Diversion of ALS ambulances: characteristics, causes, and effects in a large urban system

Urban emergency department overcrowding: defining the problem and eliminating misconceptions

STUDY OBJECTIVE

To develop an operational definition and a parsimonious list of postulated determinants for urban emergency department (ED) overcrowding.

METHODS

A panel was formed from clinical and administrative experts in pre-hospital, ED and hospital domains. Key studies and reports were reviewed in advance by panel members, an experienced health services researcher facilitated the panel's discussions, and a formal content analysis of audiotaped recordings was conducted.

RESULTS

The panel considered community, patient, ED and hospital determinants of overcrowding. Of 46 factors postulated in the literature, 21 were not retained by the experts as potentially important determinants of overcrowding. Factors not retained included access to primary care services and seasonal influenza outbreaks. Key determinants retained included admitted patients awaiting beds and patient characteristics. Ambulance diversion was considered to be an appropriate operational definition and proxy measure of ED overcrowding.

CONCLUSION

These results help to clarify the conceptual framework around ED overcrowding, and may provide a guide for future research. The relative importance of the determinants must be assessed by prospective studies.

The Effect of Ambulance Diversions on the Development of Trauma Systems

This report examines the complex relationship between the diversion of ambulances within an emergency medical services system and the management of trauma patients.

Prevalence of morphine use and time to initial analgesia in an Australian emergency department

OBJECTIVE

To explore the association of morphine use with factors influencing time to initial analgesia (T-A).

METHODS

A retrospective cohort review was conducted. Morphine data were collected from a register for restricted drugs located in the ED. T-A was the time interval between triage and signing out of morphine's first dose. Statistical analyses were performed to determine the association between morphine use and patient volume.

RESULTS

In total, 8% of ED attendees received at least one dose of morphine sulphate in the ED. Prevalence of morphine use significantly (P < 0.05) varied by patient's age, Australasian Triage Scale category, time of arrival and type of illness. The median time of T-A was 79 min (95% CI 71-85) with substantially longer (median 107 min) for those who arrived during the afternoon and triaged as less urgent (median 127 min). Patients who arrived late at night (median 47 min), triaged as immediately/imminently life-threatening (median 58 min) and diagnosed as renal colic (median 27 min) or fractures/injuries (median 67 min) were more likely to receive i.v. morphine faster than other patients. The findings confirmed that large volume of patients in ED was associated with longer T-A. Patient volume in the ED showed a significant positive association with T-A (r = 0.568, 32% variation explained, P < 0.01).

CONCLUSION

T-A is an important indicator of the quality of ED services. Severity of illness and patient volume were significant factors associated with extended T-A. Strategies for improving pain management in the complex ED environment are discussed.

Likelihood of reroute during ambulance diversion periods in central Maryland

OBJECTIVES

To determine the proportion of patients rerouted during ambulance diversion periods and factors associated with reroute.

METHODS

A retrospective cohort design was used to examine reroute practices of prehospital providers in central Maryland in 2000. Ambulance transport and diversion data were merged to identify transports that occurred during diversion periods. The proportion of patients rerouted when the closest hospital was on diversion was determined. Generalized estimating equation modeling identified patient, transport, and hospital factors that influenced the likelihood of reroute.

RESULTS

Central Maryland hospitals were on diversion 25% of the time in 2000, although it varied by hospital (range of 1-34%). There were 128,165 transports during the study period, of which 18,633 occurred when the closest hospital was on diversion. Of these, only 23% were rerouted. More than half of all transports during a diversion period (53%) occurred when multiple neighboring hospitals were also on diversion. The factors that influenced the likelihood of reroute the most were hospital-related factors. Large volume hospitals and hospitals that spent more time on diversion were less likely to have transports rerouted to them.

CONCLUSIONS

Rerouted transports more frequently go to lower volume, less busy hospitals. However, only a small proportion of patients were rerouted. Prehospital providers have limited options because often when one hospital is on diversion, other nearby hospitals are as well. Although ambulance diversion may be an important signal of hospital distress, in this region it infrequently resulted in its intended outcome, rerouting patients to less crowded facilities.

The effects of ambulance diversion: a comprehensive review

OBJECTIVES

To review the current literature on the effects of ambulance diversion (AD).

METHODS

The authors performed a systematic review of AD and its effects. PubMed, EMBASE, the Cochrane database, societal meeting abstracts, and references from relevant articles were searched. All articles were screened for relevance to AD.

RESULTS

The authors examined 600 citations and reviewed the 107 articles relevant to AD. AD is a common occurrence that is increasing in frequency. AD is associated with periods of emergency department (ED) crowding (Mondays, mid-afternoon to early evening, influenza season, and when hospitals are at capacity). Interventions that redesign the AD process or that provide additional hospital or ED resources reduce diversion frequency. AD is associated with increased patient transport times and time to thrombolytics but not with mortality. AD is associated with loss of estimated hospital revenues. Short of anecdotal or case reports, no studies measured the effect of AD on ED crowding, morbidity, patient and provider satisfaction, or EMS resource utilization.

CONCLUSIONS

Despite its common use, there is a relative paucity of studies on the effects of AD. Further research into these effects should be performed so that we may understand the role of AD in the health system.

Ambulance diversion reduction: the Sacramento solution

PURPOSE

The diversion of ambulances away from their intended emergency departments (EDs) in the United States has become commonplace and may compromise patient care. Although ambulance diversion resulting from ED overcrowding has been well described in the literature, little is known about how to reduce the incidence of ambulance diversion on a regional level. We describe the development, implementation, and impact of a region-wide program to reduce ambulance diversion.

BASIC PROCEDURES

This study was undertaken in the greater Sacramento, California region from January 2001 to December 2003. This comprehensive ambulance diversion reduction program was implemented May 15, 2002, with analysis of data for this 3-year time frame. The data for this study were obtained from 17 hospitals with ambulance diversion hours being the main outcome measure for this study.

FINDINGS

The greater Sacramento region had 23785 hours of ambulance diversion in 2001. In 2003, there were 7143 ambulance diversion hours. Comparing the 17-month period before implementation of this program with the 19-month period after implementation, the difference in the means of these two groups was -1428 hours per month (95% confidence interval, -1252 to -1597), a 74% decrease in ambulance diversion hours. Notably, this reduction occurred despite overall increases in ED census (6.5%), hospital admissions from the ED (8.8%), EMS arrivals to the ED (17.1%), inpatient hospital census (7.4%), and overall Sacramento population (5.7%).

CONCLUSIONS

Our results demonstrate a sizeable reduction of ambulance diversion in a large urban region after the successful implementation of a comprehensive ambulance diversion reduction program. The description of this effort may serve as a model for other regions across the country that do not have an organized approach in place for ambulance diversion, although boarding of admitted patients will still be a major hurdle to effective reduction of ambulance diversion.

Effects of hospital closures and hospital characteristics on emergency department ambulance diversion, Los Angeles County, 1998 to 2004

STUDY OBJECTIVE

We assess the effects of nearby hospital closures and other hospital characteristics on emergency department (ED) ambulance diversion.

METHODS

The study design was a retrospective, multiple interrupted time series with control group. We studied all ambulance-receiving hospitals with EDs in Los Angeles County from 1998 to 2004. The main outcome measure was monthly ambulance diversion hours because of ED saturation.

RESULTS

Our sample included 80 hospitals, of which 9 closed during the study period. There were increasing monthly diversion hours over time, from an average of 57 hours (95% confidence interval [CI] 51 to 63 hours) in 1998 to 190 hours (95% CI 180 to 200 hours) in 2004. In multivariate modeling, hospital closure increased ambulance monthly diversion hours by an average of 56 hours (95% CI 28 to 84 hours) for 4 months at the nearest ED. County-operated hospitals had 150 hours (95% CI 90 to 200 hours) and trauma centers had 48 hours (95% CI 9 to 87 hours) more diversion than other hospitals. Diversion hours for a given facility were positively correlated with diversion hours of the nearest ED (0.3; 95% CI 0.28 to 0.32). There was a significant and positive interaction between diversion hours of the nearest ED and time, suggesting that the effects of an adjacent facility's diversion hours increased during the study period.

CONCLUSION

Hospital closure was associated with a significant but transient increase in ambulance diversion for the nearest ED. The temporal trend toward more diversion hours, as well as increasing effects of the nearest facility's diversion hours over time, implies that the capacity to absorb future hospital closures is declining.

Description and evaluation of a pilot physician-directed emergency medical services diversion control program

OBJECTIVES

To describe the characteristics and feasibility of a physician-directed ambulance destination-control program to reduce emergency department (ED) overcrowding, as measured by hospital ambulance diversion hours.

METHODS

This controlled trial took place in Rochester, New York and included a university hospital and a university-affiliated community hospital. During July 2003, emergency medical services (EMS) providers were asked to call an EMS destination-control physician for patients requesting transport to either hospital. The destination-control physician determined the optimal patient destination by using patient and system variables as well as EMS providers' and patients' input. Program process measures were evaluated to characterize the program. Administrative data were reviewed to compare system characteristics between the intervention program month and a control month.

RESULTS

During the intervention month, 2,708 patients were transported to the participating hospitals. EMS providers contacted the destination-control physician for 1,866 (69%) patients. The original destination was changed for 253 (14%) patients. Reasons for redirecting patients included system needs, patient needs, physician affiliation, recent ED or hospital care, patient wishes, and primary care physician wishes. During the intervention month, EMS diversion decreased 190 (41%) hours at the university hospital and 62 (61%) hours at the community hospital, as compared with the control month.

CONCLUSIONS

A voluntary, physician-directed destination-control program that directs EMS units to the ED most able to provide appropriate and timely care is feasible. Patients were redirected to maximize continuity of care and optimally use available emergency health care resources. This type of program may be effective in reducing overcrowding.

Community trial to decrease ambulance diversion hours: the San Diego county patient destination trial

STUDY OBJECTIVE

Emergency department (ED) ambulance diversion is a major issue in many communities. When patients do not reach requested facilities, challenges in care are compounded by lack of available medical records and delays in transferring admitted patients back to the originally requested facility. We seek to evaluate a community intervention to reduce ambulance diversion.

METHODS

This was a community intervention in a county of 2.8 million individuals. Ambulance diversion guidelines were revised for all ambulance agencies and EDs. Participation by EDs was voluntary, and main outcome measures, which included ambulance transports, ambulance diversions, and bypass hours, were compared for the pretrial, trial, and posttrial periods.

RESULTS

A total of 235,766 patients were transported to an ED by advanced life support ambulance during the 2-year study period. There was a significant decrease in the number of patients who did not reach the requested facility because of ambulance diversion for the trial period (n=322) and posttrial period (n=449) compared with the pretrial period (n=1,320; -998 diverted patients per month [95% confidence interval (CI) -1,162 to -833 patients] and -871 diverted patients per month [95% CI -963 to -780 patients], respectively). There was also a significant decrease in average monthly hours on diversion for the trial period (n=1,079) and posttrial period (n=1,774) compared with the pretrial period (n=4,007; -2,928 hours on bypass [95% CI -3,936 to -1,919 hours on bypass] and -2,232 hours on bypass [95% CI -3,620 to -2,235 hours on bypass], respectively).

CONCLUSION

A voluntary community-wide approach to reducing hospital ED diversion and getting more ambulance patients to requested facilities was effective.

Emergency Department Diversion and Trauma Mortality: Evidence From Houston, Texas

BACKGROUND

This study examined the relation between trauma death rates and hospital diversion in the Houston emergency medical service area.

METHODS

A risk analysis and logistic regression were performed comparing death rates for trauma patients hospitalized on significant emergency department diversion days, defined as days when both of two level 1 hospitals were on diversion for more than 8 hours, and on nonsignificant diversion days, defined as one or both hospitals on diversion for fewer than 8 hours or not on diversion at all.

RESULTS

The percentage of deaths among all trauma patients, transfers, and nontransfers admitted on significant diversion days was consistently higher than on nonsignificant diversion days, but the difference was not statistically significant. A higher mortality rate, approaching statistical significance, was found for one subgroup of the most severe trauma patients who had been transferred from another hospital.

CONCLUSIONS

A possible association between emergency department diversion and death rates in Houston trauma hospitals was found, particularly among the most severe trauma patients transferred from lower-level hospitals. A follow-up study is needed for further investigation of this relation.

Approach to decreasing emergency department ambulance diversion hours

Analysis between two local Emergency Departments (EDs) suggested an oscillatory phenomenon for ambulance diversion: When one hospital went on diversion it led to a disproportionate flow of ambulance traffic to a neighboring facility that subsequently was forced to go on divert. We hypothesized if one hospital could avoid diversion status, the need for diversion could be averted in the neighboring facility. ED A secured additional resources and made a commitment to no diversion for 1 week. No changes in operations occurred in hospital B. We found no differences in ambulance runs or ED census at either facility comparing the week before, during, and after the trial. There was a dramatic decline in diversion hours from 19.7 to 1.4 and 27.7 to 0 at hospitals A and B, respectively, during the trial period (p < 0.05) compared to the weeks before and after. We conclude that reciprocating effects can be decreased with one institution's commitment to avoid diversion, thus decreasing the need for diversion at a neighboring facility.

A conceptual model of emergency department crowding

Emergency department (ED) crowding has become a major barrier to receiving timely emergency care in the United States. Despite widespread recognition of the problem, the research and policy agendas needed to understand and address ED crowding are just beginning to unfold. We present a conceptual model of ED crowding to help researchers, administrators, and policymakers understand its causes and develop potential solutions. The conceptual model partitions ED crowding into 3 interdependent components: input, throughput, and output. These components exist within an acute care system that is characterized by the delivery of unscheduled care. The goal of the conceptual model is to provide a practical framework on which an organized research, policy, and operations management agenda can be based to alleviate ED crowding.