Brief Report

Trauma systems and timing of patient transfer: are we improving?

James Svenson MD, MS?

Section of Emergency Medicine, University of Wisconsin, Madison, WI 53792, USA

Received 16 February 2007; revised 12 May 2007; accepted 14 May 2007

Abstract

Introduction: The regionalization of trauma services is based on the premise that injured persons presenting to nontertiary facilities will be stabilized and rapidly transported to a more definitive center. Although trauma systems seem to improve outcomes for urban patients, this same benefit has not been shown for Rural patients. There are many factors associated with the decision to transfer injured patients to a regional trauma center, including referral hospital and patient age, for example. The purpose of this study is to examine factors that influence the timing of transfer of trauma patients and specifically to determine if establishing specific trauma systems has led to any changes in transfer timing over time. Methods: The trauma registry at the University of Wisconsin was queried for all patients admitted between July 1, 1999, and June 30, 2005. Patients were included in this study if they had been transferred to the university hospital after evaluation at an outside hospital. The registry variables that were abstracted were age, referring hospital, emergency department (ED) time at referring hospital, injury severity score (ISS), the presence of a head injury, performance of a head computed tomography , Mode of transport, and the date of ED evaluation.

Results: There were 1656 patients with ISS higher than 9 transferred during the period. The mean ED time was 153 +- 82 minutes. Emergency department time was significantly shorter for those with ISS higher than 25 and for those transported by helicopter. Four hundred ninety-two (30%) patients had a head CT performed at the outside hospital, of which 221 (44%) were repeated at the trauma center. The mean ED time for those in whom a CT was performed was significantly longer than those without CT (179 +- 81 vs 142 +- 84 minutes). The ED times were slightly longer for level III hospitals (158 +- 82 minutes) than for level IV hospitals (137 +- 74 minutes). Emergency department times were longer for older patients. The times in the ED showed an upward, but not statistically significant, trend. After controlling for all other variables, ED times were not significantly different over the period studied.

Conclusion: Development of a statewide trauma system and outreach education has not significantly affected Transfer times from nontrauma centers in our system. Outreach educational efforts should focus on systematic trauma evaluation, prompt transfer, and limitation of nontherapeutic testing.

(C) 2008

Introduction

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E-mail address: [email protected].

The regionalization of trauma services is based on the premise that injured persons presenting to nontertiary facilities will be stabilized and rapidly transported to a

0735-6757/$ - see front matter (C) 2008 doi:10.1016/j.ajem.2007.05.013

466 J. Svenson

more definitive center. Although trauma systems seem to improve outcomes for urban patients [1-3], this same benefit has not been shown for rural patients [4]. The institution of a trauma system leads to increases in transfer rates and redistribution of hospitalized injured patients [5], so the factors involved in the lack of outcome benefit are unknown. There are many factors associated with the decision to transfer injured patients to a regional trauma center, including referral hospital and patient age, for example [6]. Transfer times to definitive care facilities are often significantly prolonged in all but the most severely injured patients [7]. Whether Delayed transfer of trauma patients is related to outcome is unknown. Delays in transfer may be related to attempts at stabilization of severely injured patients but also may be more related to performing nontherapeutic testing. These delays may lead to departures from standard advanced trauma life support (ATLS) guidelines and proper

stabilization of patients [7-9].

Another consequence of nontherapeutic testing at outside hospitals is the cost of repetition of tests. Repetition of tests for patients transferred by helicopter to a level I trauma center increased costs by a mean of US $600 per patient, but the appropriateness of repeated testing was not examined [10].

The purpose of this study is to examine factors that influence the timing of transfer of trauma patients and specifically to determine if establishing specific trauma systems has led to any changes in transfer timing over time.

Methods

The University of Wisconsin is a level I trauma center serving the area of South Central Wisconsin. The State Trauma Advisory Council has designated it as the regional trauma and referral center within this area. It is the only designated trauma center in this region. Hospitals within the university’s referral area have all been designated as level III or level IV within the state trauma system classification. This designation is based loosely on the American College of Surgeons (ACS) trauma center classification, but these hospitals have not necessarily gone through formal certifica- tion by the ACS [11].

The trauma registry at the university of hospital was queried for all patients admitted between July 1, 1999, and June 30, 2005. Patients were included in this study if they had been transferred to the institution after evaluation at an outside hospital. The registry variables that were abstracted were age, referring hospital, emergency department (ED) time at referring hospital, injury severity score (ISS), presence of a head injury, performance of a head computed tomography , mode of transport, and date of ED evaluation.

Comparison between groups was performed by a Student t test or ?2 as appropriate. Transfer times were analyzed by 1-way analysis of variance. Multivariate analysis was performed using generalized linear regression (SAS for

Windows, version 8.2, SAS, Cary, NC). All variables were included in the models regardless of statistical association because all variables were believed to potentially contribute to decision-making in the timing of Transfer of patients.

Results

There were 3393 patients transferred to our level I trauma center from an outside hospital during the study period. Nine hundred sixty-one (28%) had an ISS of less than 9 and were excluded from further analysis regarding timing of transfer. One hundred fifty-four patients had times at the referral hospital of longer than 7 hours and were considered to have been admitted to the outside hospital and not included in the analysis of transfer times for analysis of ED decision- making. Finally, 622 patients had no recorded transfer times at the outside hospital and so were not included in the analysis. These patients had a similar distribution of characteristics as those included in the analysis. Thus there were 1656 patients included in the final analysis. Of these, 761 (46%) had an ISS of 9 to 15, 419 (25%) with an ISS of 15 to 25, and 476 (29%) with an ISS of higher than 25. Eight hundred ninety-five (54%) were transported by helicopter, 178 (11%) by an Advanced life support service, 381 (23%) by a basic life support (BLS) service, and 202 (12%) had no service recorded. Type of transport was related to the patient’s severity of injury (?2 b 0.001), with 75% of those with an ISS higher than 25 transported by air. Mean age was

36 +- 21 years (Fig. 1). Number per year has steadily increased over the period studied (Fig. 2). Sixty-four percent of patients were transferred from level III hospitals, 36% from level IV hospitals.

The mean ED time was 153 +- 82 minutes. Emergency department time was shorter for those with an ISS higher than 25 (P b .001) and for those transported by helicopter (P b .001) (Table 1). transport times were significantly related to injury severity and type of transport (Table 2). Four hundred ninety-two patients (30%) had a head CT performed at the outside hospital, of which 221 (44%) were repeated at

Fig. 1 age distribution and mean ED times by age.

Timing of trauma transfer

Fig. 2 Distribution of transfers and ED times by year.

the trauma center. The mean ED time for those in whom a CT was performed was significantly longer than those without CT (179 +- 81 vs 142 +- 84 minutes; P b .001). The ED times were slightly longer for level III hospitals (158 +- 82 minutes) than for level IV hospitals (137 +-74 minutes; P b .001). Emergency department times were longer for older patients (Fig. 1). The times in the ED showed an upward trend, but this was not statistically significant (Fig. 2). After controlling for all other variables, ED times were not significantly different over the period studied.

There was a trend toward more testing over the period studied (P b .001). This was true regardless of ISS.

Discussion

Establishment of trauma centers and trauma systems have been shown to improve patient outcomes [12-15]. These improvements are predicated on rapid stabilization and transfer of severely injured patients to definitive care facilities. Harrington et al [16] recently examined the process of transfer of trauma patients in Rhode Island after establishment of a trauma system. They found that times spent in a referring hospital were not shortened except for the most severely injured patients. They attributed this to the lack of formal trauma protocols and the time spent performing nontherapeutic testing.

The state of Wisconsin has committed to developing a statewide trauma system. In 1997, a statewide trauma

Table 1 Emergency department times by ISS and transport type

ED		time (min)
ISS
9-15	166	+- 82
15-25	162	+- 80
N25	124	+- 79
Transport type
Helicopter	133	+- 77
ALS ambulance	166	+- 79
BLS ambulance	180	+- 88

467

Table 2 Emergency department times by type of transport ISS Type of transport
		Air	ALS	BLS
9-15	N	298	86	249
	ED time (min)	142 +- 77	179 +- 72	181 +- 82
15-25	N	238	56	83
	ED time (min)	142 +- 72	179 +- 83	193 +- 78
N25	N	359	36	49
	ED time (min)	119 +- 78	114 +- 73	148 +- 82

advisory council was created. In addition, the state mandated classification/designation of all Wisconsin hospitals. The framework for the development of the system was provided in 2001. Regional trauma advisory councils were created in 2002 and statewide triage and transport guidelines developed in 2004. During this period, outreach programs have targeted outside hospitals to develop transfer agreements and protocols with regional trauma centers. Despite these efforts, our data show that rather than minimizing time at outside hospitals and minimizing nontherapeutic testing, transfer times and testing have not been affected over this period. Even for the most severely injured patients, more CT scans were being done, and, if anything, ED times were increasing rather than prompt stabilization and referral to our center. Whether the time spent in outside hospitals is a consequence of an immature system and inadequate education or the easy availability of CT scanning is not clear from our data. Only over time and with increasing maturity of our system will some of these variables become clearer.

We have not explored whether this delayed transfer from nontrauma centers has increased morbidity or mortality. There are many variables besides ED times that contribute to mortality: severity of injury, age, trauma designation of the referring hospital [17], and type of transport available. Unlike Rhode Island and Seattle, our area is predominantly rural. Thus, direct transfer from the scene is often not practical, and evaluation and stabilization at nontrauma hospitals is often necessary.

The goal of a trauma system is to identify resources within an extended system and to facilitate transfer to definitive care facilities for injured patients. Once injuries beyond the capability of the referring hospital are identified, whether on the primary or secondary survey or after further evaluation, further nontherapeutic testing should be curtailed and transfer initiated. The costs of nontherapeutic testing and repeated testing at referral centers is not known but can be significant [10]. Our data indicate that head CT scans are often repeated on initial ED evaluation at our center.

Conclusion

Development of a statewide trauma system and outreach education has not significantly affected transfer times from

468 J. Svenson

nontrauma centers in our system. Outreach education should target ED physicians at nontrauma centers. These efforts should focus on systematic trauma evaluation, prompt transfer, and limitation of nontherapeutic testing. Continued evaluation of ED times at outside institutions and their impact on morbidity and mortality for severely injured patients are important in the continuing evolution of our trauma system.

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