Diaphragm Pacing in Lung Transplant Patients: To Identify and Treat Diaphragm Function Abnormalities

Abstract

Purpose Lung disease and transplantation can lead to diaphragm dysfunction (DD). Phrenic neuropathy in lung transplants increases morbidity. Diaphragm pacing (DP) improves nerve recovery and prevents ventilator induced diaphragm dysfunction (VIDD). The FDA authorized temporary DP to decrease the burden of mechanical ventilators (MV) during the COVID-19 pandemic. We report the largest experience of DP in lung transplantation. Methods 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 was laparoscopically implanted in those with identified (either pre or post-transplant) phrenic nerve injury. Post implantation, diaphragm stimulation ensued and results evaluated radiographically and with diaphragm electromyography (dEMG). Transplant recipients had the temporary DP system implanted percutaneously via their chest incision. Diaphragm activity was monitored with the electrodes and stimulation applied for MV weaning. Results 8 patients utilized DP with no device adverse events. 3 patients with DD, 6 months average post-transplant, had chronic DP implanted. All had evidence of subsequent recovery of diaphragm function. 1 patient had DP pre-transplant for unilateral DD with subsequent diaphragm recovery. At time of unilateral transplant on contralateral side a phrenic nerve injury was identified. DP was used during the recovery. 4 patients underwent implantation of temporary DP electrodes during lung transplant. 2 patients had bilateral dEMG identified post-operatively with uneventful recovery and removal of electrodes. 2 patient had no dEMG activity or movement bilaterally post-operatively. Retrospectively this was a pre-operative condition. 1 recovered diaphragm function at 2 weeks with DP therapy. The 2nd is still undergoing DP. 3 patients with phrenic nerve dysfunction post operatively also had intercostal nerve cryoanalgesia which decreases external intercostal muscles use for respiration. These 3 patients had prolonged ventilation difficulties. Conclusion DP was safely used in lung transplantation in identifying and improving recovery of phrenic nerve injuries and preventing VIDD. Intercostal nerve cryoanalgesia should not be used if there is DD. DP should be considered in all lung transplants for improved outcomes.