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Hyperinflation prevalent in patients with poorly controlled asthma, dyspnea

Patients with poorly controlled asthma and/or dyspnea demonstrated high rates of hyperinflation, according to study results.

“[The findings suggest] small airway dysfunction and may represent an additional criteria for evaluating responsiveness to bronchodilators,” Thierry Perez, MD, of Clinique des Maladies Respiratoires at Hôpital Calmette at Université Lille Nord de France, and colleagues wrote.

Perez and colleagues evaluated 305 patients with either poor asthma control (n = 287) or dyspnea (n = 18) for presence of hyperinflation.

Patients with poor asthma control had an Asthma Control Test (ACT) score of less than 20, whereas patients with dyspnea had a modified Medical Research Council Score of 1 or greater.

Hyperinflation was defined by a residual volume/total lung capacity above the normal limit (RV-HI) or a functional residual capacity of more than 120% of predicted level (FRC-HI).

The researchers determined hyperinflation had been reversed after administration of salbutamol 400 mg if patients had a greater than 20% reduction in residual volume or a reduction of more than 10% in functional residual capacity.

Perez and colleagues used a visual analogue scale to assess chest tightness and changes in dyspnea.

Researchers determined 48% of the cohort had both RV-HI and FRC-HI. They observed a higher prevalence of hyperinflation among patients with a predicted forced expiratory volume in 1 second (FEV₁) of less than 60%.

Prevalence of hyperinflation was higher among patients with FEV₁ less than 60% predicted (93% for RV-HI and 71% for FRC-HI) than patients with FEV₁ greater than 80% predicted (21% for RV-HI and 41% for FRC-HI).

Patients with hyperinflation had lower Asthma Control test scores and higher chest tightness. Thirty-eight percent of asthmatics with FRC-HI and 29% of asthmatics with RV-HI attained hyperinflation reversibility; however, only half of these patients attained FEV₁ reversibility. – by Jeff Craven

Disclosure: Healio.com/Allergy was unable to confirm the researchers’ relevant financial disclosures at the time of publication.