IMPLANTATION OF A PHRENIC-NERVE STIMULATO R IN A CASE OF CENTRAL RESPIRATORY PARALYSIS

Neoplastic or traumatic lesions of the brain stem or the upper spinal cord frequently cause respiratory insufficiency necessitating permanen t mechanical ventilation. If the integrity of the diaphragm and its ne rves is not affected, adequate ventilation can be achieved by electric stimulation of the phrenic nerves [1, 3, 5, 6]. Diaphragm pacing syst ems mean the patients can be independent of ventilator treatment. This is a psychological advantage for the patient, giving him or her the o ption of living in less specialized medical care units and perhaps eve n at home [4, 9]. 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 insufficie ncy developed, which finally made continuous mechanical ventilation ne cessary. After the viability of the phrenic nerves and contractility o f the diaphragm had been shown by direct stimulation of the nerves to be still intact, it was decided that a diaphragm pacer system should b e implanted. A ''Diaphragm Pacer System S232 G'' (Avery Laboratories, Glen Cove, N.Y., USA: external transmitter, antenna, implanted electro de and receiver) was implanted. Using a supraclavicular approach, phre nic nerve electrodes were placed around each nerve and connected with subcutaneous implants of radio signal receivers. Six days after implan tation phrenic nerves were stimulated for a first short period. Extern al antenna loops were taped to the skin over the implanted receiver si tes (Fig. 3). The impulses produced by the transmitter were delivered via these antenna loops and led to contraction of the diaphragm, provi ding almost normal respiration. The duration of stimulation was increa sed stepwise from 1 h a day to full-time stimulation. Three weeks afte r implantation of the diaphragm pacer system the patient could be tota lly weaned from mechanical ventilation. After a further 2 weeks it was possible to discharge him from the intensive care unit, and he was th en transferred to a rehabilitation centre.