BACKGROUND: Intensive care is one of the most resource-intensive forms of care because seriously ill patients are cared for in units with high staffing levels. Studies show that the number of registered nurses (RNs) per patient and nurse education level affects patient outcome. However, there is a lack of studies that consider how nurses/patient ratio with an advanced educational level of specialized nurses in intensive care, affect the intensive care performed in different patient populations.

AIM: To investigate if differences in patient characteristics and nurse-patient ratio have an impact on the quality of care.

STUDY DESIGN: This is a retrospective observational study with a review of all patients >15 years receiving care at two general intensive care units with different nurse/patient ratio (unit A, 1:1 nurse/patient ratio and unit B, 0.5:1 nurse/patient ratio).

RESULTS: There was no significant difference in the initial severity of illness between the units. However, younger patients, male patients and patients requiring surgery entailed a higher workload and a longer intensive care unit (ICU) stay despite a 1:1 critical care nurse/patient ratio. A small difference, but not significant, with more unplanned re-intubations occurred at unit A compared with unit B.

CONCLUSION: The differences in the nurse/patient ratio did not reflect a difference in the severity of illness among admitted patients but might be explained by patient characteristics with different needs.

RELEVANCE TO CLINICAL PRACTICE: Health care managers should consider not only the number of nurses but also their educational level, specific competencies and skills mix and nursing-sensitive measures to provide high-quality ICU care in settings with different patient characteristics. Nursing-sensitive patient outcomes should be considered in relation to nurse/patient ratio, as important to measure to ensure a high quality of patient care in the ICU.