Differences in peak cough flow values assessed by mouthpiece and facemask on healthy subjects

Abstract

Background: Coughing is the most important mechanism for evacuating mucus secretions from the airways. Its efficacy directly depends on the Peak Cough Flow (PCF), the maximum air-flow generated during a cough. PCF is used to assess cough in patients with respiratory muscle weakness, mainly in neuromuscular diseases. This measure is performed using a flow meter. However, the literature describes two forms of evaluation: one using a facemask or and the other using a cylindrical mouthpiece and a nose clip. Objective: To compare the efficacy of measuring the PCF using a cylindrical disposable mouthpiece and a nose clip (PCFmouth) with measurements obtained using a silicone facemask with an inflatable pneumatic border (PCFmask) in healthy adults. Method: We recruited 34 (16 men) healthy adult subjects that performed the cough maneuver. Three valid maneuvers were performed by each of the subjects to obtain reproducible values. The PCF was measured using both interfaces applied in a random order. Results: The population characteristics were: mean age 22.1 ± 2.3 years (range 18-29), 11 smokers (32.4%) and 12 subjects (35.3%) performed physical activity at least 3 times per week. The PCFmouth was 4.6% higher than the PCFmask (499.1 ± 114.5 vs. 477.9 ± 94.5 L/min), exhibiting a statistically significant difference (p < 0.01). Conclusion: In a healthy population, there is a significant difference in PCF values obtained using a mouthpiece with a nose clip versus a facemask. Based on these results, we recommend using a mouthpiece to obtain the best peak cough flow measurement.