The impact of nursing skill-mix on adverse events in intensive care: a single centre cohort study.

Background: The highly complex and technological environment of critical care manages the most critically unwell patients in the hospital system, as such there is a need for a highly trained nursing workforce. Intensive care is considered a high-risk area for errors and adverse events (AE) due to the severity of illness and number of procedures performed.

Objective: To investigate if the percentage of Critical Care Registered Nurses (CCRN) within an Intensive Care Unit (ICU) is associated with an increased risk of patients experiencing an AE.

Design & setting: We conducted a retrospective cohort study of patients admitted between January 2016 and December 2020 to a tertiary ICU in Australia. Descriptive statistics and multivariable logistic regression were used to investigate the relationship between the proportion of CCRNs each month and the occurrence of an AE defined as any one of a medication error, fall, pressure injury or unplanned removal of a central venous catheter or endotracheal tube per patient.

Results: A total of 13,560 patients were included in the study, with 854 (6.3%) experiencing one AE. Patients with an AE were associated with higher illness severity and frailty scores. They were more commonly admitted after medical emergency team response calls and were less commonly elective ICU admissions. Those with an AE had longer ICU and in-hospital length of stay, and higher ICU and in-hospital mortality, on average. After adjusting for ICU LOS and acute severity of illness, being admitted during a month of higher critical care nursing skill-mix was associated with a statistically significant lower odds of having a subsequent AE (OR 0.966 [95% CI: 0.944-0.988], p 0.003).

Conclusion: An increasing percentage of CCRNs is independently associated with a lower risk-adjusted likelihood of an AE. Increasing the skill-mix of the ICU nursing staff may reduce the occurrence of AEs and lead to improved patient outcomes.