Impact of Hospital Characteristics on Ambulance Offload Delay Dynamics in Sacramento County

Ambulance patient offload times (APOT) exceed California's mandated 30-minute standard in 47% of local EMS agencies, with statewide mean offload times reaching 42.8 minutes. Despite standardized protocols across Sacramento County EMS Agency (SCEMSA), significant inter-hospital variability persists, with some facilities reporting delays 40% longer than others. Prolonged offload times are associated with increased mortality, delayed care, and reduced EMS availability. However, specific hospital-level characteristics driving these delays remain inadequately characterized, limiting evidence-based interventions.

We conducted a retrospective analysis of SCEMSA APOT-1 reports from 10 hospitals (2021-2025). APOT-1 reports provide monthly aggregate data representing time (minutes) under which 90% of patients have care transferred from EMS to hospital staff. Primary outcome was monthly 90th percentile offload time. Hospital characteristics were obtained from OSHPD profiles and ACS trauma verification. Predictors included trauma center designation, referral center status, and behavioral health unit (BHU) availability. We used linear mixed-effects regression with hospital random effects, adjusting for month and year.

540 hospital-months across 10 hospitals were analyzed. Mean 90th percentile offload time was 55.2±23.1 minutes, with 84.3% exceeding 30 minutes. None of the hospital characteristics showed significant associations: trauma centers (β=-6.0 min, p=0.57), referral centers (β=+8.9 min, p=0.42), or BHU presence (β=+16.4 min, p=0.26). Time trend showed significant improvement (β=-0.52 min/month, 95%CI:-0.61,-0.42, p<0.001). Hospital random effects accounted for 30% of total variance (ICC=0.296), with marginal R²=0.21 and conditional R²=0.45. Findings remained robust across sensitivity analyses, including GEE and univariate models.

In this exploratory analysis of 10 Sacramento County hospitals, structural hospital characteristics (trauma, referral, BHU status) showed no significant association with ambulance offload delays. Substantial inter-hospital variability and consistent improvement over time suggest operational factors beyond measured characteristics drive offload performance. Limited statistical power (n=10 hospitals) precludes definitive conclusions; larger multi-agency studies are needed.