PILOT STUDY OF PERCUTANEOUS TEMPORARY DIAPHRAGM PACING WIRES IN CARDIAC SURGERY PATIENTS AT RISK OF PROLONGED MECHANICAL VENTILATION DURING THE COVID-19 PANDEMIC

BACKGROUND: Prolonged mechanical ventilation (PMV) after cardiac surgery occurs in 12% of patients, and significantly increases morbidity and mortality. Diaphragm pacing (DP) decreases ventilation times by 64% in other patient groups. We investigated the feasibility and outcomes of DP in urgent cardiac surgeries to decrease ventilator burden during the COVID-19 pandemic. METHODS AND RESULTS: This pilot study is an open-label FDA (IDE# G170294) prospective trial of temporary DP electrode use in high risk cardiac surgery patients (ClinicalTrials.gov Identifier–NCT04309123). Prior to sternotomy closure, the pleural space is opened, two electrodes (Figure 1) are placed in each diaphragm muscle, and the wires are tunneled percutaneously. The electrodes record diaphragm burst electromyography (dEMG) continuously for the first 24 hours and then once daily (Figure 2). In PMV patients (MV>24 hours), DP is initiated to prevent diaphragm atrophy and ventilator induced diaphragm dysfunction. The primary outcome was incidence of serious device related adverse events. The secondary outcome was time on MV. From 4/2/20–6/25/20, 44 patients were consented, 32 were implanted, and 12 were not. PMV was required in 10 patients implanted and 4 not implanted. There were no serious adverse events related to DP electrode implantation, all stimulated patients had improved ventilation and diaphragm function, and all electrodes were removed successfully. Criteria that best predicted PMV were: IABP, history of TIA or CVA, COPD, LVEF < 20%, and prior open-heart surgery. Using these criteria, the median time on mechanical ventilation in the first 120 hours was 35.7% versus 80.0% for the stimulated and non-stimulated groups, respectively. CONCLUSION: Temporary DP electrode placement during cardiac surgery is feasible and safe. DP improved diaphragm function and ventilation, and increased the likelihood of extubation by 48 hours. These results provide a catalyst for a prospective randomized controlled trial to decrease the MV burden in an enhanced recovery after surgery (ERAS) protocol.