Effects of posture on cough flow after breath-stacking maneuver in healthy subjects

Background : The breathing-stacking maneuver (BS) increases inspired volume and may influence the cough flow generation. Aim : To evaluate the effects of BS in voluntary cough flow and chest wall volume in two different positions in healthy subjects by opto-electronic plethysmography (OEP). Methods : 14 healthy subjects (7 M) age 23.8 ± 2.5 years, BMI 23.3 ± 1.84 kg/m2, FVC 4.26 ± 0.6 L, FEV1/FVC 0.83 ± 0.01 L) were assessed. Voluntary cough flow, tidal volume (Vt) of rib cage compartments (VtRc) and abdominal compartments (VtAb) as well as inspiratory capacity (IC) were analyzed before and after the BS maneuver by OEP in two positions, supine and 45o inclination. Results : After BS, cough flow significantly increased only in the 45o inclined position (5.21 ± 0.48 L/s vs 6.09 ± 0.30 L/s, p < 0.005). VtRc increased after the BS, in both positions (supine: 0.182 L vs 0.220L; 45o: 0.211 L vs 0.279 L (p < 0.05). There were no changes in the IC after BS in both positions. Conclusion : These results show that in healthy subjects breath-stacking maneuver increases pulmonary volumes leading to an increase in cough flow only in the 45o inclination position. The decrease of lung volume in supine position annuls the beneficial effects of breath-stacking. ![Figure][1] Figure 1. Cough peak flow before and after breath-stacking (BS) * p< 0.05 – Supine vs . 45o – ANOVA two-way (beforeBS e afterBS); † p <0.05 – Supine vs. 45o – ANOVA two-way (between groups). [1]: pending:yes