Abstract
Cough- and asthma-like symptoms are common adverse reactions to angiotensin-converting enzyme inhibitors (ACEi). However, attributing these symptoms to the use of ACEi might be masked by clinical confounders. We report a 68-year-old female residing in a long-term acute-care facility for patients requiring prolonged invasive mechanical ventilation treated for years with ACEi. Daily reversible bouts of life-threatening severe bronchospasm gradually developed over 6 weeks and abruptly resolved following the cessation of ACEi treatment. The late appearance of bronchospasm and the unique clinical setup of chronic invasive ventilation in a patient with smoking-related chronic obstructive lung disease are among the principal confounders that delay the identification of the causative association between ACEi and respiratory compromise. Chronic positive pressure ventilation may also conceal small airway reactivity and obstruction, similar to auto-positive end-expiratory pressure (auto-PEEP). Conceivably, angiotensin receptor blockers should be preferred over ACEi in such patients.