Anaesthetic aspects of implanting diaphragmatic pacing in patients with spinal cord injury.

Abstract

Some patients with high cervical spinal cord injury are largely or completely dependent on mechanical ventilator support. Diaphragmatic phrenic nerve pacing is a new technique that offers some patients greater independence from mechanical ventilation. In selected patients, electrodes are placed on the abdominal side of the diaphragm via laparoscopy. An external pacing box provides the pacing stimulus. We report our experience with four patients with spinal cord injury in a pilot project, presenting for laparoscopic insertion of diaphragmatic phrenic nerve pacing leads inserted. The surgery took about two hours and diaphragmatic mapping precluded muscle relaxants. We used desflurane with remifentanil for maintenance. Apart from transferring the patients to and from their usual ventilators, other anaesthesia issues were difficult venous and arterial access for lines and long-term tracheostomies with no cuff or cuffs filled with water While hypotension was a frequent problem, one patient also developed intraoperative hypertension secondary to autonomic dysreflexia. Preoperative testing predicted pacing outcome with three of the four patients having successful pacing with tidal volumes of up to 10 ml/kg at the end of surgery. This initial Australian experience may lead to greater use of the technique.