"On the Wall": A Descriptive Analysis of Ambulance Patient Offload Times in the United States

Prolonged Ambulance Patient Offload Times (APOT) can lead to decreased ambulance availability and delays for subsequent patients but there is no standardized definition for this interval. We aimed to describe various APOT definitions and compare prolonged APOT intervals by agency characteristics in a large national dataset.

We conducted a retrospective analysis of the 2024 ESO Research Collaborative dataset, including all 9-1-1 response transports. We calculated median APOT intervals using the difference between the "Arrival at Hospital" timestamp and "Receiving Facility Signature" (APOT 1), "Transfer of Care" (APOT 2), "Incident Closed" (APOT 3), and a "Composite" interval (APOT 4) using the "Receiving Facility Signature" timestamp where available and "Transfer of Care" timestamp where not available. Using the composite APOT interval, we described characteristics among agencies with >100 annual transports with ≥25% of transports with prolonged APOTs compared to agencies with <25%.

Of the 7,237,606 included records, calculable intervals were available for 1,691,745 for APOT 1; 5,613,315 for APOT 2; 7,235,713 for APOT 3; and 6,025,643 for APOT 4. Median and interquartile (IQR) time in minutes for APOT 1 was 10.9 (6.6, 17.5), APOT 2 was 6.6 (4.4, 13.1), APOT 3 was 19.7 (13.1, 30.6), and APOT 4 was 8.7 (4.4, 15.3). Among agencies with ≥100 annual transports (2,020), 3.3% (67) had ≥25% transports with a prolonged APOT of more than 30 min. These agencies were more urban (79.1% vs 58.9%) and had a higher median annual 9-1-1 call volume of 2,772 (IQR:1,145, 5,978) compared to agencies where <25% of transports had a prolonged APOT (1,817 (IQR:719, 4,473)).

Overall, median APOT intervals were short, independent of the definition. A small number of EMS agencies experienced prolonged offload times for at least 1-in-4 transports, indicating that though not widespread nationally, APOT challenges are prevalent in a subset of EMS systems.