Abstract
BACKGROUND: Diaphragmatic electrical stimulation (DES) describes the process whereby electrical impulses are delivered to the diaphragm or phrenic nerves to elicit diaphragmatic contraction. DES is also known as diaphragmatic pacing, phrenic pacing, electrophrenic respiration or electroventilation. DES may be used as an alternative to positive pressure ventilation in selected patients with high spinal cord injury (SCI) or central hypoventilation syndromes (CHS). By enabling a more physiological form of respiration, it can allow speech, improve olfaction, decrease the frequency of respiratory infections, and ultimately it may improve both the duration and quality of patients' lives. CASE DESCRIPTION: This case report provides an overview of the use of DES in 3 patients, one with diaphragmatic intramuscular electrodes and 2 with phrenic nerve stimulation (PNS) leads. We provide details of our assessment strategy prior to implantation and videos of the expected diaphragmatic descent and flow diversion created in a ventilated patient with a single twitch stimulus. Within two months of implantation, our first patient had measurably improved speech in addition to periods of ventilator independence. Our second and third patients were successfully weaned from the ventilator within 6 months. Staffing and safety concerns have mandated a return to overnight mechanical ventilation for both patients. Despite this, liberation from the ventilator and its ancillary tubing has yielded improvements in quality of life and a reduction in the frequency of respiratory infections over the past 4 years for both patients. CONCLUSIONS: The patients in this case report derived significant benefit from DES, however, the lack of physiological responsiveness, particularly in quadriplegic patients, and the open loop design requiring repeated manual adjustment are ongoing issues. These systems require external components and frequent battery changes due to high energy demands. Those interested in this technology should expect a steep learning curve. Despite these limitations, with careful patient selection, DES has the potential to make a positive contribution to each patient's quality of life.