Diaphragm pacing: a paradigm shift in the management of respiratory insufficiency for Pompe disease?

Pompe disease is an inherited disorder notable for severe, progressive ventilatory compromise. Although ventilatory failure has been attributed to myofiber dysfunction secondary to diaphragmatic glycogen accumulation, neural involvement of the phrenic motor system is also a prominent feature. Direct diaphragm pacing supplements respiratory function in other disorders of the phrenic motor system. Consequently, the authors hypothesised that augmented neuromuscular activity via diaphragm pacing would promote weaning from mechanical ventilation in patients with Pompe disease unresponsive to conventional, muscle-directed treatments. This case series describes three patients with Pompe disease who developed diaphragm paresis that resulted in chronic mechanical ventilation dependence. After pre-operative inspiratory muscle strengthening exercises failed to improve function, fine-wire pacing electrodes were laparoscopically implanted into the diaphragm. Diaphragm conditioning was initiated the first post-operative week and consisted of gradual increases in stimulation parameters, lengthening of stimulation sessions, and ventilator weaning. Ventilation and intramuscular EMG were recorded periodically during conditioning, to quantify diaphragm neuromuscular function. During paced breathing without mechanical ventilation, tidal volumes increased and two patients weaned from daytime ventilator dependence within the first 3 months of pacing, which has been sustained over the long-term. A third patient reduced reliance on daytime ventilation, but weaning was delayed by malacia of the large airways. In all patients, pacing appeared to facilitate spontaneous phrenic motor unit activity during independent breathing without ventilator or pacer support.

Smith BK, Fuller DD, Martin AD, et al. Diaphragm Pacing as a Rehabilitative Tool for Ventilator-Dependent Pompe Disease: Case Series. Phys Ther. 2016 Feb 18. [Epub ahead of print]