ICU efficiency Methods and applications in the general and COVID-19 ICU population

Healthcare organizations continuously face challenges in providing optimal patient care while effectively and efficiently utilizing their resources. While doing so, they also continuously work on improving the quality of patient care. In this thesis, we focus on, effectiveness, in terms of (long-term) outcomes, and on efficiency in the context of intensive care. Efficiency in healthcare often focuses on the costs or cost-effectiveness of medical treatments. Although it is considered valuable, measuring and interpreting efficiency in terms of cost-effectiveness in an ICU setting can be difficult. We consider ICU efficiency in terms of ICU length of stay as a proxy for resource use under the condition that care is effective. With the knowledge of which organizational factors affect healthcare costs, care can be made more efficient. In this thesis, we focus on evaluating care provided in the ICU by measuring ICU efficiency and using conventional and machine learning methods to determine the effect of organizational factors on ICU efficiency. In the first part of this thesis, we measure efficiency in Dutch and Brazilian ICUs and explore different approaches to determine which ICU characteristics affect ICU efficiency. The duration of the PhD program partly overlapped with the COVID-19 pandemic, which had a significant impact on ICU care. In the second part of this thesis, we focus on long-term mortality as a measure of effectiveness for Dutch COVID-19 patients admitted to the ICU. In addition, we also focus on the effect of transfers on mortality as a measure of timeliness and efficiency.