Emergency Transfers: An Important Predictor of Adverse Outcomes in Hospitalized Children

These findings provide additional support for the use of the ET metric in children’s hospitals as a proximal measure for significant clinical deterioration. We found mortality rates that were overall high for a children’s hospital (22% in ET cases and 9% among controls) compared with a national average mortality rate of 2.3% in pediatric ICUs.¹¹ This is likely due to the study sample containing a significant proportion of children with medical complexity.

Aoki et al. recently demonstrated that ETs, compared with non-ETs, were associated with longer LOS and higher mortality in a bivariate analysis.¹² In our study, we found similar results with the important addition that these findings were robust when ETs were compared with matched controls who were likely at a higher risk of poor outcomes than ICU transfers in general. In addition, we demonstrated that ETs were associated with adverse outcomes in a United States children’s hospital with a mature, long-standing RRS process. As ETs are considerably more common than cardiac and respiratory arrests, use of the ET metric in children’s hospitals may enable more rapid learning and systems improvement implementations. We also found that most of the children with ETs present from units that care for children with substantial medical complexity, including Cardiology, Hematology/Oncology, and Neurosciences. Future work should continue to examine the relationship between medical complexity and ET risk.

The ET metric is complementary to the CDE measure developed by Bonafide et al. Both metrics capture potential events of unrecognized clinical deterioration, and both offer researchers the opportunity to better understand and improve their RRSs. Both ETs and CDEs are more common than arrests, and CDEs are more common than ETs. ETs, which by definition occur in the first hour of ICU care, are likely a more specific measure of unrecognized clinical deterioration. CDEs will capture therapies that may have been started up to 12 hours after transfer and thus are possibly more sensitive to identify unrecognized clinical deterioration. However, CDEs also may encompass some patients who arrived at the ICU after prompt recognition and then had a subacute deterioration in the ICU.

The maturity of the RRS and the bandwidth of teams to collect data may inform which metric(s) are best for individual centers. As ETs are less common and likely more specific to unrecognized clinical deterioration, they might be the first tracked as a center improves its RRS through QI methods. Alternatively, CDEs may be a useful metric for centers where unrecognized clinical deterioration is less common or in research studies where this more common outcome would lead to more power to detect the effect of interventions to improve care.

Our study had several limitations. Data collection was confined to one tertiary care children’s hospital with a high burden of complex cardiac and oncology care. The results may not generalize well to children hospitalized in smaller or community hospitals or in hospitals without a mature RRS. There is also the possibility of misclassification of covariates and outcomes, but any misclassification would likely be nondifferential and bias toward the null. Matching was not possible based on exact diagnosis, and the unit is a good but imperfect proxy for diagnosis grouping. At our center, overflow of patients into the Cardiology and Hematology/Oncology units is uncommon, mitigating this partially, although residual confounding may remain. The finding that ETs are associated with adverse outcomes does not necessarily mean that these events were preventable; however, it is important and encouraging that the rate of ETs has been reduced at two centers using improvement science interventions.^8,10