3.4 Time to CT Scan

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Description of Indicator

Relationship to Quality  Medical care should be timely
Type of Indicator Hospital process, Hospital level
Proposed Data Source ED Records, Trauma Registry
Definition ED patients with blunt force injuries AND trauma team activation (TTA)* OR ED documented GCS < 9, receiving CT scan‡ within 1 hour of ED arrival per 100 patients
Numerator All ED patients age 18 years and older with blunt force injuries AND TTA* OR ED documented GCS < 9 AND CT scan performed within 1 hour of ED arrival†β
Denominator All ED patients age 18 years and older with blunt force injuries AND TTA* OR ED documented GCS < 9†
Benchmark Not specified at present
Risk Adjustment Not applicable

* Ideal to use local TTA guidelines to make the indicator as relevant as possible to local practice. Alternatively physiological compromise (RR < 10 or > 29 breaths per minute or intubated or GCS < 9 or SBP < 90 mmHg) or presence of major anatomic injuries (penetrating injury to head, neck, torso, extremities proximal to elbow or knee, flail chest, > 2 proximal long-bone fractures, crush, degloved or mangled extremity, amputation proximal to wrist and ankle, pelvic fracture, open or depressed skull fracture, paralysis) derived from the field triage published by the CDC9,10 may be employed.
‡ Body region for CT scan is not specified. The indicator is designed to encourage early use of CT imaging and CT guided therapy for patients with injuries for whom this may be beneficial. It applies to patients at ANY trauma hospital or hospital of any level with CT scanner.
† Time period of interest = Time stamp for CT scan – Time of ED registration.
ß Exclude patients with surgery or percutaneous therapy within 1 hour of ED arrival as these likely represent patients receiving interventions based on clinical examination.

This indicator is intended to monitor the proportion of patients with severe blunt force injuries (that do not proceed directly for surgical or percutaneous therapy) who receive CT imaging within 1 hour of ED arrival.

Panel Review
Panelists highlighted this as a very important system indicator that is designed to encourage early CT and CT guided therapy. They also indicated that it may be a surrogate measure of whether the trauma team is working well. They emphasized the importance of time for certain injuries (e.g. brain injury), but noted that it is unclear what time threshold is most appropriate other than the general criteria that earlier is better.
Panelists reported that it would be necessary to precisely define ED arrival and address the issue of CT image availability at the final treating hospital. In relation to this they indicated that it would be important to evaluate the impact of CT imaging at initial centers on the timeliness of patient transfer to a definitive care center and whether imaging was sent with the patient. Controversy between panelists existed as to whether body region of injury should be specified in the indicator as earlier imaging may be more important for certain injuries (e.g. head injury, abdominal injury).

Trauma Center Review
The trauma centers indicated that it would be important to capture the reasons for delays in getting a CT scan (e.g. may be unlikely for early imaging to influence care). It was suggested that in cases where a patient is transported from a lower to a higher-level center, CT imaging should be delayed until arrival at the higher-level center or there is a need to ensure that CT images are transported with the patient. In relation to the time threshold, the trauma centers indicated that 1 hour was too long and that both CT imaging and interpretation should be performed within this time frame. They also noted that it would be important to restrict the application of this indicator to appropriately selected patients (e.g. defined by injury body region) in order to prevent unnecessary use of resources and radiation exposure for the patient.

Review of Literature & Evidence
Face Validity: No studies identified.
Construct Validity: Five studies demonstrated no significant association between timely CT head and hospital mortality15,16,36,44,47. Two studies demonstrated that implementation of a trauma quality improvement program that included time to CT was associated with reduced hospital mortality44,45.
Reliability: No studies identified.
Risk Adjustment: Not applicable.
Utilization: Measures of time to diagnostic imaging are used by a moderate number of trauma centers: USA 34% (68/200), Canada 37% (13/35), Australasia 42% (5/12).
In one study the introduction of an algorithm for early management of severely injured patients reduced time to CT scan completion and reduced mortality48. Similarly, in another study the inclusion of high resolution CT scanning within 8 minutes of arrival into the early diagnostic workup reduced length of stay in the trauma room49.

The indicator is an amalgamation of two indicators, Time to Body CT and Time to Head CT, previously proposed by Chadbunchachai et al.44,45.


9. Centers for Disease Control and Prevention (CDC). CDC - Injury Prevention and Control: Field Triage - Guidelines for the Field Triage of Injured Patients. 2011; http://www.cdc.gov/fieldtriage/index.html. Accessed July 8, 2012.
10. Sasser SM, Hunt RC, Sullivent EE, et al. Guidelines for field triage of injured patients. Recommendations of the National Expert Panel on Field Triage. MMWR Recomm Rep. 2009;58(RR-1):1-35.
15. Copes WS, Staz CF, Konvolinka CW, Sacco WJ. American College of Surgeons audit filters: associations with patient outcome and resource utilization. J Trauma. 1995;38(3):432-438.
16. Di Bartolomeo S, Valent F, Sanson G, Nardi G, Gambale G, Barbone F. Are the ACSCOT filters associated with outcome? Examining morbidity and mortality in a European setting. Injury. 2008;39(9):1001-1006.
36. Willis CD, Stoelwinder JU, Cameron PA. Interpreting process indicators in trauma care: construct validity versus confounding by indication. Int J Qual Health Care. 2008;20(5):331-338.
44. Chadbunchachai W, Saranrittichai S, Sriwiwat S, Chumsri J, Kulleab S, Jaikwang P. Study on performance following Key Performance Indicators for trauma care: Khon Kaen Hospital 2000. J Med Assoc Thai. 2003;86(1):1-7.
45. Chadbunchachai W, Sriwiwat S, Kulleab S, Saranrittichai S, Chumsri J, Jaikwang P. The comparative study for quality of trauma treatment before and after the revision of trauma audit filter, Khon Kaen hospital 1998. J Med Assoc Thai. 2001;84(6):782-790.
47. Cryer HG, Hiatt JR, Fleming AW, Gruen JP, Sterling J. Continuous use of standard process audit filters has limited value in an established trauma system. J Trauma. 1996;41(3):389-394; discussion 394-385.
48. Bernhard M, Becker TK, Nowe T, et al. Introduction of a treatment algorithm can improve the early management of emergency patients in the resuscitation room. Resuscitation. 2007;73(3):362-373.
49. Hilbert P, zur NK, Hofmann GO, Hoeller I, Koch R, Stuttmann R. New aspects in the emergency room management of critically injured patients: a multi-slice CT-oriented care algorithm. Injury. 2007;38(5):552-558.