BACKGROUND: The limited literature on closed-system suctioning suggests a need for further research in this area. Information is lacking about the frequency of use of the closed versus the open system of suctioning and about the current patterns of practice of closed-system suctioning among nurses. OBJECTIVES: To determine the frequency of use of closed- versus open-system suctioning by critical care nurses and to describe the endotracheal suctioning practices of nurses who use closed-system suctioning, in particular the current practice of hyperoxygenation and hyperinflation. METHODS: A survey developed by the investigators was mailed to a stratified proportional sample of 241 critical care nurses who are members of the American Association of Critical-Care Nurses in a tristate area in the mid-Atlantic region of the United States. The 19-item questionnaire included both open and forced-choice items. The response rate was 50%. RESULTS: Closed-system suctioning is common in the critical care setting, and current nursing practices of closed-system suctioning vary. Use of hyperoxygenation is more common than use of hyperinflation with closed-system suctioning. Nurses had knowledge deficits about the proper performance of hyperoxygenation and hyperinflation. CONCLUSIONS: Further research on closed-system suctioning is warranted, especially on the practices of hyperoxygenation and hyperinflation and the effect of these interventions on the prevention of suctioning-induced hypoxemia.