The arrival of an EMS-transported patient to the hospital implies that a transfer of the patient from the transporting vehicle into the ED must take place. This ambulance patient offload time (APOT) requires the physical movement of patients who reflect the spectrum of emergency medical conditions. Considerations during the APOT include:
- The length of time from exiting the ambulance until patients are in physical attendance by receiving medical team members that are aware of the clinical condition of the patient and are actively managing it;
- The criticality of the patient’s condition;
- The equipment that must optimally accompany the patient during the APOT;
- Treatments that must continue during the APOT; and
- The ongoing evaluation of the patient during the APOT by the transporting staff.
Our study sought to evaluate the literature and gauge EMS medical direction concern regarding the hazards presented by the APOT, as well as to propose best practices for reducing patient risk during this period.
We conducted a literature search regarding the APOT. PubMed and Ovid MEDLINE were utilized as search tools. Search terms included: ambulance transition, ambulance offload, EMS offload, ambulance delivery interval, and EMS delivery interval.
Reference lists were then screened for relevant literature. Articles were reviewed if their authors studied the APOT, including studies with variations on the APOT parameters and time intervals.
A series of questions was then distributed via an online survey mechanism to an international coalition of EMS Medical Directors of large urban centers (the “Eagles”) to assess common practices regarding the APOT. Survey data was compiled and statistically analyzed.
The literature review revealed wide variation in both the title of the APOT and its exact definition. At least six different names were found that describe this time frame, including APOT, ambulance offload time (AOT), ambulance offload delay (AOD), offload delay (OD), offload, and the delivery interval (DI).
Each study measuring the APOT duration presented its own slightly varied definition of the beginning and end of the time period.
Thirty-three medical directors from large EMS systems responded to the survey. Of survey respondents, 100% agreed that there’s a potential for patient deterioration during the APOT.
Eighty-five percent were aware of at least one episode in which a patient’s condition deteriorated during the APOT. Seventy percent of respondents weren’t aware of any provider training that specifically targets the APOT.
Finally, EMS medical directors were asked about their desire for a common approach to training for this time period. Seventy-six percent agreed that a standard for training providers to safely handle the APOT should be established, while 91% also believed that a standard should exist for equipment to accompany patients during the APOT.
When an ambulance bearing a patient arrives at a hospital, a period of transition occurs for that patient. For example, any tubes or wires attached to the patient must be managed, a decision made on what equipment to carry in with the stretcher, and the patient must be relocated physically to a hospital bed, chair, or other location.
The time period between ambulance arrival to the hospital EMS bay and the transfer of patient care to ED staff has been addressed in the scientific literature and has received various names, including ambulance patient offload time (APOT)1, ambulance offload time (AOT),2,3 ambulance offload delay (AOD),4,5 offload delay (OD),6,7 offload,8,9 and the delivery interval (DI).10-14
Since a consistent terminology is not available, the authors herein adopt APOT for the purpose of discussion.
Multiple studies have measured the duration of the APOT and factors affecting this period, though exact specifications vary. One study, for example, performed at an academic level one trauma center, found that their average time from ambulance arrival to patient transfer to an ED bed was 14 minutes, and that APOT times increase with higher NEDOCS scores, a standardized measurement for ED overcrowding.4
A statewide initiative in California measured the interval from ambulance arrival to receiving nurse handover signature and found a mean offload time of 36 minutes, with a wide range of durations.1
Methods such as direct offload observation by research assistants, analysis of electronic documentation by EMS personnel, and radio frequency tagging of ambulance stretchers have all been utilized to study the offload time period.1,4,5,10,15-17
To the authors, it seemed that the average published APOT varied greatly based upon a number of factors, and that as EDs approach—or exceed—capacity, APOTs lengthen.4,5,18
Few studies have addressed patient care during the APOT. In practice, it’s most commonly the EMS personnel that monitor the patient until the receiving ED staff members are available to take over patient care.10,12,18,19
Regardless of the exact length of the APOT—including any delays encountered—this is a critical period in which the patient has been moved away from the vehicle and is in physical transition to the ED.
Our study found that 100% of EMS medical directors surveyed agreed that there’s a significant potential for patient deterioration during the APOT. (See Figure 1.)
Indeed, 84% of the medical directors responding to the survey were aware of patients whose conditions worsened during the APOT, as would be expected during the timeline of the management of critically ill patients. (See Figure 2.)
The out-of-hospital nature of EMS inherently necessitates that much of the equipment on the ambulance or other response vehicles be portable. As such, equipment that would be used for patient care in the field can and often should accompany patients during the APOT. EMS personnel must choose which equipment to bring with each patient during the APOT.20
Addressing training of EMS personnel regarding the choice of equipment for the APOT, our study showed that 69% of medical directors polled aren’t aware of any training practices that target equipment selection to accompany the patient during the APOT. (See Figure 3.)
Since the APOT is an incremental part of the care of every EMS patient that’s transported to a hospital, the question arises whether there should be training standards that target this transition period.
Seventy-five percent of responding medical directors in this study indicated a belief that training standards should exist for the APOT. (See Figure 4.)
Opinions over the selection of equipment to accompany patients were even stronger, with 91% of medical directors expressing a belief that standards should be in place for the equipment to accompany patients for the duration of the APOT. (See Figure 5.)
The authors feel that three basic principles can guide the decision-making process for the APOT:
- A treatment protocol that has been begun for an EMS patient being transported by ambulance should continue during the APOT;
- A risk decision for the patient regarding the APOT should be made prior to the initiation of patient movement from the ambulance; and
- Ongoing patient assessment, including the observation of the patient for potentially life-threatening emergencies and the response to care, must be continued until the patient is under the direct care of the ED receiving personnel.
Finally, the authors also call for a consistent nomenclature to address the various periods of the patient encounter, from pre-patient contact until the unit is back in service.
Such standardization will assist in the creation of metrics that may be monitored in the interest of assuring optimal outcomes for patients.
The APOT presents a critical point in patient care: responsibility is transferred to new providers, a physical movement of the patient must occur, and patient monitoring can suffer in the interim.
A consensus among EMS medical directors polled for this study indicated that the APOT holds a potential for patient deterioration.
The authors believe patient care will benefit by training of emergency personnel for the APOT, including which equipment should accompany patients for its duration, as part of a comprehensive system of risk management.
1. Backer HD, D’Arcy NT, Davis AJ, et al. Statewide method of measuring ambulance patient offload times. Prehosp Emerg Care. October 25, 2018. [Epub ahead of print.]
2. Crilly J, Keijzers G, Tippett V, et al. Improved outcomes for emergency department patients whose ambulance off-stretcher time is not delayed. Emerg Med Australas. 2015;27(3):216-224.
3. Greaves T, Mitchell M, Zhang P, et al. The impact of an emergency department ambulance offload nurse role: a retrospective comparative study. Int Emerg Nurs. 2017;32:39-44.
4. Cooney DR, Vasisko C, Stimson K, et al. Analysis of ambulance offload delay at an academic level 1 trauma center with adult and pediatric emergency departments. Ann Emerg Med. 2013;62(4):S2.
5. Cooney DR, Wojcik S, Seth N, et al. Evaluation of ambulance offload delay at a university hospital emergency department. Int J Emerg Med. 2013;6(1):15.
6. Schwartz B. Transfer of care and offload delay: continued resistance or integrative thinking? CJEM. 2015;17(6):679-684.
7. National Association of EMS Physicians. Ambulance diversion and emergency department offload delay. Prehosp Emerg Care. 2011;15(4):543.
8. Almehdawe E, Jewkes B, He Q-M. Analysis and optimization of an ambulance offload delay and allocation problem. Omega. 2016;65(1):148-158.
9. Laan CM, Vanberkel PT, Boucherie RJ, et al. Offload zone patient selection criteria to reduce ambulance offload delay. Oper Res Health Care. 2016;11:13-19
10. Carter AJ, Overton J, Terashima M, et al. Can emergency medical services use turnaround time as a proxy for measuring ambulance offload time? J Emerg Med. 2014;47(1):30-35.
11. Eckstein M, Isaacs SM, Slovis CM, et al. Facilitating EMS turnaround intervals at hospitals in the face of receiving facility overcrowding. Prehosp Emerg Care. 2005;9(3);267-275.
12. Li M, Vanberkel P, Carter AJE. A review on ambulance offload delay literature. Health Care Manag Sci. July 7, 2018. [Epub ahead of print.]
13. Cone DC, Davidson SJ, Nguyen Q. A time-motion study of the emergency medical services turnaround interval. Ann Emerg Med. 1998;31(2):241-246.
14. Spaite DW, Valenzuela TD, Meislin HW, et al. Prospective validation of a new model for evaluating emergency medical services systems by in-field observation of specific time intervals in prehospital care. Ann Emerg Med. 1993;22(4):638-645.
15. Steer S, Bhalla MC, Zalewski J, et al. Use of radio frequency identification to establish emergency medical service offload times. Prehosp Emerg Care. 2016;20(2):254-259.
16. Segal E, Verter V, Colacone A, et al. The in-hospital interval: A description of EMT time spent in the emergency department. Prehosp Emerg Care. 2006;10(3):378-382.
17. Cone DC, Middleton PM, Marashi Pour S. Analysis and impact of delays in ambulance to emergency department handovers. Emerg Med Australas. 2012;24(5):525-533.
18. Eckstein M, Chan LS. The effect of emergency department crowding on paramedic ambulance availability. Ann Emerg Med. 2004;43(1):100-105.
19. Kingswell C, Shaban RZ, Crilly J. Concepts, antecedents, and consequences of ambulance ramping in the emergency department: aSscoping review. Australas Emerg Nurs J. 2017;20(4):153-160.
20. Friend FC. (March 31, 2014.) Transitions of care. EMS World. Retrieved Jan. 7, 2019, from www.emsworld.com/article/12015329/transitions-during-ems-patient-transport.