ICU capacity, ICU staffing, and postcardiotomy ECMO outcomes in China: a multilevel cross-sectional study

As the complexity of cardiac surgeries increases and patient selection criteria expand, the use of veno-arterial extracorporeal membrane oxygenation for high-risk patients has become more prevalent. Despite its critical role in sustaining life, postcardiotomy ECMO (PC-ECMO) is associated with high in-hospital mortality rates. Intensive care unit (ICU) capacity and staffing are crucial in determining patient outcomes. This study aimed to investigate the relationships among ICU capacity, staffing levels, and outcomes in PC-ECMO patients in China.

A multilevel cross-sectional analysis was conducted using data from 586 hospitals that participated in China's National Quality Improvement Program in 2018. From these hospitals, we selected those that performed PC-ECMO procedures between April 2016 and December 2021. The novel ICU Capacity Comprehensive Index (ICUCCI) was calculated for each hospital, incorporating medical service capacity, technical ability, quality and safety, and service efficiency. ICU staffing was assessed by patient-to-bed, patient-to-physician, and patient-to-nurse ratios. The primary outcome was in-hospital mortality, with secondary outcomes including complications, length of stay (LOS), and hospitalization costs.

A total of 102 hospitals, encompassing 2,601 patients, were included in the analysis. Higher ICUCCI values were associated with reduced in-hospital mortality (OR: 0.83, 95% CI: 0.70-0.97, P = 0.025) and fewer complications (OR: 0.82, 95% CI: 0.68-0.99, P = 0.046). However, higher ICUCCI values correlated with longer LOSs (IRR: 1.14, 95% CI: 1.06-1.22, P < 0.001) and increased hospitalization costs (IRR: 1.32, 95% CI: 1.24-1.40, P < 0.001). ICU staffing ratios, including patients per bed, physician, and nurse, were protective against mortality, with the ratio of patients per ICU bed showing the most pronounced effect (OR: 0.69, 95% CI: 0.55-0.87, P = 0.002). Increased staffing was also associated with longer LOS but did not affect overall complication rates or costs. The ratio of patients per ICU bed was linked to a greater risk of bloodstream infection (OR: 1.96, 95% CI: 1.14-3.46, P = 0.022).

This study highlights the critical role of ICU capacity and staffing levels in improving outcomes for patients receiving PC-ECMO. While higher ICU capacity and staffing are associated with reduced mortality, they also correlate with longer hospital stays and/or increased costs, suggesting the need for a balanced approach in resource allocation. Our findings underline the importance of optimizing ICU staffing ratios and enhancing healthcare equity to improve patient care across diverse healthcare institutions.