Limits of Effective Cough-Augmentation Techniques in Patients With Neuromuscular Disease

BACKGROUND: Manual and mechanical cough-augmentation techniques can improve peak cough flow (PCF) in patients with respiratory insufficiency caused by neuromuscular disease. METHODS: We studied cough-augmentation techniques in 179 clinically stable patients with various neuromuscular diseases. We measured vital capacity (VC), maximum expiratory pressure (MEP), and PCF, with and without 3 cough-augmentation techniques: manually assisted cough (MAC); breath-stacking (in a subgroup of 60 patients receiving noninvasive mechanical ventilation); and breath-stacking in combination with MAC (also in the 60-patient subgroup). We analyzed the data with the receiver operating characteristic (ROC), to predict the lower limits (assisted PCF > 180 L/min) and upper limits (assisted PCF 1,030 mL (ROC 0.86, P 558 mL (ROC 0.92, P 340 mL (ROC 0.90, P 34 cm H2O (ROC 0.89, P 340 mL and MEP < 34 cm H2O would optimally benefit from the combination of