Addressing Diaphragm Dysfunction in Lung Transplant Recipients: The Expanding Role of Diaphragm Pacing

Abstract

<h3>Purpose</h3> Diaphragmatic dysfunction is documented after lung transplantation and can affect up to 62% patients. Diaphragm pacing (DP) prevents ventilator induced diaphragm dysfunction (VIDD) while on mechanical ventilation (MV) and has been shown via functional electrical stimulation to improve phrenic nerve recovery. We report the largest experience of DP in lung transplantation recipients. <h3>Methods</h3> This is a retrospective analysis of an IRB approved prospective, non-randomized interventional experience at a single institution with two DP systems. A chronic DP system [NeuRx, Synapse Biomedical] was implanted laparoscopically in those with phrenic nerve injury or difficulty with weaning from MV remotely after their transplant. A temporary DP system [TransAeris, Synapse Biomedical] was implanted at the time of transplantation or laparoscopically. In both types of implantation, diaphragm stimulation ensued if needed to wean from MV or for nerve recovery. Results evaluated radiographically and with diaphragm electromyography (dEMG). <h3>Results</h3> DP was utilized in16 patients with no device adverse events. Of those, 5 patients had chronic DP system: a) 1 patient one year post transplant shows no recovery of phrenic nerve injury, still pacing; b) 3 patients showed recovery of phrenic nerve/diaphragm function through pacing; c) 1 patient 2 years post-transplant sustained hip fracture requiring surgery, developed pneumonia and became tracheostomy MV dependent; DP allowed complete diaphragm recovery, decanullation of tracheostomy and removal of DP wires. 11 patients had temporary DP electrodes placed: a) 1 recipient(two months post-transplant) had DP use during ECMO for COVID- 19 sepsis and respiratory failure and subsequently expired when family withdrew therapy; b) 10 implanted at time of lung transplant. Of those 10, 3 patients had bilateral dEMG identified post-operatively with uneventful recovery and removal of electrodes; 7 patients had diaphragm abnormalities identified post-operatively and underwent DP. Of those 7, 5 showed recovery and DP electrodes removed and 2 are still pacing 1 and 9 months post-transplant. <h3>Conclusion</h3> DP was safely used in lung transplantation to identify and improve recovery of phrenic nerve injuries, wean from MV and prevent VIDD. DP shows promise in addressing diaphragm dysfunction after lung transplantation and improving outcomes.