Discharge decision-making in a medical ICU: characteristics of unexpected readmissions.

To identify those patients most likely to be readmitted to a Medical ICU (MICU), we studied 512 MICU admissions during a 1-yr period. There were 36 readmissions within the same hospitalization in that interval. When ICU deaths and short-term drug overdoses were excluded, these 36 readmissions comprised 12% of all patients discharged from MICU. The mortality rate of this group was 58%, greater than twice the overall mortality rate for the year. Fifty-three % of the patients were readmitted because of recurrence of their initial disease on admission, with septicemia being the most common disease. Another 30% were readmitted because of a new complication, one-half of which were medication toxicities. We have attempted to delineate diseases, medications, and complications which may predict the high-risk discharge from MICU. Further studies to identify high-risk and low-risk admissions and discharges will effect better use of intensive care.