Ambulance offload delays and patient outcomes: a systematic review

Ambulance offload delay, also known as ambulance ramping, is increasingly common in emergency care systems experiencing capacity strain. While such delays may have operational and clinical consequences, the extent of patient harm remains uncertain. We conducted a systematic review to examine the association between ambulance offload delays and patient outcomes.

Six electronic databases were searched for peer-reviewed research articles from inception to April 2025, alongside citation tracking. Eligible studies reported quantitative associations between offload delay and patient outcomes. Two reviewers independently extracted data and assessed risk of bias using the MASTER scale for observational studies. Narrative synthesis and causal inference principles guided data interpretation.

Four observational studies (three cohort, one case-control) met inclusion criteria from 420 screened articles, encompassing over 3 26 474 patients across Australia and Canada. Only one study reported a statistically significant increase in 30-day mortality with longer offload times, whereas the others found no difference or inconsistent effects. Three studies consistently reported longer emergency department (ED) length of stay in delayed patients. One study found a modest increase in 30-day repeat ambulance attendance. No studies assessed time to treatment or clinical deterioration. Definitions of offload delay varied widely (≥15 min to≥60 min), study populations differed in acuity and case mix, and risk adjustment was limited, with only one study incorporating pre-handover physiological measures. Risk of bias was moderate to high across all studies, largely due to incomplete control for baseline illness risk and system-level confounding, since higher-acuity patients are often prioritised for rapid offload.

Ambulance offload delays are consistently associated with prolonged ED stays, underscoring their significant operational burden on already strained health systems. However, direct evidence of clinical harm associated with offload delay remains unclear, largely due to methodological limitations and inconsistent definitions. Future research employing rigorous causal inference methods is urgently needed to determine whether ambulance offload delays directly contribute to adverse patient outcomes, thereby informing policies to strengthen timely and high-quality patient care.