Modification of Little’s law estimates a higher number of needed staff for a veterinary anesthesia service compared to the traditional formula

Objective: To compare Little's law formula (LL) and a health care modification of LL (HCM) that includes efficiency and patient-to-staff ratio to estimate the staff needed for a veterinary anesthesia service. Methods: This study was conducted between May 7 and August 9, 2024. Calculations were performed for 1 to 25 cases with a mean duration of 60 to 300 minutes, at 30-minute intervals, using LL (N = [λ·T]/H, where N = the number of anesthesia personnel, λ = the number of cases per day, T = the mean duration of anesthesia [time from premedication to extubation], and H = work hours per day [shift length]) and HCM (N = [λ·T]/[H·EF·SR], where EF = efficiency factor [0.8], and SR = patient to staff ratio [1:1 for anesthesia]). Results were rounded up to the nearest whole number. For each duration interval, results from LL and the HCM were compared with a Wilcoxon signed rank test. A P value < .05 was used for significance. Results: The HCM estimated a significantly larger number of staff for all case duration intervals compared to LL. Conclusions: Calculations utilizing a formula that included efficiency and patient-to-staff ratio resulted in an estimation of a larger number of anesthesia staff compared to calculations that did not. Clinical Relevance: Modifications of LL that incorporate staff efficiency and patient-to-staff ratio may estimate higher staffing needs. Because of adaptability, the HCM may be useful to estimate staffing needs in other areas of veterinary medicine beyond anesthesia.