We present our series of patients with chronic ventilatory failure treated with electrophrenic respiration: 13 males and nine females with a mean age of 12+11.5 years. The etiology was, 13 tetraplegia, ®ve sequelae of surgical treatment of intracranial lesions, and four central alveolar hypoventilation. The mean duration of the conditioning period were 3 ± 4 months. Eighteen patients (81.8%) achieved permanent, diaphragmatically-paced breathing with bilateral stimulation and in four (18.2%) patients, pacing was only during sleep. Five patients died (22.7%): two during the hospital stay and three at home; two deaths had unknown cause and three were due respectively to, lack of at-home care, recurrence of an epidermoid tumor, and sequelae of accidental disconnection of the mechanical ventilation before beginning the conditioning period. Two cases were considered failures: One patient had transitory neurapraxia lasting 80 days, and the other had an ischemic spinal cord syndrome with progressive deterioration of the left-side response to stimulation. One patient had right phrenic nerve entrapment by scar tissue and four suered infections. The follow-up periods since pacemaker implantation are currently: 1, 11 years; 4, 10 years, and 17, less than 5 years. The results of our experience demonstrate that complete stable ventilation can be achieved using diaphragmatic pacing and that it improves the prognosis and life quality of patients with severe chronic respiratory failure.

Background -Electrophrenic pacing can be used in the management of ventilatory failure in quadriplegic patients. A study was undertaken to determine the pattern oftransdiaphragmatic pressure (PDI) during the conditioning phase of electrophrenic pacing to see if it had a possible role in optimising the process of conditioning. Methods -The tidal volume (TV) and PDI were measured in a group of six quadriplegic patients commencing ventilation by low frequency pulse stimulation (7-10 Hz) and low respiratory rate stimulation (<10 breaths/min). Results -Tidal volume increased between baseline and month 1 (4.33 mllkg, p<0001) and between months 1 and 2 (3.00 mllkg, p<005) and then stabilised. PDI was higher during bilateral diaphragmatic pacing (mean (SD) 1-73 (0.30) kPa) than with either left (1 15 (0.34) kPa) or right (0.86 (0.37) kPa) unilateral pacing. PDI varied throughout the observation period, probably by interaction between recovery of the diaphragmatic fibres and the pacing regimen. Conclusions -Patients with quadriplegia due to high spinal injury can be maintained with ventilation by continuous electrophrenic pacing. The control criteria used in this study for pacing were tidal volume and the patient's tolerance, and the PDI measurement did not contribute any additional information to help with managing the conditioning process. (Thorax 1996;51:420-423)