Overstaffing and Understaffing Are Associated With Adverse Events In a Level III Neonatal Intensive Care Unit

OBJECTIVES: This study evaluates the association between the nurse-to-patient ratio (NPR) and adverse events (AEs) in a level III neonatal intensive care unit (NICU). METHODS: This retrospective register study used data from 2020 to 2022 from 3 digital sources: a patient safety incident reporting database, the unit's nurse shift scheduling system, and the hospital information system. The NPR was calculated using the following categories to define patient care intensity: 0.33:1, 0.75:1, 1:1, and 1.5:1, based on the number of patients and nurses assigned to each shift. RESULTS: A total of 382 AEs were reported during the study. Most of the AEs occurred while the NICU was understaffed (61%, n=232) or overstaffed (29.8%, n=114). They also frequently occurred during shift overlaps (26%, n=101) and during morning shifts (49%, n=186). When AEs occurred, there was a significant difference in how the patient number was divided between different shift-level staffing in intensive care (P=0.0013) and in high maintenance intensive care (P