Mechanical Ventilation and Predictors of In-Hospital Mortality in Fibrotic Interstitial Lung Disease with Acute Respiratory Failure: A Cohort Analysis through the Paradigm of Acute Respiratory Distress Syndrome

Objectives: Prior studies report significant mortality in fibrotic interstitial lung disease patients undergoing mechanical ventilation. Little is known about baseline characteristics or ventilator strategies that might improve outcomes. We analyzed the ventilator characteristics of a large cohort of fibrotic interstitial lung disease patients from the perspective of an acute respiratory distress syndrome paradigm to see if any specific mechanical ventilation strategies might improve in-hospital mortality. Design: Retrospective cohort study. Setting: Single-center, multihospital medical ICUs. Patients: Consecutive fibrotic interstitial lung disease patients who experienced mechanical ventilation for acute respiratory failure. Interventions: Interstitial lung disease characteristics, demographics, and ventilator variables were analyzed for univariable and multivariable predictors of in-hospital mortality, adjusted for confounding with an a priori causation model. Measurements and Main Results: A total of 111 patients accounted for 114 admissions. Idiopathic pulmonary fibrosis comprised 34% with idiopathic acute exacerbation (65%) being the most common admission type. Ninety-five percent were initiated on mandatory volume-control ventilation with only 50% achieving a low tidal volume strategy (plateau pressure ≤ 30 cm H₂O) within 3 hours of intubation. Unadjusted clinical predictors of in-hospital mortality included age (unit odds ratio, 1.05; 1.01-1.10; p = 0.015), time from admission to intubation (hr) (unit odds ratio, 1.01; 1.01-1.03; p = 0.017), and use of paralytics (relative risk, 1.54; 1.26-1.90, p < 0.001). Adjusted mechanical ventilation-related predictors of in-hospital mortality included achieving early targeted plateau pressures (odds ratio, 0.23; 0.07-0.76; p = 0.016), Pao₂/Fio₂ ratio at 3 (unit odds ratio, 0.98; 0.96-0.99, p = 0.002) and 48 hours (unit odds ratio, 0.98; 0.97-0.99, p = 0.018), initial mean airway pressure (unit odds ratio, 1.13; 1.02-1.28, p = 0.019), and total net fluid status (mL) (unit odds ratio, 1.01; 1.001-1.02, p = 0.0001). Conclusions: Several factors predict in-hospital mortality in fibrotic interstitial lung disease-associated mechanical ventilation when viewed through an acute respiratory distress syndrome model. Further research is needed to refine strategies that may perhaps improve survival if mechanical ventilation is pursued in this set of patients.