Posture, Interface, and Peak Cough Flow (PCF P/I)

Cough is an essential protective mechanism that requires intact neuromuscular function and precise coordination across the inspiratory, compressive, and expulsive phases. Peak cough flow (PCF) is a simple, non-invasive measure, widely used to assess cough intensity and guide clinical decisions. Because of its clinical relevance, standardized procedures are essential. Current ATS/ERS recommendations specify seated testing with a mouthpiece and a noseclip (MP). However, this configuration is not always possible or consistently used in practice. Many patients cannot maintain adequate posture or mouthpiece seal, and a facial mask (FM) may be a feasible alternative. Evidence regarding the effects of posture (sitting vs standing) and interface (MP vs FM) on PCF remains inconsistent, with few studies comparing both factors within the same individuals using a randomized crossover design.

Aims To determine the effects of body position (sitting vs standing) and measurement interface (FM vs MP) on PCF in healthy young adults. We hypothesized that both factors would influence PCF.

Methods This randomized within subject crossover study included healthy, non smoking adults aged 20-30 years. Exclusion criteria were chronic disease, top-level athletic status and any signs of obstruction and/or auscultatory noise (wheezing or stridor) before the trial. Each participant completed four randomized conditions during a single session: Sit-Mask, Stand-Mask, Sit-Mouthpiece, and Stand-Mouthpiece. PCF (L/s) was measured using an ultrasonic spirometer (SpiroScout, Ganshorn). For each condition, participants performed three standardized maneuvers consisting of three tidal breaths, a rapid inspiration to total lung capacity, and a maximal cough; the highest PCF per condition was used for analysis. A two factor repeated measures ANOVA evaluated the effects of posture, interface, and their interaction (α = 0.05).