This section describes safety outcomes from the published literature that the committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview.
5.1 Capnothorax was reported in 42% (21/50) of patients with spinal cord injuries in a case series of 88 patients included in a systematic review of 148 patients. Capnothorax was managed successfully with simple aspiration, drainage or observation.
5.2 Asymptomatic pneumothorax (which was treated by chest tube drainage) was reported in 1 patient in a case series of 6 patients with spinal cord injuries included in the systematic review of 148 patients.
5.3 Superficial wound infection along tunnelled wires (which resolved with oral antibiotics, shortening and terminating electrodes) was reported postoperatively in 1 patient with spinal cord injuries in the case series of 88 patients included in the systematic review. Delayed wound infection at the superficial wire connection site was reported in 1 patient in the case series of 6 patients included in the systematic review.
5.4 The diaphragm pacing stimulator interacting with a pre-existing cardiac pacemaker was reported in 1 patient in a case series of 20 patients included in the systematic review.
5.5 Right shoulder pain during maximum stimulation of a single electrode (which was relieved by reducing the current) was reported in 1 patient in the case series of 6 patients included in the systematic review.
5.6 Fever symptoms redeveloped in 1 patient (which were common before injury but absent during mechanical ventilation) in the case series of 6 patients included in the systematic review.
5.7 Intermittent aspiration of food was reported in 1 patient in the case series of 6 patients included in the systematic review. This was thought to be related to the large negative airway pressure generated during contraction of the diaphragm. It was stopped by using a 1‑way valve, designed for patients with a tracheostomy tube, during meals.
5.8 Progressive pacing failure was reported in 1 quadriplegic patient who was successfully weaned off mechanical ventilation with an intra-diaphragm phrenic stimulator. After a year hypoventilation developed without obvious cause. The patient had gained a massive amount of weight as a result of endocrine disorders. Pacing failure was because of excessive chest wall and abdominal weight preventing diaphragm contractions to adequately inflate the rib cage.
5.9 In addition to safety outcomes reported in the literature, specialist advisers are asked about anecdotal adverse events (events which they have heard about) and about theoretical adverse events (events which they think might possibly occur, even if they have never done so). For this procedure, specialist advisers listed the following anecdotal adverse event: excess mortality. They considered that the following were theoretical adverse events: decompensated respiratory failure and breathlessness related to diaphragm pacing.