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Respiratory resistance increases in patients with obesity, OSA

Total respiratory resistance and peripheral airway resistance appeared more likely to occur in obese patients who had obstructive sleep apnea, according to study results.

Specific respiratory conductance decreased significantly as well in comparison with patients who did not have obstructive sleep apnea (OSA), according to the researchers.

Arikin Abdeyrim, PhD, of Xinjiang Medical University in China, and colleagues conducted a cross-sectional study to assess lung volume and respiratory mechanical properties in patients with obesity who did and did not have OSA. The analysis included men (n = 193) and women (n = 70) with some degree of obesity without any history of lung diseases and a suspicion of OSA. The researchers then separated the participants by sex and analyzed the results.

Functional residual capacity and expiratory reserve volume (P < .001 for both) appeared to significantly diminish in the men with OSA (n = 106) compared with those without OSA.

Expiratory reserve volume (P = .022) and functional residual capacity (P = .037) also decreased in the women with OSA (n = 35).

The researchers said OSA, based on its severity, affects lung elasticity and its recoil pressure is increased in OSA. This may result in decreased lung volume and greater airflow resistance in upper and intrathoracic airways in this population.

The study had several limitations, according to the researchers.

“To explicate the effects of OSA on lung volumes and mechanical properties of respiratory, with the goal of eliminating a confounding effect of BMI differences on respiratory function tests, initially, we carried out a case-control study,” the researchers wrote. “Although we found that the BMI matched in the female OSA and non-OSA subjects, this was not the case for the male groups. As this study was not intended to evaluate the relationship between BMI and OSA, we then had to perform statistical analysis to account for the differences.” – by Ryan McDonald

Disclosure: The researchers report no relevant financial disclosures.