Highlight
- The association between ED-to-ICU transfer time and hospital mortality varies significantly across ICU admission diagnoses and hospital types.
- In out-of-hospital cardiac arrest (OHCA) patients, prolonged ED-to-ICU transfer time correlates with increased mortality in academic hospitals but a paradoxical reduction in mortality in nonacademic teaching hospitals.
- No significant mortality association was found between transfer time and other diagnoses such as overdose, sepsis, pneumonia, respiratory failure, or intracranial hemorrhage.
- Findings underline the need for prospective studies focusing on diagnosis-specific pathways and hospital processes to optimize ED-to-ICU transfer times.
Study Background
Timely transfer from the emergency department (ED) to the intensive care unit (ICU) is a critical component of acute clinical care, often impacting patient outcomes. Extended delays may perpetuate inadequate monitoring, delayed treatment intensification, and prolonged exposure to suboptimal care environments. However, the relationship between ED-to-ICU transfer time and patient mortality remains incompletely characterized, particularly across a spectrum of ICU admission diagnoses. This knowledge gap limits the development of tailored process improvements and transfer time benchmarks critical for quality of care in critically ill patients across varying clinical contexts.
Study Design
This investigation is a secondary, post hoc subgroup analysis of a large retrospective cohort from the Netherlands, spanning 2009 to 2020, involving twelve hospitals (four academic and eight nonacademic teaching hospitals). The study included 18,798 adult patients admitted directly from the ED to the ICU, categorized into seven diagnostic groups with more than 1,500 patients each: out-of-hospital cardiac arrest (OHCA), nonoperative trauma, overdose, sepsis, pneumonia, respiratory failure (excluding pneumonia), and intracranial hemorrhage (ICH).
The primary exposure evaluated was time from ED arrival to ICU admission, stratified into quintiles. Hospital mortality served as the primary outcome. Logistic regression models adjusted for hospital type and severity of illness quantified associations of transfer time with mortality, with specific stratified analyses for hospital type.
Key Findings
The median ED-to-ICU transfer time was 1.9 hours (IQR 1.2–3.1 hours).
Among OHCA patients (n=3,818), significant differences emerged based on hospital type. In academic hospitals, longer transfer times were associated with significantly increased hospital mortality, with adjusted odds ratios (ORs) of 1.48 (95% CI, 1.08–2.02) for times between 1.1 and 1.6 hours and 2.94 (95% CI, 1.80–4.78) for delays exceeding 3.4 hours (Wald χ2 p < 0.001). Conversely, in nonacademic teaching hospitals, prolonged transfer times correlated inversely with mortality, with ORs below 1.0 across quintiles (Wald χ2 p < 0.001), suggesting a complex, context-dependent relationship.
For nonoperative trauma patients, an overall positive association between longer ED-to-ICU transfer and mortality was found (OR 1.90; 95% CI, 1.12–3.21 for > 3.4 hours; p = 0.05), yet this did not hold on analysis stratified by hospital type, indicating potential confounders.
No statistically significant associations between transfer time and mortality were observed in the cohorts of overdose, sepsis, pneumonia, respiratory failure, or intracranial hemorrhage.
Expert Commentary
This study contributes important insights into the heterogeneous effects of ED-to-ICU transfer delay on patient outcomes. The opposing mortality trends seen in OHCA patients based on academic versus nonacademic teaching hospital status may reflect differences in resource availability, staffing, patient triage strategies, and hospital workflow dynamics. Academic centers might have higher acuity or complexity, where delays critically impair patient trajectory, while nonacademic centers’ shorter stay or alternative care strategies may modify these relationships.
The absence of association in other diagnostic groups suggests that disease pathophysiology, acuity, and the immediacy of therapeutic interventions mediate the impact of transfer delays. Particularly in sepsis and respiratory failure, timely initiation of specific treatments often begins in the ED, potentially mitigating the standalone effect of transfer time.
Study limitations include its retrospective nature, lack of granular process-of-care data, and possible residual confounding despite adjustment for severity scores. Further, the post hoc design means findings are hypothesis-generating rather than confirmatory. Prospective, diagnosis-specific studies incorporating detailed timestamps, care process metrics, and outcomes are needed to elucidate causality and identify actionable thresholds for transfer time reduction.
Conclusion
This secondary analysis of a large national cohort highlights diagnosis- and hospital-type-dependent variability in the relationship between ED-to-ICU transfer time and hospital mortality. Particularly in OHCA, prolonged transfer time portends higher mortality in academic hospitals but inversely associates with mortality in nonacademic teaching hospitals, illustrating the complexity of emergency care pathways. Points of intervention to reduce harmful delays may differ substantially across settings and diagnoses.
Pragmatic, prospective research targeting homogeneous patient subsets with detailed clinical and operational data will be essential to define modifiable delays, optimize transfer processes, and improve critical care outcomes.
Funding and ClinicalTrials.gov
Funding information is not specified within the source article. This was an observational secondary analysis of existing clinical data and does not reference registration in ClinicalTrials.gov.
References
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