Comparison of Two Cough-Augmentation Techniques Delivered by a Home Ventilator in Subjects With Neuromuscular Disease

Abstract

Background: Breath-stacking, which consists of taking 2 or more consecutive ventilator insufflations without exhaling, is a noninvasive and inexpensive cough-assistance technique for patients with neuromuscular disease. Volumetric cough mode (VCM) is a recently introduced ventilator mode consisting of a programmable intermittent deep breath equal to a set percentage of the baseline tidal volume. Here, our objective was to compare VCM to breath-stacking during volume-control continuous mandatory ventilation in subjects on long-term noninvasive mechanical ventilation at home.

Methods: We included 20 subjects with neuromuscular disease causing severe respiratory muscle dysfunction with a cough peak flow (CPF) < 270 L/min or maximum expiratory pressure < 45 cm H₂O. Each subject tested breath-stacking and VCM in random order.

Results: CPF increased with both techniques but was higher with VCM than with breath-stacking in 16 subjects. In 17 subjects, CPF was highest with the technique that produced the greatest inspiratory capacity.

Conclusion: Our results indicate that both breath-stacking and VCM are useful cough-augmentation techniques. Displaying insufflated volumes on the ventilator screen is a simple and accessible method for selecting the most efficient cough-augmentation technique delivered by a home ventilator.

Keywords: cough; intermittent positive-pressure breathing; mechanical insufflation; neuromuscular diseases; respiratory failure.