Suboptimal Peak Inspiratory Flow Rate Present in 20% of Patients With COPD

Spirometry test
Spirometry test

Suboptimal peak inspiratory flow rate (PIFR) was present in 20% of stable, ambulatory patients with chronic obstructive pulmonary disease (COPD), according to a study published in Chronic Obstructive Pulmonary Diseases.

This cohort study was designed to determine the prevalence of suboptimal PIFR (≤60 L/min) and associated patient characteristics and compare measurements of PIFR obtained with In-Check DIAL® device (Clement Clarke International Ltd; Harlow, UK) and spirometry in ambulatory patients with COPD (N=303). Receiver-operating curve analysis determined the best maximal forced inspiratory flow (FIF max) value in identifying optimal PIFR by height and sex. The mean age of participants was 65.5±11.3 years, and the distribution between the sexes was equal.

Of the 303 participants, 61 (20.1%) had suboptimal PIFR. The correlation seen between PIFR and inspiratory capacity was stronger than between residual volume to total lung capacity ratio and PIFR (r=0.40; P < .0001 and r= -0.19; P =.002, respectively). Furthermore, a strong correlation was also seen between PIFR and FIF max (r=0.65; P <.0001).

In participants with suboptimal PIFR, mean FIF max as measured by spirometry was significantly lower than that seen in participants with optimal PIFR (178.5±56.9 L/min and 263.4±89.9 L/min, respectively; P <.0001). Analysis of receiver operator curve FIF max to identify optimal PIRF yielded an area under the curve of 0.79. Of the men shorter than 65 inches, 16.7% had suboptimal PIFR compared with 27.4% of women of the same height.

Investigators concluded that “[s]uboptimal PIFR measurements were identified more frequently in females, short stature individuals, and those with air trapping. Spirometry determined values of FIF max corresponded with PIFR measurements according to gender and height. Spirometry allows identification of patients with a decreased FIF max based on gender and height that can be used as a physiologic threshold value for future interventional studies.”

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Disclosures: Dr Sharma served on the advisory board of Astra Zeneca, Mylan, Boehringer Ingelheim, and Sunovion Pharmaceuticals.


Duarte AG, Tung L, Zhang W, Hsu ES, Kuo Y-F, Sharma G. Spirometry measurement of peak inspiratory flow identifies suboptimal use of dry powder inhalers in ambulatory patients with COPD [published online June 4, 2019]. Chronic Obstr Pulm Dis. doi:10.15326/jcopdf.6.3.2018.0163