This study evaluated the efficacy of reviewing ED return visits that result in an ICU admission to determine if they were associated with deviations in care and to understand the common errors. They found that of patients who were return ED visits and admitted to the ICU, 44% (223 cases) returned for reasons associated with the index visit and, in those, 14% (31 cases) had a deviation in care at the index visit. Implementing a standard diagnostic process of care framework to those 31 cases with a deviation in care, 47.3% had a failure in the initial diagnostic pathway. The authors concluded reviewing 14 day returns with ICU admissions contribute to better understanding of diagnostic and systems errors.