Workload and severity of illness of patients on intensive care units with available intermediate care units: a multicenter cohort study

BACKGROUND: Intermediate Care Units (IMCU) are established in many hospitals to better match the requirements of patient care with respect to their personnel, equipment and other resources. This should relieve Intensive Care Unit (ICU) capacities for more severely ill patients and reduce readmissions to ICU. This study was conducted to investigate the effects of IMCU use on ICU populations. METHODS: This is a retrospective analysis of the German National Registry of Intensive Care from the years 2000 to 2010. RESULTS: We included 39 ICUs with high and 11 ICUs with low IMCU use. Patients in ICUs with high IMCU use were younger (mean age [high vs. low]: 60.5 vs. 64.5 years, P<0.001), while the severity of illness was higher (percentage of ventilated patients during ICU stay [high vs. low ICMU use]: 67.2% vs. 40.2%, P<0.001; patients ventilated >24 hours: 22% vs. 18%, P<0.001; mean therapeutic intervention scoring system-28 (TISS-28) score: 25.7 vs. 23.3, P<0.001). Readmission rates to ICU did not differ between ICU groups ([high vs. low]: 4.5% vs. 4.4%, P=0.25). ICUs with high IMCU use discharged 90.3% of all patients who were discharged to the IMCU or general ward between the regular workday hours of 06:00 and 14:59, while ICUs with low IMCU use discharged 83.8% of all patients discharged to the general ward in the same time period. CONCLUSIONS: The use of IMCUs influences resource utilization of ICUs. Severity of illness and workload was higher in ICUs with high IMCU and more scheduled discharges occurred during the main working hours while readmission rates were similar.