Calculating Optimal Patient to Nursing Capacity: Comparative Analysis of Traditional and New Methods

Abstract

Background: Optimal nurse staffing levels have been shown to impact patients' prognoses and safety, as well as staff burnout. The predominant method for calculating staffing levels has been patient-to-nurse (P/N) ratios and nursing hours per patient day. However, both methods fall short of addressing the dynamic nature of staffing needs that often fluctuate throughout the day as patients' clinical status changes and new patients are admitted or discharged from the unit.

Objective: In this evaluation, the Veterans Affairs Palo Alto Health Care System (VAPAHCS) piloted a new dynamic bed count calculation in an effort to target optimal staffing levels every hour to provide greater temporal resolution on nurse staffing levels within the Veterans Health Administration.

Methods: The dynamic bed count uses elements from both the nursing hours per patient day and P/N ratio to calculate current and target staffing levels, every hour, while balancing across nurse types (registered nurses to nurse assistants) to provide improved temporal insight into staff allocation. The dynamic bed count was compared with traditional P/N ratio methods of calculating patient capacity at the VAPAHCS, to assess optimal patient capacity within their acute care ward from January 1, 2023, through May 25, 2023. Descriptive statistics summarized patient capacity variables across the intensive care unit (ICU), medical-surgical ICU, and 3 acute care units. Student t tests (2-tailed) were used to analyze differences between patient capacity measures.

Results: Hourly analysis of patient capacity information displayed how the dynamic bed count provided improved temporal resolution on patient capacity. Comparing the dynamic bed count to the P/N ratio, we found the patient capacity, as determined by the P/N ratio, was, on average, higher than that of the dynamic bed count across VAPAHCS acute care units and the medical-surgical ICU (P<.001). For example, in acute care unit 3C, the average dynamic bed count was 21.6 (SD 4.2) compared with a P/N ratio of 28.6 (SD 3.2). This suggests that calculating patient capacity using P/N ratios alone could lead to units taking on more patients than what the dynamic bed count suggests the unit can optimally handle.

Conclusions: As a new patient capacity calculation, the dynamic bed count provided additional details and timely information about clinical staffing levels, patient acuity, and patient turnover. Implementing this calculation into the management process has the potential to empower departments to further optimize staffing and patient care.

Keywords: NHPPD; comparative analysis; nurse; nurse assistants; nurse scheduling; nurse staffing; nursing; nursing administration; nursing hours per patient day; patient capacity; patient ratio; registered nurses; staff allocation; staffing; workload.

Figure 1.. Average patient capacity across Palo Alto Veterans Affairs Health Care System’s acute units, January 1, 2023, through May 25, 2023. In this graph, the yellow lines depict the authorized bed count, which is the maximum number of physical beds a unit could successfully support. The blue lines represent the average patient census for each unit location. The red lines depict the average dynamic bed count calculation for patient capacity while the green lines represent the average patient-to-nurse (P/N) ratio across the assessment period for each acute care unit. Med-Surg ICU: medical-surgical intensive care unit.

Figure 2.. Average patient-to-nurse (P/N) ratio and dynamic bed count calculations across Veterans Affairs Palo Alto Health Care System’s acute unit 3C Location, January 1, 2023, through May 25, 2023. The analysis of patient capacity metrics over the evaluation period revealed an upward trend in the P/N ratio, indicated by the green line, suggesting an increase in the number of patients assigned to each nurse on average. In contrast, the dynamic bed count, shown in red, demonstrates a slight downward trend. Notably, the shaded regions around the trend lines, which represent the SE, suggest greater variability in the dynamic bed count than in the P/N ratio. The divergence in trends between the 2 metrics underscores the complexity of health care resource management and the need for strategies that optimize staffing levels.