Tag Archives: ct scan

How Often Are Imaging Studies Repeated After Trauma Transfers?

Smaller trauma hospitals, both designated and undesignated, are the front line for the initial care of the majority of trauma patients. Many patients can be evaluated and sent home or admitted to the initial hospital. More severely injured patients are commonly transferred to the nearest Level I or Level II trauma center for care of injuries requiring specialists.

Imaging studies such as conventional xray and CT scan are a necessary part of the initial trauma evaluation. But is it necessary to do a full radiographic evaluation, even when it is known that the patient will have to be transferred?

Researchers at Dartmouth Hitchcock Medical Center examined the issue of repeat imaging at their Level I center. They looked at 138 patients that were transferred to them from other rural hospitals. They found that 75% underwent CT scanning prior to transfer, and 58% underwent repeat scanning upon arriving at Dartmouth.

The authors discovered the following:

  • Head CTs were repeated 52% of the time, primarily due to clinical indications
  • Spine reconstructions were repeated 33-50% of the time due to inadequate reconstruction technique
  • Chest (31%) and abdomen (20%) were repeated due to inappropriate use of IV contrast
  • 13% of image disks used incompatible software
  • 7% of images were not sent with the patient

Here are my recommendations for imaging by hospitals that refer patients to Level I or II trauma center:

  • Obtain the essential plain films recommended by ATLS (chest, pelvis)
  • If an obvious injury requiring transfer is found on exam (e.g. open fracture) do no further studies
  • Obtain any imaging studies needed to decide if you can admit the patient to your own hospital (example: abdominal CT for abdominal pain and negative FAST. Keep if no injury, transfer if solid organ injury)
  • As soon as an injury is identified that mandates transfer, do no further studies
  • Always send image disks with the patient
  • Work with your referral trauma center to obtain a copy of their CT imaging protocols so if you do need to perform a study you can duplicate their technique

Reference: Gupta et al. Inefficiencies in a Rural Trauma System: The Burden of Repeat Imaging in Interfacility Transfers. J Trauma 69(2):253-255, 2010.

Cervical Spine Clearance in Obtunded Patients

Cervical spine clearance in obtunded trauma patients has always been controversial. Most physicians believe that evaluation of bones and ligaments is required, although there is a minority that say that the spine can be cleared purely by radiographs. This would greatly simplify the process and decrease costs.

A prospective study was presented at EAST in January that evaluated the use of CT alone to clear the c-spine in these patients. It was presented by Claridge et al from MetroHealth in Cleveland, and is an expansion of an earlier prospective they performed. Based on the original study, the protocol was revised and the results of this re-study was presented.

The study involved 197 patients who were victims of blunt trauma, obtunded, and were noted to move all extremities. Short term mortality was 13% and long term mortality was 27%, which shows how badly injured this group was. The average ISS was 23 and the initial GCS was 8.

The following radiographic criteria were used to diagnose a significant c-spine injury:

  • Fracture line extending on 2 consecutive CT slices
  • Marked prevertebral soft tissue swelling or hematoma
  • Malalignment not explained by degenerative changes
  • Abnormal facets or posterior malalignment on sagittal reconstruction
  • Occipital condyle injury involving the craniocervical junction

Followup was performed either by re-examination after awakening (62%), followup by phone or chart review (12%), or MRI for persistent c-spine pain (2%). Thirteen percent died before re-evaluation, and 11% were lost to followup.

Using this protocol, the average hospital day of clearance decreased from 7.5 to 3.3, the incidence of decubitus ulcer from the collar decreased from 5% to 0.5%, and the average length of stay decreased from 23 to 14 days. All of these results were statistically significant.

The authors recognized that long term followup was lacking in this study and there was the potential for missed injury. Power calculations show that there are not enough patients enrolled to give a statistically sound result. The issue of spinal cord injury without radiographic abnormality (SCIWORA) is always a possibility.

The bottom line: clearance based on radiographs alone is still not ready for prime time. Some injuries will ultimately be missed, and a fraction of those can cause devastating injury. The real question to be answered is “How many missed injuries is okay?” Until more and better work is done, some combination of radiographic and clinical techniques must be used.

Reference: A normal CT alone may clear the cervical spine in obtunded blunt trauma patients with gross extremity movement – a prospective evaluation of a revised protocol. Claridge et al, MetroHealth Medical Center. Presented at the 23rd Annual Scientific Assembly of the Eastern Association for the Surgery of Trauma, January 2010.

Repeated Head CT Scans: Are They Really Necessary?

There is an increasing public interest regarding exposure to medical radiation. It represents the major exposure source for the population at large. There may be a presumption on the part of medical providers that “what you can’t see can’t hurt you” but this is just not the case.

A number of studies have shown that there is risk association with repeated exposure to xray. This risk is particularly important when dealing with pediatric patients. It’s time to start critically looking at our imaging practices and to start critically thinking about every one that we order.

One common source of repeat radiation is the repetitive CT scans of the head that patients who suffer TBI undergo. Frequently, there is little rhyme or reason to the patter of these scans. Should we repeat in 6 hours? 24 hours? When any lesions finish evolving?

It turns out that there is a reasonable amount of guidance in the brain literature. For the most part, they suggest that patients who are not in an ICU only need a repeat CT if their mental status changes. Any others obtained did not result in any management change. The first 6 papers listed below agree with this.

However, number 7 is interesting. It was published in the Journal of the American College of Surgeons and was a retrospective study of patients seen at a Level I Trauma Center. All patients had a lesion seen on initial scan, and underwent repeat scanning. The authors found that 6% of their patients underwent a surgical or medical “intervention” based on changes on the repeat head CT. What troubled them the most was that 21 of these 51 patients did not have any substantial neurologic change. They conclude that routine repeat head CT is very useful.

It’s not clear why their results are so disparate from the others. It is retrospective, and the authors do not state what the interventions exactly are. Nor do they speculate on why their results are so different from others. Nor do they show any difference in outcomes.

The bottom line: Repeat head CT is probably not needed in patients with mild TBI who are not on anti-coagulants or anti-platelet agents. However, regular mental status checks and GCS measurements must be taken.

References:

  1. Is repeated head computed tomography necessary for traumatic intracranial hemorrhage? American Surgeon 2005 Sep;71(9):701-4.
  2. Routine repeat head CT for minimal head injury is unnecessary. J Trauma 2006, Mar;60(3):494-9.
  3. A prospective evaluation of the value of repeat cranial computed tomography in patients with minimal head injury and an intracranial bleed. J Trauma 2006 Oct;61(4):862-7.
  4. Indications for routine repeat head computed tomography (CT) stratified by severity of traumatic brain injury. J Trauma 2007 Jun;62(6):1339-44.
  5. The role of early follow-up computed tomography imaging in the management of traumatic brain injury patients with intracranial hemorrhage. J Trauma 2007 Jul;63(1):75-82.
  6. Value of repeat cranial computed tomography in pediatric patients sustaining moderate to severe traumatic brain injury. J Trauma 2008 Dec;65(6):1293-7.
  7. Schedule repeat CT scanning for traumatic brain injury remains important in assessing head injury progression. J Amer Coll Surgeons 2010 May;210:824-32.