Acute Respiratory Distress Syndrome Exacerbated by Inappropriate Use of Mechanical Insufflation-Exsufflation Following Infection in a Patient With Amyotrophic Lateral Sclerosis: A Case Report

Mechanical insufflation-exsufflation (MI-E) is widely used to assist airway secretion clearance in patients with neuromuscular disorders such as amyotrophic lateral sclerosis (ALS). While MI-E is generally considered safe when used intermittently for cough augmentation, its prolonged and unsupervised use as a substitute for invasive ventilation is discouraged by current clinical guidelines, including those issued by the American College of Chest Physicians and the American Academy of Neurology. We report the case of a 53-year-old man with advanced ALS, diagnosed approximately 10 years earlier, who developed acute respiratory distress syndrome (ARDS) exacerbated by inappropriate use of MI-E following a recent respiratory infection. The patient had previously relied on tracheostomy invasive ventilation (TIV) but chose to suspend its use, instead employing MI-E continuously for 62 hours (28,234 cycles), based on prior positive experiences and personal preference. Upon hospital admission, the patient was diagnosed with mild ARDS, bacterial pneumonia, and influenza B infection. Although the respiratory infection was likely the primary cause of deterioration, MI-E-related pressure changes may have exacerbated pulmonary injury, particularly in the context of acute infection. Rapid improvement in gas exchange and imaging findings within 48 hours of MI-E discontinuation further supports this hypothesis. We discuss possible mechanisms linking excessive MI-E usage to lung injury, including barotrauma and negative pressure pulmonary edema. We also emphasize the importance of clearly defined device indications, structured caregiver education, and regular clinical supervision in home respiratory care. To our knowledge, this may be the first reported case of ARDS potentially resulting from the combined effects of infection and inappropriate MI-E application, highlighting the need for multidisciplinary coordination and proper device supervision in managing advanced neuromuscular respiratory failure at home.