Objective: To determine the prevalence of undiagnosed diaphragmatic dysfunction in a long-term acute care hospital setting in patients on prolonged mechanical ventilation and its association with weaning outcomes. Design: This is a single-center, retrospective cohort study including 451 patients on prolonged mechanical ventilation admitted to a longterm acute care hospital facility between 2012 and 2017. Diaphragmatic dysfunction was assessed using fluoroscopy. Results: Three hundred nineteen patients on prolonged mechanical ventilation were assessed for diaphragmatic dysfunction. Nine patients were diagnosed with diaphragmatic dysfunction before admission. Eighty (72.7%) without diaphragmatic dysfunction were successfully weaned and 30 (27.3%) failed to wean, whereas 51 participants (31.9%) with diaphragmatic dysfunction were successfully weaned and 109 (68.1%) failed to wean (P < 0.001). When analyzing days to wean, the median was 13 days for those with no diaphragmatic dysfunction, 19 days with unilateral diaphragmatic dysfunction, and 28 days with bilateral diaphragmatic dysfunction (P < 0.001). Weaning success was not statistically associated with generalized neuromuscular disorders, age, sex, body mass index, smoking history, or diabetes. Conclusions: Diaphragmatic dysfunction was found to be strongly associated with time to wean and weaning success in the long-term acute care hospital setting. Very few patients despite being on prolonged mechanical ventilation were diagnosed with diaphragmatic dysfunction before longterm acute care hospital admission. Given this information, early diagnosis of diaphragmatic dysfunction among prolonged mechanical ventilation patients in the long-term acute care hospital setting is paramount in preventing secondary complications associated with mechanical ventilation.

Research Objectives To examine weaning outcomes of patients with a history of COVID-19 on prolonged mechanical ventilation (PMV) in the LTACH setting. Design Retrospective cohort. Setting A long-term acute care facility. Participants Participants (N=25; mean±sd age, 58±13.2 yr) mostly consisted of overweight diabetic men with diaphragmatic dysfunction (DD) and no history of COPD or sleep apnea. Interventions Pulmonary function was determined using spirometry and arterial blood gas measurements. Diaphragmatic dysfunction was assessed using fluoroscopy; neuromuscular function measured via EMG. Main Outcome Measures The primary outcome was weaned status at discharge. Weaning success was defined as MV liberation for over 48 hours at time of discharge. Variables included MIP, MEP, FVC, FEV1/FVC, DD (bilateral/unilateral/none) and PCO2. Results Most participants (57.7%) had either unilateral or bilateral diaphragmatic dysfunction. The proportion of participants with ventilator liberation success was 53.8% at time of discharge with a median [IQR] LOS of 41 [33-68] days. The mean (sd) FVC and PCO2 were 0.6 (±0.3)% and 51.4 (±9.7), respectively; the MEP and MIP were 43.9 (±16.7) and -36.5 (±15.9) cmH2O. Univariate logistic regression analyses found a significant association with MIP (OR 95% CI = (0.87-0.99); p-value = 0.0391) on wean status. Conclusions Liberation from MV has been a challenge in the COVID-19 population with a large number of individuals subjected to PMV. Many studies have sought to examine the parameters for weaning in the ICU setting, but few have discussed weaning strategies in LTACHs. MIP may have the potential to help prognosticate weaning outcomes in the COVID-19 population. Further studies are needed to confirm and identify other parameters associated with successful weaning. Author(s) Disclosures The authors have no conflicts of interest.