The 6-hour window: is the sepsis transfer guideline enough?

Kyeongman Jeon

doi:10.4266/acc.006000

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Editorial Infection The 6-hour window: is the sepsis transfer guideline enough?: Acute and Critical Care 2025;40(4):627-629.
DOI: https://doi.org/10.4266/acc.006000
Published online: November 28, 2025

Kyeongman Jeon

Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea

Corresponding author: Kyeongman Jeon Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 06351, Korea Tel: +82-2-3410-3429 Fax 82-2-3412-3996 Email: kjeon@skku.edu

• Received: November 16, 2025 • Accepted: November 19, 2025

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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REFERENCES

Sepsis, a life-threatening organ dysfunction resulting from a dysregulated host response to infection [1], carries a persistently high mortality risk [2]. Although recent advances have improved early identification and resuscitation in the emergency department (ED) and hospital wards [3], the prognosis for critically ill sepsis patients depends on the timely application of critical care interventions in an appropriate environment. Consequently, many sepsis patients require admission to the intensive care unit (ICU). A Korean multicenter cohort study reported that one-third of all sepsis patients presenting to the ED required ICU admission [4].

The current Surviving Sepsis Campaign 2021 guidelines recommend that adult patients with sepsis or septic shock be admitted to the ICU within 6 hours of their ED visit [3]. However, the evidence supporting this specific cutoff is limited and is largely derived from studies including a broad range of critically ill patients rather than sepsis patients alone [5-7]. Research on the impact of ED length of stay before ICU transfer has yielded mixed findings. Some studies indicate that earlier ICU admission may reduce hospital mortality, particularly among more severe patients [8,9]. Other studies have not demonstrated a significant difference, suggesting that high-quality ED care may offset the effects of transfer delays [10,11]. More recent investigations, however, suggest that more immediate transfer may confer benefit [12,13]. For example, one major study found that an ED length of stay of less than 3.3 hours was associated with lower 28-day mortality among sepsis patients requiring intensive care [13]. Nevertheless, the optimal transfer time from the ED to the ICU remains debated, as evidence comes primarily from observational studies and registry databases [3].

In this issue of Acute and Critical Care, Cha et al. [14] present a secondary observational analysis of data from the Korean Sepsis Alliance examining the impact of delayed ICU transfer on mortality in adult patients with septic shock. The primary finding was that a 3-hour threshold for ICU transfer was associated with differential in-hospital mortality risk. Specifically, transfer within 3 hours was associated with a lower mortality risk than transfer after 3 hours. The authors [14] used restricted cubic spline analysis to model the relationship between ED-to-ICU transfer time and hospital mortality. Notably, mortality risk increased up to 6 hours of transfer time, after which it did not continue to rise but instead showed a downward trend. Furthermore, the benefits of early ICU transfer were most evident in patients with severe organ failure requiring complex interventions such as mechanical ventilation, extracorporeal membrane oxygenation, or renal replacement therapy. These advanced therapies require the specialized environment and expertise of intensive care.

Although well-designed randomized clinical trials (RCTs) remain the preferred method for addressing causal questions, observational studies using a causal inference framework can serve as a practical alternative [15]. However, causal interpretation of even well-conducted observational studies is challenging in critical care research [16]. In the absence of RCTs comparing early versus delayed ICU transfer from the ED, the authors applied a target trial emulation (TTE) [14]. TTE is a powerful framework for addressing causal questions using observational data and involves specifying a hypothetical target trial protocol and then emulating its components [17]. This approach is increasingly used in critical care research [16]. For rigorous and transparent reporting of such studies, authors are encouraged to follow the recently published Transparent Reporting of Observational Studies Emulating a Target Trial (TARGET) guideline [18], although details of the emulation process were not provided in this study. In addition, specifying “time zero,” the moment at which participant eligibility is assessed, treatment assignment occurs, and follow-up begins [17], is a critical concept in TTE methodology [16]. In this study evaluating ICU transfer time among sepsis patients, time zero was defined as the ED triage time [14], rather than the time of the decision to transfer to the ICU. If the objective is to evaluate delays occurring after the transfer decision, defining time zero at the point when the intervention becomes clinically feasible would allow more direct analysis of that causal question. The interval between ED arrival and the decision to transfer—often several hours—is a period during which ICU transfer is not yet being considered. However, the transfer-decision time is subjective, often poorly documented, and highly variable depending on physician judgment, staffing, or institutional factors, making it an inconsistent and unreliable baseline for research.

Although the positive impact of prompt ICU admission on outcomes in critically ill sepsis patients has been increasingly reported, most studies emphasize that rapid initiation of critical interventions is more important than the physical location of the patient at any given moment. These interventions can and often should begin in the ED and should not be delayed while awaiting an ICU bed. Prior studies also highlight systemic barriers such as ICU bed shortages and ED overcrowding, which contribute to delayed transfers. Current evidence underscores the need for hospitals to maintain robust systems that ensure critically ill sepsis patients are rapidly identified and receive timely, high-level critical care, whether delivered in the ED or the ICU.

In summary, although the 6-hour transfer window remains the official guideline recommendation, emerging data suggest that more immediate transfer, such as within 3 hours, may provide outcome benefits for the most severe septic shock patients. However, the central priority should be ensuring timely, high-quality critical care regardless of physical location.

NOTES

CONFLICT OF INTEREST

Kyeongman Jeon is an editorial board member of the journal but was not involved in the peer reviewer selection, evaluation, or decision process of this article. No other potential conflicts of interest relevant to this article were reported.

FUNDING

None.

ACKNOWLEDGMENTS

None.

AUTHOR CONTRIBUTIONS

All the work was done by Kyeongman Jeon.

REFERENCES

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