Early detection of changes in lung mechanics with oscillometry following bariatric surgery in severe obesity.
Obesity is associated with respiratory symptoms that are reported to improve with weight loss, but this is poorly reflected in spirometry, and few studies have measured respiratory mechanics with oscillometry. We investigated whether early changes in lung mechanics following weight loss are detectable with oscillometry. Furthermore, we investigated whether the changes in lung mechanics measured in the supine position following weight loss are associated with changes in sleep quality. Nineteen severely obese female subjects (mean body mass index, 47.2 ± 6.6 kg/m(2)) were evaluated using spirometry, oscillometry, plethysmography, and the Pittsburgh Sleep Quality Index before and 5 weeks after bariatric surgery. These tests were conducted in both the upright and the supine position, and pre- and postbronchodilation with 200 μg of salbutamol. Five weeks after surgery, weight loss of 11.5 ± 2.5 kg was not associated with changes in spirometry and plethysmography, with the exception of functional residual capacity. There were also no changes in upright respiratory system resistance (Rrs) or reactance following weight loss. Importantly, however, in the supine position, weight loss caused a substantial reduction in Rrs. In addition, sleep quality improved significantly and was highly correlated with the reduction in supine Rrs. Prior to weight loss, subjects did not respond to the bronchodilator when assessed in the upright position with either spirometry or oscillometry; however, with modest weight loss, bronchodilator responsiveness returned to the normal range. Improvements in lung mechanics occur very early after weight loss, mostly in the supine position, resulting in improved sleep quality. These improvements are detectable with oscillometry but not with spirometry.
a School of Biomedical Engineering, Dalhousie University, 5981 University Avenue, Halifax, NS B3H 4R2, Canada.
Ubong
U
Peters
b Department of Medicine, Dalhousie University, and Division of Respirology, Queen Elizabeth II Health Sciences Centre, Halifax, NS B3H 3A7, Canada.
Paul
P
Hernandez
c School of Physiotherapy, Dalhousie University, Halifax, NS B3H 4R2, Canada.
Gail
G
Dechman
d School of Biomedical Engineering, Department of Surgery, Dalhousie University, and Division of General Surgery, Queen Elizabeth II Health Sciences Centre, Halifax, NS B3H 2Y9, Canada.
James
J
Ellsmere
a School of Biomedical Engineering, Dalhousie University, 5981 University Avenue, Halifax, NS B3H 4R2, Canada.
Geoffrey
G
Maksym
D000328:Adult; D050110:Bariatric Surgery; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications / Q000601:surgery*; D009991:Oscillometry; D010991:Plethysmography; D012120:Respiration Disorders / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics; D000070263:Sleep Hygiene / Q000502:physiology; D013147:Spirometry; D011795:Surveys and Questionnaires; D055105:Waist Circumference
body mass index; bronchial reversibility; fonction pulmonaire; indice de masse corporelle; lung function; lung mechanics; mécanique pulmonaire; obesity; obésité; oscillometry (forced oscillation technique); oscillométrie (technique de l’oscillation forcée); réversibilité bronchique