Objective: to explore non quality issues in the clinical care of patients with ventilator-associated pneumonia (VAP) in an adult Intensive Care Unit in Medellin, Colombia. Methodology: a qualitative study using the case study strategy. Reason’s Organizational Model of Causality and Adverse Events was used as the source for analytical categories and the hospital operating conditions were not controllable by the research team. Results: during the analytical phase, through open coding, 441 codes were identified from interviews and 25 from medical records. They were reorganized by axial coding into 14 subcategories and 4 analytical categories. It was found that a management decision (limiting the hiring of qualified staff to take care of patients’ airways with mechanic ventilation and replacing it with support staff) was perceived as a determining factor leading to the incidence of VAP, even in presence of a relevant approach and solid safety barriers.