Unplanned hospital admissions within 24 h after 53,185 surgical procedures at a U.S. ambulatory surgery center

Unplanned admission after surgery at an ambulatory surgery center (ASC) is an established measure of the quality of care and can affect the patient's experience. Previous studies on this topic are generally dated, focused on a single specialty, or studied 30-day admissions after ambulatory surgery. Few studies have reported admission within 24 h after surgery at an ASC which is a different but important measure of the quality of anesthetic and surgical care. Understanding admissions within 24 h of surgery can identify opportunities for improvement immediately after surgery. Therefore, our study was designed to assess the incidence and risk factors for unplanned hospital admissions within 24 h after surgery performed at a hospital ASC.

After Institutional Review Board approval, a retrospective analysis was performed on all adult patients who underwent surgery at a US ASC between January 1, 2016, and December 31, 2022. Data were obtained from the hospital's electronic medical record. The study sample was divided into two groups: those with an unplanned hospital admission within 24 h after surgery and those without an unplanned hospital admission. To evaluate risk factors for unplanned hospital admissions, univariate analyses with p value < 0.05 were utilized to identify significant patient variables related to hospital admissions. These variables were further adjusted using a multivariable Firth logistic regression. Descriptive statistics were used to explore the number of patients in different variable categories.

Overall, 53,185 cases were identified for the 7-year period. The incidence of unplanned hospital admission over this period was 0.09% (95% CI 0.07-0.1122%; ranging from 0.05 to 0.12% per year. In the multivariable model, surgery duration (OR 1.010, 95% CI 1.007-1.012, p value < 0.0001), peripheral vascular disease (OR 14.489, 95% CI 4.862-43.174, p value < 0.0001), and deep venous thrombosis (OR 5.527, 95% CI 1.909-16.001, p value = 0.0016) were significantly associated with unplanned hospital admission.

The overall incidence of unplanned hospital admission after surgery at a large tertiary care ambulatory surgery center is very low. This admission rate can also serve as a reference point for future studies and quality improvement initiatives.