Developing a Clinical Guideline for CT Scans in Closed Head Injury

Abstract

Trauma Several years ago, every patient that was brought to Thomas Jefferson University Hospital with a closed head injury would receive a CT scan-regardless of whether or not that patient already had a scan performed at an outside institution. If the scan demonstrated any intracranial pathology, then a repeat CT scan was performed 12 hours after the initial scan as long as the patient remained neurologically stable. Ultimately, every patient received two CT scans at our institution separated by 12 hours. Now, each patient is followed by a total of three CT scans. If a patient had undergone a CT scan at an outside institution, this scan was loaded onto the Jefferson system and was considered their first CT scan. A follow-up CT scan was to be performed 6 hours after the initial scan if any intracranial pathology was noted. As long as the patient remained neurologically stable, a third and final CT scan was to be performed sometime between 12 to 24 hours after the initial scan. Therefore, patients with non-operative intracranial hemorrhage received two or three CT scans at our institution and were observed for at least 24 hours. In both situations, routine follow-up imaging was performed on all patients with an initial intracranial lesion resulting from head trauma. This practice is founded on the recommendation that "early imaging, rather than awaiting neurological deterioration, reduces the delay in detection and treatment of acute intracranial injury." This is based largely on the existing literature regarding epidural hematomas (EDH) and severe head injury. More than 50% of patients with severe head injuries have progression of findings on CT scan that otherwise would go undetected due to their poor initial clinical status. 1 Case reports have illustrated the need for repeat imaging in the setting of "ultra-early" CT scans, which may not capture a developing hematoma. 2 In addition, EDHs have been reported to be more likely to enlarge if captured within 6 hours of injury 3-again enforcing the importance of repeat imaging for these patients. At the same time, while such case reports and small case series have demonstrated the importance of imaging at least 6 hours after the initial injury, patients who have already had a negative CT scan generally do not get a repeated scan,-even if the negative scan was performed within 6 hours of their injury. Overall, this protocol is based on such literature and the concern for progression of intracranial lesions within the first 24 hours after a traumatic event-and the importance of changes at the 6 hour mark. The low threshold for performing an initial and subsequent follow-up CT scans allows for a high sensitivity, as is desired in an effective screening tool. Other factors that need to be considered, however, are the effects of radiation exposure and the increased costs of serial imaging. With regards to the former, the Scottish Intercollegiate Guidelines Network determined that the risk of developing a fatal cancer from a single CT scan of the head is approximately 1 in 10,000. There is little literature regarding the determination of the cost-effectiveness of routine serial CT scanning. A recent article in the Journal of Trauma, however, illustrated the slight increase in cost-effectiveness in routine serial scanning. "Since delayed hematomas are uncommon and expectant management is usually successful, relatively few patients benefit from routine CT scanning. However, the consequences of missing a delayed hematoma until permanent brain damage has occurred is so great, that the reported values of these parameters favors routine repeat scanning. 4 Contrary to this, however, some insurance companies have recently ceased reimbursements for routine serial imaging. 5 Given the variation in clinical practice regarding imaging protocols of patients suffering from head trauma, it would be useful to develop a guideline to help create some form of consensus regarding the standard of care. This may also help maintain appropriate healthcare coverage for this patient population. Researching Clinical Recommendations The US Department of Health and Human Services website (www.guidelines.gov) was searched for the term "head trauma." The following guidelines are applicable to management of patients with head trauma (Table 1). Each of these guidelines included recommendations regarding diagnosis of intracranial pathology using CT scan. After reviewing these guidelines, it was found that there was a great deal of similarity between the guidelines released by SIGN and those released since the guidelines released by the Brain Trauma Foundation in 2006. Most of these guidelines delineated the clinical criteria for selecting patients who should undergo an initial CT scan; and did not clearly outline who should undergo repeat or serial imaging. The guidelines set forth by the Brain Trauma Foundation, however , were specific to patients with intracranial pathology and outlined not only surgical, but also nonsurgical management of such patients. This included recommendations regarding serial imaging using CT scan. Therefore, it would be most useful to specifically analyze and compare the SIGN guidelines and the Brain Trauma Foundation guidelines. The SIGN guidelines were robustly created by a systematic review of current literature on early management of head trauma. This was followed