Seasonal and Regional Variations in Nursing Workload in French Intensive Care Units: A National Study Using the Nursing Activities Score

Abstract

Aim: To compare intensive care unit (ICU) nursing workload between spring-summer and winter and to examine factors associated with workload variation across French regions.

Background: Critical care nursing workload is high and may fluctuate with seasonal demand and regional ICU bed capacity, challenging fixed-staffing models.

Methods: Secondary analysis of two nationwide prospective cross-sectional surveys in French ICUs (April-July 2023; January-March 2024). Workload was measured using the Nursing Activities Score (NAS). Outcomes were NAS per patient, NAS per nurse, and NAS per nurse > 100%. ICU-level linear mixed models assessed associations with season and regional ICU bed availability (below, versus, at, or above the national mean), adjusting for ICU characteristics.

Results: Forty-three ICUs contributed 2703 nurses and 18,772 patient NAS assessments (8759 NAS per-nurse observations). At the individual level, median NAS per nurse was lower in spring-summer than in winter (124.3% vs. 127.1%; p value = 0.043), whereas NAS per patient was higher in spring-summer (61.3% vs. 59.4%; p < 0.001). The proportion of shifts with NAS per nurse > 100% was higher in winter (69.3% vs. 67.3%; p = 0.044), and the patient-to-nurse ratio was higher (2.06 ± 0.7 vs. 1.96 ± 0.7; p < 0.001). ICUs in regions with fewer ICU beds consistently showed higher NAS per nurse across seasons. In multivariable models, winter (β = 4.5, 95% CI: 2.3-6.7) and residence in under-resourced regions (β = 19.2, 95% CI: 5.9-32.5) were associated with higher NAS per nurse.

Conclusions: ICU nursing workload varies by season and regional ICU bed capacity; baseline workload frequently exceeds 100%, limiting surge adaptability and exposing limits of fixed-staffing ratios.

Implications for nursing management: Nurse managers may rely on objective and longitudinal workload information to support sustainable decision-making in intensive care. Embedding indicators such as the NAS into staffing policies may facilitate anticipatory planning, reduce reactive staffing responses, and support patient safety and workforce stability.

Keywords: ICU bed capacity; critical care nursing; nursing staff; seasonal variation; workload.