Optimizing PACU nursing resource allocation through SARIMA-based patient volume forecasting: a case study from a...

To develop and validate a Seasonal Auto-Regressive Integrated Moving Average (SARIMA) model for forecasting daily patient admissions to the Post-Anesthesia Care Unit (PACU), and to evaluate its potential for optimizing nursing staff allocation.

Daily admission data from 16,637 patients between November 2, 2020, and January 2, 2022, were analyzed. The SARIMA model was developed on a training set (Nov 2020 - Dec 2021) and its forecasting accuracy was rigorously assessed on a test set (Dec 2021 - Jan 2022) using five-fold rolling cross-validation. Model selection was based on Akaike's Information Criterion (AIC) and Bayesian Information Criterion (BIC), with residual diagnostics conducted to ensure validity. The model's performance was compared against a Long Short-Term Memory (LSTM) neural network. An operational simulation for nurse staffing was conducted based on the forecasts.

The SARIMA(1,0,2)(0,1,2)7 model was identified as optimal. It demonstrated strong forecasting performance with a mean RMSE of 14.53, MAE of 11.14, and R² of 0.75 on cross-validation. Performance was superior during stable periods (e.g. Fold 4: RMSE = 9.27, R² = 0.88) but declined during periods of potential COVID-19 disruption. The model significantly outperformed the LSTM benchmark (LSTM RMSE = 15.51, R² = 0.483). A staffing simulation showed the model's recommendations could potentially reduce overstaffing on 32.1% of days while maintaining safe coverage.

The SARIMA model provides accurate and reliable short-term forecasts for PACU patient admissions under normal operational conditions. It serves as a valuable decision-support tool for optimizing nursing staff scheduling and improving resource allocation efficiency, demonstrating superior performance and practicality compared to a more complex LSTM model in this clinical setting.