed after bariatric surgery.…”

Section: Obesity Related Changes In Static Lung Volumes and Its Romentioning

confidence: 99%

“…Impulse oscillometry (IOS) studies in obese subjects elucidate that obesity enhances frequency dependence in the airway resistance and increases lung reactance, suggesting that obesity states primarily affects the small airways and impart elastic load on lung mechanics [101, 102]. Oppenheimer et al [102] showed that excess body weight resulted in enhanced resistance and reactance in the distal airways which reversed after bariatric surgery. High resistance breathing induced by reduced FRC could increase the asthma symptoms, cause treatment refractoriness, and induce a difficulty to treat asthma state.…”

Section: Obesity Related Changes In Static Lung Volumes and Its Romentioning

confidence: 99%

Obesity and Asthma: Physiological Perspective

Brashier¹,

Salvi²

2013

Journal of Allergy

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Obesity induces some pertinent physiological changes which are conducive to either development of asthma or cause of poorly controlled asthma state. Obesity related mechanical stress forces induced by abdominal and thoracic fat generate stiffening of the lungs and diaphragmatic movements to result in reduction of resting lung volumes such as functional residual capacity (FRC). Reduced FRC is primarily an outcome of decreased expiratory reserve volume, which pushes the tidal breathing more towards smaller high resistance airways, and consequentially results in expiratory flow limitation during normal breathing in obesity. Reduced FRC also induces plastic alteration in the small collapsible airways, which may generate smooth muscle contraction resulting in increased small airway resistance, which, however, is not picked up by spirometric lung volumes. There is also a possibility that chronically reduced FRC may generate permanent adaptation in the very small airways; therefore, the airway calibres may not change despite weight reduction. Obesity may also induce bronchodilator reversibility and diurnal lung functional variability. Obesity is also associated with airway hyperresponsiveness; however, the mechanism of this is not clear. Thus, obesity has effects on lung function that can generate respiratory distress similar to asthma and may also exaggerate the effects of preexisting asthma.

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Distal airway dysfunction in obese subjects corrects after bariatric surgery

Cited by 28 publications

References 56 publications

Improvement in upright and supine lung mechanics with bariatric surgery affects bronchodilator responsiveness and sleep quality

Improvement in upright and supine lung mechanics with bariatric surgery affects bronchodilator responsiveness and sleep quality

Airway Dysfunction in Obesity: Response to Voluntary Restoration of End Expiratory Lung Volume

Obesity and Asthma: Physiological Perspective

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