[Implantation of a phrenic stimulator in central respiratory paralysis]

Neoplastic or traumatic lesions of the brain stem or the upper spinal cord frequently cause respiratory insufficiency necessitating permanent mechanical ventilation. If the integrity of the diaphragm and its nerves is not affected, adequate ventilation can be achieved by electric stimulation of the phrenic nerves. Diaphragm pacing systems mean the patients can be independent of ventilator treatment. This is a psychological advantage for the patient, giving him or her the option of living in less specialized medical care units and perhaps even at home. CASE REPORT. We report the case of a 47-year-old man with a brain stem tumour, which was resected in large pieces. During the postoperative period an increasingly severe respiratory insufficiency developed, which finally made continuous mechanical ventilation necessary. After the viability of the phrenic nerves and contractility of the diaphragm had been shown by direct stimulation of the nerves to be still intact, it was decided that a diaphragm pacer system should be implanted. A "Diaphragm Pacer System S232 G" (Avery Laboratories, Glen Cove, N.Y., USA: external transmitter, antenna, implanted electrode and receiver) was implanted. Using a supraclavicular approach, phrenic nerve electrodes were placed around each nerve and connected with subcutaneous implants of radio signal receivers. Six days after implantation phrenic nerves were stimulated for a first short period. External antenna loops were taped to the skin over the implanted receiver sites (Fig. 3). The impulses produced by the transmitter were delivered via these antenna loops and led to contraction of the diaphragm, providing almost normal respiration. The duration of stimulation was increased stepwise from 1 h a day to full-time stimulation. Three weeks after implantation of the diaphragm pacer system the patient could be totally weaned from mechanical ventilation. After a further 2 weeks it was possible to discharge him from the intensive care unit, and he was then transferred to a rehabilitation centre.